99 files changed, 2893 insertions, 3816 deletions
diff --git a/Timeline/Auth/MyAuthenticationHandler.cs b/Timeline/Auth/MyAuthenticationHandler.cs
index f5dcd697..3c97c329 100644
--- a/Timeline/Auth/MyAuthenticationHandler.cs
+++ b/Timeline/Auth/MyAuthenticationHandler.cs
@@ -3,11 +3,11 @@ using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using Microsoft.Net.Http.Headers;
 using System;
+using System.Globalization;
 using System.Linq;
 using System.Security.Claims;
 using System.Text.Encodings.Web;
 using System.Threading.Tasks;
-using Timeline.Models;
 using Timeline.Services;
 using static Timeline.Resources.Authentication.AuthHandler;
 
@@ -30,13 +30,13 @@ namespace Timeline.Auth
     public class MyAuthenticationHandler : AuthenticationHandler<MyAuthenticationOptions>
     {
         private readonly ILogger<MyAuthenticationHandler> _logger;
-        private readonly IUserService _userService;
+        private readonly IUserTokenManager _userTokenManager;
 
-        public MyAuthenticationHandler(IOptionsMonitor<MyAuthenticationOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock, IUserService userService)
+        public MyAuthenticationHandler(IOptionsMonitor<MyAuthenticationOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock, IUserTokenManager userTokenManager)
             : base(options, logger, encoder, clock)
         {
             _logger = logger.CreateLogger<MyAuthenticationHandler>();
-            _userService = userService;
+            _userTokenManager = userTokenManager;
         }
 
         // return null if no token is found
@@ -78,11 +78,12 @@ namespace Timeline.Auth
 
             try
             {
-                var userInfo = await _userService.VerifyToken(token);
+                var userInfo = await _userTokenManager.VerifyToken(token);
 
                 var identity = new ClaimsIdentity(AuthenticationConstants.Scheme);
+                identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, userInfo.Id!.Value.ToString(CultureInfo.InvariantCulture), ClaimValueTypes.Integer64));
                 identity.AddClaim(new Claim(identity.NameClaimType, userInfo.Username, ClaimValueTypes.String));
-                identity.AddClaims(UserRoleConvert.ToArray(userInfo.Administrator).Select(role => new Claim(identity.RoleClaimType, role, ClaimValueTypes.String)));
+                identity.AddClaims(UserRoleConvert.ToArray(userInfo.Administrator!.Value).Select(role => new Claim(identity.RoleClaimType, role, ClaimValueTypes.String)));
 
                 var principal = new ClaimsPrincipal();
                 principal.AddIdentity(identity);
diff --git a/Timeline/Controllers/ControllerAuthExtensions.cs b/Timeline/Controllers/ControllerAuthExtensions.cs
new file mode 100644
index 00000000..00a65454
--- /dev/null
+++ b/Timeline/Controllers/ControllerAuthExtensions.cs
@@ -0,0 +1,40 @@
+using Microsoft.AspNetCore.Mvc;
+using System;
+using System.Security.Claims;
+using Timeline.Auth;
+using static Timeline.Resources.Controllers.ControllerAuthExtensions;
+
+namespace Timeline.Controllers
+{
+    public static class ControllerAuthExtensions
+    {
+        public static bool IsAdministrator(this ControllerBase controller)
+        {
+            return controller.User != null && controller.User.IsAdministrator();
+        }
+
+        public static long GetUserId(this ControllerBase controller)
+        {
+            var claim = controller.User.FindFirst(ClaimTypes.NameIdentifier);
+            if (claim == null)
+                throw new InvalidOperationException(ExceptionNoUserIdentifierClaim);
+
+            if (long.TryParse(claim.Value, out var value))
+                return value;
+
+            throw new InvalidOperationException(ExceptionUserIdentifierClaimBadFormat);
+        }
+
+        public static long? GetOptionalUserId(this ControllerBase controller)
+        {
+            var claim = controller.User.FindFirst(ClaimTypes.NameIdentifier);
+            if (claim == null)
+                return null;
+
+            if (long.TryParse(claim.Value, out var value))
+                return value;
+
+            throw new InvalidOperationException(ExceptionUserIdentifierClaimBadFormat);
+        }
+    }
+}
diff --git a/Timeline/Controllers/PersonalTimelineController.cs b/Timeline/Controllers/PersonalTimelineController.cs
index c864ed39..11353bb5 100644
--- a/Timeline/Controllers/PersonalTimelineController.cs
+++ b/Timeline/Controllers/PersonalTimelineController.cs
@@ -3,64 +3,22 @@ using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Logging;
 using System.Collections.Generic;
-using System.Globalization;
 using System.Threading.Tasks;
-using Timeline.Auth;
 using Timeline.Filters;
-using Timeline.Models;
 using Timeline.Models.Http;
 using Timeline.Models.Validation;
 using Timeline.Services;
-using static Timeline.Resources.Controllers.TimelineController;
-
-namespace Timeline
-{
-    public static partial class ErrorCodes
-    {
-        public static partial class Http
-        {
-            public static class Timeline // ccc = 004
-            {
-                public const int PostListGetForbid = 10040101;
-                public const int PostOperationCreateForbid = 10040102;
-                public const int PostOperationDeleteForbid = 10040103;
-                public const int PostOperationDeleteNotExist = 10040201;
-                public const int ChangeMemberUserNotExist = 10040301;
-            }
-        }
-    }
-}
 
 namespace Timeline.Controllers
 {
     [ApiController]
+    [CatchTimelineNotExistException]
     public class PersonalTimelineController : Controller
     {
         private readonly ILogger<PersonalTimelineController> _logger;
 
         private readonly IPersonalTimelineService _service;
 
-        private bool IsAdmin()
-        {
-            if (User != null)
-            {
-                return User.IsAdministrator();
-            }
-            return false;
-        }
-
-        private string? GetAuthUsername()
-        {
-            if (User == null)
-            {
-                return null;
-            }
-            else
-            {
-                return User.Identity.Name;
-            }
-        }
-
         public PersonalTimelineController(ILogger<PersonalTimelineController> logger, IPersonalTimelineService service)
         {
             _logger = logger;
@@ -68,100 +26,105 @@ namespace Timeline.Controllers
         }
 
         [HttpGet("users/{username}/timeline")]
-        [CatchTimelineNotExistException]
         public async Task<ActionResult<BaseTimelineInfo>> TimelineGet([FromRoute][Username] string username)
         {
             return await _service.GetTimeline(username);
         }
 
         [HttpGet("users/{username}/timeline/posts")]
-        [CatchTimelineNotExistException]
         public async Task<ActionResult<IList<TimelinePostInfo>>> PostListGet([FromRoute][Username] string username)
         {
-            if (!IsAdmin() && !await _service.HasReadPermission(username, GetAuthUsername()))
+            if (!this.IsAdministrator() && !await _service.HasReadPermission(username, this.GetOptionalUserId()))
             {
-                return StatusCode(StatusCodes.Status403Forbidden,
-                    new CommonResponse(ErrorCodes.Http.Timeline.PostListGetForbid, MessagePostListGetForbid));
+                return StatusCode(StatusCodes.Status403Forbidden, ErrorResponse.Common.Forbid());
             }
 
             return await _service.GetPosts(username);
         }
 
-        [HttpPost("users/{username}/timeline/postop/create")]
+        [HttpPost("users/{username}/timeline/posts")]
         [Authorize]
-        [CatchTimelineNotExistException]
-        public async Task<ActionResult<TimelinePostCreateResponse>> PostOperationCreate([FromRoute][Username] string username, [FromBody] TimelinePostCreateRequest body)
+        public async Task<ActionResult<TimelinePostInfo>> PostPost([FromRoute][Username] string username, [FromBody] TimelinePostCreateRequest body)
         {
-            if (!IsAdmin() && !await _service.IsMemberOf(username, GetAuthUsername()!))
+            var id = this.GetUserId();
+            if (!this.IsAdministrator() && !await _service.IsMemberOf(username, id))
             {
-                return StatusCode(StatusCodes.Status403Forbidden,
-                    new CommonResponse(ErrorCodes.Http.Timeline.PostOperationCreateForbid, MessagePostOperationCreateForbid));
+                return StatusCode(StatusCodes.Status403Forbidden, ErrorResponse.Common.Forbid());
             }
 
-            var res = await _service.CreatePost(username, User.Identity.Name!, body.Content, body.Time);
+            var res = await _service.CreatePost(username, id, body.Content, body.Time);
             return res;
         }
 
-        [HttpPost("users/{username}/timeline/postop/delete")]
+        [HttpDelete("users/{username}/timeline/posts/{id}")]
         [Authorize]
-        [CatchTimelineNotExistException]
-        public async Task<ActionResult> PostOperationDelete([FromRoute][Username] string username, [FromBody] TimelinePostDeleteRequest body)
+        public async Task<ActionResult> PostDelete([FromRoute][Username] string username, [FromRoute] long id)
         {
             try
             {
-                var postId = body.Id!.Value;
-                if (!IsAdmin() && !await _service.HasPostModifyPermission(username, postId, GetAuthUsername()!))
+                if (!this.IsAdministrator() && !await _service.HasPostModifyPermission(username, id, this.GetUserId()))
                 {
-                    return StatusCode(StatusCodes.Status403Forbidden,
-                        new CommonResponse(ErrorCodes.Http.Timeline.PostOperationDeleteForbid, MessagePostOperationCreateForbid));
+                    return StatusCode(StatusCodes.Status403Forbidden, ErrorResponse.Common.Forbid());
                 }
-                await _service.DeletePost(username, postId);
+                await _service.DeletePost(username, id);
+                return Ok(CommonDeleteResponse.Delete());
             }
             catch (TimelinePostNotExistException)
             {
-                return BadRequest(new CommonResponse(
-                    ErrorCodes.Http.Timeline.PostOperationDeleteNotExist,
-                    MessagePostOperationDeleteNotExist));
+                return Ok(CommonDeleteResponse.NotExist());
             }
-            return Ok();
         }
 
-        [HttpPost("users/{username}/timeline/op/property")]
+        [HttpPatch("users/{username}/timeline")]
         [Authorize]
-        [SelfOrAdmin]
-        [CatchTimelineNotExistException]
-        public async Task<ActionResult> TimelineChangeProperty([FromRoute][Username] string username, [FromBody] TimelinePropertyChangeRequest body)
+        public async Task<ActionResult<BaseTimelineInfo>> TimelinePatch([FromRoute][Username] string username, [FromBody] TimelinePatchRequest body)
         {
+            if (!this.IsAdministrator() && !(User.Identity.Name == username))
+            {
+                return StatusCode(StatusCodes.Status403Forbidden, ErrorResponse.Common.Forbid());
+            }
             await _service.ChangeProperty(username, body);
-            return Ok();
+            var timeline = await _service.GetTimeline(username);
+            return Ok(timeline);
         }
 
-        [HttpPost("users/{username}/timeline/op/member")]
+        [HttpPut("users/{username}/timeline/members/{member}")]
         [Authorize]
-        [SelfOrAdmin]
-        [CatchTimelineNotExistException]
-        public async Task<ActionResult> TimelineChangeMember([FromRoute][Username] string username, [FromBody] TimelineMemberChangeRequest body)
+        public async Task<ActionResult> TimelineMemberPut([FromRoute][Username] string username, [FromRoute][Username] string member)
         {
+            if (!this.IsAdministrator() && !(User.Identity.Name == username))
+            {
+                return StatusCode(StatusCodes.Status403Forbidden, ErrorResponse.Common.Forbid());
+            }
+
             try
             {
-                await _service.ChangeMember(username, body.Add, body.Remove);
+                await _service.ChangeMember(username, new List<string> { member }, null);
                 return Ok();
             }
-            catch (TimelineMemberOperationUserException e)
+            catch (UserNotExistException)
             {
-                if (e.InnerException is UsernameBadFormatException)
-                {
-                    return BadRequest(CommonResponse.InvalidModel(
-                        string.Format(CultureInfo.CurrentCulture, MessageMemberUsernameBadFormat, e.Index, e.Operation)));
-                }
-                else if (e.InnerException is UserNotExistException)
-                {
-                    return BadRequest(new CommonResponse(ErrorCodes.Http.Timeline.ChangeMemberUserNotExist,
-                        string.Format(CultureInfo.CurrentCulture, MessageMemberUserNotExist, e.Index, e.Operation)));
-                }
+                return BadRequest(ErrorResponse.TimelineController.MemberPut_NotExist());
+            }
+        }
+
+        [HttpDelete("users/{username}/timeline/members/{member}")]
+        [Authorize]
+        public async Task<ActionResult> TimelineMemberDelete([FromRoute][Username] string username, [FromRoute][Username] string member)
+        {
+            if (!this.IsAdministrator() && !(User.Identity.Name == username))
+            {
+                return StatusCode(StatusCodes.Status403Forbidden, ErrorResponse.Common.Forbid());
+            }
 
-                _logger.LogError(e, LogUnknownTimelineMemberOperationUserException);
-                throw;
+            try
+            {
+                await _service.ChangeMember(username, null, new List<string> { member });
+                return Ok(CommonDeleteResponse.Delete());
+            }
+            catch (UserNotExistException)
+            {
+                return Ok(CommonDeleteResponse.NotExist());
             }
         }
     }
diff --git a/Timeline/Controllers/Testing/TestingI18nController.cs b/Timeline/Controllers/Testing/TestingI18nController.cs
deleted file mode 100644
index febb56a5..00000000
--- a/Timeline/Controllers/Testing/TestingI18nController.cs
+++ /dev/null
@@ -1,36 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
-using Microsoft.AspNetCore.Mvc;
-using Microsoft.Extensions.Localization;
-
-// For more information on enabling Web API for empty projects, visit https://go.microsoft.com/fwlink/?LinkID=397860
-
-namespace Timeline.Controllers.Testing
-{
-    [Route("testing/i18n")]
-    [ApiController]
-    public class TestingI18nController : Controller
-    {
-        private readonly IStringLocalizer<TestingI18nController> _stringLocalizer;
-
-        public TestingI18nController(IStringLocalizer<TestingI18nController> stringLocalizer)
-        {
-            _stringLocalizer = stringLocalizer;
-        }
-
-        [HttpGet("direct")]
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Performance", "CA1822:Mark members as static")]
-        public ActionResult<string> Direct()
-        {
-            return Resources.Controllers.Testing.TestingI18nController.TestString;
-        }
-
-        [HttpGet("localizer")]
-        public ActionResult<string> Localizer()
-        {
-            return _stringLocalizer["TestString"].Value;
-        }
-    }
-}
diff --git a/Timeline/Controllers/TokenController.cs b/Timeline/Controllers/TokenController.cs
index 01f4778f..1fb0b17a 100644
--- a/Timeline/Controllers/TokenController.cs
+++ b/Timeline/Controllers/TokenController.cs
@@ -1,7 +1,7 @@
+using AutoMapper;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Logging;
-using Microsoft.IdentityModel.Tokens;
 using System;
 using System.Globalization;
 using System.Threading.Tasks;
@@ -10,46 +10,24 @@ using Timeline.Models.Http;
 using Timeline.Services;
 using static Timeline.Resources.Controllers.TokenController;
 
-namespace Timeline
-{
-    public static partial class ErrorCodes
-    {
-        public static partial class Http
-        {
-            public static class Token // bbb = 001
-            {
-                public static class Create // cc = 01
-                {
-                    public const int BadCredential = 10010101;
-                }
-
-                public static class Verify // cc = 02
-                {
-                    public const int BadFormat = 10010201;
-                    public const int UserNotExist = 10010202;
-                    public const int OldVersion = 10010203;
-                    public const int Expired = 10010204;
-                }
-            }
-        }
-    }
-}
-
 namespace Timeline.Controllers
 {
     [Route("token")]
     [ApiController]
     public class TokenController : Controller
     {
-        private readonly IUserService _userService;
+        private readonly IUserTokenManager _userTokenManager;
         private readonly ILogger<TokenController> _logger;
         private readonly IClock _clock;
 
-        public TokenController(IUserService userService, ILogger<TokenController> logger, IClock clock)
+        private readonly IMapper _mapper;
+
+        public TokenController(IUserTokenManager userTokenManager, ILogger<TokenController> logger, IClock clock, IMapper mapper)
         {
-            _userService = userService;
+            _userTokenManager = userTokenManager;
             _logger = logger;
             _clock = clock;
+            _mapper = mapper;
         }
 
         [HttpPost("create")]
@@ -72,7 +50,7 @@ namespace Timeline.Controllers
                 if (request.Expire != null)
                     expireTime = _clock.GetCurrentTime().AddDays(request.Expire.Value);
 
-                var result = await _userService.CreateToken(request.Username, request.Password, expireTime);
+                var result = await _userTokenManager.CreateToken(request.Username, request.Password, expireTime);
 
                 _logger.LogInformation(Log.Format(LogCreateSuccess,
                     ("Username", request.Username),
@@ -81,22 +59,18 @@ namespace Timeline.Controllers
                 return Ok(new CreateTokenResponse
                 {
                     Token = result.Token,
-                    User = result.User
+                    User = _mapper.Map<UserInfo>(result.User)
                 });
             }
             catch (UserNotExistException e)
             {
                 LogFailure(LogUserNotExist, e);
-                return BadRequest(new CommonResponse(
-                    ErrorCodes.Http.Token.Create.BadCredential,
-                    ErrorBadCredential));
+                return BadRequest(ErrorResponse.TokenController.Create_BadCredential());
             }
             catch (BadPasswordException e)
             {
                 LogFailure(LogBadPassword, e);
-                return BadRequest(new CommonResponse(
-                    ErrorCodes.Http.Token.Create.BadCredential,
-                     ErrorBadCredential));
+                return BadRequest(ErrorResponse.TokenController.Create_BadCredential());
             }
         }
 
@@ -115,44 +89,34 @@ namespace Timeline.Controllers
 
             try
             {
-                var result = await _userService.VerifyToken(request.Token);
+                var result = await _userTokenManager.VerifyToken(request.Token);
                 _logger.LogInformation(Log.Format(LogVerifySuccess,
                     ("Username", result.Username), ("Token", request.Token)));
                 return Ok(new VerifyTokenResponse
                 {
-                    User = result
+                    User = _mapper.Map<UserInfo>(result)
                 });
             }
-            catch (JwtVerifyException e)
+            catch (UserTokenTimeExpireException e)
             {
-                if (e.ErrorCode == JwtVerifyException.ErrorCodes.Expired)
-                {
-                    var innerException = e.InnerException as SecurityTokenExpiredException;
-                    LogFailure(LogVerifyExpire, e, ("Expires", innerException?.Expires),
-                        ("Current Time", _clock.GetCurrentTime()));
-                    return BadRequest(new CommonResponse(
-                        ErrorCodes.Http.Token.Verify.Expired, ErrorVerifyExpire));
-                }
-                else if (e.ErrorCode == JwtVerifyException.ErrorCodes.OldVersion)
-                {
-                    var innerException = e.InnerException as JwtBadVersionException;
-                    LogFailure(LogVerifyOldVersion, e,
-                        ("Token Version", innerException?.TokenVersion), ("Required Version", innerException?.RequiredVersion));
-                    return BadRequest(new CommonResponse(
-                        ErrorCodes.Http.Token.Verify.OldVersion, ErrorVerifyOldVersion));
-                }
-                else
-                {
-                    LogFailure(LogVerifyBadFormat, e);
-                    return BadRequest(new CommonResponse(
-                        ErrorCodes.Http.Token.Verify.BadFormat, ErrorVerifyBadFormat));
-                }
+                LogFailure(LogVerifyExpire, e, ("Expire Time", e.ExpireTime), ("Verify Time", e.VerifyTime));
+                return BadRequest(ErrorResponse.TokenController.Verify_TimeExpired());
+            }
+            catch (UserTokenBadVersionException e)
+            {
+                LogFailure(LogVerifyOldVersion, e, ("Token Version", e.TokenVersion), ("Required Version", e.RequiredVersion));
+                return BadRequest(ErrorResponse.TokenController.Verify_OldVersion());
+
+            }
+            catch (UserTokenBadFormatException e)
+            {
+                LogFailure(LogVerifyBadFormat, e);
+                return BadRequest(ErrorResponse.TokenController.Verify_BadFormat());
             }
             catch (UserNotExistException e)
             {
                 LogFailure(LogVerifyUserNotExist, e);
-                return BadRequest(new CommonResponse(
-                    ErrorCodes.Http.Token.Verify.UserNotExist, ErrorVerifyUserNotExist));
+                return BadRequest(ErrorResponse.TokenController.Verify_UserNotExist());
             }
         }
     }
diff --git a/Timeline/Controllers/UserAvatarController.cs b/Timeline/Controllers/UserAvatarController.cs
index 7625f962..2dd279a8 100644
--- a/Timeline/Controllers/UserAvatarController.cs
+++ b/Timeline/Controllers/UserAvatarController.cs
@@ -14,39 +14,6 @@ using Timeline.Models.Validation;
 using Timeline.Services;
 using static Timeline.Resources.Controllers.UserAvatarController;
 
-namespace Timeline
-{
-    public static partial class ErrorCodes
-    {
-        public static partial class Http
-        {
-            public static class UserAvatar // bbb = 003
-            {
-                public static class Get // cc = 01
-                {
-                    public const int UserNotExist = 10030101;
-                }
-
-                public static class Put // cc = 02
-                {
-                    public const int UserNotExist = 10030201;
-                    public const int Forbid = 10030202;
-                    public const int BadFormat_CantDecode = 10030203;
-                    public const int BadFormat_UnmatchedFormat = 10030204;
-                    public const int BadFormat_BadSize = 10030205;
-
-                }
-
-                public static class Delete // cc = 03
-                {
-                    public const int UserNotExist = 10030301;
-                    public const int Forbid = 10030302;
-                }
-            }
-        }
-    }
-}
-
 namespace Timeline.Controllers
 {
     [ApiController]
@@ -54,11 +21,13 @@ namespace Timeline.Controllers
     {
         private readonly ILogger<UserAvatarController> _logger;
 
+        private readonly IUserService _userService;
         private readonly IUserAvatarService _service;
 
-        public UserAvatarController(ILogger<UserAvatarController> logger, IUserAvatarService service)
+        public UserAvatarController(ILogger<UserAvatarController> logger, IUserService userService, IUserAvatarService service)
         {
             _logger = logger;
+            _userService = userService;
             _service = service;
         }
 
@@ -66,41 +35,45 @@ namespace Timeline.Controllers
         [ResponseCache(NoStore = false, Location = ResponseCacheLocation.None, Duration = 0)]
         public async Task<IActionResult> Get([FromRoute][Username] string username)
         {
+            long id;
+            try
+            {
+                id = await _userService.GetUserIdByUsername(username);
+            }
+            catch (UserNotExistException e)
+            {
+                _logger.LogInformation(e, Log.Format(LogGetUserNotExist, ("Username", username)));
+                return NotFound(ErrorResponse.UserCommon.NotExist());
+            }
+
             const string IfNonMatchHeaderKey = "If-None-Match";
 
-            try
+            var eTagValue = $"\"{await _service.GetAvatarETag(id)}\"";
+            var eTag = new EntityTagHeaderValue(eTagValue);
+
+            if (Request.Headers.TryGetValue(IfNonMatchHeaderKey, out var value))
             {
-                var eTagValue = $"\"{await _service.GetAvatarETag(username)}\"";
-                var eTag = new EntityTagHeaderValue(eTagValue);
+                if (!EntityTagHeaderValue.TryParseStrictList(value, out var eTagList))
+                {
+                    _logger.LogInformation(Log.Format(LogGetBadIfNoneMatch,
+                        ("Username", username), ("If-None-Match", value)));
+                    return BadRequest(ErrorResponse.Common.Header.IfNonMatch_BadFormat());
+                }
 
-                if (Request.Headers.TryGetValue(IfNonMatchHeaderKey, out var value))
+                if (eTagList.FirstOrDefault(e => e.Equals(eTag)) != null)
                 {
-                    if (!EntityTagHeaderValue.TryParseStrictList(value, out var eTagList))
-                    {
-                        _logger.LogInformation(Log.Format(LogGetBadIfNoneMatch,
-                            ("Username", username), ("If-None-Match", value)));
-                        return BadRequest(HeaderErrorResponse.BadIfNonMatch());
-                    }
-
-                    if (eTagList.FirstOrDefault(e => e.Equals(eTag)) != null)
-                    {
-                        Response.Headers.Add("ETag", eTagValue);
-                        _logger.LogInformation(Log.Format(LogGetReturnNotModify, ("Username", username)));
-                        return StatusCode(StatusCodes.Status304NotModified);
-                    }
+                    Response.Headers.Add("ETag", eTagValue);
+                    _logger.LogInformation(Log.Format(LogGetReturnNotModify, ("Username", username)));
+                    return StatusCode(StatusCodes.Status304NotModified);
                 }
+            }
 
-                var avatarInfo = await _service.GetAvatar(username);
-                var avatar = avatarInfo.Avatar;
+            var avatarInfo = await _service.GetAvatar(id);
+            var avatar = avatarInfo.Avatar;
+
+            _logger.LogInformation(Log.Format(LogGetReturnData, ("Username", username)));
+            return File(avatar.Data, avatar.Type, new DateTimeOffset(avatarInfo.LastModified), eTag);
 
-                _logger.LogInformation(Log.Format(LogGetReturnData, ("Username", username)));
-                return File(avatar.Data, avatar.Type, new DateTimeOffset(avatarInfo.LastModified), eTag);
-            }
-            catch (UserNotExistException e)
-            {
-                _logger.LogInformation(e, Log.Format(LogGetUserNotExist, ("Username", username)));
-                return NotFound(new CommonResponse(ErrorCodes.Http.UserAvatar.Get.UserNotExist, ErrorGetUserNotExist));
-            }
         }
 
         [HttpPut("users/{username}/avatar")]
@@ -111,14 +84,24 @@ namespace Timeline.Controllers
         {
             var contentLength = Request.ContentLength!.Value;
             if (contentLength > 1000 * 1000 * 10)
-                return BadRequest(ContentErrorResponse.TooBig("10MB"));
+                return BadRequest(ErrorResponse.Common.Content.TooBig("10MB"));
 
             if (!User.IsAdministrator() && User.Identity.Name != username)
             {
                 _logger.LogInformation(Log.Format(LogPutForbid,
                     ("Operator Username", User.Identity.Name), ("Username To Put Avatar", username)));
-                return StatusCode(StatusCodes.Status403Forbidden,
-                    new CommonResponse(ErrorCodes.Http.UserAvatar.Put.Forbid, ErrorPutForbid));
+                return StatusCode(StatusCodes.Status403Forbidden, ErrorResponse.Common.Forbid());
+            }
+
+            long id;
+            try
+            {
+                id = await _userService.GetUserIdByUsername(username);
+            }
+            catch (UserNotExistException e)
+            {
+                _logger.LogInformation(e, Log.Format(LogPutUserNotExist, ("Username", username)));
+                return BadRequest(ErrorResponse.UserCommon.NotExist());
             }
 
             try
@@ -127,13 +110,13 @@ namespace Timeline.Controllers
                 var bytesRead = await Request.Body.ReadAsync(data);
 
                 if (bytesRead != contentLength)
-                    return BadRequest(ContentErrorResponse.UnmatchedLength_Smaller());
+                    return BadRequest(ErrorResponse.Common.Content.UnmatchedLength_Smaller());
 
                 var extraByte = new byte[1];
                 if (await Request.Body.ReadAsync(extraByte) != 0)
-                    return BadRequest(ContentErrorResponse.UnmatchedLength_Bigger());
+                    return BadRequest(ErrorResponse.Common.Content.UnmatchedLength_Bigger());
 
-                await _service.SetAvatar(username, new Avatar
+                await _service.SetAvatar(id, new Avatar
                 {
                     Data = data,
                     Type = Request.ContentType
@@ -143,27 +126,17 @@ namespace Timeline.Controllers
                     ("Username", username), ("Mime Type", Request.ContentType)));
                 return Ok();
             }
-            catch (UserNotExistException e)
-            {
-                _logger.LogInformation(e, Log.Format(LogPutUserNotExist, ("Username", username)));
-                return BadRequest(new CommonResponse(ErrorCodes.Http.UserAvatar.Put.UserNotExist, ErrorPutUserNotExist));
-            }
             catch (AvatarFormatException e)
             {
-                var (code, message) = e.Error switch
+                _logger.LogInformation(e, Log.Format(LogPutUserBadFormat, ("Username", username)));
+                return BadRequest(e.Error switch
                 {
-                    AvatarFormatException.ErrorReason.CantDecode =>
-                        (ErrorCodes.Http.UserAvatar.Put.BadFormat_CantDecode, ErrorPutBadFormatCantDecode),
-                    AvatarFormatException.ErrorReason.UnmatchedFormat =>
-                       (ErrorCodes.Http.UserAvatar.Put.BadFormat_UnmatchedFormat, ErrorPutBadFormatUnmatchedFormat),
-                    AvatarFormatException.ErrorReason.BadSize =>
-                       (ErrorCodes.Http.UserAvatar.Put.BadFormat_BadSize, ErrorPutBadFormatBadSize),
+                    AvatarFormatException.ErrorReason.CantDecode => ErrorResponse.UserAvatar.BadFormat_CantDecode(),
+                    AvatarFormatException.ErrorReason.UnmatchedFormat => ErrorResponse.UserAvatar.BadFormat_UnmatchedFormat(),
+                    AvatarFormatException.ErrorReason.BadSize => ErrorResponse.UserAvatar.BadFormat_BadSize(),
                     _ =>
                         throw new Exception(ExceptionUnknownAvatarFormatError)
-                };
-
-                _logger.LogInformation(e, Log.Format(LogPutUserBadFormat, ("Username", username)));
-                return BadRequest(new CommonResponse(code, message));
+                });
             }
         }
 
@@ -173,24 +146,24 @@ namespace Timeline.Controllers
         {
             if (!User.IsAdministrator() && User.Identity.Name != username)
             {
-                _logger.LogInformation(Log.Format(LogPutUserBadFormat,
+                _logger.LogInformation(Log.Format(LogDeleteForbid,
                     ("Operator Username", User.Identity.Name), ("Username To Delete Avatar", username)));
-                return StatusCode(StatusCodes.Status403Forbidden,
-                    new CommonResponse(ErrorCodes.Http.UserAvatar.Delete.Forbid, ErrorDeleteForbid));
+                return StatusCode(StatusCodes.Status403Forbidden, ErrorResponse.Common.Forbid());
             }
 
+            long id;
             try
             {
-                await _service.SetAvatar(username, null);
-
-                _logger.LogInformation(Log.Format(LogDeleteSuccess, ("Username", username)));
-                return Ok();
+                id = await _userService.GetUserIdByUsername(username);
             }
             catch (UserNotExistException e)
             {
                 _logger.LogInformation(e, Log.Format(LogDeleteNotExist, ("Username", username)));
-                return BadRequest(new CommonResponse(ErrorCodes.Http.UserAvatar.Delete.UserNotExist, ErrorDeleteUserNotExist));
+                return BadRequest(ErrorResponse.UserCommon.NotExist());
             }
+
+            await _service.SetAvatar(id, null);
+            return Ok();
         }
     }
 }
diff --git a/Timeline/Controllers/UserController.cs b/Timeline/Controllers/UserController.cs
index 0d950cd7..a3e8d816 100644
--- a/Timeline/Controllers/UserController.cs
+++ b/Timeline/Controllers/UserController.cs
@@ -1,158 +1,124 @@
+using AutoMapper;
 using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Logging;
-using System.Globalization;
+using System.Linq;
 using System.Threading.Tasks;
 using Timeline.Auth;
 using Timeline.Helpers;
-using Timeline.Models;
 using Timeline.Models.Http;
 using Timeline.Models.Validation;
 using Timeline.Services;
 using static Timeline.Resources.Controllers.UserController;
-
-namespace Timeline
-{
-    public static partial class ErrorCodes
-    {
-        public static partial class Http
-        {
-            public static class User // bbb = 002
-            {
-                public static class Get // cc = 01
-                {
-                    public const int NotExist = 10020101; // dd = 01
-                }
-
-                public static class Patch // cc = 03
-                {
-                    public const int NotExist = 10020301; // dd = 01
-                }
-
-                public static class Op // cc = 1x
-                {
-                    public static class ChangeUsername // cc = 11
-                    {
-                        public const int NotExist = 10021101; // dd = 01
-                        public const int AlreadyExist = 10021102; // dd = 02
-                    }
-
-                    public static class ChangePassword // cc = 12
-                    {
-                        public const int BadOldPassword = 10021201; // dd = 01
-                    }
-                }
-
-            }
-        }
-    }
-}
+using static Timeline.Resources.Messages;
 
 namespace Timeline.Controllers
 {
     [ApiController]
     public class UserController : Controller
     {
-
         private readonly ILogger<UserController> _logger;
         private readonly IUserService _userService;
+        private readonly IMapper _mapper;
 
-        public UserController(ILogger<UserController> logger, IUserService userService)
+        public UserController(ILogger<UserController> logger, IUserService userService, IMapper mapper)
         {
             _logger = logger;
             _userService = userService;
+            _mapper = mapper;
         }
 
-        [HttpGet("users"), AdminAuthorize]
+        private UserInfo ConvertToUserInfo(User user) => _mapper.Map<UserInfo>(user);
+
+        [HttpGet("users")]
         public async Task<ActionResult<UserInfo[]>> List()
         {
-            return Ok(await _userService.ListUsers());
+            var users = await _userService.GetUsers();
+            var result = users.Select(u => ConvertToUserInfo(u)).ToArray();
+            return Ok(result);
         }
 
-        [HttpGet("users/{username}"), AdminAuthorize]
+        [HttpGet("users/{username}")]
         public async Task<ActionResult<UserInfo>> Get([FromRoute][Username] string username)
         {
-            var user = await _userService.GetUser(username);
-            if (user == null)
+            try
             {
-                _logger.LogInformation(Log.Format(LogGetUserNotExist, ("Username", username)));
-                return NotFound(new CommonResponse(ErrorCodes.Http.User.Get.NotExist, ErrorGetUserNotExist));
+                var user = await _userService.GetUserByUsername(username);
+                return Ok(ConvertToUserInfo(user));
             }
-            return Ok(user);
-        }
-
-        [HttpPut("users/{username}"), AdminAuthorize]
-        public async Task<ActionResult<CommonPutResponse>> Put([FromBody] UserPutRequest request, [FromRoute][Username] string username)
-        {
-            var result = await _userService.PutUser(username, request.Password, request.Administrator!.Value);
-            switch (result)
+            catch (UserNotExistException e)
             {
-                case PutResult.Create:
-                    _logger.LogInformation(Log.Format(LogPutCreate, ("Username", username)));
-                    return CreatedAtAction("Get", new { username }, CommonPutResponse.Create());
-                case PutResult.Modify:
-                    _logger.LogInformation(Log.Format(LogPutModify, ("Username", username)));
-                    return Ok(CommonPutResponse.Modify());
-                default:
-                    throw new InvalidBranchException();
+                _logger.LogInformation(e, Log.Format(LogGetUserNotExist, ("Username", username)));
+                return NotFound(ErrorResponse.UserCommon.NotExist());
             }
         }
 
-        [HttpPatch("users/{username}"), AdminAuthorize]
-        public async Task<ActionResult> Patch([FromBody] UserPatchRequest request, [FromRoute][Username] string username)
+        [HttpPatch("users/{username}"), Authorize]
+        public async Task<ActionResult<UserInfo>> Patch([FromBody] UserPatchRequest body, [FromRoute][Username] string username)
         {
-            try
+            if (this.IsAdministrator())
             {
-                await _userService.PatchUser(username, request.Password, request.Administrator);
-                return Ok();
+                try
+                {
+                    var user = await _userService.ModifyUser(username, _mapper.Map<User>(body));
+                    return Ok(ConvertToUserInfo(user));
+                }
+                catch (UserNotExistException e)
+                {
+                    _logger.LogInformation(e, Log.Format(LogPatchUserNotExist, ("Username", username)));
+                    return NotFound(ErrorResponse.UserCommon.NotExist());
+                }
+                catch (ConflictException)
+                {
+                    return BadRequest(ErrorResponse.UserController.UsernameConflict());
+                }
             }
-            catch (UserNotExistException e)
+            else
             {
-                _logger.LogInformation(e, Log.Format(LogPatchUserNotExist, ("Username", username)));
-                return NotFound(new CommonResponse(ErrorCodes.Http.User.Patch.NotExist, ErrorPatchUserNotExist));
+                if (User.Identity.Name != username)
+                    return StatusCode(StatusCodes.Status403Forbidden,
+                        ErrorResponse.Common.CustomMessage_Forbid(Common_Forbid_NotSelf));
+
+                if (body.Username != null)
+                    return StatusCode(StatusCodes.Status403Forbidden,
+                        ErrorResponse.Common.CustomMessage_Forbid(UserController_Patch_Forbid_Username));
+
+                if (body.Password != null)
+                    return StatusCode(StatusCodes.Status403Forbidden,
+                        ErrorResponse.Common.CustomMessage_Forbid(UserController_Patch_Forbid_Password));
+
+                if (body.Administrator != null)
+                    return StatusCode(StatusCodes.Status403Forbidden,
+                        ErrorResponse.Common.CustomMessage_Forbid(UserController_Patch_Forbid_Administrator));
+
+                var user = await _userService.ModifyUser(this.GetUserId(), _mapper.Map<User>(body));
+                return Ok(ConvertToUserInfo(user));
             }
         }
 
         [HttpDelete("users/{username}"), AdminAuthorize]
         public async Task<ActionResult<CommonDeleteResponse>> Delete([FromRoute][Username] string username)
         {
-            try
-            {
-                await _userService.DeleteUser(username);
-                _logger.LogInformation(Log.Format(LogDeleteDelete, ("Username", username)));
+            var delete = await _userService.DeleteUser(username);
+            if (delete)
                 return Ok(CommonDeleteResponse.Delete());
-            }
-            catch (UserNotExistException e)
-            {
-                _logger.LogInformation(e, Log.Format(LogDeleteNotExist, ("Username", username)));
+            else
                 return Ok(CommonDeleteResponse.NotExist());
-            }
         }
 
-        [HttpPost("userop/changeusername"), AdminAuthorize]
-        public async Task<ActionResult> ChangeUsername([FromBody] ChangeUsernameRequest request)
+        [HttpPost("userop/createuser"), AdminAuthorize]
+        public async Task<ActionResult<UserInfo>> CreateUser([FromBody] CreateUserRequest body)
         {
             try
             {
-                await _userService.ChangeUsername(request.OldUsername, request.NewUsername);
-                _logger.LogInformation(Log.Format(LogChangeUsernameSuccess,
-                    ("Old Username", request.OldUsername), ("New Username", request.NewUsername)));
-                return Ok();
-            }
-            catch (UserNotExistException e)
-            {
-                _logger.LogInformation(e, Log.Format(LogChangeUsernameNotExist,
-                    ("Old Username", request.OldUsername), ("New Username", request.NewUsername)));
-                return BadRequest(new CommonResponse(ErrorCodes.Http.User.Op.ChangeUsername.NotExist,
-                    string.Format(CultureInfo.CurrentCulture, ErrorChangeUsernameNotExist, request.OldUsername)));
+                var user = await _userService.CreateUser(_mapper.Map<User>(body));
+                return Ok(ConvertToUserInfo(user));
             }
-            catch (UsernameConfictException e)
+            catch (ConflictException)
             {
-                _logger.LogInformation(e, Log.Format(LogChangeUsernameAlreadyExist,
-                    ("Old Username", request.OldUsername), ("New Username", request.NewUsername)));
-                return BadRequest(new CommonResponse(ErrorCodes.Http.User.Op.ChangeUsername.AlreadyExist, ErrorChangeUsernameAlreadyExist));
+                return BadRequest(ErrorResponse.UserController.UsernameConflict());
             }
-            // there is no need to catch bad format exception because it is already checked in model validation.
         }
 
         [HttpPost("userop/changepassword"), Authorize]
@@ -160,18 +126,16 @@ namespace Timeline.Controllers
         {
             try
             {
-                await _userService.ChangePassword(User.Identity.Name!, request.OldPassword, request.NewPassword);
-                _logger.LogInformation(Log.Format(LogChangePasswordSuccess, ("Username", User.Identity.Name)));
+                await _userService.ChangePassword(this.GetUserId(), request.OldPassword, request.NewPassword);
                 return Ok();
             }
             catch (BadPasswordException e)
             {
                 _logger.LogInformation(e, Log.Format(LogChangePasswordBadPassword,
                     ("Username", User.Identity.Name), ("Old Password", request.OldPassword)));
-                return BadRequest(new CommonResponse(ErrorCodes.Http.User.Op.ChangePassword.BadOldPassword,
-                    ErrorChangePasswordBadPassword));
+                return BadRequest(ErrorResponse.UserController.ChangePassword_BadOldPassword());
             }
-            // User can't be non-existent or the token is bad. 
+            // User can't be non-existent or the token is bad.
         }
     }
 }
diff --git a/Timeline/Controllers/UserDetailController.cs b/Timeline/Controllers/UserDetailController.cs
deleted file mode 100644
index 9de9899e..00000000
--- a/Timeline/Controllers/UserDetailController.cs
+++ /dev/null
@@ -1,49 +0,0 @@
-using Microsoft.AspNetCore.Mvc;
-using System.Threading.Tasks;
-using Timeline.Filters;
-using Timeline.Models.Validation;
-using Timeline.Services;
-using System.ComponentModel.DataAnnotations;
-using Microsoft.AspNetCore.Authorization;
-
-namespace Timeline.Controllers
-{
-    [ApiController]
-    public class UserDetailController : Controller
-    {
-        private readonly IUserDetailService _service;
-
-        public UserDetailController(IUserDetailService service)
-        {
-            _service = service;
-        }
-
-        [HttpGet("users/{username}/nickname")]
-        [CatchUserNotExistException]
-        public async Task<ActionResult<string>> GetNickname([FromRoute][Username] string username)
-        {
-            return Ok(await _service.GetNickname(username));
-        }
-
-        [HttpPut("users/{username}/nickname")]
-        [Authorize]
-        [SelfOrAdmin]
-        [CatchUserNotExistException]
-        public async Task<ActionResult> PutNickname([FromRoute][Username] string username,
-            [FromBody][StringLength(10, MinimumLength = 1)] string body)
-        {
-            await _service.SetNickname(username, body);
-            return Ok();
-        }
-
-        [HttpDelete("users/{username}/nickname")]
-        [Authorize]
-        [SelfOrAdmin]
-        [CatchUserNotExistException]
-        public async Task<ActionResult> DeleteNickname([FromRoute][Username] string username)
-        {
-            await _service.SetNickname(username, null);
-            return Ok();
-        }
-    }
-}
diff --git a/Timeline/Entities/DatabaseContext.cs b/Timeline/Entities/DatabaseContext.cs
index ffb6158a..cac33379 100644
--- a/Timeline/Entities/DatabaseContext.cs
+++ b/Timeline/Entities/DatabaseContext.cs
@@ -10,16 +10,14 @@ namespace Timeline.Entities
 
         }
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods")]
         protected override void OnModelCreating(ModelBuilder modelBuilder)
         {
-            modelBuilder.Entity<User>().Property(e => e.Version).HasDefaultValue(0);
-            modelBuilder.Entity<User>().HasIndex(e => e.Name).IsUnique();
+            modelBuilder.Entity<UserEntity>().Property(e => e.Version).HasDefaultValue(0);
+            modelBuilder.Entity<UserEntity>().HasIndex(e => e.Username).IsUnique();
         }
 
-        public DbSet<User> Users { get; set; } = default!;
-        public DbSet<UserAvatar> UserAvatars { get; set; } = default!;
-        public DbSet<UserDetail> UserDetails { get; set; } = default!;
+        public DbSet<UserEntity> Users { get; set; } = default!;
+        public DbSet<UserAvatarEntity> UserAvatars { get; set; } = default!;
         public DbSet<TimelineEntity> Timelines { get; set; } = default!;
         public DbSet<TimelinePostEntity> TimelinePosts { get; set; } = default!;
         public DbSet<TimelineMemberEntity> TimelineMembers { get; set; } = default!;
diff --git a/Timeline/Entities/TimelineEntity.cs b/Timeline/Entities/TimelineEntity.cs
index 9cacfcae..c50fe6dd 100644
--- a/Timeline/Entities/TimelineEntity.cs
+++ b/Timeline/Entities/TimelineEntity.cs
@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
-using Timeline.Models;
+using Timeline.Models.Http;
 
 namespace Timeline.Entities
 {
@@ -26,7 +26,7 @@ namespace Timeline.Entities
         public long OwnerId { get; set; }
 
         [ForeignKey(nameof(OwnerId))]
-        public User Owner { get; set; } = default!;
+        public UserEntity Owner { get; set; } = default!;
 
         [Column("visibility")]
         public TimelineVisibility Visibility { get; set; }
diff --git a/Timeline/Entities/TimelineMemberEntity.cs b/Timeline/Entities/TimelineMemberEntity.cs
index dbe861bd..e76f2099 100644
--- a/Timeline/Entities/TimelineMemberEntity.cs
+++ b/Timeline/Entities/TimelineMemberEntity.cs
@@ -13,7 +13,7 @@ namespace Timeline.Entities
         public long UserId { get; set; }
 
         [ForeignKey(nameof(UserId))]
-        public User User { get; set; } = default!;
+        public UserEntity User { get; set; } = default!;
 
         [Column("timeline")]
         public long TimelineId { get; set; }
diff --git a/Timeline/Entities/TimelinePostEntity.cs b/Timeline/Entities/TimelinePostEntity.cs
index efef3ab5..a615c61f 100644
--- a/Timeline/Entities/TimelinePostEntity.cs
+++ b/Timeline/Entities/TimelinePostEntity.cs
@@ -20,7 +20,7 @@ namespace Timeline.Entities
         public long AuthorId { get; set; }
 
         [ForeignKey(nameof(AuthorId))]
-        public User Author { get; set; } = default!;
+        public UserEntity Author { get; set; } = default!;
 
         [Column("content")]
         public string? Content { get; set; }
diff --git a/Timeline/Entities/UserAvatar.cs b/Timeline/Entities/UserAvatarEntity.cs
index 114246f3..6cecce1a 100644
--- a/Timeline/Entities/UserAvatar.cs
+++ b/Timeline/Entities/UserAvatarEntity.cs
@@ -6,7 +6,7 @@ namespace Timeline.Entities
 {
     [System.Diagnostics.CodeAnalysis.SuppressMessage("Performance", "CA1819:Properties should not return arrays", Justification = "This is data base entity.")]
     [Table("user_avatars")]
-    public class UserAvatar
+    public class UserAvatarEntity
     {
         [Column("id"), Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
         public long Id { get; set; }
@@ -23,6 +23,10 @@ namespace Timeline.Entities
         [Column("last_modified"), Required]
         public DateTime LastModified { get; set; }
 
+        [Column("user"), Required]
         public long UserId { get; set; }
+
+        [ForeignKey(nameof(UserId))]
+        public UserEntity User { get; set; } = default!;
     }
 }
diff --git a/Timeline/Entities/UserDetail.cs b/Timeline/Entities/UserDetail.cs
deleted file mode 100644
index 45f87e2b..00000000
--- a/Timeline/Entities/UserDetail.cs
+++ /dev/null
@@ -1,21 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations.Schema;
-using System.Linq;
-using System.Threading.Tasks;
-
-namespace Timeline.Entities
-{
-    [Table("user_details")]
-    public class UserDetail
-    {
-        [Column("id"), Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
-        public long Id { get; set; }
-
-        [Column("nickname"), MaxLength(26)]
-        public string? Nickname { get; set; }
-
-        public long UserId { get; set; }
-    }
-}
diff --git a/Timeline/Entities/User.cs b/Timeline/Entities/UserEntity.cs
index e725a69a..946c3fa2 100644
--- a/Timeline/Entities/User.cs
+++ b/Timeline/Entities/UserEntity.cs
@@ -12,26 +12,27 @@ namespace Timeline.Entities
 
     [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "CA2227:Collection properties should be read only", Justification = "This is an entity class.")]
     [Table("users")]
-    public class User
+    public class UserEntity
     {
         [Column("id"), Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
         public long Id { get; set; }
 
-        [Column("name"), MaxLength(26), Required]
-        public string Name { get; set; } = default!;
+        [Column("username"), MaxLength(26), Required]
+        public string Username { get; set; } = default!;
 
         [Column("password"), Required]
-        public string EncryptedPassword { get; set; } = default!;
+        public string Password { get; set; } = default!;
 
         [Column("roles"), Required]
-        public string RoleString { get; set; } = default!;
+        public string Roles { get; set; } = default!;
 
         [Column("version"), Required]
         public long Version { get; set; }
 
-        public UserAvatar? Avatar { get; set; }
+        [Column("nickname"), MaxLength(100)]
+        public string? Nickname { get; set; }
 
-        public UserDetail? Detail { get; set; }
+        public UserAvatarEntity? Avatar { get; set; }
 
         public List<TimelineEntity> Timelines { get; set; } = default!;
 
diff --git a/Timeline/ErrorCodes.cs b/Timeline/ErrorCodes.cs
deleted file mode 100644
index c246953b..00000000
--- a/Timeline/ErrorCodes.cs
+++ /dev/null
@@ -1,35 +0,0 @@
-namespace Timeline
-{
-    /// <summary>
-    /// All error code constants.
-    /// </summary>
-    /// <remarks>
-    /// Scheme:
-    /// abbbccdd
-    /// </remarks>
-    public static partial class ErrorCodes
-    {
-        public static partial class Http // a = 1 
-        {
-            public static class Common // bbb = 000
-            {
-                public const int InvalidModel = 10000000;
-
-                public static class Header // cc = 0x
-                {
-                    public static class IfNonMatch // cc = 01
-                    {
-                        public const int BadFormat = 10000101;
-                    }
-                }
-
-                public static class Content // cc = 11
-                {
-                    public const int TooBig = 10001101;
-                    public const int UnmatchedLength_Smaller = 10001102;
-                    public const int UnmatchedLength_Bigger = 10001103;
-                }
-            }
-        }
-    }
-}
diff --git a/Timeline/Filters/Header.cs b/Timeline/Filters/Header.cs
index f5fb16aa..0db11faf 100644
--- a/Timeline/Filters/Header.cs
+++ b/Timeline/Filters/Header.cs
@@ -1,72 +1,22 @@
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.Filters;
 using Timeline.Models.Http;
-using static Timeline.Resources.Filters;
-
-namespace Timeline
-{
-    public static partial class ErrorCodes
-    {
-        public static partial class Http
-        {
-            public static partial class Filter // bxx = 1xx
-            {
-                public static partial class Header // bbb = 100
-                {
-                    public static class ContentType // cc = 01
-                    {
-                        public const int Missing = 11000101; // dd = 01
-                    }
-
-                    public static class ContentLength // cc = 02
-                    {
-                        public const int Missing = 11000201; // dd = 01
-                        public const int Zero = 11000202; // dd = 02
-                    }
-                }
-            }
-
-        }
-    }
-}
 
 namespace Timeline.Filters
 {
     public class RequireContentTypeAttribute : ActionFilterAttribute
     {
-        internal static CommonResponse CreateResponse()
-        {
-            return new CommonResponse(
-                ErrorCodes.Http.Filter.Header.ContentType.Missing,
-                MessageHeaderContentTypeMissing);
-        }
-
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods")]
         public override void OnActionExecuting(ActionExecutingContext context)
         {
             if (context.HttpContext.Request.ContentType == null)
             {
-                context.Result = new BadRequestObjectResult(CreateResponse());
+                context.Result = new BadRequestObjectResult(ErrorResponse.Common.Header.ContentType_Missing());
             }
         }
     }
 
     public class RequireContentLengthAttribute : ActionFilterAttribute
     {
-        internal static CommonResponse CreateMissingResponse()
-        {
-            return new CommonResponse(
-                ErrorCodes.Http.Filter.Header.ContentLength.Missing,
-                MessageHeaderContentLengthMissing);
-        }
-
-        internal static CommonResponse CreateZeroResponse()
-        {
-            return new CommonResponse(
-                ErrorCodes.Http.Filter.Header.ContentLength.Zero,
-                MessageHeaderContentLengthZero);
-        }
-
         public RequireContentLengthAttribute()
         : this(true)
         {
@@ -80,18 +30,17 @@ namespace Timeline.Filters
 
         public bool RequireNonZero { get; set; }
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods")]
         public override void OnActionExecuting(ActionExecutingContext context)
         {
             if (context.HttpContext.Request.ContentLength == null)
             {
-                context.Result = new BadRequestObjectResult(CreateMissingResponse());
+                context.Result = new BadRequestObjectResult(ErrorResponse.Common.Header.ContentLength_Missing());
                 return;
             }
 
             if (RequireNonZero && context.HttpContext.Request.ContentLength.Value == 0)
             {
-                context.Result = new BadRequestObjectResult(CreateZeroResponse());
+                context.Result = new BadRequestObjectResult(ErrorResponse.Common.Header.ContentLength_Zero());
                 return;
             }
         }
diff --git a/Timeline/Filters/Timeline.cs b/Timeline/Filters/Timeline.cs
index 7859d409..ed78e645 100644
--- a/Timeline/Filters/Timeline.cs
+++ b/Timeline/Filters/Timeline.cs
@@ -2,44 +2,22 @@
 using Microsoft.AspNetCore.Mvc.Filters;
 using Timeline.Models.Http;
 using Timeline.Services;
-using static Timeline.Resources.Filters;
-
-namespace Timeline
-{
-    public static partial class ErrorCodes
-    {
-        public static partial class Http
-        {
-            public static partial class Filter // bxx = 1xx
-            {
-                public static class Timeline // bbb = 102
-                {
-                    public const int UserNotExist = 11020101;
-                    public const int NameNotExist = 11020102;
-                }
-            }
-        }
-    }
-}
 
 namespace Timeline.Filters
 {
     public class CatchTimelineNotExistExceptionAttribute : ExceptionFilterAttribute
     {
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods")]
         public override void OnException(ExceptionContext context)
         {
             if (context.Exception is TimelineNotExistException e)
             {
                 if (e.InnerException is UserNotExistException)
                 {
-                    context.Result = new BadRequestObjectResult(
-                        new CommonResponse(ErrorCodes.Http.Filter.Timeline.UserNotExist, MessageTimelineNotExistUser));
+                    context.Result = new NotFoundObjectResult(ErrorResponse.UserCommon.NotExist());
                 }
                 else
                 {
-                    context.Result = new BadRequestObjectResult(
-                        new CommonResponse(ErrorCodes.Http.Filter.Timeline.NameNotExist, MessageTimelineNotExist));
+                    throw new System.NotImplementedException();
                 }
             }
         }
diff --git a/Timeline/Filters/User.cs b/Timeline/Filters/User.cs
deleted file mode 100644
index 16c76750..00000000
--- a/Timeline/Filters/User.cs
+++ /dev/null
@@ -1,88 +0,0 @@
-using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Mvc;
-using Microsoft.AspNetCore.Mvc.Filters;
-using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Logging;
-using System;
-using Timeline.Auth;
-using Timeline.Models.Http;
-using Timeline.Services;
-using static Timeline.Resources.Filters;
-
-namespace Timeline
-{
-    public static partial class ErrorCodes
-    {
-        public static partial class Http
-        {
-            public static partial class Filter // bxx = 1xx
-            {
-                public static class User // bbb = 101
-                {
-                    public const int NotExist = 11010101;
-
-                    public const int NotSelfOrAdminForbid = 11010201;
-                }
-            }
-        }
-    }
-}
-
-namespace Timeline.Filters
-{
-    public class SelfOrAdminAttribute : ActionFilterAttribute
-    {
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods")]
-        public override void OnActionExecuting(ActionExecutingContext context)
-        {
-            var logger = context.HttpContext.RequestServices.GetRequiredService<ILogger<SelfOrAdminAttribute>>();
-
-            var user = context.HttpContext.User;
-
-            if (user == null)
-            {
-                logger.LogError(LogSelfOrAdminNoUser);
-                return;
-            }
-
-            if (context.ModelState.TryGetValue("username", out var model))
-            {
-                if (model.RawValue is string username)
-                {
-                    if (!user.IsAdministrator() && user.Identity.Name != username)
-                    {
-                        context.Result = new ObjectResult(
-                            new CommonResponse(ErrorCodes.Http.Filter.User.NotSelfOrAdminForbid, MessageSelfOrAdminForbid))
-                        { StatusCode = StatusCodes.Status403Forbidden };
-                    }
-                }
-                else
-                {
-                    logger.LogError(LogSelfOrAdminUsernameNotString);
-                }
-            }
-            else
-            {
-                logger.LogError(LogSelfOrAdminNoUsername);
-            }
-        }
-    }
-
-    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true, Inherited = true)]
-    public class CatchUserNotExistExceptionAttribute : ExceptionFilterAttribute
-    {
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods", Justification = "ASP.Net already checked.")]
-        public override void OnException(ExceptionContext context)
-        {
-            if (context.Exception is UserNotExistException)
-            {
-                var body = new CommonResponse(ErrorCodes.Http.Filter.User.NotExist, MessageUserNotExist);
-
-                if (context.HttpContext.Request.Method == "GET")
-                    context.Result = new NotFoundObjectResult(body);
-                else
-                    context.Result = new BadRequestObjectResult(body);
-            }
-        }
-    }
-}
diff --git a/Timeline/Formatters/StringInputFormatter.cs b/Timeline/Formatters/StringInputFormatter.cs
index 90847e36..b1924268 100644
--- a/Timeline/Formatters/StringInputFormatter.cs
+++ b/Timeline/Formatters/StringInputFormatter.cs
@@ -15,7 +15,6 @@ namespace Timeline.Formatters
             SupportedEncodings.Add(Encoding.UTF8);
         }
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods")]
         public override async Task<InputFormatterResult> ReadRequestBodyAsync(InputFormatterContext context, Encoding effectiveEncoding)
         {
             var request = context.HttpContext.Request;
diff --git a/Timeline/GlobalSuppressions.cs b/Timeline/GlobalSuppressions.cs
index 076c2005..2b0da576 100644
--- a/Timeline/GlobalSuppressions.cs
+++ b/Timeline/GlobalSuppressions.cs
@@ -7,6 +7,8 @@
 [assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1034:Nested types should not be visible", Justification = "This is not bad.")]
 [assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods", Justification = "No need to check the null because it's ASP.Net's duty.", Scope = "namespaceanddescendants", Target = "Timeline.Controllers")]
 [assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods", Justification = "Migrations code are auto generated.", Scope = "namespaceanddescendants", Target = "Timeline.Migrations")]
-[assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1707:Identifiers should not contain underscores", Justification = "Error code constant identifiers.", Scope = "type", Target = "Timeline.ErrorCodes")]
-[assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1716:Identifiers should not match keywords", Justification = "Error code constant identifiers.", Scope = "type", Target = "Timeline.ErrorCodes")]
-[assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1724:Type names should not match namespaces", Justification = "Error code constant identifiers.", Scope = "type", Target = "Timeline.ErrorCodes")]
+[assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1707:Identifiers should not contain underscores", Justification = "Generated error response identifiers.", Scope = "type", Target = "Timeline.Models.Http.ErrorResponse")]
+[assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1724:Type names should not match namespaces", Justification = "Generated error response identifiers.", Scope = "type", Target = "Timeline.Models.Http.ErrorResponse")]
+[assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Globalization", "CA1305:Specify IFormatProvider", Justification = "Generated error response.", Scope = "type", Target = "Timeline.Models.Http.ErrorResponse")]
+[assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1056:Uri properties should not be strings", Justification = "That's unnecessary.")]
+[assembly: System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods", Justification = "Adundant")]
diff --git a/Timeline/Helpers/InvalidModelResponseFactory.cs b/Timeline/Helpers/InvalidModelResponseFactory.cs
index 643c99ac..9b253e7d 100644
--- a/Timeline/Helpers/InvalidModelResponseFactory.cs
+++ b/Timeline/Helpers/InvalidModelResponseFactory.cs
@@ -6,7 +6,6 @@ namespace Timeline.Helpers
 {
     public static class InvalidModelResponseFactory
     {
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods")]
         public static IActionResult Factory(ActionContext context)
         {
             var modelState = context.ModelState;
@@ -20,7 +19,7 @@ namespace Timeline.Helpers
                     messageBuilder.AppendLine(error.ErrorMessage);
                 }
 
-            return new BadRequestObjectResult(CommonResponse.InvalidModel(messageBuilder.ToString()));
+            return new BadRequestObjectResult(ErrorResponse.Common.CustomMessage_InvalidModel(messageBuilder.ToString()));
         }
     }
 }
diff --git a/Timeline/InvalidBranchException.cs b/Timeline/InvalidBranchException.cs
deleted file mode 100644
index 32937c5d..00000000
--- a/Timeline/InvalidBranchException.cs
+++ /dev/null
@@ -1,16 +0,0 @@
-using System;
-
-namespace Timeline
-{
-
-    [Serializable]
-    public class InvalidBranchException : Exception
-    {
-        public InvalidBranchException() : base(Resources.Common.ExceptionInvalidBranch) { }
-        public InvalidBranchException(string message) : base(message) { }
-        public InvalidBranchException(string message, Exception inner) : base(message, inner) { }
-        protected InvalidBranchException(
-          System.Runtime.Serialization.SerializationInfo info,
-          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
-    }
-}
diff --git a/Timeline/Migrations/DevelopmentDatabase/20200131100517_RefactorUser.Designer.cs b/Timeline/Migrations/DevelopmentDatabase/20200131100517_RefactorUser.Designer.cs
new file mode 100644
index 00000000..13e322c8
--- /dev/null
+++ b/Timeline/Migrations/DevelopmentDatabase/20200131100517_RefactorUser.Designer.cs
@@ -0,0 +1,243 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Timeline.Entities;
+
+namespace Timeline.Migrations.DevelopmentDatabase
+{
+    [DbContext(typeof(DevelopmentDatabaseContext))]
+    [Migration("20200131100517_RefactorUser")]
+    partial class RefactorUser
+    {
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "3.1.1");
+
+            modelBuilder.Entity("Timeline.Entities.TimelineEntity", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("id")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<DateTime>("CreateTime")
+                        .HasColumnName("create_time")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Description")
+                        .HasColumnName("description")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Name")
+                        .HasColumnName("name")
+                        .HasColumnType("TEXT");
+
+                    b.Property<long>("OwnerId")
+                        .HasColumnName("owner")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<int>("Visibility")
+                        .HasColumnName("visibility")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("OwnerId");
+
+                    b.ToTable("timelines");
+                });
+
+            modelBuilder.Entity("Timeline.Entities.TimelineMemberEntity", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("id")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<long>("TimelineId")
+                        .HasColumnName("timeline")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<long>("UserId")
+                        .HasColumnName("user")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TimelineId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("timeline_members");
+                });
+
+            modelBuilder.Entity("Timeline.Entities.TimelinePostEntity", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("id")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<long>("AuthorId")
+                        .HasColumnName("author")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Content")
+                        .HasColumnName("content")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("LastUpdated")
+                        .HasColumnName("last_updated")
+                        .HasColumnType("TEXT");
+
+                    b.Property<DateTime>("Time")
+                        .HasColumnName("time")
+                        .HasColumnType("TEXT");
+
+                    b.Property<long>("TimelineId")
+                        .HasColumnName("timeline")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("AuthorId");
+
+                    b.HasIndex("TimelineId");
+
+                    b.ToTable("timeline_posts");
+                });
+
+            modelBuilder.Entity("Timeline.Entities.UserAvatarEntity", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("id")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<byte[]>("Data")
+                        .HasColumnName("data")
+                        .HasColumnType("BLOB");
+
+                    b.Property<string>("ETag")
+                        .HasColumnName("etag")
+                        .HasColumnType("TEXT")
+                        .HasMaxLength(30);
+
+                    b.Property<DateTime>("LastModified")
+                        .HasColumnName("last_modified")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Type")
+                        .HasColumnName("type")
+                        .HasColumnType("TEXT");
+
+                    b.Property<long>("UserId")
+                        .HasColumnName("user")
+                        .HasColumnType("INTEGER");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId")
+                        .IsUnique();
+
+                    b.ToTable("user_avatars");
+                });
+
+            modelBuilder.Entity("Timeline.Entities.UserEntity", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("id")
+                        .HasColumnType("INTEGER");
+
+                    b.Property<string>("Nickname")
+                        .HasColumnName("nickname")
+                        .HasColumnType("TEXT")
+                        .HasMaxLength(100);
+
+                    b.Property<string>("Password")
+                        .IsRequired()
+                        .HasColumnName("password")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Roles")
+                        .IsRequired()
+                        .HasColumnName("roles")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnName("username")
+                        .HasColumnType("TEXT")
+                        .HasMaxLength(26);
+
+                    b.Property<long>("Version")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("version")
+                        .HasColumnType("INTEGER")
+                        .HasDefaultValue(0L);
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Username")
+                        .IsUnique();
+
+                    b.ToTable("users");
+                });
+
+            modelBuilder.Entity("Timeline.Entities.TimelineEntity", b =>
+                {
+                    b.HasOne("Timeline.Entities.UserEntity", "Owner")
+                        .WithMany("Timelines")
+                        .HasForeignKey("OwnerId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Timeline.Entities.TimelineMemberEntity", b =>
+                {
+                    b.HasOne("Timeline.Entities.TimelineEntity", "Timeline")
+                        .WithMany("Members")
+                        .HasForeignKey("TimelineId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Timeline.Entities.UserEntity", "User")
+                        .WithMany("TimelinesJoined")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Timeline.Entities.TimelinePostEntity", b =>
+                {
+                    b.HasOne("Timeline.Entities.UserEntity", "Author")
+                        .WithMany("TimelinePosts")
+                        .HasForeignKey("AuthorId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Timeline.Entities.TimelineEntity", "Timeline")
+                        .WithMany("Posts")
+                        .HasForeignKey("TimelineId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Timeline.Entities.UserAvatarEntity", b =>
+                {
+                    b.HasOne("Timeline.Entities.UserEntity", "User")
+                        .WithOne("Avatar")
+                        .HasForeignKey("Timeline.Entities.UserAvatarEntity", "UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/Timeline/Migrations/DevelopmentDatabase/20200131100517_RefactorUser.cs b/Timeline/Migrations/DevelopmentDatabase/20200131100517_RefactorUser.cs
new file mode 100644
index 00000000..ade65eb1
--- /dev/null
+++ b/Timeline/Migrations/DevelopmentDatabase/20200131100517_RefactorUser.cs
@@ -0,0 +1,129 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace Timeline.Migrations.DevelopmentDatabase
+{
+    public partial class RefactorUser : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.RenameColumn(name: "name", table: "users", newName: "username");
+            migrationBuilder.RenameIndex(name: "IX_users_name", table: "users", newName: "IX_users_username");
+
+            migrationBuilder.AddColumn<string>(
+                name: "nickname",
+                table: "users",
+                maxLength: 100,
+                nullable: true);
+
+            migrationBuilder.Sql(@"
+UPDATE users 
+    SET nickname = (
+        SELECT nickname
+        FROM user_details
+        WHERE user_details.UserId = users.id
+    );
+            ");
+
+            /*
+            migrationBuilder.RenameColumn(name: "UserId", table: "user_avatars", newName: "user");
+
+            migrationBuilder.DropForeignKey(
+                name: "FK_user_avatars_users_UserId",
+                table: "user_avatars");
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_user_avatars_users_user",
+                table: "user_avatars",
+                column: "user",
+                principalTable: "users",
+                principalColumn: "id",
+                onDelete: ReferentialAction.Cascade);
+
+             migrationBuilder.RenameIndex(
+                name: "IX_user_avatars_UserId",
+                table: "user_avatars",
+                newName: "IX_user_avatars_user");
+             */
+
+            migrationBuilder.Sql(@"
+CREATE TABLE user_avatars_backup (
+    id            INTEGER NOT NULL
+                          CONSTRAINT PK_user_avatars PRIMARY KEY AUTOINCREMENT,
+    data          BLOB,
+    type          TEXT,
+    etag          TEXT,
+    last_modified TEXT    NOT NULL,
+    user          INTEGER NOT NULL,
+    CONSTRAINT FK_user_avatars_users_user FOREIGN KEY (
+        user
+    )
+    REFERENCES users (id) ON DELETE CASCADE
+);
+
+INSERT INTO user_avatars_backup (id, data, type, etag, last_modified, user)
+    SELECT id, data, type, etag, last_modified, UserId FROM user_avatars;
+
+DROP TABLE user_avatars;
+
+ALTER TABLE user_avatars_backup
+    RENAME TO user_avatars;
+
+CREATE UNIQUE INDEX IX_user_avatars_user ON user_avatars (user);
+            ");
+
+            // migrationBuilder.DropTable(name: "user_details");
+
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.Sql(@"
+CREATE TABLE user_avatars_backup (
+    id            INTEGER NOT NULL
+                          CONSTRAINT PK_user_avatars PRIMARY KEY AUTOINCREMENT,
+    data          BLOB,
+    type          TEXT,
+    etag          TEXT,
+    last_modified TEXT    NOT NULL,
+    UserId        INTEGER NOT NULL,
+    CONSTRAINT FK_user_avatars_users_UserId FOREIGN KEY (
+        user
+    )
+    REFERENCES users (id) ON DELETE CASCADE
+);
+
+INSERT INTO user_avatars_backup (id, data, type, etag, last_modified, UserId)
+    SELECT id, data, type, etag, last_modified, user FROM user_avatars;
+
+DROP TABLE user_avatars;
+
+ALTER TABLE user_avatars_backup
+    RENAME TO user_avatars;
+
+CREATE UNIQUE INDEX IX_user_avatars_UserId ON user_avatars (UserId);
+            ");
+
+            migrationBuilder.Sql(@"
+CREATE TABLE users_backup (
+    id       INTEGER NOT NULL
+                     CONSTRAINT PK_users PRIMARY KEY AUTOINCREMENT,
+    name     TEXT    NOT NULL,
+    password TEXT    NOT NULL,
+    roles    TEXT    NOT NULL,
+    version  INTEGER NOT NULL
+                     DEFAULT 0
+);
+
+INSERT INTO users_backup (id, name, password, roles, version)
+    SELECT id, username, password, roles, version FROM users;
+
+DROP TABLE users;
+
+ALTER TABLE users_backup
+    RENAME TO users;
+
+CREATE UNIQUE INDEX IX_users_name ON users (name);
+            ");
+        }
+    }
+}
diff --git a/Timeline/Migrations/DevelopmentDatabase/DevelopmentDatabaseContextModelSnapshot.cs b/Timeline/Migrations/DevelopmentDatabase/DevelopmentDatabaseContextModelSnapshot.cs
index 6fbaea5f..5da49dbe 100644
--- a/Timeline/Migrations/DevelopmentDatabase/DevelopmentDatabaseContextModelSnapshot.cs
+++ b/Timeline/Migrations/DevelopmentDatabase/DevelopmentDatabaseContextModelSnapshot.cs
@@ -14,7 +14,7 @@ namespace Timeline.Migrations.DevelopmentDatabase
         {
 #pragma warning disable 612, 618
             modelBuilder
-                .HasAnnotation("ProductVersion", "3.1.0");
+                .HasAnnotation("ProductVersion", "3.1.1");
 
             modelBuilder.Entity("Timeline.Entities.TimelineEntity", b =>
                 {
@@ -110,44 +110,7 @@ namespace Timeline.Migrations.DevelopmentDatabase
                     b.ToTable("timeline_posts");
                 });
 
-            modelBuilder.Entity("Timeline.Entities.User", b =>
-                {
-                    b.Property<long>("Id")
-                        .ValueGeneratedOnAdd()
-                        .HasColumnName("id")
-                        .HasColumnType("INTEGER");
-
-                    b.Property<string>("EncryptedPassword")
-                        .IsRequired()
-                        .HasColumnName("password")
-                        .HasColumnType("TEXT");
-
-                    b.Property<string>("Name")
-                        .IsRequired()
-                        .HasColumnName("name")
-                        .HasColumnType("TEXT")
-                        .HasMaxLength(26);
-
-                    b.Property<string>("RoleString")
-                        .IsRequired()
-                        .HasColumnName("roles")
-                        .HasColumnType("TEXT");
-
-                    b.Property<long>("Version")
-                        .ValueGeneratedOnAdd()
-                        .HasColumnName("version")
-                        .HasColumnType("INTEGER")
-                        .HasDefaultValue(0L);
-
-                    b.HasKey("Id");
-
-                    b.HasIndex("Name")
-                        .IsUnique();
-
-                    b.ToTable("users");
-                });
-
-            modelBuilder.Entity("Timeline.Entities.UserAvatar", b =>
+            modelBuilder.Entity("Timeline.Entities.UserAvatarEntity", b =>
                 {
                     b.Property<long>("Id")
                         .ValueGeneratedOnAdd()
@@ -172,6 +135,7 @@ namespace Timeline.Migrations.DevelopmentDatabase
                         .HasColumnType("TEXT");
 
                     b.Property<long>("UserId")
+                        .HasColumnName("user")
                         .HasColumnType("INTEGER");
 
                     b.HasKey("Id");
@@ -182,7 +146,7 @@ namespace Timeline.Migrations.DevelopmentDatabase
                     b.ToTable("user_avatars");
                 });
 
-            modelBuilder.Entity("Timeline.Entities.UserDetail", b =>
+            modelBuilder.Entity("Timeline.Entities.UserEntity", b =>
                 {
                     b.Property<long>("Id")
                         .ValueGeneratedOnAdd()
@@ -192,22 +156,41 @@ namespace Timeline.Migrations.DevelopmentDatabase
                     b.Property<string>("Nickname")
                         .HasColumnName("nickname")
                         .HasColumnType("TEXT")
+                        .HasMaxLength(100);
+
+                    b.Property<string>("Password")
+                        .IsRequired()
+                        .HasColumnName("password")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Roles")
+                        .IsRequired()
+                        .HasColumnName("roles")
+                        .HasColumnType("TEXT");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnName("username")
+                        .HasColumnType("TEXT")
                         .HasMaxLength(26);
 
-                    b.Property<long>("UserId")
-                        .HasColumnType("INTEGER");
+                    b.Property<long>("Version")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("version")
+                        .HasColumnType("INTEGER")
+                        .HasDefaultValue(0L);
 
                     b.HasKey("Id");
 
-                    b.HasIndex("UserId")
+                    b.HasIndex("Username")
                         .IsUnique();
 
-                    b.ToTable("user_details");
+                    b.ToTable("users");
                 });
 
             modelBuilder.Entity("Timeline.Entities.TimelineEntity", b =>
                 {
-                    b.HasOne("Timeline.Entities.User", "Owner")
+                    b.HasOne("Timeline.Entities.UserEntity", "Owner")
                         .WithMany("Timelines")
                         .HasForeignKey("OwnerId")
                         .OnDelete(DeleteBehavior.Cascade)
@@ -222,7 +205,7 @@ namespace Timeline.Migrations.DevelopmentDatabase
                         .OnDelete(DeleteBehavior.Cascade)
                         .IsRequired();
 
-                    b.HasOne("Timeline.Entities.User", "User")
+                    b.HasOne("Timeline.Entities.UserEntity", "User")
                         .WithMany("TimelinesJoined")
                         .HasForeignKey("UserId")
                         .OnDelete(DeleteBehavior.Cascade)
@@ -231,7 +214,7 @@ namespace Timeline.Migrations.DevelopmentDatabase
 
             modelBuilder.Entity("Timeline.Entities.TimelinePostEntity", b =>
                 {
-                    b.HasOne("Timeline.Entities.User", "Author")
+                    b.HasOne("Timeline.Entities.UserEntity", "Author")
                         .WithMany("TimelinePosts")
                         .HasForeignKey("AuthorId")
                         .OnDelete(DeleteBehavior.Cascade)
@@ -244,20 +227,11 @@ namespace Timeline.Migrations.DevelopmentDatabase
                         .IsRequired();
                 });
 
-            modelBuilder.Entity("Timeline.Entities.UserAvatar", b =>
+            modelBuilder.Entity("Timeline.Entities.UserAvatarEntity", b =>
                 {
-                    b.HasOne("Timeline.Entities.User", null)
+                    b.HasOne("Timeline.Entities.UserEntity", "User")
                         .WithOne("Avatar")
-                        .HasForeignKey("Timeline.Entities.UserAvatar", "UserId")
-                        .OnDelete(DeleteBehavior.Cascade)
-                        .IsRequired();
-                });
-
-            modelBuilder.Entity("Timeline.Entities.UserDetail", b =>
-                {
-                    b.HasOne("Timeline.Entities.User", null)
-                        .WithOne("Detail")
-                        .HasForeignKey("Timeline.Entities.UserDetail", "UserId")
+                        .HasForeignKey("Timeline.Entities.UserAvatarEntity", "UserId")
                         .OnDelete(DeleteBehavior.Cascade)
                         .IsRequired();
                 });
diff --git a/Timeline/Migrations/ProductionDatabase/20200131152033_RefactorUser.Designer.cs b/Timeline/Migrations/ProductionDatabase/20200131152033_RefactorUser.Designer.cs
new file mode 100644
index 00000000..bb0bb5af
--- /dev/null
+++ b/Timeline/Migrations/ProductionDatabase/20200131152033_RefactorUser.Designer.cs
@@ -0,0 +1,244 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Timeline.Entities;
+
+namespace Timeline.Migrations.ProductionDatabase
+{
+    [DbContext(typeof(ProductionDatabaseContext))]
+    [Migration("20200131152033_RefactorUser")]
+    partial class RefactorUser
+    {
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "3.1.1")
+                .HasAnnotation("Relational:MaxIdentifierLength", 64);
+
+            modelBuilder.Entity("Timeline.Entities.TimelineEntity", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("id")
+                        .HasColumnType("bigint");
+
+                    b.Property<DateTime>("CreateTime")
+                        .HasColumnName("create_time")
+                        .HasColumnType("datetime(6)");
+
+                    b.Property<string>("Description")
+                        .HasColumnName("description")
+                        .HasColumnType("longtext CHARACTER SET utf8mb4");
+
+                    b.Property<string>("Name")
+                        .HasColumnName("name")
+                        .HasColumnType("longtext CHARACTER SET utf8mb4");
+
+                    b.Property<long>("OwnerId")
+                        .HasColumnName("owner")
+                        .HasColumnType("bigint");
+
+                    b.Property<int>("Visibility")
+                        .HasColumnName("visibility")
+                        .HasColumnType("int");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("OwnerId");
+
+                    b.ToTable("timelines");
+                });
+
+            modelBuilder.Entity("Timeline.Entities.TimelineMemberEntity", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("id")
+                        .HasColumnType("bigint");
+
+                    b.Property<long>("TimelineId")
+                        .HasColumnName("timeline")
+                        .HasColumnType("bigint");
+
+                    b.Property<long>("UserId")
+                        .HasColumnName("user")
+                        .HasColumnType("bigint");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TimelineId");
+
+                    b.HasIndex("UserId");
+
+                    b.ToTable("timeline_members");
+                });
+
+            modelBuilder.Entity("Timeline.Entities.TimelinePostEntity", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("id")
+                        .HasColumnType("bigint");
+
+                    b.Property<long>("AuthorId")
+                        .HasColumnName("author")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Content")
+                        .HasColumnName("content")
+                        .HasColumnType("longtext CHARACTER SET utf8mb4");
+
+                    b.Property<DateTime>("LastUpdated")
+                        .HasColumnName("last_updated")
+                        .HasColumnType("datetime(6)");
+
+                    b.Property<DateTime>("Time")
+                        .HasColumnName("time")
+                        .HasColumnType("datetime(6)");
+
+                    b.Property<long>("TimelineId")
+                        .HasColumnName("timeline")
+                        .HasColumnType("bigint");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("AuthorId");
+
+                    b.HasIndex("TimelineId");
+
+                    b.ToTable("timeline_posts");
+                });
+
+            modelBuilder.Entity("Timeline.Entities.UserAvatarEntity", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("id")
+                        .HasColumnType("bigint");
+
+                    b.Property<byte[]>("Data")
+                        .HasColumnName("data")
+                        .HasColumnType("longblob");
+
+                    b.Property<string>("ETag")
+                        .HasColumnName("etag")
+                        .HasColumnType("varchar(30) CHARACTER SET utf8mb4")
+                        .HasMaxLength(30);
+
+                    b.Property<DateTime>("LastModified")
+                        .HasColumnName("last_modified")
+                        .HasColumnType("datetime(6)");
+
+                    b.Property<string>("Type")
+                        .HasColumnName("type")
+                        .HasColumnType("longtext CHARACTER SET utf8mb4");
+
+                    b.Property<long>("UserId")
+                        .HasColumnName("user")
+                        .HasColumnType("bigint");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserId")
+                        .IsUnique();
+
+                    b.ToTable("user_avatars");
+                });
+
+            modelBuilder.Entity("Timeline.Entities.UserEntity", b =>
+                {
+                    b.Property<long>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("id")
+                        .HasColumnType("bigint");
+
+                    b.Property<string>("Nickname")
+                        .HasColumnName("nickname")
+                        .HasColumnType("varchar(100) CHARACTER SET utf8mb4")
+                        .HasMaxLength(100);
+
+                    b.Property<string>("Password")
+                        .IsRequired()
+                        .HasColumnName("password")
+                        .HasColumnType("longtext CHARACTER SET utf8mb4");
+
+                    b.Property<string>("Roles")
+                        .IsRequired()
+                        .HasColumnName("roles")
+                        .HasColumnType("longtext CHARACTER SET utf8mb4");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnName("username")
+                        .HasColumnType("varchar(26) CHARACTER SET utf8mb4")
+                        .HasMaxLength(26);
+
+                    b.Property<long>("Version")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("version")
+                        .HasColumnType("bigint")
+                        .HasDefaultValue(0L);
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Username")
+                        .IsUnique();
+
+                    b.ToTable("users");
+                });
+
+            modelBuilder.Entity("Timeline.Entities.TimelineEntity", b =>
+                {
+                    b.HasOne("Timeline.Entities.UserEntity", "Owner")
+                        .WithMany("Timelines")
+                        .HasForeignKey("OwnerId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Timeline.Entities.TimelineMemberEntity", b =>
+                {
+                    b.HasOne("Timeline.Entities.TimelineEntity", "Timeline")
+                        .WithMany("Members")
+                        .HasForeignKey("TimelineId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Timeline.Entities.UserEntity", "User")
+                        .WithMany("TimelinesJoined")
+                        .HasForeignKey("UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Timeline.Entities.TimelinePostEntity", b =>
+                {
+                    b.HasOne("Timeline.Entities.UserEntity", "Author")
+                        .WithMany("TimelinePosts")
+                        .HasForeignKey("AuthorId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.HasOne("Timeline.Entities.TimelineEntity", "Timeline")
+                        .WithMany("Posts")
+                        .HasForeignKey("TimelineId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("Timeline.Entities.UserAvatarEntity", b =>
+                {
+                    b.HasOne("Timeline.Entities.UserEntity", "User")
+                        .WithOne("Avatar")
+                        .HasForeignKey("Timeline.Entities.UserAvatarEntity", "UserId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}
diff --git a/Timeline/Migrations/ProductionDatabase/20200131152033_RefactorUser.cs b/Timeline/Migrations/ProductionDatabase/20200131152033_RefactorUser.cs
new file mode 100644
index 00000000..a0ca5212
--- /dev/null
+++ b/Timeline/Migrations/ProductionDatabase/20200131152033_RefactorUser.cs
@@ -0,0 +1,55 @@
+using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace Timeline.Migrations.ProductionDatabase
+{
+    public partial class RefactorUser : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.Sql(@"
+START TRANSACTION;
+
+ALTER TABLE `users`
+    CHANGE COLUMN `name` `username` varchar (26) NOT NULL,
+    RENAME INDEX IX_users_name TO IX_users_username,
+    ADD `nickname` varchar(100) CHARACTER SET utf8mb4 NULL;
+
+UPDATE users 
+    SET nickname = (
+        SELECT nickname
+        FROM user_details
+        WHERE user_details.UserId = users.id
+    );
+
+ALTER TABLE `user_avatars`
+    CHANGE COLUMN `UserId` `user` bigint (20) NOT NULL,
+    RENAME INDEX IX_user_avatars_UserId TO IX_user_avatars_user,
+    DROP FOREIGN KEY FK_user_avatars_users_UserId,
+    ADD CONSTRAINT FK_user_avatars_users_user FOREIGN KEY (`user`) REFERENCES `users` (`id`) ON DELETE CASCADE;
+
+COMMIT;
+            ");
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.Sql(@"
+START TRANSACTION;
+
+ALTER TABLE `users`
+    CHANGE COLUMN `username` `name` varchar (26) NOT NULL,
+    RENAME INDEX IX_users_username TO IX_users_name,
+    DROP COLUMN `nickname`;
+
+ALTER TABLE `user_avatars`
+    CHANGE COLUMN `user` `UserId` bigint (20) NOT NULL,
+    RENAME INDEX IX_user_avatars_user TO IX_user_avatars_UserId,
+    DROP FOREIGN KEY FK_user_avatars_users_user,
+    ADD CONSTRAINT FK_user_avatars_users_UserId FOREIGN KEY (`UserId`) REFERENCES `users` (`id`) ON DELETE CASCADE;
+
+COMMIT;
+            ");
+        }
+    }
+}
diff --git a/Timeline/Migrations/ProductionDatabase/ProductionDatabaseContextModelSnapshot.cs b/Timeline/Migrations/ProductionDatabase/ProductionDatabaseContextModelSnapshot.cs
index 67ef52a4..bfc9b768 100644
--- a/Timeline/Migrations/ProductionDatabase/ProductionDatabaseContextModelSnapshot.cs
+++ b/Timeline/Migrations/ProductionDatabase/ProductionDatabaseContextModelSnapshot.cs
@@ -14,7 +14,7 @@ namespace Timeline.Migrations.ProductionDatabase
         {
 #pragma warning disable 612, 618
             modelBuilder
-                .HasAnnotation("ProductVersion", "3.1.0")
+                .HasAnnotation("ProductVersion", "3.1.1")
                 .HasAnnotation("Relational:MaxIdentifierLength", 64);
 
             modelBuilder.Entity("Timeline.Entities.TimelineEntity", b =>
@@ -111,44 +111,7 @@ namespace Timeline.Migrations.ProductionDatabase
                     b.ToTable("timeline_posts");
                 });
 
-            modelBuilder.Entity("Timeline.Entities.User", b =>
-                {
-                    b.Property<long>("Id")
-                        .ValueGeneratedOnAdd()
-                        .HasColumnName("id")
-                        .HasColumnType("bigint");
-
-                    b.Property<string>("EncryptedPassword")
-                        .IsRequired()
-                        .HasColumnName("password")
-                        .HasColumnType("longtext CHARACTER SET utf8mb4");
-
-                    b.Property<string>("Name")
-                        .IsRequired()
-                        .HasColumnName("name")
-                        .HasColumnType("varchar(26) CHARACTER SET utf8mb4")
-                        .HasMaxLength(26);
-
-                    b.Property<string>("RoleString")
-                        .IsRequired()
-                        .HasColumnName("roles")
-                        .HasColumnType("longtext CHARACTER SET utf8mb4");
-
-                    b.Property<long>("Version")
-                        .ValueGeneratedOnAdd()
-                        .HasColumnName("version")
-                        .HasColumnType("bigint")
-                        .HasDefaultValue(0L);
-
-                    b.HasKey("Id");
-
-                    b.HasIndex("Name")
-                        .IsUnique();
-
-                    b.ToTable("users");
-                });
-
-            modelBuilder.Entity("Timeline.Entities.UserAvatar", b =>
+            modelBuilder.Entity("Timeline.Entities.UserAvatarEntity", b =>
                 {
                     b.Property<long>("Id")
                         .ValueGeneratedOnAdd()
@@ -173,6 +136,7 @@ namespace Timeline.Migrations.ProductionDatabase
                         .HasColumnType("longtext CHARACTER SET utf8mb4");
 
                     b.Property<long>("UserId")
+                        .HasColumnName("user")
                         .HasColumnType("bigint");
 
                     b.HasKey("Id");
@@ -183,7 +147,7 @@ namespace Timeline.Migrations.ProductionDatabase
                     b.ToTable("user_avatars");
                 });
 
-            modelBuilder.Entity("Timeline.Entities.UserDetail", b =>
+            modelBuilder.Entity("Timeline.Entities.UserEntity", b =>
                 {
                     b.Property<long>("Id")
                         .ValueGeneratedOnAdd()
@@ -192,23 +156,42 @@ namespace Timeline.Migrations.ProductionDatabase
 
                     b.Property<string>("Nickname")
                         .HasColumnName("nickname")
+                        .HasColumnType("varchar(100) CHARACTER SET utf8mb4")
+                        .HasMaxLength(100);
+
+                    b.Property<string>("Password")
+                        .IsRequired()
+                        .HasColumnName("password")
+                        .HasColumnType("longtext CHARACTER SET utf8mb4");
+
+                    b.Property<string>("Roles")
+                        .IsRequired()
+                        .HasColumnName("roles")
+                        .HasColumnType("longtext CHARACTER SET utf8mb4");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnName("username")
                         .HasColumnType("varchar(26) CHARACTER SET utf8mb4")
                         .HasMaxLength(26);
 
-                    b.Property<long>("UserId")
-                        .HasColumnType("bigint");
+                    b.Property<long>("Version")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnName("version")
+                        .HasColumnType("bigint")
+                        .HasDefaultValue(0L);
 
                     b.HasKey("Id");
 
-                    b.HasIndex("UserId")
+                    b.HasIndex("Username")
                         .IsUnique();
 
-                    b.ToTable("user_details");
+                    b.ToTable("users");
                 });
 
             modelBuilder.Entity("Timeline.Entities.TimelineEntity", b =>
                 {
-                    b.HasOne("Timeline.Entities.User", "Owner")
+                    b.HasOne("Timeline.Entities.UserEntity", "Owner")
                         .WithMany("Timelines")
                         .HasForeignKey("OwnerId")
                         .OnDelete(DeleteBehavior.Cascade)
@@ -223,7 +206,7 @@ namespace Timeline.Migrations.ProductionDatabase
                         .OnDelete(DeleteBehavior.Cascade)
                         .IsRequired();
 
-                    b.HasOne("Timeline.Entities.User", "User")
+                    b.HasOne("Timeline.Entities.UserEntity", "User")
                         .WithMany("TimelinesJoined")
                         .HasForeignKey("UserId")
                         .OnDelete(DeleteBehavior.Cascade)
@@ -232,7 +215,7 @@ namespace Timeline.Migrations.ProductionDatabase
 
             modelBuilder.Entity("Timeline.Entities.TimelinePostEntity", b =>
                 {
-                    b.HasOne("Timeline.Entities.User", "Author")
+                    b.HasOne("Timeline.Entities.UserEntity", "Author")
                         .WithMany("TimelinePosts")
                         .HasForeignKey("AuthorId")
                         .OnDelete(DeleteBehavior.Cascade)
@@ -245,20 +228,11 @@ namespace Timeline.Migrations.ProductionDatabase
                         .IsRequired();
                 });
 
-            modelBuilder.Entity("Timeline.Entities.UserAvatar", b =>
+            modelBuilder.Entity("Timeline.Entities.UserAvatarEntity", b =>
                 {
-                    b.HasOne("Timeline.Entities.User", null)
+                    b.HasOne("Timeline.Entities.UserEntity", "User")
                         .WithOne("Avatar")
-                        .HasForeignKey("Timeline.Entities.UserAvatar", "UserId")
-                        .OnDelete(DeleteBehavior.Cascade)
-                        .IsRequired();
-                });
-
-            modelBuilder.Entity("Timeline.Entities.UserDetail", b =>
-                {
-                    b.HasOne("Timeline.Entities.User", null)
-                        .WithOne("Detail")
-                        .HasForeignKey("Timeline.Entities.UserDetail", "UserId")
+                        .HasForeignKey("Timeline.Entities.UserAvatarEntity", "UserId")
                         .OnDelete(DeleteBehavior.Cascade)
                         .IsRequired();
                 });
diff --git a/Timeline/Models/Converters/JsonDateTimeConverter.cs b/Timeline/Models/Converters/JsonDateTimeConverter.cs
index 69af53c1..ef129a01 100644
--- a/Timeline/Models/Converters/JsonDateTimeConverter.cs
+++ b/Timeline/Models/Converters/JsonDateTimeConverter.cs
@@ -6,7 +6,6 @@ using System.Text.Json.Serialization;
 
 namespace Timeline.Models.Converters
 {
-    [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods")]
     public class JsonDateTimeConverter : JsonConverter<DateTime>
     {
         public override DateTime Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
diff --git a/Timeline/Models/Http/Common.cs b/Timeline/Models/Http/Common.cs
index d1e95397..a9fc8a79 100644
--- a/Timeline/Models/Http/Common.cs
+++ b/Timeline/Models/Http/Common.cs
@@ -1,15 +1,9 @@
-using System.Globalization;
 using static Timeline.Resources.Models.Http.Common;
 
 namespace Timeline.Models.Http
 {
     public class CommonResponse
     {
-        internal static CommonResponse InvalidModel(string message)
-        {
-            return new CommonResponse(ErrorCodes.Http.Common.InvalidModel, message);
-        }
-
         public CommonResponse()
         {
 
@@ -25,33 +19,6 @@ namespace Timeline.Models.Http
         public string? Message { get; set; }
     }
 
-    internal static class HeaderErrorResponse
-    {
-        internal static CommonResponse BadIfNonMatch()
-        {
-            return new CommonResponse(ErrorCodes.Http.Common.Header.IfNonMatch.BadFormat, MessageHeaderIfNonMatchBad);
-        }
-    }
-
-    internal static class ContentErrorResponse
-    {
-        internal static CommonResponse TooBig(string maxLength)
-        {
-            return new CommonResponse(ErrorCodes.Http.Common.Content.TooBig,
-                string.Format(CultureInfo.CurrentCulture, MessageContentTooBig, maxLength));
-        }
-
-        internal static CommonResponse UnmatchedLength_Smaller()
-        {
-            return new CommonResponse(ErrorCodes.Http.Common.Content.UnmatchedLength_Smaller, MessageContentUnmatchedLengthSmaller);
-        }
-        internal static CommonResponse UnmatchedLength_Bigger()
-        {
-            return new CommonResponse(ErrorCodes.Http.Common.Content.UnmatchedLength_Bigger, MessageContentUnmatchedLengthBigger);
-        }
-    }
-
-
     public class CommonDataResponse<T> : CommonResponse
     {
         public CommonDataResponse()
diff --git a/Timeline/Models/Http/ErrorResponse.cs b/Timeline/Models/Http/ErrorResponse.cs
new file mode 100644
index 00000000..87516638
--- /dev/null
+++ b/Timeline/Models/Http/ErrorResponse.cs
@@ -0,0 +1,261 @@
+using static Timeline.Resources.Messages;
+
+namespace Timeline.Models.Http
+{
+
+    public static class ErrorResponse
+    {
+
+        public static class Common
+        {
+
+            public static CommonResponse InvalidModel(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.Common.InvalidModel, string.Format(Common_InvalidModel, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_InvalidModel(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.Common.InvalidModel, string.Format(message, formatArgs));
+            }
+
+            public static CommonResponse Forbid(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.Common.Forbid, string.Format(Common_Forbid, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_Forbid(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.Common.Forbid, string.Format(message, formatArgs));
+            }
+
+            public static class Header
+            {
+
+                public static CommonResponse IfNonMatch_BadFormat(params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Header.IfNonMatch_BadFormat, string.Format(Common_Header_IfNonMatch_BadFormat, formatArgs));
+                }
+
+                public static CommonResponse CustomMessage_IfNonMatch_BadFormat(string message, params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Header.IfNonMatch_BadFormat, string.Format(message, formatArgs));
+                }
+
+                public static CommonResponse ContentType_Missing(params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Header.ContentType_Missing, string.Format(Common_Header_ContentType_Missing, formatArgs));
+                }
+
+                public static CommonResponse CustomMessage_ContentType_Missing(string message, params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Header.ContentType_Missing, string.Format(message, formatArgs));
+                }
+
+                public static CommonResponse ContentLength_Missing(params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Header.ContentLength_Missing, string.Format(Common_Header_ContentLength_Missing, formatArgs));
+                }
+
+                public static CommonResponse CustomMessage_ContentLength_Missing(string message, params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Header.ContentLength_Missing, string.Format(message, formatArgs));
+                }
+
+                public static CommonResponse ContentLength_Zero(params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Header.ContentLength_Zero, string.Format(Common_Header_ContentLength_Zero, formatArgs));
+                }
+
+                public static CommonResponse CustomMessage_ContentLength_Zero(string message, params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Header.ContentLength_Zero, string.Format(message, formatArgs));
+                }
+
+            }
+
+            public static class Content
+            {
+
+                public static CommonResponse TooBig(params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Content.TooBig, string.Format(Common_Content_TooBig, formatArgs));
+                }
+
+                public static CommonResponse CustomMessage_TooBig(string message, params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Content.TooBig, string.Format(message, formatArgs));
+                }
+
+                public static CommonResponse UnmatchedLength_Smaller(params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Content.UnmatchedLength_Smaller, string.Format(Common_Content_UnmatchedLength_Smaller, formatArgs));
+                }
+
+                public static CommonResponse CustomMessage_UnmatchedLength_Smaller(string message, params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Content.UnmatchedLength_Smaller, string.Format(message, formatArgs));
+                }
+
+                public static CommonResponse UnmatchedLength_Bigger(params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Content.UnmatchedLength_Bigger, string.Format(Common_Content_UnmatchedLength_Bigger, formatArgs));
+                }
+
+                public static CommonResponse CustomMessage_UnmatchedLength_Bigger(string message, params object?[] formatArgs)
+                {
+                    return new CommonResponse(ErrorCodes.Common.Content.UnmatchedLength_Bigger, string.Format(message, formatArgs));
+                }
+
+            }
+
+        }
+
+        public static class UserCommon
+        {
+
+            public static CommonResponse NotExist(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserCommon.NotExist, string.Format(UserCommon_NotExist, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_NotExist(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserCommon.NotExist, string.Format(message, formatArgs));
+            }
+
+        }
+
+        public static class TokenController
+        {
+
+            public static CommonResponse Create_BadCredential(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TokenController.Create_BadCredential, string.Format(TokenController_Create_BadCredential, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_Create_BadCredential(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TokenController.Create_BadCredential, string.Format(message, formatArgs));
+            }
+
+            public static CommonResponse Verify_BadFormat(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TokenController.Verify_BadFormat, string.Format(TokenController_Verify_BadFormat, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_Verify_BadFormat(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TokenController.Verify_BadFormat, string.Format(message, formatArgs));
+            }
+
+            public static CommonResponse Verify_UserNotExist(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TokenController.Verify_UserNotExist, string.Format(TokenController_Verify_UserNotExist, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_Verify_UserNotExist(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TokenController.Verify_UserNotExist, string.Format(message, formatArgs));
+            }
+
+            public static CommonResponse Verify_OldVersion(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TokenController.Verify_OldVersion, string.Format(TokenController_Verify_OldVersion, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_Verify_OldVersion(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TokenController.Verify_OldVersion, string.Format(message, formatArgs));
+            }
+
+            public static CommonResponse Verify_TimeExpired(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TokenController.Verify_TimeExpired, string.Format(TokenController_Verify_TimeExpired, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_Verify_TimeExpired(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TokenController.Verify_TimeExpired, string.Format(message, formatArgs));
+            }
+
+        }
+
+        public static class UserController
+        {
+
+            public static CommonResponse UsernameConflict(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserController.UsernameConflict, string.Format(UserController_UsernameConflict, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_UsernameConflict(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserController.UsernameConflict, string.Format(message, formatArgs));
+            }
+
+            public static CommonResponse ChangePassword_BadOldPassword(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserController.ChangePassword_BadOldPassword, string.Format(UserController_ChangePassword_BadOldPassword, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_ChangePassword_BadOldPassword(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserController.ChangePassword_BadOldPassword, string.Format(message, formatArgs));
+            }
+
+        }
+
+        public static class UserAvatar
+        {
+
+            public static CommonResponse BadFormat_CantDecode(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserAvatar.BadFormat_CantDecode, string.Format(UserAvatar_BadFormat_CantDecode, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_BadFormat_CantDecode(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserAvatar.BadFormat_CantDecode, string.Format(message, formatArgs));
+            }
+
+            public static CommonResponse BadFormat_UnmatchedFormat(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserAvatar.BadFormat_UnmatchedFormat, string.Format(UserAvatar_BadFormat_UnmatchedFormat, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_BadFormat_UnmatchedFormat(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserAvatar.BadFormat_UnmatchedFormat, string.Format(message, formatArgs));
+            }
+
+            public static CommonResponse BadFormat_BadSize(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserAvatar.BadFormat_BadSize, string.Format(UserAvatar_BadFormat_BadSize, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_BadFormat_BadSize(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.UserAvatar.BadFormat_BadSize, string.Format(message, formatArgs));
+            }
+
+        }
+
+        public static class TimelineController
+        {
+
+            public static CommonResponse MemberPut_NotExist(params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TimelineController.MemberPut_NotExist, string.Format(TimelineController_MemberPut_NotExist, formatArgs));
+            }
+
+            public static CommonResponse CustomMessage_MemberPut_NotExist(string message, params object?[] formatArgs)
+            {
+                return new CommonResponse(ErrorCodes.TimelineController.MemberPut_NotExist, string.Format(message, formatArgs));
+            }
+
+        }
+
+    }
+
+}
+\ No newline at end of file
diff --git a/Timeline/Models/Http/Timeline.cs b/Timeline/Models/Http/Timeline.cs
deleted file mode 100644
index 06b88ad1..00000000
--- a/Timeline/Models/Http/Timeline.cs
+++ /dev/null
@@ -1,45 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations;
-using System.Linq;
-using System.Threading.Tasks;
-using Timeline.Entities;
-
-namespace Timeline.Models.Http
-{
-    public class TimelinePostCreateRequest
-    {
-        [Required(AllowEmptyStrings = true)]
-        public string Content { get; set; } = default!;
-
-        public DateTime? Time { get; set; }
-    }
-
-    public class TimelinePostCreateResponse
-    {
-        public long Id { get; set; }
-
-        public DateTime Time { get; set; }
-    }
-
-    public class TimelinePostDeleteRequest
-    {
-        [Required]
-        public long? Id { get; set; }
-    }
-
-    public class TimelinePropertyChangeRequest
-    {
-        public string? Description { get; set; }
-
-        public TimelineVisibility? Visibility { get; set; }
-    }
-
-    [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "CA2227:Collection properties should be read only", Justification = "This is a DTO class.")]
-    public class TimelineMemberChangeRequest
-    {
-        public List<string>? Add { get; set; }
-
-        public List<string>? Remove { get; set; }
-    }
-}
diff --git a/Timeline/Models/Timeline.cs b/Timeline/Models/Http/TimelineCommon.cs
index 752c698d..febb8186 100644
--- a/Timeline/Models/Timeline.cs
+++ b/Timeline/Models/Http/TimelineCommon.cs
@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
 
-namespace Timeline.Models
+namespace Timeline.Models.Http
 {
     public enum TimelineVisibility
     {
@@ -22,30 +22,19 @@ namespace Timeline.Models
     public class TimelinePostInfo
     {
         public long Id { get; set; }
-
-        public string? Content { get; set; }
-
+        public string Content { get; set; } = default!;
         public DateTime Time { get; set; }
-
-        /// <summary>
-        /// The username of the author.
-        /// </summary>
-        public string Author { get; set; } = default!;
+        public UserInfo Author { get; set; } = default!;
+        public DateTime LastUpdated { get; set; } = default!;
     }
 
     [System.Diagnostics.CodeAnalysis.SuppressMessage("Usage", "CA2227:Collection properties should be read only", Justification = "This is a DTO class.")]
     public class BaseTimelineInfo
     {
-        public string? Description { get; set; }
-
-        /// <summary>
-        /// The username of the owner.
-        /// </summary>
-        public string Owner { get; set; } = default!;
-
+        public string Description { get; set; } = default!;
+        public UserInfo Owner { get; set; } = default!;
         public TimelineVisibility Visibility { get; set; }
-
-        public List<string> Members { get; set; } = default!;
+        public List<UserInfo> Members { get; set; } = default!;
     }
 
     public class TimelineInfo : BaseTimelineInfo
diff --git a/Timeline/Models/Http/TimelineController.cs b/Timeline/Models/Http/TimelineController.cs
new file mode 100644
index 00000000..f9a4d3e5
--- /dev/null
+++ b/Timeline/Models/Http/TimelineController.cs
@@ -0,0 +1,20 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+
+namespace Timeline.Models.Http
+{
+    public class TimelinePostCreateRequest
+    {
+        [Required(AllowEmptyStrings = true)]
+        public string Content { get; set; } = default!;
+
+        public DateTime? Time { get; set; }
+    }
+
+    public class TimelinePatchRequest
+    {
+        public string? Description { get; set; }
+
+        public TimelineVisibility? Visibility { get; set; }
+    }
+}
diff --git a/Timeline/Models/Http/Token.cs b/Timeline/Models/Http/TokenController.cs
index ea8b59ed..ea8b59ed 100644
--- a/Timeline/Models/Http/Token.cs
+++ b/Timeline/Models/Http/TokenController.cs
diff --git a/Timeline/Models/Http/User.cs b/Timeline/Models/Http/User.cs
deleted file mode 100644
index 516c1329..00000000
--- a/Timeline/Models/Http/User.cs
+++ /dev/null
@@ -1,38 +0,0 @@
-using System.ComponentModel.DataAnnotations;
-using Timeline.Models.Validation;
-
-namespace Timeline.Models.Http
-{
-    public class UserPutRequest
-    {
-        [Required]
-        public string Password { get; set; } = default!;
-        [Required]
-        public bool? Administrator { get; set; }
-    }
-
-    public class UserPatchRequest
-    {
-        public string? Password { get; set; }
-        public bool? Administrator { get; set; }
-    }
-
-    public class ChangeUsernameRequest
-    {
-        [Required]
-        [Username]
-        public string OldUsername { get; set; } = default!;
-
-        [Required]
-        [Username]
-        public string NewUsername { get; set; } = default!;
-    }
-
-    public class ChangePasswordRequest
-    {
-        [Required]
-        public string OldPassword { get; set; } = default!;
-        [Required]
-        public string NewPassword { get; set; } = default!;
-    }
-}
diff --git a/Timeline/Models/Http/UserController.cs b/Timeline/Models/Http/UserController.cs
new file mode 100644
index 00000000..e4c95cbd
--- /dev/null
+++ b/Timeline/Models/Http/UserController.cs
@@ -0,0 +1,53 @@
+using AutoMapper;
+using System.ComponentModel.DataAnnotations;
+using Timeline.Models.Validation;
+using Timeline.Services;
+
+namespace Timeline.Models.Http
+{
+    public class UserPatchRequest
+    {
+        [Username]
+        public string? Username { get; set; }
+
+        [MinLength(1)]
+        public string? Password { get; set; }
+
+        [Nickname]
+        public string? Nickname { get; set; }
+
+        public bool? Administrator { get; set; }
+    }
+
+    public class CreateUserRequest
+    {
+        [Required, Username]
+        public string Username { get; set; } = default!;
+
+        [Required, MinLength(1)]
+        public string Password { get; set; } = default!;
+
+        [Required]
+        public bool? Administrator { get; set; }
+
+        [Nickname]
+        public string? Nickname { get; set; }
+    }
+
+    public class ChangePasswordRequest
+    {
+        [Required(AllowEmptyStrings = false)]
+        public string OldPassword { get; set; } = default!;
+        [Required(AllowEmptyStrings = false)]
+        public string NewPassword { get; set; } = default!;
+    }
+
+    public class UserControllerAutoMapperProfile : Profile
+    {
+        public UserControllerAutoMapperProfile()
+        {
+            CreateMap<UserPatchRequest, User>(MemberList.Source);
+            CreateMap<CreateUserRequest, User>(MemberList.Source);
+        }
+    }
+}
diff --git a/Timeline/Models/Http/UserInfo.cs b/Timeline/Models/Http/UserInfo.cs
new file mode 100644
index 00000000..0d1d702b
--- /dev/null
+++ b/Timeline/Models/Http/UserInfo.cs
@@ -0,0 +1,59 @@
+using AutoMapper;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
+using Microsoft.AspNetCore.Mvc.Routing;
+using Timeline.Controllers;
+using Timeline.Services;
+
+namespace Timeline.Models.Http
+{
+    public class UserInfo
+    {
+        public string Username { get; set; } = default!;
+        public string Nickname { get; set; } = default!;
+        public bool? Administrator { get; set; } = default!;
+#pragma warning disable CA1707 
+        public UserInfoLinks? _links { get; set; }
+#pragma warning restore CA1707
+    }
+
+    public class UserInfoLinks
+    {
+        public string Avatar { get; set; } = default!;
+        public string Timeline { get; set; } = default!;
+    }
+
+    public class UserInfoLinksValueResolver : IValueResolver<User, UserInfo, UserInfoLinks?>
+    {
+        private readonly IActionContextAccessor _actionContextAccessor;
+        private readonly IUrlHelperFactory _urlHelperFactory;
+
+        public UserInfoLinksValueResolver(IActionContextAccessor actionContextAccessor, IUrlHelperFactory urlHelperFactory)
+        {
+            _actionContextAccessor = actionContextAccessor;
+            _urlHelperFactory = urlHelperFactory;
+        }
+
+        public UserInfoLinks? Resolve(User source, UserInfo destination, UserInfoLinks? destMember, ResolutionContext context)
+        {
+            if (_actionContextAccessor.ActionContext == null)
+                return null;
+
+            var urlHelper = _urlHelperFactory.GetUrlHelper(_actionContextAccessor.ActionContext);
+            var result = new UserInfoLinks
+            {
+                Avatar = urlHelper.ActionLink(nameof(UserAvatarController.Get), nameof(UserAvatarController)[0..^nameof(Controller).Length], new { destination.Username }),
+                Timeline = urlHelper.ActionLink(nameof(PersonalTimelineController.TimelineGet), nameof(PersonalTimelineController)[0..^nameof(Controller).Length], new { destination.Username })
+            };
+            return result;
+        }
+    }
+
+    public class UserInfoAutoMapperProfile : Profile
+    {
+        public UserInfoAutoMapperProfile()
+        {
+            CreateMap<User, UserInfo>().ForMember(u => u._links, opt => opt.MapFrom<UserInfoLinksValueResolver>());
+        }
+    }
+}
diff --git a/Timeline/Models/PutResult.cs b/Timeline/Models/PutResult.cs
deleted file mode 100644
index cecf86e6..00000000
--- a/Timeline/Models/PutResult.cs
+++ /dev/null
@@ -1,17 +0,0 @@
-namespace Timeline.Models
-{
-    /// <summary>
-    /// Represents the result of a "put" operation.
-    /// </summary>
-    public enum PutResult
-    {
-        /// <summary>
-        /// Indicates the item did not exist and now is created.
-        /// </summary>
-        Create,
-        /// <summary>
-        /// Indicates the item exists already and is modified.
-        /// </summary>
-        Modify
-    }
-}
diff --git a/Timeline/Models/UserInfo.cs b/Timeline/Models/UserInfo.cs
deleted file mode 100644
index b60bdfa2..00000000
--- a/Timeline/Models/UserInfo.cs
+++ /dev/null
@@ -1,23 +0,0 @@
-namespace Timeline.Models
-{
-    public sealed class UserInfo
-    {
-        public UserInfo()
-        {
-        }
-
-        public UserInfo(string username, bool administrator)
-        {
-            Username = username;
-            Administrator = administrator;
-        }
-
-        public string Username { get; set; } = default!;
-        public bool Administrator { get; set; } = default!;
-
-        public override string ToString()
-        {
-            return $"Username: {Username} ; Administrator: {Administrator}";
-        }
-    }
-}
diff --git a/Timeline/Models/Validation/NicknameValidator.cs b/Timeline/Models/Validation/NicknameValidator.cs
new file mode 100644
index 00000000..1d6ab163
--- /dev/null
+++ b/Timeline/Models/Validation/NicknameValidator.cs
@@ -0,0 +1,25 @@
+using System;
+using static Timeline.Resources.Models.Validation.NicknameValidator;
+
+namespace Timeline.Models.Validation
+{
+    public class NicknameValidator : Validator<string>
+    {
+        protected override (bool, string) DoValidate(string value)
+        {
+            if (value.Length > 25)
+                return (false, MessageTooLong);
+
+            return (true, GetSuccessMessage());
+        }
+    }
+
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter, AllowMultiple = false)]
+    public class NicknameAttribute : ValidateWithAttribute
+    {
+        public NicknameAttribute() : base(typeof(NicknameValidator))
+        {
+
+        }
+    }
+}
diff --git a/Timeline/Models/Validation/UsernameValidator.cs b/Timeline/Models/Validation/UsernameValidator.cs
index fc6cdf37..d8f3bdc0 100644
--- a/Timeline/Models/Validation/UsernameValidator.cs
+++ b/Timeline/Models/Validation/UsernameValidator.cs
@@ -8,7 +8,6 @@ namespace Timeline.Models.Validation
     {
         public const int MaxLength = 26;
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods", Justification = "Already checked in base class.")]
         protected override (bool, string) DoValidate(string value)
         {
             if (value.Length == 0)
diff --git a/Timeline/Models/Validation/Validator.cs b/Timeline/Models/Validation/Validator.cs
index a16f6f81..ead7dbef 100644
--- a/Timeline/Models/Validation/Validator.cs
+++ b/Timeline/Models/Validation/Validator.cs
@@ -20,24 +20,46 @@ namespace Timeline.Models.Validation
         (bool, string) Validate(object? value);
     }
 
+    public static class ValidatorExtensions
+    {
+        public static bool Validate(this IValidator validator, object? value, out string message)
+        {
+            if (validator == null)
+                throw new ArgumentNullException(nameof(validator));
+
+            var (r, m) = validator.Validate(value);
+            message = m;
+            return r;
+        }
+    }
+
     /// <summary>
     /// Convenient base class for validator.
     /// </summary>
     /// <typeparam name="T">The type of accepted value.</typeparam>
     /// <remarks>
     /// Subclass should override <see cref="DoValidate(T, out string)"/> to do the real validation.
-    /// This class will check the nullity and type of value. If value is null or not of type <typeparamref name="T"/>
-    /// it will return false and not call <see cref="DoValidate(T, out string)"/>.
+    /// This class will check the nullity and type of value.
+    /// If value is null, it will pass or fail depending on <see cref="PermitNull"/>.
+    /// If value is not null and not of type <typeparamref name="T"/>
+    /// it will fail and not call <see cref="DoValidate(T, out string)"/>.
+    /// 
+    /// <see cref="PermitNull"/> is true by default.
     /// 
     /// If you want some other behaviours, write the validator from scratch.
     /// </remarks>
     public abstract class Validator<T> : IValidator
     {
+        protected bool PermitNull { get; set; } = true;
+
         public (bool, string) Validate(object? value)
         {
             if (value == null)
             {
-                return (false, ValidatorMessageNull);
+                if (PermitNull)
+                    return (true, GetSuccessMessage());
+                else
+                    return (false, ValidatorMessageNull);
             }
 
             if (value is T v)
diff --git a/Timeline/Resources/Common.resx b/Timeline/Resources/Common.resx
deleted file mode 100644
index 8a036996..00000000
--- a/Timeline/Resources/Common.resx
+++ /dev/null
@@ -1,123 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<root>
-  <!-- 
-    Microsoft ResX Schema 
-    
-    Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
-    associated with the data types.
-    
-    Example:
-    
-    ... ado.net/XML headers & schema ...
-    <resheader name="resmimetype">text/microsoft-resx</resheader>
-    <resheader name="version">2.0</resheader>
-    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
-    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
-    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
-    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
-    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
-        <value>[base64 mime encoded serialized .NET Framework object]</value>
-    </data>
-    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
-        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
-        <comment>This is a comment</comment>
-    </data>
-                
-    There are any number of "resheader" rows that contain simple 
-    name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
-    mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
-    extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
-    read any of the formats listed below.
-    
-    mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
-            : and then encoded with base64 encoding.
-    
-    mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
-            : and then encoded with base64 encoding.
-
-    mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
-            : using a System.ComponentModel.TypeConverter
-            : and then encoded with base64 encoding.
-    -->
-  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
-    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
-    <xsd:element name="root" msdata:IsDataSet="true">
-      <xsd:complexType>
-        <xsd:choice maxOccurs="unbounded">
-          <xsd:element name="metadata">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" />
-              </xsd:sequence>
-              <xsd:attribute name="name" use="required" type="xsd:string" />
-              <xsd:attribute name="type" type="xsd:string" />
-              <xsd:attribute name="mimetype" type="xsd:string" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="assembly">
-            <xsd:complexType>
-              <xsd:attribute name="alias" type="xsd:string" />
-              <xsd:attribute name="name" type="xsd:string" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="data">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
-              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
-              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="resheader">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" />
-            </xsd:complexType>
-          </xsd:element>
-        </xsd:choice>
-      </xsd:complexType>
-    </xsd:element>
-  </xsd:schema>
-  <resheader name="resmimetype">
-    <value>text/microsoft-resx</value>
-  </resheader>
-  <resheader name="version">
-    <value>2.0</value>
-  </resheader>
-  <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <data name="ExceptionInvalidBranch" xml:space="preserve">
-    <value>The branch is invalid. Normally this branch is not reachable.</value>
-  </data>
-</root>
-\ No newline at end of file
diff --git a/Timeline/Resources/Services/UserDetailService.Designer.cs b/Timeline/Resources/Controllers/ControllerAuthExtensions.Designer.cs
index 2f586b36..70a1d605 100644
--- a/Timeline/Resources/Services/UserDetailService.Designer.cs
+++ b/Timeline/Resources/Controllers/ControllerAuthExtensions.Designer.cs
@@ -8,7 +8,7 @@
 // </auto-generated>
 //------------------------------------------------------------------------------
 
-namespace Timeline.Resources.Services {
+namespace Timeline.Resources.Controllers {
     using System;
     
     
@@ -22,14 +22,14 @@ namespace Timeline.Resources.Services {
     [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "16.0.0.0")]
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
-    internal class UserDetailService {
+    internal class ControllerAuthExtensions {
         
         private static global::System.Resources.ResourceManager resourceMan;
         
         private static global::System.Globalization.CultureInfo resourceCulture;
         
         [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
-        internal UserDetailService() {
+        internal ControllerAuthExtensions() {
         }
         
         /// <summary>
@@ -39,7 +39,7 @@ namespace Timeline.Resources.Services {
         internal static global::System.Resources.ResourceManager ResourceManager {
             get {
                 if (object.ReferenceEquals(resourceMan, null)) {
-                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Timeline.Resources.Services.UserDetailService", typeof(UserDetailService).Assembly);
+                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Timeline.Resources.Controllers.ControllerAuthExtensions", typeof(ControllerAuthExtensions).Assembly);
                     resourceMan = temp;
                 }
                 return resourceMan;
@@ -61,38 +61,20 @@ namespace Timeline.Resources.Services {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Length of nickname can&apos;t be bigger than 10..
+        ///   Looks up a localized string similar to Failed to get user id because User has no NameIdentifier claim..
         /// </summary>
-        internal static string ExceptionNicknameTooLong {
+        internal static string ExceptionNoUserIdentifierClaim {
             get {
-                return ResourceManager.GetString("ExceptionNicknameTooLong", resourceCulture);
+                return ResourceManager.GetString("ExceptionNoUserIdentifierClaim", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to A user_details entity has been created. User id is {0}. Nickname is {1}..
+        ///   Looks up a localized string similar to Failed to get user id because NameIdentifier claim is not a number..
         /// </summary>
-        internal static string LogEntityNicknameCreate {
+        internal static string ExceptionUserIdentifierClaimBadFormat {
             get {
-                return ResourceManager.GetString("LogEntityNicknameCreate", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Nickname of a user_details entity has been updated to a new value. User id is {0}. New value is {1}..
-        /// </summary>
-        internal static string LogEntityNicknameSetNotNull {
-            get {
-                return ResourceManager.GetString("LogEntityNicknameSetNotNull", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Nickname of a user_details entity has been updated to null. User id is {0}..
-        /// </summary>
-        internal static string LogEntityNicknameSetToNull {
-            get {
-                return ResourceManager.GetString("LogEntityNicknameSetToNull", resourceCulture);
+                return ResourceManager.GetString("ExceptionUserIdentifierClaimBadFormat", resourceCulture);
             }
         }
     }
diff --git a/Timeline/Resources/Models/Validation/Validator.zh.resx b/Timeline/Resources/Controllers/ControllerAuthExtensions.resx
index 2f98e7e3..03e6d95a 100644
--- a/Timeline/Resources/Models/Validation/Validator.zh.resx
+++ b/Timeline/Resources/Controllers/ControllerAuthExtensions.resx
@@ -117,13 +117,10 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
-  <data name="ValidatorMessageBadType" xml:space="preserve">
-    <value>值不是类型{0}的实例。</value>
+  <data name="ExceptionNoUserIdentifierClaim" xml:space="preserve">
+    <value>Failed to get user id because User has no NameIdentifier claim.</value>
   </data>
-  <data name="ValidatorMessageNull" xml:space="preserve">
-    <value>值不能为null.</value>
-  </data>
-  <data name="ValidatorMessageSuccess" xml:space="preserve">
-    <value>验证成功。</value>
+  <data name="ExceptionUserIdentifierClaimBadFormat" xml:space="preserve">
+    <value>Failed to get user id because NameIdentifier claim is not a number.</value>
   </data>
 </root>
 \ No newline at end of file
diff --git a/Timeline/Resources/Controllers/TimelineController.Designer.cs b/Timeline/Resources/Controllers/TimelineController.Designer.cs
index 47c43fa2..ae6414e6 100644
--- a/Timeline/Resources/Controllers/TimelineController.Designer.cs
+++ b/Timeline/Resources/Controllers/TimelineController.Designer.cs
@@ -77,59 +77,5 @@ namespace Timeline.Resources.Controllers {
                 return ResourceManager.GetString("LogUnknownTimelineMemberOperationUserException", resourceCulture);
             }
         }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The {0}-st username to do operation {1} on is of bad format..
-        /// </summary>
-        internal static string MessageMemberUsernameBadFormat {
-            get {
-                return ResourceManager.GetString("MessageMemberUsernameBadFormat", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The {0}-st user to do operation {1} on does not exist..
-        /// </summary>
-        internal static string MessageMemberUserNotExist {
-            get {
-                return ResourceManager.GetString("MessageMemberUserNotExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to You have no permission to read posts of the timeline..
-        /// </summary>
-        internal static string MessagePostListGetForbid {
-            get {
-                return ResourceManager.GetString("MessagePostListGetForbid", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to You have no permission to create posts in the timeline..
-        /// </summary>
-        internal static string MessagePostOperationCreateForbid {
-            get {
-                return ResourceManager.GetString("MessagePostOperationCreateForbid", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to You have no permission to delete posts in the timeline..
-        /// </summary>
-        internal static string MessagePostOperationDeleteForbid {
-            get {
-                return ResourceManager.GetString("MessagePostOperationDeleteForbid", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The post to delete does not exist..
-        /// </summary>
-        internal static string MessagePostOperationDeleteNotExist {
-            get {
-                return ResourceManager.GetString("MessagePostOperationDeleteNotExist", resourceCulture);
-            }
-        }
     }
 }
diff --git a/Timeline/Resources/Controllers/TimelineController.resx b/Timeline/Resources/Controllers/TimelineController.resx
index 0cf7e881..4cf3d6fb 100644
--- a/Timeline/Resources/Controllers/TimelineController.resx
+++ b/Timeline/Resources/Controllers/TimelineController.resx
@@ -123,22 +123,4 @@
   <data name="LogUnknownTimelineMemberOperationUserException" xml:space="preserve">
     <value>An unknown TimelineMemberOperationUserException is thrown. Can't recognize its inner exception. It is rethrown.</value>
   </data>
-  <data name="MessageMemberUsernameBadFormat" xml:space="preserve">
-    <value>The {0}-st username to do operation {1} on is of bad format.</value>
-  </data>
-  <data name="MessageMemberUserNotExist" xml:space="preserve">
-    <value>The {0}-st user to do operation {1} on does not exist.</value>
-  </data>
-  <data name="MessagePostListGetForbid" xml:space="preserve">
-    <value>You have no permission to read posts of the timeline.</value>
-  </data>
-  <data name="MessagePostOperationCreateForbid" xml:space="preserve">
-    <value>You have no permission to create posts in the timeline.</value>
-  </data>
-  <data name="MessagePostOperationDeleteForbid" xml:space="preserve">
-    <value>You have no permission to delete posts in the timeline.</value>
-  </data>
-  <data name="MessagePostOperationDeleteNotExist" xml:space="preserve">
-    <value>The post to delete does not exist.</value>
-  </data>
 </root>
 \ No newline at end of file
diff --git a/Timeline/Resources/Controllers/TimelineController.zh.resx b/Timeline/Resources/Controllers/TimelineController.zh.resx
deleted file mode 100644
index 170ab4cd..00000000
--- a/Timeline/Resources/Controllers/TimelineController.zh.resx
+++ /dev/null
@@ -1,138 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<root>
-  <!-- 
-    Microsoft ResX Schema 
-    
-    Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
-    associated with the data types.
-    
-    Example:
-    
-    ... ado.net/XML headers & schema ...
-    <resheader name="resmimetype">text/microsoft-resx</resheader>
-    <resheader name="version">2.0</resheader>
-    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
-    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
-    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
-    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
-    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
-        <value>[base64 mime encoded serialized .NET Framework object]</value>
-    </data>
-    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
-        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
-        <comment>This is a comment</comment>
-    </data>
-                
-    There are any number of "resheader" rows that contain simple 
-    name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
-    mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
-    extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
-    read any of the formats listed below.
-    
-    mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
-            : and then encoded with base64 encoding.
-    
-    mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
-            : and then encoded with base64 encoding.
-
-    mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
-            : using a System.ComponentModel.TypeConverter
-            : and then encoded with base64 encoding.
-    -->
-  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
-    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
-    <xsd:element name="root" msdata:IsDataSet="true">
-      <xsd:complexType>
-        <xsd:choice maxOccurs="unbounded">
-          <xsd:element name="metadata">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" />
-              </xsd:sequence>
-              <xsd:attribute name="name" use="required" type="xsd:string" />
-              <xsd:attribute name="type" type="xsd:string" />
-              <xsd:attribute name="mimetype" type="xsd:string" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="assembly">
-            <xsd:complexType>
-              <xsd:attribute name="alias" type="xsd:string" />
-              <xsd:attribute name="name" type="xsd:string" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="data">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
-              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
-              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="resheader">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" />
-            </xsd:complexType>
-          </xsd:element>
-        </xsd:choice>
-      </xsd:complexType>
-    </xsd:element>
-  </xsd:schema>
-  <resheader name="resmimetype">
-    <value>text/microsoft-resx</value>
-  </resheader>
-  <resheader name="version">
-    <value>2.0</value>
-  </resheader>
-  <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <data name="MessageMemberUsernameBadFormat" xml:space="preserve">
-    <value>第{0}个做{1}操作的用户名格式错误。</value>
-  </data>
-  <data name="MessageMemberUserNotExist" xml:space="preserve">
-    <value>第{0}个做{1}操作的用户不存在。</value>
-  </data>
-  <data name="MessagePostListGetForbid" xml:space="preserve">
-    <value>你没有权限读取这个时间线消息。</value>
-  </data>
-  <data name="MessagePostOperationCreateForbid" xml:space="preserve">
-    <value>你没有权限在这个时间线中创建消息。</value>
-  </data>
-  <data name="MessagePostOperationDeleteForbid" xml:space="preserve">
-    <value>你没有权限在这个时间线中删除消息。</value>
-  </data>
-  <data name="MessagePostOperationDeleteNotExist" xml:space="preserve">
-    <value>要删除的消息不存在。</value>
-  </data>
-</root>
-\ No newline at end of file
diff --git a/Timeline/Resources/Controllers/TokenController.Designer.cs b/Timeline/Resources/Controllers/TokenController.Designer.cs
index 22e6a8be..a7c2864b 100644
--- a/Timeline/Resources/Controllers/TokenController.Designer.cs
+++ b/Timeline/Resources/Controllers/TokenController.Designer.cs
@@ -61,51 +61,6 @@ namespace Timeline.Resources.Controllers {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Username or password is invalid..
-        /// </summary>
-        internal static string ErrorBadCredential {
-            get {
-                return ResourceManager.GetString("ErrorBadCredential", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The token is of bad format. It might not be created by the server..
-        /// </summary>
-        internal static string ErrorVerifyBadFormat {
-            get {
-                return ResourceManager.GetString("ErrorVerifyBadFormat", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The token is expired..
-        /// </summary>
-        internal static string ErrorVerifyExpire {
-            get {
-                return ResourceManager.GetString("ErrorVerifyExpire", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Token has an old version. User might have update some info..
-        /// </summary>
-        internal static string ErrorVerifyOldVersion {
-            get {
-                return ResourceManager.GetString("ErrorVerifyOldVersion", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to User does not exist. Administrator might have deleted this user..
-        /// </summary>
-        internal static string ErrorVerifyUserNotExist {
-            get {
-                return ResourceManager.GetString("ErrorVerifyUserNotExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
         ///   Looks up a localized string similar to The password is wrong..
         /// </summary>
         internal static string LogBadPassword {
diff --git a/Timeline/Resources/Controllers/TokenController.resx b/Timeline/Resources/Controllers/TokenController.resx
index 42e1ff92..683d6cc9 100644
--- a/Timeline/Resources/Controllers/TokenController.resx
+++ b/Timeline/Resources/Controllers/TokenController.resx
@@ -117,21 +117,6 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
-  <data name="ErrorBadCredential" xml:space="preserve">
-    <value>Username or password is invalid.</value>
-  </data>
-  <data name="ErrorVerifyBadFormat" xml:space="preserve">
-    <value>The token is of bad format. It might not be created by the server.</value>
-  </data>
-  <data name="ErrorVerifyExpire" xml:space="preserve">
-    <value>The token is expired.</value>
-  </data>
-  <data name="ErrorVerifyOldVersion" xml:space="preserve">
-    <value>Token has an old version. User might have update some info.</value>
-  </data>
-  <data name="ErrorVerifyUserNotExist" xml:space="preserve">
-    <value>User does not exist. Administrator might have deleted this user.</value>
-  </data>
   <data name="LogBadPassword" xml:space="preserve">
     <value>The password is wrong.</value>
   </data>
diff --git a/Timeline/Resources/Controllers/TokenController.zh.resx b/Timeline/Resources/Controllers/TokenController.zh.resx
deleted file mode 100644
index 51e0f25b..00000000
--- a/Timeline/Resources/Controllers/TokenController.zh.resx
+++ /dev/null
@@ -1,135 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<root>
-  <!-- 
-    Microsoft ResX Schema 
-    
-    Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
-    associated with the data types.
-    
-    Example:
-    
-    ... ado.net/XML headers & schema ...
-    <resheader name="resmimetype">text/microsoft-resx</resheader>
-    <resheader name="version">2.0</resheader>
-    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
-    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
-    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
-    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
-    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
-        <value>[base64 mime encoded serialized .NET Framework object]</value>
-    </data>
-    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
-        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
-        <comment>This is a comment</comment>
-    </data>
-                
-    There are any number of "resheader" rows that contain simple 
-    name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
-    mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
-    extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
-    read any of the formats listed below.
-    
-    mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
-            : and then encoded with base64 encoding.
-    
-    mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
-            : and then encoded with base64 encoding.
-
-    mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
-            : using a System.ComponentModel.TypeConverter
-            : and then encoded with base64 encoding.
-    -->
-  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
-    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
-    <xsd:element name="root" msdata:IsDataSet="true">
-      <xsd:complexType>
-        <xsd:choice maxOccurs="unbounded">
-          <xsd:element name="metadata">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" />
-              </xsd:sequence>
-              <xsd:attribute name="name" use="required" type="xsd:string" />
-              <xsd:attribute name="type" type="xsd:string" />
-              <xsd:attribute name="mimetype" type="xsd:string" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="assembly">
-            <xsd:complexType>
-              <xsd:attribute name="alias" type="xsd:string" />
-              <xsd:attribute name="name" type="xsd:string" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="data">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
-              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
-              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="resheader">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" />
-            </xsd:complexType>
-          </xsd:element>
-        </xsd:choice>
-      </xsd:complexType>
-    </xsd:element>
-  </xsd:schema>
-  <resheader name="resmimetype">
-    <value>text/microsoft-resx</value>
-  </resheader>
-  <resheader name="version">
-    <value>2.0</value>
-  </resheader>
-  <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <data name="ErrorBadCredential" xml:space="preserve">
-    <value>用户名或密码错误。</value>
-  </data>
-  <data name="ErrorVerifyBadFormat" xml:space="preserve">
-    <value>符号格式错误。这个符号可能不是这个服务器创建的。</value>
-  </data>
-  <data name="ErrorVerifyExpire" xml:space="preserve">
-    <value>符号过期了。</value>
-  </data>
-  <data name="ErrorVerifyOldVersion" xml:space="preserve">
-    <value>符号是一个旧版本。用户可能已经更新了信息。</value>
-  </data>
-  <data name="ErrorVerifyUserNotExist" xml:space="preserve">
-    <value>用户不存在。管理员可能已经删除了这个用户。</value>
-  </data>
-</root>
-\ No newline at end of file
diff --git a/Timeline/Resources/Controllers/UserAvatarController.Designer.cs b/Timeline/Resources/Controllers/UserAvatarController.Designer.cs
index 1dacb19f..e6eeb1e8 100644
--- a/Timeline/Resources/Controllers/UserAvatarController.Designer.cs
+++ b/Timeline/Resources/Controllers/UserAvatarController.Designer.cs
@@ -61,78 +61,6 @@ namespace Timeline.Resources.Controllers {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Normal user can&apos;t delete other&apos;s avatar..
-        /// </summary>
-        internal static string ErrorDeleteForbid {
-            get {
-                return ResourceManager.GetString("ErrorDeleteForbid", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to User does not exist..
-        /// </summary>
-        internal static string ErrorDeleteUserNotExist {
-            get {
-                return ResourceManager.GetString("ErrorDeleteUserNotExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to User does not exist..
-        /// </summary>
-        internal static string ErrorGetUserNotExist {
-            get {
-                return ResourceManager.GetString("ErrorGetUserNotExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Image is not a square..
-        /// </summary>
-        internal static string ErrorPutBadFormatBadSize {
-            get {
-                return ResourceManager.GetString("ErrorPutBadFormatBadSize", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Decoding image failed..
-        /// </summary>
-        internal static string ErrorPutBadFormatCantDecode {
-            get {
-                return ResourceManager.GetString("ErrorPutBadFormatCantDecode", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Image format is not the one in header..
-        /// </summary>
-        internal static string ErrorPutBadFormatUnmatchedFormat {
-            get {
-                return ResourceManager.GetString("ErrorPutBadFormatUnmatchedFormat", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Normal user can&apos;t change other&apos;s avatar..
-        /// </summary>
-        internal static string ErrorPutForbid {
-            get {
-                return ResourceManager.GetString("ErrorPutForbid", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to User does not exist..
-        /// </summary>
-        internal static string ErrorPutUserNotExist {
-            get {
-                return ResourceManager.GetString("ErrorPutUserNotExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
         ///   Looks up a localized string similar to Unknown AvatarDataException.ErrorReason value..
         /// </summary>
         internal static string ExceptionUnknownAvatarFormatError {
diff --git a/Timeline/Resources/Controllers/UserAvatarController.resx b/Timeline/Resources/Controllers/UserAvatarController.resx
index 3f444b04..58860c83 100644
--- a/Timeline/Resources/Controllers/UserAvatarController.resx
+++ b/Timeline/Resources/Controllers/UserAvatarController.resx
@@ -117,30 +117,6 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
-  <data name="ErrorDeleteForbid" xml:space="preserve">
-    <value>Normal user can't delete other's avatar.</value>
-  </data>
-  <data name="ErrorDeleteUserNotExist" xml:space="preserve">
-    <value>User does not exist.</value>
-  </data>
-  <data name="ErrorGetUserNotExist" xml:space="preserve">
-    <value>User does not exist.</value>
-  </data>
-  <data name="ErrorPutBadFormatBadSize" xml:space="preserve">
-    <value>Image is not a square.</value>
-  </data>
-  <data name="ErrorPutBadFormatCantDecode" xml:space="preserve">
-    <value>Decoding image failed.</value>
-  </data>
-  <data name="ErrorPutBadFormatUnmatchedFormat" xml:space="preserve">
-    <value>Image format is not the one in header.</value>
-  </data>
-  <data name="ErrorPutForbid" xml:space="preserve">
-    <value>Normal user can't change other's avatar.</value>
-  </data>
-  <data name="ErrorPutUserNotExist" xml:space="preserve">
-    <value>User does not exist.</value>
-  </data>
   <data name="ExceptionUnknownAvatarFormatError" xml:space="preserve">
     <value>Unknown AvatarDataException.ErrorReason value.</value>
   </data>
diff --git a/Timeline/Resources/Controllers/UserAvatarController.zh.resx b/Timeline/Resources/Controllers/UserAvatarController.zh.resx
deleted file mode 100644
index 94de1606..00000000
--- a/Timeline/Resources/Controllers/UserAvatarController.zh.resx
+++ /dev/null
@@ -1,144 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<root>
-  <!-- 
-    Microsoft ResX Schema 
-    
-    Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
-    associated with the data types.
-    
-    Example:
-    
-    ... ado.net/XML headers & schema ...
-    <resheader name="resmimetype">text/microsoft-resx</resheader>
-    <resheader name="version">2.0</resheader>
-    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
-    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
-    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
-    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
-    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
-        <value>[base64 mime encoded serialized .NET Framework object]</value>
-    </data>
-    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
-        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
-        <comment>This is a comment</comment>
-    </data>
-                
-    There are any number of "resheader" rows that contain simple 
-    name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
-    mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
-    extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
-    read any of the formats listed below.
-    
-    mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
-            : and then encoded with base64 encoding.
-    
-    mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
-            : and then encoded with base64 encoding.
-
-    mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
-            : using a System.ComponentModel.TypeConverter
-            : and then encoded with base64 encoding.
-    -->
-  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
-    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
-    <xsd:element name="root" msdata:IsDataSet="true">
-      <xsd:complexType>
-        <xsd:choice maxOccurs="unbounded">
-          <xsd:element name="metadata">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" />
-              </xsd:sequence>
-              <xsd:attribute name="name" use="required" type="xsd:string" />
-              <xsd:attribute name="type" type="xsd:string" />
-              <xsd:attribute name="mimetype" type="xsd:string" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="assembly">
-            <xsd:complexType>
-              <xsd:attribute name="alias" type="xsd:string" />
-              <xsd:attribute name="name" type="xsd:string" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="data">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
-              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
-              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="resheader">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" />
-            </xsd:complexType>
-          </xsd:element>
-        </xsd:choice>
-      </xsd:complexType>
-    </xsd:element>
-  </xsd:schema>
-  <resheader name="resmimetype">
-    <value>text/microsoft-resx</value>
-  </resheader>
-  <resheader name="version">
-    <value>2.0</value>
-  </resheader>
-  <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <data name="ErrorDeleteForbid" xml:space="preserve">
-    <value>普通用户不能删除其他用户的头像。</value>
-  </data>
-  <data name="ErrorDeleteUserNotExist" xml:space="preserve">
-    <value>用户不存在。</value>
-  </data>
-  <data name="ErrorGetUserNotExist" xml:space="preserve">
-    <value>用户不存在。</value>
-  </data>
-  <data name="ErrorPutBadFormatBadSize" xml:space="preserve">
-    <value>图片不是正方形。</value>
-  </data>
-  <data name="ErrorPutBadFormatCantDecode" xml:space="preserve">
-    <value>解码图片失败。</value>
-  </data>
-  <data name="ErrorPutBadFormatUnmatchedFormat" xml:space="preserve">
-    <value>图片格式与请求头中指示的不一样。</value>
-  </data>
-  <data name="ErrorPutForbid" xml:space="preserve">
-    <value>普通用户不能修改其他用户的头像。</value>
-  </data>
-  <data name="ErrorPutUserNotExist" xml:space="preserve">
-    <value>用户不存在。</value>
-  </data>
-</root>
-\ No newline at end of file
diff --git a/Timeline/Resources/Controllers/UserController.Designer.cs b/Timeline/Resources/Controllers/UserController.Designer.cs
index 0c9ac0d7..c8067614 100644
--- a/Timeline/Resources/Controllers/UserController.Designer.cs
+++ b/Timeline/Resources/Controllers/UserController.Designer.cs
@@ -61,56 +61,11 @@ namespace Timeline.Resources.Controllers {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Old password is wrong..
+        ///   Looks up a localized string similar to Unknown PutResult..
         /// </summary>
-        internal static string ErrorChangePasswordBadPassword {
+        internal static string ExceptionUnknownPutResult {
             get {
-                return ResourceManager.GetString("ErrorChangePasswordBadPassword", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The new username {0} already exists..
-        /// </summary>
-        internal static string ErrorChangeUsernameAlreadyExist {
-            get {
-                return ResourceManager.GetString("ErrorChangeUsernameAlreadyExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The old username {0} does not exist..
-        /// </summary>
-        internal static string ErrorChangeUsernameNotExist {
-            get {
-                return ResourceManager.GetString("ErrorChangeUsernameNotExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The user does not exist..
-        /// </summary>
-        internal static string ErrorGetUserNotExist {
-            get {
-                return ResourceManager.GetString("ErrorGetUserNotExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Can&apos;t patch a user that does not exist..
-        /// </summary>
-        internal static string ErrorPatchUserNotExist {
-            get {
-                return ResourceManager.GetString("ErrorPatchUserNotExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Username is of bad format..
-        /// </summary>
-        internal static string ErrorPutBadUsername {
-            get {
-                return ResourceManager.GetString("ErrorPutBadUsername", resourceCulture);
+                return ResourceManager.GetString("ExceptionUnknownPutResult", resourceCulture);
             }
         }
         
@@ -124,20 +79,11 @@ namespace Timeline.Resources.Controllers {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to A user has changed password..
-        /// </summary>
-        internal static string LogChangePasswordSuccess {
-            get {
-                return ResourceManager.GetString("LogChangePasswordSuccess", resourceCulture);
-            }
-        }
-        
-        /// <summary>
         ///   Looks up a localized string similar to Attempt to change a user&apos;s username to a existent one failed..
         /// </summary>
-        internal static string LogChangeUsernameAlreadyExist {
+        internal static string LogChangeUsernameConflict {
             get {
-                return ResourceManager.GetString("LogChangeUsernameAlreadyExist", resourceCulture);
+                return ResourceManager.GetString("LogChangeUsernameConflict", resourceCulture);
             }
         }
         
@@ -151,33 +97,6 @@ namespace Timeline.Resources.Controllers {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to A user has changed username..
-        /// </summary>
-        internal static string LogChangeUsernameSuccess {
-            get {
-                return ResourceManager.GetString("LogChangeUsernameSuccess", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to A user has been deleted..
-        /// </summary>
-        internal static string LogDeleteDelete {
-            get {
-                return ResourceManager.GetString("LogDeleteDelete", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Attempt to delete a user that does not exist..
-        /// </summary>
-        internal static string LogDeleteNotExist {
-            get {
-                return ResourceManager.GetString("LogDeleteNotExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
         ///   Looks up a localized string similar to Attempt to retrieve info of a user that does not exist failed..
         /// </summary>
         internal static string LogGetUserNotExist {
@@ -194,32 +113,5 @@ namespace Timeline.Resources.Controllers {
                 return ResourceManager.GetString("LogPatchUserNotExist", resourceCulture);
             }
         }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Attempt to create a user with bad username failed..
-        /// </summary>
-        internal static string LogPutBadUsername {
-            get {
-                return ResourceManager.GetString("LogPutBadUsername", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to A user has been created..
-        /// </summary>
-        internal static string LogPutCreate {
-            get {
-                return ResourceManager.GetString("LogPutCreate", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to A user has been modified..
-        /// </summary>
-        internal static string LogPutModify {
-            get {
-                return ResourceManager.GetString("LogPutModify", resourceCulture);
-            }
-        }
     }
 }
diff --git a/Timeline/Resources/Controllers/UserController.resx b/Timeline/Resources/Controllers/UserController.resx
index 50aa13d6..0bdf4845 100644
--- a/Timeline/Resources/Controllers/UserController.resx
+++ b/Timeline/Resources/Controllers/UserController.resx
@@ -117,58 +117,22 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
-  <data name="ErrorChangePasswordBadPassword" xml:space="preserve">
-    <value>Old password is wrong.</value>
-  </data>
-  <data name="ErrorChangeUsernameAlreadyExist" xml:space="preserve">
-    <value>The new username {0} already exists.</value>
-  </data>
-  <data name="ErrorChangeUsernameNotExist" xml:space="preserve">
-    <value>The old username {0} does not exist.</value>
-  </data>
-  <data name="ErrorGetUserNotExist" xml:space="preserve">
-    <value>The user does not exist.</value>
-  </data>
-  <data name="ErrorPatchUserNotExist" xml:space="preserve">
-    <value>Can't patch a user that does not exist.</value>
-  </data>
-  <data name="ErrorPutBadUsername" xml:space="preserve">
-    <value>Username is of bad format.</value>
+  <data name="ExceptionUnknownPutResult" xml:space="preserve">
+    <value>Unknown PutResult.</value>
   </data>
   <data name="LogChangePasswordBadPassword" xml:space="preserve">
     <value>Attempt to change password with wrong old password failed.</value>
   </data>
-  <data name="LogChangePasswordSuccess" xml:space="preserve">
-    <value>A user has changed password.</value>
-  </data>
-  <data name="LogChangeUsernameAlreadyExist" xml:space="preserve">
+  <data name="LogChangeUsernameConflict" xml:space="preserve">
     <value>Attempt to change a user's username to a existent one failed.</value>
   </data>
   <data name="LogChangeUsernameNotExist" xml:space="preserve">
     <value>Attempt to change a username of a user that does not exist failed.</value>
   </data>
-  <data name="LogChangeUsernameSuccess" xml:space="preserve">
-    <value>A user has changed username.</value>
-  </data>
-  <data name="LogDeleteDelete" xml:space="preserve">
-    <value>A user has been deleted.</value>
-  </data>
-  <data name="LogDeleteNotExist" xml:space="preserve">
-    <value>Attempt to delete a user that does not exist.</value>
-  </data>
   <data name="LogGetUserNotExist" xml:space="preserve">
     <value>Attempt to retrieve info of a user that does not exist failed.</value>
   </data>
   <data name="LogPatchUserNotExist" xml:space="preserve">
     <value>Attempt to patch a user that does not exist failed.</value>
   </data>
-  <data name="LogPutBadUsername" xml:space="preserve">
-    <value>Attempt to create a user with bad username failed.</value>
-  </data>
-  <data name="LogPutCreate" xml:space="preserve">
-    <value>A user has been created.</value>
-  </data>
-  <data name="LogPutModify" xml:space="preserve">
-    <value>A user has been modified.</value>
-  </data>
 </root>
 \ No newline at end of file
diff --git a/Timeline/Resources/Controllers/UserController.zh.resx b/Timeline/Resources/Controllers/UserController.zh.resx
deleted file mode 100644
index 3556083e..00000000
--- a/Timeline/Resources/Controllers/UserController.zh.resx
+++ /dev/null
@@ -1,138 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<root>
-  <!-- 
-    Microsoft ResX Schema 
-    
-    Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
-    associated with the data types.
-    
-    Example:
-    
-    ... ado.net/XML headers & schema ...
-    <resheader name="resmimetype">text/microsoft-resx</resheader>
-    <resheader name="version">2.0</resheader>
-    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
-    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
-    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
-    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
-    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
-        <value>[base64 mime encoded serialized .NET Framework object]</value>
-    </data>
-    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
-        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
-        <comment>This is a comment</comment>
-    </data>
-                
-    There are any number of "resheader" rows that contain simple 
-    name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
-    mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
-    extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
-    read any of the formats listed below.
-    
-    mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
-            : and then encoded with base64 encoding.
-    
-    mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
-            : and then encoded with base64 encoding.
-
-    mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
-            : using a System.ComponentModel.TypeConverter
-            : and then encoded with base64 encoding.
-    -->
-  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
-    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
-    <xsd:element name="root" msdata:IsDataSet="true">
-      <xsd:complexType>
-        <xsd:choice maxOccurs="unbounded">
-          <xsd:element name="metadata">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" />
-              </xsd:sequence>
-              <xsd:attribute name="name" use="required" type="xsd:string" />
-              <xsd:attribute name="type" type="xsd:string" />
-              <xsd:attribute name="mimetype" type="xsd:string" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="assembly">
-            <xsd:complexType>
-              <xsd:attribute name="alias" type="xsd:string" />
-              <xsd:attribute name="name" type="xsd:string" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="data">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
-              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
-              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="resheader">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" />
-            </xsd:complexType>
-          </xsd:element>
-        </xsd:choice>
-      </xsd:complexType>
-    </xsd:element>
-  </xsd:schema>
-  <resheader name="resmimetype">
-    <value>text/microsoft-resx</value>
-  </resheader>
-  <resheader name="version">
-    <value>2.0</value>
-  </resheader>
-  <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <data name="ErrorChangePasswordBadPassword" xml:space="preserve">
-    <value>旧密码错误。</value>
-  </data>
-  <data name="ErrorChangeUsernameAlreadyExist" xml:space="preserve">
-    <value>新用户名{0}已经存在。</value>
-  </data>
-  <data name="ErrorChangeUsernameNotExist" xml:space="preserve">
-    <value>旧用户名{0}不存在。</value>
-  </data>
-  <data name="ErrorGetUserNotExist" xml:space="preserve">
-    <value>用户不存在。</value>
-  </data>
-  <data name="ErrorPatchUserNotExist" xml:space="preserve">
-    <value>不能修改一个不存在的用户。</value>
-  </data>
-  <data name="ErrorPutBadUsername" xml:space="preserve">
-    <value>用户名格式错误。</value>
-  </data>
-</root>
-\ No newline at end of file
diff --git a/Timeline/Resources/Filters.Designer.cs b/Timeline/Resources/Filters.Designer.cs
index 5576190d..dedfe498 100644
--- a/Timeline/Resources/Filters.Designer.cs
+++ b/Timeline/Resources/Filters.Designer.cs
@@ -86,68 +86,5 @@ namespace Timeline.Resources {
                 return ResourceManager.GetString("LogSelfOrAdminUsernameNotString", resourceCulture);
             }
         }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Header Content-Length is missing or of bad format..
-        /// </summary>
-        internal static string MessageHeaderContentLengthMissing {
-            get {
-                return ResourceManager.GetString("MessageHeaderContentLengthMissing", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Header Content-Length must not be 0..
-        /// </summary>
-        internal static string MessageHeaderContentLengthZero {
-            get {
-                return ResourceManager.GetString("MessageHeaderContentLengthZero", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Header Content-Type is required..
-        /// </summary>
-        internal static string MessageHeaderContentTypeMissing {
-            get {
-                return ResourceManager.GetString("MessageHeaderContentTypeMissing", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to You can&apos;t access the resource unless you are the owner or administrator..
-        /// </summary>
-        internal static string MessageSelfOrAdminForbid {
-            get {
-                return ResourceManager.GetString("MessageSelfOrAdminForbid", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The requested timeline does not exist..
-        /// </summary>
-        internal static string MessageTimelineNotExist {
-            get {
-                return ResourceManager.GetString("MessageTimelineNotExist", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The requested personal timeline does not exist because the user does not exist..
-        /// </summary>
-        internal static string MessageTimelineNotExistUser {
-            get {
-                return ResourceManager.GetString("MessageTimelineNotExistUser", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The user does not exist..
-        /// </summary>
-        internal static string MessageUserNotExist {
-            get {
-                return ResourceManager.GetString("MessageUserNotExist", resourceCulture);
-            }
-        }
     }
 }
diff --git a/Timeline/Resources/Filters.resx b/Timeline/Resources/Filters.resx
index 7bfbc703..22620889 100644
--- a/Timeline/Resources/Filters.resx
+++ b/Timeline/Resources/Filters.resx
@@ -126,25 +126,4 @@
   <data name="LogSelfOrAdminUsernameNotString" xml:space="preserve">
     <value>You apply a SelfOrAdminAttribute on an action, found a model named username, but it is not string.</value>
   </data>
-  <data name="MessageHeaderContentLengthMissing" xml:space="preserve">
-    <value>Header Content-Length is missing or of bad format.</value>
-  </data>
-  <data name="MessageHeaderContentLengthZero" xml:space="preserve">
-    <value>Header Content-Length must not be 0.</value>
-  </data>
-  <data name="MessageHeaderContentTypeMissing" xml:space="preserve">
-    <value>Header Content-Type is required.</value>
-  </data>
-  <data name="MessageSelfOrAdminForbid" xml:space="preserve">
-    <value>You can't access the resource unless you are the owner or administrator.</value>
-  </data>
-  <data name="MessageTimelineNotExist" xml:space="preserve">
-    <value>The requested timeline does not exist.</value>
-  </data>
-  <data name="MessageTimelineNotExistUser" xml:space="preserve">
-    <value>The requested personal timeline does not exist because the user does not exist.</value>
-  </data>
-  <data name="MessageUserNotExist" xml:space="preserve">
-    <value>The user does not exist.</value>
-  </data>
 </root>
 \ No newline at end of file
diff --git a/Timeline/Resources/Filters.zh.resx b/Timeline/Resources/Filters.zh.resx
deleted file mode 100644
index 36aac788..00000000
--- a/Timeline/Resources/Filters.zh.resx
+++ /dev/null
@@ -1,141 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<root>
-  <!-- 
-    Microsoft ResX Schema 
-    
-    Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
-    associated with the data types.
-    
-    Example:
-    
-    ... ado.net/XML headers & schema ...
-    <resheader name="resmimetype">text/microsoft-resx</resheader>
-    <resheader name="version">2.0</resheader>
-    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
-    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
-    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
-    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
-    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
-        <value>[base64 mime encoded serialized .NET Framework object]</value>
-    </data>
-    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
-        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
-        <comment>This is a comment</comment>
-    </data>
-                
-    There are any number of "resheader" rows that contain simple 
-    name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
-    mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
-    extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
-    read any of the formats listed below.
-    
-    mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
-            : and then encoded with base64 encoding.
-    
-    mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
-            : and then encoded with base64 encoding.
-
-    mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
-            : using a System.ComponentModel.TypeConverter
-            : and then encoded with base64 encoding.
-    -->
-  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
-    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
-    <xsd:element name="root" msdata:IsDataSet="true">
-      <xsd:complexType>
-        <xsd:choice maxOccurs="unbounded">
-          <xsd:element name="metadata">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" />
-              </xsd:sequence>
-              <xsd:attribute name="name" use="required" type="xsd:string" />
-              <xsd:attribute name="type" type="xsd:string" />
-              <xsd:attribute name="mimetype" type="xsd:string" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="assembly">
-            <xsd:complexType>
-              <xsd:attribute name="alias" type="xsd:string" />
-              <xsd:attribute name="name" type="xsd:string" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="data">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
-              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
-              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="resheader">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" />
-            </xsd:complexType>
-          </xsd:element>
-        </xsd:choice>
-      </xsd:complexType>
-    </xsd:element>
-  </xsd:schema>
-  <resheader name="resmimetype">
-    <value>text/microsoft-resx</value>
-  </resheader>
-  <resheader name="version">
-    <value>2.0</value>
-  </resheader>
-  <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <data name="MessageHeaderContentLengthMissing" xml:space="preserve">
-    <value>请求头Content-Length缺失或者格式不对。</value>
-  </data>
-  <data name="MessageHeaderContentLengthZero" xml:space="preserve">
-    <value>请求头Content-Length不能为0。</value>
-  </data>
-  <data name="MessageHeaderContentTypeMissing" xml:space="preserve">
-    <value>缺少必需的请求头Content-Type。</value>
-  </data>
-  <data name="MessageSelfOrAdminForbid" xml:space="preserve">
-    <value>你无权访问该资源除非你是资源的拥有者或者管理员。</value>
-  </data>
-  <data name="MessageTimelineNotExist" xml:space="preserve">
-    <value>请求的时间线不存在。</value>
-  </data>
-  <data name="MessageTimelineNotExistUser" xml:space="preserve">
-    <value>请求的个人时间线不存在因为该用户不存在。</value>
-  </data>
-  <data name="MessageUserNotExist" xml:space="preserve">
-    <value>用户不存在。</value>
-  </data>
-</root>
-\ No newline at end of file
diff --git a/Timeline/Resources/Messages.Designer.cs b/Timeline/Resources/Messages.Designer.cs
new file mode 100644
index 00000000..332c8817
--- /dev/null
+++ b/Timeline/Resources/Messages.Designer.cs
@@ -0,0 +1,315 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//     Runtime Version:4.0.30319.42000
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+namespace Timeline.Resources {
+    using System;
+    
+    
+    /// <summary>
+    ///   A strongly-typed resource class, for looking up localized strings, etc.
+    /// </summary>
+    // This class was auto-generated by the StronglyTypedResourceBuilder
+    // class via a tool like ResGen or Visual Studio.
+    // To add or remove a member, edit your .ResX file then rerun ResGen
+    // with the /str option, or rebuild your VS project.
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "16.0.0.0")]
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+    [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
+    internal class Messages {
+        
+        private static global::System.Resources.ResourceManager resourceMan;
+        
+        private static global::System.Globalization.CultureInfo resourceCulture;
+        
+        [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
+        internal Messages() {
+        }
+        
+        /// <summary>
+        ///   Returns the cached ResourceManager instance used by this class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Resources.ResourceManager ResourceManager {
+            get {
+                if (object.ReferenceEquals(resourceMan, null)) {
+                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Timeline.Resources.Messages", typeof(Messages).Assembly);
+                    resourceMan = temp;
+                }
+                return resourceMan;
+            }
+        }
+        
+        /// <summary>
+        ///   Overrides the current thread's CurrentUICulture property for all
+        ///   resource lookups using this strongly typed resource class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Globalization.CultureInfo Culture {
+            get {
+                return resourceCulture;
+            }
+            set {
+                resourceCulture = value;
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Body is too big. It can&apos;t be bigger than {0}..
+        /// </summary>
+        internal static string Common_Content_TooBig {
+            get {
+                return ResourceManager.GetString("Common_Content_TooBig", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Actual body length is bigger than it in header..
+        /// </summary>
+        internal static string Common_Content_UnmatchedLength_Bigger {
+            get {
+                return ResourceManager.GetString("Common_Content_UnmatchedLength_Bigger", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Actual body length is smaller than it in header..
+        /// </summary>
+        internal static string Common_Content_UnmatchedLength_Smaller {
+            get {
+                return ResourceManager.GetString("Common_Content_UnmatchedLength_Smaller", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to You have no permission to do the operation..
+        /// </summary>
+        internal static string Common_Forbid {
+            get {
+                return ResourceManager.GetString("Common_Forbid", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to You are not the resource owner..
+        /// </summary>
+        internal static string Common_Forbid_NotSelf {
+            get {
+                return ResourceManager.GetString("Common_Forbid_NotSelf", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Header Content-Length is missing or of bad format..
+        /// </summary>
+        internal static string Common_Header_ContentLength_Missing {
+            get {
+                return ResourceManager.GetString("Common_Header_ContentLength_Missing", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Header Content-Length must not be 0..
+        /// </summary>
+        internal static string Common_Header_ContentLength_Zero {
+            get {
+                return ResourceManager.GetString("Common_Header_ContentLength_Zero", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Header Content-Type is missing..
+        /// </summary>
+        internal static string Common_Header_ContentType_Missing {
+            get {
+                return ResourceManager.GetString("Common_Header_ContentType_Missing", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Header If-Non-Match is of bad format..
+        /// </summary>
+        internal static string Common_Header_IfNonMatch_BadFormat {
+            get {
+                return ResourceManager.GetString("Common_Header_IfNonMatch_BadFormat", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Model is of bad format..
+        /// </summary>
+        internal static string Common_InvalidModel {
+            get {
+                return ResourceManager.GetString("Common_InvalidModel", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The {0}-st username to do operation {1} on is of bad format..
+        /// </summary>
+        internal static string TimelineController_ChangeMember_UsernameBadFormat {
+            get {
+                return ResourceManager.GetString("TimelineController_ChangeMember_UsernameBadFormat", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The {0}-st user to do operation {1} on does not exist..
+        /// </summary>
+        internal static string TimelineController_ChangeMember_UserNotExist {
+            get {
+                return ResourceManager.GetString("TimelineController_ChangeMember_UserNotExist", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The user to set as member does not exist..
+        /// </summary>
+        internal static string TimelineController_MemberPut_NotExist {
+            get {
+                return ResourceManager.GetString("TimelineController_MemberPut_NotExist", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The post to delete does not exist..
+        /// </summary>
+        internal static string TimelineController_PostOperationDelete_NotExist {
+            get {
+                return ResourceManager.GetString("TimelineController_PostOperationDelete_NotExist", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Username or password is invalid..
+        /// </summary>
+        internal static string TokenController_Create_BadCredential {
+            get {
+                return ResourceManager.GetString("TokenController_Create_BadCredential", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The token is of bad format. It might not be created by the server..
+        /// </summary>
+        internal static string TokenController_Verify_BadFormat {
+            get {
+                return ResourceManager.GetString("TokenController_Verify_BadFormat", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Token has an old version. User might have update some info..
+        /// </summary>
+        internal static string TokenController_Verify_OldVersion {
+            get {
+                return ResourceManager.GetString("TokenController_Verify_OldVersion", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The token is expired..
+        /// </summary>
+        internal static string TokenController_Verify_TimeExpired {
+            get {
+                return ResourceManager.GetString("TokenController_Verify_TimeExpired", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to User does not exist. Administrator might have deleted this user..
+        /// </summary>
+        internal static string TokenController_Verify_UserNotExist {
+            get {
+                return ResourceManager.GetString("TokenController_Verify_UserNotExist", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Image is not a square..
+        /// </summary>
+        internal static string UserAvatar_BadFormat_BadSize {
+            get {
+                return ResourceManager.GetString("UserAvatar_BadFormat_BadSize", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Image decode failed..
+        /// </summary>
+        internal static string UserAvatar_BadFormat_CantDecode {
+            get {
+                return ResourceManager.GetString("UserAvatar_BadFormat_CantDecode", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Image format does not match the one in header..
+        /// </summary>
+        internal static string UserAvatar_BadFormat_UnmatchedFormat {
+            get {
+                return ResourceManager.GetString("UserAvatar_BadFormat_UnmatchedFormat", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The user to operate on does not exist..
+        /// </summary>
+        internal static string UserCommon_NotExist {
+            get {
+                return ResourceManager.GetString("UserCommon_NotExist", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Old password is wrong..
+        /// </summary>
+        internal static string UserController_ChangePassword_BadOldPassword {
+            get {
+                return ResourceManager.GetString("UserController_ChangePassword_BadOldPassword", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to You can&apos;t set permission unless you are administrator..
+        /// </summary>
+        internal static string UserController_Patch_Forbid_Administrator {
+            get {
+                return ResourceManager.GetString("UserController_Patch_Forbid_Administrator", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to You can&apos;t set password unless you are administrator. If you want to change password, use /userop/changepassword ..
+        /// </summary>
+        internal static string UserController_Patch_Forbid_Password {
+            get {
+                return ResourceManager.GetString("UserController_Patch_Forbid_Password", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to You can&apos;t set username unless you are administrator..
+        /// </summary>
+        internal static string UserController_Patch_Forbid_Username {
+            get {
+                return ResourceManager.GetString("UserController_Patch_Forbid_Username", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to A user with given username already exists..
+        /// </summary>
+        internal static string UserController_UsernameConflict {
+            get {
+                return ResourceManager.GetString("UserController_UsernameConflict", resourceCulture);
+            }
+        }
+    }
+}
diff --git a/Timeline/Resources/Models/Http/Common.zh.resx b/Timeline/Resources/Messages.resx
index 467916a2..cb6c3891 100644
--- a/Timeline/Resources/Models/Http/Common.zh.resx
+++ b/Timeline/Resources/Messages.resx
@@ -117,28 +117,88 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
-  <data name="MessageContentTooBig" xml:space="preserve">
-    <value>请求体太大。它不能超过{0}.</value>
+  <data name="Common_Content_TooBig" xml:space="preserve">
+    <value>Body is too big. It can't be bigger than {0}.</value>
   </data>
-  <data name="MessageContentUnmatchedLengthBigger" xml:space="preserve">
-    <value>实际的请求体长度比头中指示的大。</value>
+  <data name="Common_Content_UnmatchedLength_Bigger" xml:space="preserve">
+    <value>Actual body length is bigger than it in header.</value>
   </data>
-  <data name="MessageContentUnmatchedLengthSmaller" xml:space="preserve">
-    <value>实际的请求体长度比头中指示的小。</value>
+  <data name="Common_Content_UnmatchedLength_Smaller" xml:space="preserve">
+    <value>Actual body length is smaller than it in header.</value>
   </data>
-  <data name="MessageDeleteDelete" xml:space="preserve">
-    <value>删除了一个项目。</value>
+  <data name="Common_Forbid" xml:space="preserve">
+    <value>You have no permission to do the operation.</value>
   </data>
-  <data name="MessageDeleteNotExist" xml:space="preserve">
-    <value>要删除的项目不存在，什么都没有修改。</value>
+  <data name="Common_Forbid_NotSelf" xml:space="preserve">
+    <value>You are not the resource owner.</value>
   </data>
-  <data name="MessageHeaderIfNonMatchBad" xml:space="preserve">
-    <value>请求头If-Non-Match格式不对。</value>
+  <data name="Common_Header_ContentLength_Missing" xml:space="preserve">
+    <value>Header Content-Length is missing or of bad format.</value>
   </data>
-  <data name="MessagePutCreate" xml:space="preserve">
-    <value>创建了一个新项目。</value>
+  <data name="Common_Header_ContentLength_Zero" xml:space="preserve">
+    <value>Header Content-Length must not be 0.</value>
   </data>
-  <data name="MessagePutModify" xml:space="preserve">
-    <value>修改了一个已存在的项目。</value>
+  <data name="Common_Header_ContentType_Missing" xml:space="preserve">
+    <value>Header Content-Type is missing.</value>
+  </data>
+  <data name="Common_Header_IfNonMatch_BadFormat" xml:space="preserve">
+    <value>Header If-Non-Match is of bad format.</value>
+  </data>
+  <data name="Common_InvalidModel" xml:space="preserve">
+    <value>Model is of bad format.</value>
+  </data>
+  <data name="TimelineController_ChangeMember_UsernameBadFormat" xml:space="preserve">
+    <value>The {0}-st username to do operation {1} on is of bad format.</value>
+  </data>
+  <data name="TimelineController_ChangeMember_UserNotExist" xml:space="preserve">
+    <value>The {0}-st user to do operation {1} on does not exist.</value>
+  </data>
+  <data name="TimelineController_MemberPut_NotExist" xml:space="preserve">
+    <value>The user to set as member does not exist.</value>
+  </data>
+  <data name="TimelineController_PostOperationDelete_NotExist" xml:space="preserve">
+    <value>The post to delete does not exist.</value>
+  </data>
+  <data name="TokenController_Create_BadCredential" xml:space="preserve">
+    <value>Username or password is invalid.</value>
+  </data>
+  <data name="TokenController_Verify_BadFormat" xml:space="preserve">
+    <value>The token is of bad format. It might not be created by the server.</value>
+  </data>
+  <data name="TokenController_Verify_OldVersion" xml:space="preserve">
+    <value>Token has an old version. User might have update some info.</value>
+  </data>
+  <data name="TokenController_Verify_TimeExpired" xml:space="preserve">
+    <value>The token is expired.</value>
+  </data>
+  <data name="TokenController_Verify_UserNotExist" xml:space="preserve">
+    <value>User does not exist. Administrator might have deleted this user.</value>
+  </data>
+  <data name="UserAvatar_BadFormat_BadSize" xml:space="preserve">
+    <value>Image is not a square.</value>
+  </data>
+  <data name="UserAvatar_BadFormat_CantDecode" xml:space="preserve">
+    <value>Image decode failed.</value>
+  </data>
+  <data name="UserAvatar_BadFormat_UnmatchedFormat" xml:space="preserve">
+    <value>Image format does not match the one in header.</value>
+  </data>
+  <data name="UserCommon_NotExist" xml:space="preserve">
+    <value>The user to operate on does not exist.</value>
+  </data>
+  <data name="UserController_ChangePassword_BadOldPassword" xml:space="preserve">
+    <value>Old password is wrong.</value>
+  </data>
+  <data name="UserController_Patch_Forbid_Administrator" xml:space="preserve">
+    <value>You can't set permission unless you are administrator.</value>
+  </data>
+  <data name="UserController_Patch_Forbid_Password" xml:space="preserve">
+    <value>You can't set password unless you are administrator. If you want to change password, use /userop/changepassword .</value>
+  </data>
+  <data name="UserController_Patch_Forbid_Username" xml:space="preserve">
+    <value>You can't set username unless you are administrator.</value>
+  </data>
+  <data name="UserController_UsernameConflict" xml:space="preserve">
+    <value>A user with given username already exists.</value>
   </data>
 </root>
 \ No newline at end of file
diff --git a/Timeline/Resources/Models/Http/Common.Designer.cs b/Timeline/Resources/Models/Http/Common.Designer.cs
index 4eebd2bc..5165463e 100644
--- a/Timeline/Resources/Models/Http/Common.Designer.cs
+++ b/Timeline/Resources/Models/Http/Common.Designer.cs
@@ -61,33 +61,6 @@ namespace Timeline.Resources.Models.Http {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Body is too big. It can&apos;t be bigger than {0}..
-        /// </summary>
-        internal static string MessageContentTooBig {
-            get {
-                return ResourceManager.GetString("MessageContentTooBig", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Actual body length is bigger than it in header..
-        /// </summary>
-        internal static string MessageContentUnmatchedLengthBigger {
-            get {
-                return ResourceManager.GetString("MessageContentUnmatchedLengthBigger", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to Actual body length is smaller than it in header..
-        /// </summary>
-        internal static string MessageContentUnmatchedLengthSmaller {
-            get {
-                return ResourceManager.GetString("MessageContentUnmatchedLengthSmaller", resourceCulture);
-            }
-        }
-        
-        /// <summary>
         ///   Looks up a localized string similar to An existent item is deleted..
         /// </summary>
         internal static string MessageDeleteDelete {
@@ -106,15 +79,6 @@ namespace Timeline.Resources.Models.Http {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Header If-Non-Match is of bad format..
-        /// </summary>
-        internal static string MessageHeaderIfNonMatchBad {
-            get {
-                return ResourceManager.GetString("MessageHeaderIfNonMatchBad", resourceCulture);
-            }
-        }
-        
-        /// <summary>
         ///   Looks up a localized string similar to A new item is created..
         /// </summary>
         internal static string MessagePutCreate {
diff --git a/Timeline/Resources/Models/Http/Common.resx b/Timeline/Resources/Models/Http/Common.resx
index 540c6c58..85ec4d32 100644
--- a/Timeline/Resources/Models/Http/Common.resx
+++ b/Timeline/Resources/Models/Http/Common.resx
@@ -117,24 +117,12 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
-  <data name="MessageContentTooBig" xml:space="preserve">
-    <value>Body is too big. It can't be bigger than {0}.</value>
-  </data>
-  <data name="MessageContentUnmatchedLengthBigger" xml:space="preserve">
-    <value>Actual body length is bigger than it in header.</value>
-  </data>
-  <data name="MessageContentUnmatchedLengthSmaller" xml:space="preserve">
-    <value>Actual body length is smaller than it in header.</value>
-  </data>
   <data name="MessageDeleteDelete" xml:space="preserve">
     <value>An existent item is deleted.</value>
   </data>
   <data name="MessageDeleteNotExist" xml:space="preserve">
     <value>The item does not exist, so nothing is changed.</value>
   </data>
-  <data name="MessageHeaderIfNonMatchBad" xml:space="preserve">
-    <value>Header If-Non-Match is of bad format.</value>
-  </data>
   <data name="MessagePutCreate" xml:space="preserve">
     <value>A new item is created.</value>
   </data>
diff --git a/Timeline/Resources/Common.Designer.cs b/Timeline/Resources/Models/Validation/NicknameValidator.Designer.cs
index 4f1c8e3f..522f305a 100644
--- a/Timeline/Resources/Common.Designer.cs
+++ b/Timeline/Resources/Models/Validation/NicknameValidator.Designer.cs
@@ -8,7 +8,7 @@
 // </auto-generated>
 //------------------------------------------------------------------------------
 
-namespace Timeline.Resources {
+namespace Timeline.Resources.Models.Validation {
     using System;
     
     
@@ -22,14 +22,14 @@ namespace Timeline.Resources {
     [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "16.0.0.0")]
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
-    internal class Common {
+    internal class NicknameValidator {
         
         private static global::System.Resources.ResourceManager resourceMan;
         
         private static global::System.Globalization.CultureInfo resourceCulture;
         
         [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
-        internal Common() {
+        internal NicknameValidator() {
         }
         
         /// <summary>
@@ -39,7 +39,7 @@ namespace Timeline.Resources {
         internal static global::System.Resources.ResourceManager ResourceManager {
             get {
                 if (object.ReferenceEquals(resourceMan, null)) {
-                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Timeline.Resources.Common", typeof(Common).Assembly);
+                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Timeline.Resources.Models.Validation.NicknameValidator", typeof(NicknameValidator).Assembly);
                     resourceMan = temp;
                 }
                 return resourceMan;
@@ -61,11 +61,11 @@ namespace Timeline.Resources {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to The branch is invalid. Normally this branch is not reachable..
+        ///   Looks up a localized string similar to Nickname is too long..
         /// </summary>
-        internal static string ExceptionInvalidBranch {
+        internal static string MessageTooLong {
             get {
-                return ResourceManager.GetString("ExceptionInvalidBranch", resourceCulture);
+                return ResourceManager.GetString("MessageTooLong", resourceCulture);
             }
         }
     }
diff --git a/Timeline/Resources/Controllers/Testing/TestingI18nController.resx b/Timeline/Resources/Models/Validation/NicknameValidator.resx
index 57dfd5b9..b191b505 100644
--- a/Timeline/Resources/Controllers/Testing/TestingI18nController.resx
+++ b/Timeline/Resources/Models/Validation/NicknameValidator.resx
@@ -117,7 +117,7 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
-  <data name="TestString" xml:space="preserve">
-    <value>English test string.</value>
+  <data name="MessageTooLong" xml:space="preserve">
+    <value>Nickname is too long.</value>
   </data>
 </root>
 \ No newline at end of file
diff --git a/Timeline/Resources/Models/Validation/UsernameValidator.zh.resx b/Timeline/Resources/Models/Validation/UsernameValidator.zh.resx
deleted file mode 100644
index 89d519b0..00000000
--- a/Timeline/Resources/Models/Validation/UsernameValidator.zh.resx
+++ /dev/null
@@ -1,129 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<root>
-  <!-- 
-    Microsoft ResX Schema 
-    
-    Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
-    associated with the data types.
-    
-    Example:
-    
-    ... ado.net/XML headers & schema ...
-    <resheader name="resmimetype">text/microsoft-resx</resheader>
-    <resheader name="version">2.0</resheader>
-    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
-    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
-    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
-    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
-    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
-        <value>[base64 mime encoded serialized .NET Framework object]</value>
-    </data>
-    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
-        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
-        <comment>This is a comment</comment>
-    </data>
-                
-    There are any number of "resheader" rows that contain simple 
-    name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
-    mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
-    extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
-    read any of the formats listed below.
-    
-    mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
-            : and then encoded with base64 encoding.
-    
-    mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
-            : and then encoded with base64 encoding.
-
-    mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
-            : using a System.ComponentModel.TypeConverter
-            : and then encoded with base64 encoding.
-    -->
-  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
-    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
-    <xsd:element name="root" msdata:IsDataSet="true">
-      <xsd:complexType>
-        <xsd:choice maxOccurs="unbounded">
-          <xsd:element name="metadata">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" />
-              </xsd:sequence>
-              <xsd:attribute name="name" use="required" type="xsd:string" />
-              <xsd:attribute name="type" type="xsd:string" />
-              <xsd:attribute name="mimetype" type="xsd:string" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="assembly">
-            <xsd:complexType>
-              <xsd:attribute name="alias" type="xsd:string" />
-              <xsd:attribute name="name" type="xsd:string" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="data">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
-              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
-              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="resheader">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" />
-            </xsd:complexType>
-          </xsd:element>
-        </xsd:choice>
-      </xsd:complexType>
-    </xsd:element>
-  </xsd:schema>
-  <resheader name="resmimetype">
-    <value>text/microsoft-resx</value>
-  </resheader>
-  <resheader name="version">
-    <value>2.0</value>
-  </resheader>
-  <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <data name="MessageEmptyString" xml:space="preserve">
-    <value>空字符串是不允许的。</value>
-  </data>
-  <data name="MessageInvalidChar" xml:space="preserve">
-    <value>无效的字符，只能使用字母、数字、下划线和连字符。</value>
-  </data>
-  <data name="MessageTooLong" xml:space="preserve">
-    <value>太长了，不能大于26个字符。</value>
-  </data>
-</root>
-\ No newline at end of file
diff --git a/Timeline/Resources/Services/Exception.Designer.cs b/Timeline/Resources/Services/Exception.Designer.cs
index 1b46f9e9..e6806873 100644
--- a/Timeline/Resources/Services/Exception.Designer.cs
+++ b/Timeline/Resources/Services/Exception.Designer.cs
@@ -115,6 +115,15 @@ namespace Timeline.Resources.Services {
         }
         
         /// <summary>
+        ///   Looks up a localized string similar to A present resource conflicts with the given resource..
+        /// </summary>
+        internal static string ConflictException {
+            get {
+                return ResourceManager.GetString("ConflictException", resourceCulture);
+            }
+        }
+        
+        /// <summary>
         ///   Looks up a localized string similar to The hashes password is of bad format. It might not be created by server..
         /// </summary>
         internal static string HashedPasswordBadFromatException {
@@ -178,128 +187,74 @@ namespace Timeline.Resources.Services {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to The version of the jwt token is old..
-        /// </summary>
-        internal static string JwtBadVersionException {
-            get {
-                return ResourceManager.GetString("JwtBadVersionException", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to The token didn&apos;t pass verification because {0}, see inner exception for information..
-        /// </summary>
-        internal static string JwtVerifyException {
-            get {
-                return ResourceManager.GetString("JwtVerifyException", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to token is expired..
+        ///   Looks up a localized string similar to The token didn&apos;t pass verification because {0}..
         /// </summary>
-        internal static string JwtVerifyExceptionExpired {
+        internal static string JwtUserTokenBadFormatException {
             get {
-                return ResourceManager.GetString("JwtVerifyExceptionExpired", resourceCulture);
+                return ResourceManager.GetString("JwtUserTokenBadFormatException", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to id claim is not a number..
+        ///   Looks up a localized string similar to id claim is not a number.
         /// </summary>
-        internal static string JwtVerifyExceptionIdClaimBadFormat {
+        internal static string JwtUserTokenBadFormatExceptionIdBadFormat {
             get {
-                return ResourceManager.GetString("JwtVerifyExceptionIdClaimBadFormat", resourceCulture);
+                return ResourceManager.GetString("JwtUserTokenBadFormatExceptionIdBadFormat", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to id claim does not exist..
+        ///   Looks up a localized string similar to id claim does not exist.
         /// </summary>
-        internal static string JwtVerifyExceptionNoIdClaim {
+        internal static string JwtUserTokenBadFormatExceptionIdMissing {
             get {
-                return ResourceManager.GetString("JwtVerifyExceptionNoIdClaim", resourceCulture);
+                return ResourceManager.GetString("JwtUserTokenBadFormatExceptionIdMissing", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to version claim does not exist..
+        ///   Looks up a localized string similar to other error, see inner exception for information.
         /// </summary>
-        internal static string JwtVerifyExceptionNoVersionClaim {
+        internal static string JwtUserTokenBadFormatExceptionOthers {
             get {
-                return ResourceManager.GetString("JwtVerifyExceptionNoVersionClaim", resourceCulture);
+                return ResourceManager.GetString("JwtUserTokenBadFormatExceptionOthers", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to version of token is old..
-        /// </summary>
-        internal static string JwtVerifyExceptionOldVersion {
-            get {
-                return ResourceManager.GetString("JwtVerifyExceptionOldVersion", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to uncommon error..
-        /// </summary>
-        internal static string JwtVerifyExceptionOthers {
-            get {
-                return ResourceManager.GetString("JwtVerifyExceptionOthers", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to unknown error code..
+        ///   Looks up a localized string similar to unknown error.
         /// </summary>
-        internal static string JwtVerifyExceptionUnknown {
+        internal static string JwtUserTokenBadFormatExceptionUnknown {
             get {
-                return ResourceManager.GetString("JwtVerifyExceptionUnknown", resourceCulture);
+                return ResourceManager.GetString("JwtUserTokenBadFormatExceptionUnknown", resourceCulture);
             }
         }
         
         /// <summary>
         ///   Looks up a localized string similar to version claim is not a number..
         /// </summary>
-        internal static string JwtVerifyExceptionVersionClaimBadFormat {
+        internal static string JwtUserTokenBadFormatExceptionVersionBadFormat {
             get {
-                return ResourceManager.GetString("JwtVerifyExceptionVersionClaimBadFormat", resourceCulture);
+                return ResourceManager.GetString("JwtUserTokenBadFormatExceptionVersionBadFormat", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to The timeline with that name already exists..
-        /// </summary>
-        internal static string TimelineAlreadyExistException {
-            get {
-                return ResourceManager.GetString("TimelineAlreadyExistException", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to An exception happened when add or remove member on timeline..
-        /// </summary>
-        internal static string TimelineMemberOperationException {
-            get {
-                return ResourceManager.GetString("TimelineMemberOperationException", resourceCulture);
-            }
-        }
-        
-        /// <summary>
-        ///   Looks up a localized string similar to An exception happened when do operation {0} on the {1} member on timeline..
+        ///   Looks up a localized string similar to version claim does not exist..
         /// </summary>
-        internal static string TimelineMemberOperationExceptionDetail {
+        internal static string JwtUserTokenBadFormatExceptionVersionMissing {
             get {
-                return ResourceManager.GetString("TimelineMemberOperationExceptionDetail", resourceCulture);
+                return ResourceManager.GetString("JwtUserTokenBadFormatExceptionVersionMissing", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Timeline name is of bad format. If this is a personal timeline, it means the username is of bad format and inner exception should be a UsernameBadFormatException..
+        ///   Looks up a localized string similar to Password is of bad format..
         /// </summary>
-        internal static string TimelineNameBadFormatException {
+        internal static string PasswordBadFormatException {
             get {
-                return ResourceManager.GetString("TimelineNameBadFormatException", resourceCulture);
+                return ResourceManager.GetString("PasswordBadFormatException", resourceCulture);
             }
         }
         
@@ -322,38 +277,38 @@ namespace Timeline.Resources.Services {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to The use is not a member of the timeline..
+        ///   Looks up a localized string similar to The user does not exist..
         /// </summary>
-        internal static string TimelineUserNotMemberException {
+        internal static string UserNotExistException {
             get {
-                return ResourceManager.GetString("TimelineUserNotMemberException", resourceCulture);
+                return ResourceManager.GetString("UserNotExistException", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to The username is of bad format..
+        ///   Looks up a localized string similar to The token is of bad format, which means it may not be created by the server..
         /// </summary>
-        internal static string UsernameBadFormatException {
+        internal static string UserTokenBadFormatException {
             get {
-                return ResourceManager.GetString("UsernameBadFormatException", resourceCulture);
+                return ResourceManager.GetString("UserTokenBadFormatException", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to The username already exists..
+        ///   Looks up a localized string similar to The token is of bad version..
         /// </summary>
-        internal static string UsernameConfictException {
+        internal static string UserTokenBadVersionException {
             get {
-                return ResourceManager.GetString("UsernameConfictException", resourceCulture);
+                return ResourceManager.GetString("UserTokenBadVersionException", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to The user does not exist..
+        ///   Looks up a localized string similar to The token is expired because its expiration time has passed..
         /// </summary>
-        internal static string UserNotExistException {
+        internal static string UserTokenTimeExpireException {
             get {
-                return ResourceManager.GetString("UserNotExistException", resourceCulture);
+                return ResourceManager.GetString("UserTokenTimeExpireException", resourceCulture);
             }
         }
     }
diff --git a/Timeline/Resources/Services/Exception.resx b/Timeline/Resources/Services/Exception.resx
index 1d9c0037..11ae5f27 100644
--- a/Timeline/Resources/Services/Exception.resx
+++ b/Timeline/Resources/Services/Exception.resx
@@ -135,6 +135,9 @@
   <data name="BadPasswordException" xml:space="preserve">
     <value>The password is wrong.</value>
   </data>
+  <data name="ConflictException" xml:space="preserve">
+    <value>A present resource conflicts with the given resource.</value>
+  </data>
   <data name="HashedPasswordBadFromatException" xml:space="preserve">
     <value>The hashes password is of bad format. It might not be created by server.</value>
   </data>
@@ -156,47 +159,29 @@
   <data name="HashedPasswordBadFromatExceptionNotUnknownMarker" xml:space="preserve">
     <value>Unknown format marker.</value>
   </data>
-  <data name="JwtBadVersionException" xml:space="preserve">
-    <value>The version of the jwt token is old.</value>
-  </data>
-  <data name="JwtVerifyException" xml:space="preserve">
-    <value>The token didn't pass verification because {0}, see inner exception for information.</value>
+  <data name="JwtUserTokenBadFormatException" xml:space="preserve">
+    <value>The token didn't pass verification because {0}.</value>
   </data>
-  <data name="JwtVerifyExceptionExpired" xml:space="preserve">
-    <value>token is expired.</value>
+  <data name="JwtUserTokenBadFormatExceptionIdBadFormat" xml:space="preserve">
+    <value>id claim is not a number</value>
   </data>
-  <data name="JwtVerifyExceptionIdClaimBadFormat" xml:space="preserve">
-    <value>id claim is not a number.</value>
+  <data name="JwtUserTokenBadFormatExceptionIdMissing" xml:space="preserve">
+    <value>id claim does not exist</value>
   </data>
-  <data name="JwtVerifyExceptionNoIdClaim" xml:space="preserve">
-    <value>id claim does not exist.</value>
-  </data>
-  <data name="JwtVerifyExceptionNoVersionClaim" xml:space="preserve">
-    <value>version claim does not exist.</value>
+  <data name="JwtUserTokenBadFormatExceptionOthers" xml:space="preserve">
+    <value>other error, see inner exception for information</value>
   </data>
-  <data name="JwtVerifyExceptionOldVersion" xml:space="preserve">
-    <value>version of token is old.</value>
-  </data>
-  <data name="JwtVerifyExceptionOthers" xml:space="preserve">
-    <value>uncommon error.</value>
-  </data>
-  <data name="JwtVerifyExceptionUnknown" xml:space="preserve">
-    <value>unknown error code.</value>
+  <data name="JwtUserTokenBadFormatExceptionUnknown" xml:space="preserve">
+    <value>unknown error</value>
   </data>
-  <data name="JwtVerifyExceptionVersionClaimBadFormat" xml:space="preserve">
+  <data name="JwtUserTokenBadFormatExceptionVersionBadFormat" xml:space="preserve">
     <value>version claim is not a number.</value>
   </data>
-  <data name="TimelineAlreadyExistException" xml:space="preserve">
-    <value>The timeline with that name already exists.</value>
-  </data>
-  <data name="TimelineMemberOperationException" xml:space="preserve">
-    <value>An exception happened when add or remove member on timeline.</value>
-  </data>
-  <data name="TimelineMemberOperationExceptionDetail" xml:space="preserve">
-    <value>An exception happened when do operation {0} on the {1} member on timeline.</value>
+  <data name="JwtUserTokenBadFormatExceptionVersionMissing" xml:space="preserve">
+    <value>version claim does not exist.</value>
   </data>
-  <data name="TimelineNameBadFormatException" xml:space="preserve">
-    <value>Timeline name is of bad format. If this is a personal timeline, it means the username is of bad format and inner exception should be a UsernameBadFormatException.</value>
+  <data name="PasswordBadFormatException" xml:space="preserve">
+    <value>Password is of bad format.</value>
   </data>
   <data name="TimelineNotExistException" xml:space="preserve">
     <value>Timeline does not exist. If this is a personal timeline, it means the user does not exist and inner exception should be a UserNotExistException.</value>
@@ -204,16 +189,16 @@
   <data name="TimelinePostNotExistException" xml:space="preserve">
     <value>The timeline post does not exist. You can't do operation on it.</value>
   </data>
-  <data name="TimelineUserNotMemberException" xml:space="preserve">
-    <value>The use is not a member of the timeline.</value>
+  <data name="UserNotExistException" xml:space="preserve">
+    <value>The user does not exist.</value>
   </data>
-  <data name="UsernameBadFormatException" xml:space="preserve">
-    <value>The username is of bad format.</value>
+  <data name="UserTokenBadFormatException" xml:space="preserve">
+    <value>The token is of bad format, which means it may not be created by the server.</value>
   </data>
-  <data name="UsernameConfictException" xml:space="preserve">
-    <value>The username already exists.</value>
+  <data name="UserTokenBadVersionException" xml:space="preserve">
+    <value>The token is of bad version.</value>
   </data>
-  <data name="UserNotExistException" xml:space="preserve">
-    <value>The user does not exist.</value>
+  <data name="UserTokenTimeExpireException" xml:space="preserve">
+    <value>The token is expired because its expiration time has passed.</value>
   </data>
 </root>
 \ No newline at end of file
diff --git a/Timeline/Resources/Controllers/Testing/TestingI18nController.Designer.cs b/Timeline/Resources/Services/TimelineService.Designer.cs
index e015c5fc..8212c252 100644
--- a/Timeline/Resources/Controllers/Testing/TestingI18nController.Designer.cs
+++ b/Timeline/Resources/Services/TimelineService.Designer.cs
@@ -8,7 +8,7 @@
 // </auto-generated>
 //------------------------------------------------------------------------------
 
-namespace Timeline.Resources.Controllers.Testing {
+namespace Timeline.Resources.Services {
     using System;
     
     
@@ -22,14 +22,14 @@ namespace Timeline.Resources.Controllers.Testing {
     [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "16.0.0.0")]
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
-    internal class TestingI18nController {
+    internal class TimelineService {
         
         private static global::System.Resources.ResourceManager resourceMan;
         
         private static global::System.Globalization.CultureInfo resourceCulture;
         
         [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
-        internal TestingI18nController() {
+        internal TimelineService() {
         }
         
         /// <summary>
@@ -39,7 +39,7 @@ namespace Timeline.Resources.Controllers.Testing {
         internal static global::System.Resources.ResourceManager ResourceManager {
             get {
                 if (object.ReferenceEquals(resourceMan, null)) {
-                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Timeline.Resources.Controllers.Testing.TestingI18nController", typeof(TestingI18nController).Assembly);
+                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Timeline.Resources.Services.TimelineService", typeof(TimelineService).Assembly);
                     resourceMan = temp;
                 }
                 return resourceMan;
@@ -61,11 +61,20 @@ namespace Timeline.Resources.Controllers.Testing {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to English test string..
+        ///   Looks up a localized string similar to The number {0} username is invalid..
         /// </summary>
-        internal static string TestString {
+        internal static string ExceptionChangeMemberUsernameBadFormat {
             get {
-                return ResourceManager.GetString("TestString", resourceCulture);
+                return ResourceManager.GetString("ExceptionChangeMemberUsernameBadFormat", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to The owner username of personal timeline is of bad format..
+        /// </summary>
+        internal static string ExceptionFindTimelineUsernameBadFormat {
+            get {
+                return ResourceManager.GetString("ExceptionFindTimelineUsernameBadFormat", resourceCulture);
             }
         }
     }
diff --git a/Timeline/Resources/Controllers/Testing/TestingI18nController.zh.resx b/Timeline/Resources/Services/TimelineService.resx
index 6931cdf6..0429a2f8 100644
--- a/Timeline/Resources/Controllers/Testing/TestingI18nController.zh.resx
+++ b/Timeline/Resources/Services/TimelineService.resx
@@ -117,7 +117,10 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
-  <data name="TestString" xml:space="preserve">
-    <value>中文测试字符串。</value>
+  <data name="ExceptionChangeMemberUsernameBadFormat" xml:space="preserve">
+    <value>The number {0} username is invalid.</value>
+  </data>
+  <data name="ExceptionFindTimelineUsernameBadFormat" xml:space="preserve">
+    <value>The owner username of personal timeline is of bad format.</value>
   </data>
 </root>
 \ No newline at end of file
diff --git a/Timeline/Resources/Services/UserDetailService.resx b/Timeline/Resources/Services/UserDetailService.resx
deleted file mode 100644
index ea32aeda..00000000
--- a/Timeline/Resources/Services/UserDetailService.resx
+++ /dev/null
@@ -1,132 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<root>
-  <!-- 
-    Microsoft ResX Schema 
-    
-    Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
-    associated with the data types.
-    
-    Example:
-    
-    ... ado.net/XML headers & schema ...
-    <resheader name="resmimetype">text/microsoft-resx</resheader>
-    <resheader name="version">2.0</resheader>
-    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
-    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
-    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
-    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
-    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
-        <value>[base64 mime encoded serialized .NET Framework object]</value>
-    </data>
-    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
-        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
-        <comment>This is a comment</comment>
-    </data>
-                
-    There are any number of "resheader" rows that contain simple 
-    name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
-    mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
-    extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
-    read any of the formats listed below.
-    
-    mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
-            : and then encoded with base64 encoding.
-    
-    mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
-            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
-            : and then encoded with base64 encoding.
-
-    mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
-            : using a System.ComponentModel.TypeConverter
-            : and then encoded with base64 encoding.
-    -->
-  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
-    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
-    <xsd:element name="root" msdata:IsDataSet="true">
-      <xsd:complexType>
-        <xsd:choice maxOccurs="unbounded">
-          <xsd:element name="metadata">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" />
-              </xsd:sequence>
-              <xsd:attribute name="name" use="required" type="xsd:string" />
-              <xsd:attribute name="type" type="xsd:string" />
-              <xsd:attribute name="mimetype" type="xsd:string" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="assembly">
-            <xsd:complexType>
-              <xsd:attribute name="alias" type="xsd:string" />
-              <xsd:attribute name="name" type="xsd:string" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="data">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
-              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
-              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
-              <xsd:attribute ref="xml:space" />
-            </xsd:complexType>
-          </xsd:element>
-          <xsd:element name="resheader">
-            <xsd:complexType>
-              <xsd:sequence>
-                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
-              </xsd:sequence>
-              <xsd:attribute name="name" type="xsd:string" use="required" />
-            </xsd:complexType>
-          </xsd:element>
-        </xsd:choice>
-      </xsd:complexType>
-    </xsd:element>
-  </xsd:schema>
-  <resheader name="resmimetype">
-    <value>text/microsoft-resx</value>
-  </resheader>
-  <resheader name="version">
-    <value>2.0</value>
-  </resheader>
-  <resheader name="reader">
-    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <resheader name="writer">
-    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
-  </resheader>
-  <data name="ExceptionNicknameTooLong" xml:space="preserve">
-    <value>Length of nickname can't be bigger than 10.</value>
-  </data>
-  <data name="LogEntityNicknameCreate" xml:space="preserve">
-    <value>A user_details entity has been created. User id is {0}. Nickname is {1}.</value>
-  </data>
-  <data name="LogEntityNicknameSetNotNull" xml:space="preserve">
-    <value>Nickname of a user_details entity has been updated to a new value. User id is {0}. New value is {1}.</value>
-  </data>
-  <data name="LogEntityNicknameSetToNull" xml:space="preserve">
-    <value>Nickname of a user_details entity has been updated to null. User id is {0}.</value>
-  </data>
-</root>
-\ No newline at end of file
diff --git a/Timeline/Resources/Services/UserService.Designer.cs b/Timeline/Resources/Services/UserService.Designer.cs
index 2a04dded..cdf7f390 100644
--- a/Timeline/Resources/Services/UserService.Designer.cs
+++ b/Timeline/Resources/Services/UserService.Designer.cs
@@ -70,6 +70,15 @@ namespace Timeline.Resources.Services {
         }
         
         /// <summary>
+        ///   Looks up a localized string similar to Nickname is of bad format, because {}..
+        /// </summary>
+        internal static string ExceptionNicknameBadFormat {
+            get {
+                return ResourceManager.GetString("ExceptionNicknameBadFormat", resourceCulture);
+            }
+        }
+        
+        /// <summary>
         ///   Looks up a localized string similar to Old username is of bad format..
         /// </summary>
         internal static string ExceptionOldUsernameBadFormat {
@@ -79,20 +88,47 @@ namespace Timeline.Resources.Services {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to A cache entry is created..
+        ///   Looks up a localized string similar to Password can&apos;t be empty..
+        /// </summary>
+        internal static string ExceptionPasswordEmpty {
+            get {
+                return ResourceManager.GetString("ExceptionPasswordEmpty", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Password can&apos;t be null..
+        /// </summary>
+        internal static string ExceptionPasswordNull {
+            get {
+                return ResourceManager.GetString("ExceptionPasswordNull", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Username is of bad format, because {}..
+        /// </summary>
+        internal static string ExceptionUsernameBadFormat {
+            get {
+                return ResourceManager.GetString("ExceptionUsernameBadFormat", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to A user with given username already exists..
         /// </summary>
-        internal static string LogCacheCreate {
+        internal static string ExceptionUsernameConflict {
             get {
-                return ResourceManager.GetString("LogCacheCreate", resourceCulture);
+                return ResourceManager.GetString("ExceptionUsernameConflict", resourceCulture);
             }
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to A cache entry is removed..
+        ///   Looks up a localized string similar to Username can&apos;t be null..
         /// </summary>
-        internal static string LogCacheRemove {
+        internal static string ExceptionUsernameNull {
             get {
-                return ResourceManager.GetString("LogCacheRemove", resourceCulture);
+                return ResourceManager.GetString("ExceptionUsernameNull", resourceCulture);
             }
         }
         
diff --git a/Timeline/Resources/Services/UserService.resx b/Timeline/Resources/Services/UserService.resx
index 3670d8f9..09bd4abb 100644
--- a/Timeline/Resources/Services/UserService.resx
+++ b/Timeline/Resources/Services/UserService.resx
@@ -120,14 +120,26 @@
   <data name="ExceptionNewUsernameBadFormat" xml:space="preserve">
     <value>New username is of bad format.</value>
   </data>
+  <data name="ExceptionNicknameBadFormat" xml:space="preserve">
+    <value>Nickname is of bad format, because {}.</value>
+  </data>
   <data name="ExceptionOldUsernameBadFormat" xml:space="preserve">
     <value>Old username is of bad format.</value>
   </data>
-  <data name="LogCacheCreate" xml:space="preserve">
-    <value>A cache entry is created.</value>
+  <data name="ExceptionPasswordEmpty" xml:space="preserve">
+    <value>Password can't be empty.</value>
+  </data>
+  <data name="ExceptionPasswordNull" xml:space="preserve">
+    <value>Password can't be null.</value>
+  </data>
+  <data name="ExceptionUsernameBadFormat" xml:space="preserve">
+    <value>Username is of bad format, because {}.</value>
+  </data>
+  <data name="ExceptionUsernameConflict" xml:space="preserve">
+    <value>A user with given username already exists.</value>
   </data>
-  <data name="LogCacheRemove" xml:space="preserve">
-    <value>A cache entry is removed.</value>
+  <data name="ExceptionUsernameNull" xml:space="preserve">
+    <value>Username can't be null.</value>
   </data>
   <data name="LogDatabaseCreate" xml:space="preserve">
     <value>A new user entry is added to the database.</value>
diff --git a/Timeline/Services/ConflictException.cs b/Timeline/Services/ConflictException.cs
new file mode 100644
index 00000000..6ede183a
--- /dev/null
+++ b/Timeline/Services/ConflictException.cs
@@ -0,0 +1,21 @@
+using System;
+
+namespace Timeline.Services
+{
+    /// <summary>
+    /// Thrown when a resource already exists and conflicts with the given resource.
+    /// </summary>
+    /// <remarks>
+    /// For example a username already exists and conflicts with the given username.
+    /// </remarks>
+    [Serializable]
+    public class ConflictException : Exception
+    {
+        public ConflictException() : base(Resources.Services.Exception.ConflictException) { }
+        public ConflictException(string message) : base(message) { }
+        public ConflictException(string message, Exception inner) : base(message, inner) { }
+        protected ConflictException(
+          System.Runtime.Serialization.SerializationInfo info,
+          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+    }
+}
diff --git a/Timeline/Services/DatabaseExtensions.cs b/Timeline/Services/DatabaseExtensions.cs
deleted file mode 100644
index 140c3146..00000000
--- a/Timeline/Services/DatabaseExtensions.cs
+++ /dev/null
@@ -1,36 +0,0 @@
-using Microsoft.EntityFrameworkCore;
-using System;
-using System.Linq;
-using System.Threading.Tasks;
-using Timeline.Entities;
-using Timeline.Models.Validation;
-
-namespace Timeline.Services
-{
-    internal static class DatabaseExtensions
-    {
-        private static readonly UsernameValidator usernameValidator = new UsernameValidator();
-
-        /// <summary>
-        /// Check the existence and get the id of the user.
-        /// </summary>
-        /// <param name="username">The username of the user.</param>
-        /// <returns>The user id.</returns>
-        /// <exception cref="ArgumentNullException">Thrown if <paramref name="username"/> is null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown if <paramref name="username"/> is of bad format.</exception>
-        /// <exception cref="UserNotExistException">Thrown if user does not exist.</exception>
-        internal static async Task<long> CheckAndGetUser(DbSet<User> userDbSet, string? username)
-        {
-            if (username == null)
-                throw new ArgumentNullException(nameof(username));
-            var (result, message) = usernameValidator.Validate(username);
-            if (!result)
-                throw new UsernameBadFormatException(username, message);
-
-            var userId = await userDbSet.Where(u => u.Name == username).Select(u => u.Id).SingleOrDefaultAsync();
-            if (userId == 0)
-                throw new UserNotExistException(username);
-            return userId;
-        }
-    }
-}
diff --git a/Timeline/Services/JwtBadVersionException.cs b/Timeline/Services/JwtBadVersionException.cs
deleted file mode 100644
index 4ce17710..00000000
--- a/Timeline/Services/JwtBadVersionException.cs
+++ /dev/null
@@ -1,36 +0,0 @@
-using System;
-using Timeline.Helpers;
-
-namespace Timeline.Services
-{
-    [Serializable]
-    public class JwtBadVersionException : Exception
-    {
-        public JwtBadVersionException() : base(Resources.Services.Exception.JwtBadVersionException) { }
-        public JwtBadVersionException(string message) : base(message) { }
-        public JwtBadVersionException(string message, Exception inner) : base(message, inner) { }
-
-        public JwtBadVersionException(long tokenVersion, long requiredVersion)
-            : base(Log.Format(Resources.Services.Exception.JwtBadVersionException,
-                ("Token Version", tokenVersion),
-                ("Required Version", requiredVersion)))
-        {
-            TokenVersion = tokenVersion;
-            RequiredVersion = requiredVersion;
-        }
-
-        protected JwtBadVersionException(
-          System.Runtime.Serialization.SerializationInfo info,
-          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
-
-        /// <summary>
-        /// The version in the token.
-        /// </summary>
-        public long? TokenVersion { get; set; }
-
-        /// <summary>
-        /// The version required.
-        /// </summary>
-        public long? RequiredVersion { get; set; }
-    }
-}
diff --git a/Timeline/Services/JwtUserTokenBadFormatException.cs b/Timeline/Services/JwtUserTokenBadFormatException.cs
new file mode 100644
index 00000000..c528c3e3
--- /dev/null
+++ b/Timeline/Services/JwtUserTokenBadFormatException.cs
@@ -0,0 +1,48 @@
+using System;
+using System.Globalization;
+using static Timeline.Resources.Services.Exception;
+
+namespace Timeline.Services
+{
+    [Serializable]
+    public class JwtUserTokenBadFormatException : UserTokenBadFormatException
+    {
+        public enum ErrorKind
+        {
+            NoIdClaim,
+            IdClaimBadFormat,
+            NoVersionClaim,
+            VersionClaimBadFormat,
+            Other
+        }
+
+        public JwtUserTokenBadFormatException() : this("", ErrorKind.Other) { }
+        public JwtUserTokenBadFormatException(string message) : base(message) { }
+        public JwtUserTokenBadFormatException(string message, Exception inner) : base(message, inner) { }
+
+        public JwtUserTokenBadFormatException(string token, ErrorKind type) : base(token, GetErrorMessage(type)) { ErrorType = type; }
+        public JwtUserTokenBadFormatException(string token, ErrorKind type, Exception inner) : base(token, GetErrorMessage(type), inner) { ErrorType = type; }
+        public JwtUserTokenBadFormatException(string token, ErrorKind type, string message, Exception inner) : base(token, message, inner) { ErrorType = type; }
+        protected JwtUserTokenBadFormatException(
+          System.Runtime.Serialization.SerializationInfo info,
+          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+
+        public ErrorKind ErrorType { get; set; }
+
+        private static string GetErrorMessage(ErrorKind type)
+        {
+            var reason = type switch
+            {
+                ErrorKind.NoIdClaim => JwtUserTokenBadFormatExceptionIdMissing,
+                ErrorKind.IdClaimBadFormat => JwtUserTokenBadFormatExceptionIdBadFormat,
+                ErrorKind.NoVersionClaim => JwtUserTokenBadFormatExceptionVersionMissing,
+                ErrorKind.VersionClaimBadFormat => JwtUserTokenBadFormatExceptionVersionBadFormat,
+                ErrorKind.Other => JwtUserTokenBadFormatExceptionOthers,
+                _ => JwtUserTokenBadFormatExceptionUnknown
+            };
+
+            return string.Format(CultureInfo.CurrentCulture,
+                Resources.Services.Exception.JwtUserTokenBadFormatException, reason);
+        }
+    }
+}
diff --git a/Timeline/Services/JwtVerifyException.cs b/Timeline/Services/JwtVerifyException.cs
deleted file mode 100644
index a915b51a..00000000
--- a/Timeline/Services/JwtVerifyException.cs
+++ /dev/null
@@ -1,59 +0,0 @@
-using Microsoft.IdentityModel.Tokens;
-using System;
-using System.Globalization;
-using static Timeline.Resources.Services.Exception;
-
-namespace Timeline.Services
-{
-    [Serializable]
-    public class JwtVerifyException : Exception
-    {
-        public static class ErrorCodes
-        {
-            // Codes in -1000 ~ -1999 usually means the user provides a token that is not created by this server.
-
-            public const int Others = -1001;
-            public const int NoIdClaim = -1002;
-            public const int IdClaimBadFormat = -1003;
-            public const int NoVersionClaim = -1004;
-            public const int VersionClaimBadFormat = -1005;
-
-            /// <summary>
-            /// Corresponds to <see cref="SecurityTokenExpiredException"/>.
-            /// </summary>
-            public const int Expired = -2001;
-            public const int OldVersion = -2002;
-        }
-
-        public JwtVerifyException() : base(GetErrorMessage(0)) { }
-        public JwtVerifyException(string message) : base(message) { }
-        public JwtVerifyException(string message, Exception inner) : base(message, inner) { }
-
-        public JwtVerifyException(int code) : base(GetErrorMessage(code)) { ErrorCode = code; }
-        public JwtVerifyException(string message, int code) : base(message) { ErrorCode = code; }
-        public JwtVerifyException(Exception inner, int code) : base(GetErrorMessage(code), inner) { ErrorCode = code; }
-        public JwtVerifyException(string message, Exception inner, int code) : base(message, inner) { ErrorCode = code; }
-        protected JwtVerifyException(
-          System.Runtime.Serialization.SerializationInfo info,
-          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
-
-        public int ErrorCode { get; set; }
-
-        private static string GetErrorMessage(int errorCode)
-        {
-            var reason = errorCode switch
-            {
-                ErrorCodes.Others => JwtVerifyExceptionOthers,
-                ErrorCodes.NoIdClaim => JwtVerifyExceptionNoIdClaim,
-                ErrorCodes.IdClaimBadFormat => JwtVerifyExceptionIdClaimBadFormat,
-                ErrorCodes.NoVersionClaim => JwtVerifyExceptionNoVersionClaim,
-                ErrorCodes.VersionClaimBadFormat => JwtVerifyExceptionVersionClaimBadFormat,
-                ErrorCodes.Expired => JwtVerifyExceptionExpired,
-                ErrorCodes.OldVersion => JwtVerifyExceptionOldVersion,
-                _ => JwtVerifyExceptionUnknown
-            };
-
-            return string.Format(CultureInfo.InvariantCulture, Resources.Services.Exception.JwtVerifyException, reason);
-        }
-    }
-}
diff --git a/Timeline/Services/PasswordBadFormatException.cs b/Timeline/Services/PasswordBadFormatException.cs
new file mode 100644
index 00000000..2029ebb4
--- /dev/null
+++ b/Timeline/Services/PasswordBadFormatException.cs
@@ -0,0 +1,27 @@
+using System;
+
+namespace Timeline.Services
+{
+
+    [Serializable]
+    public class PasswordBadFormatException : Exception
+    {
+        public PasswordBadFormatException() : base(Resources.Services.Exception.PasswordBadFormatException) { }
+        public PasswordBadFormatException(string message) : base(message) { }
+        public PasswordBadFormatException(string message, Exception inner) : base(message, inner) { }
+
+        public PasswordBadFormatException(string password, string validationMessage) : this()
+        {
+            Password = password;
+            ValidationMessage = validationMessage;
+        }
+
+        protected PasswordBadFormatException(
+          System.Runtime.Serialization.SerializationInfo info,
+          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+
+        public string Password { get; set; } = "";
+
+        public string ValidationMessage { get; set; } = "";
+    }
+}
diff --git a/Timeline/Services/TimelineAlreadyExistException.cs b/Timeline/Services/TimelineAlreadyExistException.cs
deleted file mode 100644
index c2dea1f9..00000000
--- a/Timeline/Services/TimelineAlreadyExistException.cs
+++ /dev/null
@@ -1,17 +0,0 @@
-using System;
-
-namespace Timeline.Services
-{
-    [Serializable]
-    public class TimelineAlreadyExistException : Exception
-    {
-        public TimelineAlreadyExistException() : base(Resources.Services.Exception.TimelineAlreadyExistException) { }
-        public TimelineAlreadyExistException(string name) : base(Resources.Services.Exception.TimelineAlreadyExistException) { Name = name; }
-        public TimelineAlreadyExistException(string name, Exception inner) : base(Resources.Services.Exception.TimelineAlreadyExistException, inner) { Name = name; }
-        protected TimelineAlreadyExistException(
-          System.Runtime.Serialization.SerializationInfo info,
-          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
-
-        public string? Name { get; set; }
-    }
-}
diff --git a/Timeline/Services/TimelineMemberOperationUserException.cs b/Timeline/Services/TimelineMemberOperationUserException.cs
deleted file mode 100644
index 543ee160..00000000
--- a/Timeline/Services/TimelineMemberOperationUserException.cs
+++ /dev/null
@@ -1,37 +0,0 @@
-using System;
-using System.Globalization;
-
-namespace Timeline.Services
-{
-    [Serializable]
-    public class TimelineMemberOperationUserException : Exception
-    {
-        public enum MemberOperation
-        {
-            Add,
-            Remove
-        }
-
-        public TimelineMemberOperationUserException() : base(Resources.Services.Exception.TimelineMemberOperationException) { }
-        public TimelineMemberOperationUserException(string message) : base(message) { }
-        public TimelineMemberOperationUserException(string message, Exception inner) : base(message, inner) { }
-        protected TimelineMemberOperationUserException(
-          System.Runtime.Serialization.SerializationInfo info,
-          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
-
-        public TimelineMemberOperationUserException(int index, MemberOperation operation, string username, Exception inner)
-            : base(MakeMessage(operation, index), inner) { Operation = operation; Index = index; Username = username; }
-
-        private static string MakeMessage(MemberOperation operation, int index) => string.Format(CultureInfo.CurrentCulture,
-            Resources.Services.Exception.TimelineMemberOperationExceptionDetail, operation, index);
-
-        public MemberOperation? Operation { get; set; }
-
-        /// <summary>
-        /// The index of the member on which the operation failed.
-        /// </summary>
-        public int? Index { get; set; }
-
-        public string? Username { get; set; }
-    }
-}
diff --git a/Timeline/Services/TimelineNameBadFormatException.cs b/Timeline/Services/TimelineNameBadFormatException.cs
deleted file mode 100644
index 5120a175..00000000
--- a/Timeline/Services/TimelineNameBadFormatException.cs
+++ /dev/null
@@ -1,21 +0,0 @@
-using System;
-
-namespace Timeline.Services
-{
-    [Serializable]
-    public class TimelineNameBadFormatException : Exception
-    {
-        public TimelineNameBadFormatException()
-            : base(Resources.Services.Exception.TimelineNameBadFormatException) { }
-        public TimelineNameBadFormatException(string name)
-            : base(Resources.Services.Exception.TimelineNameBadFormatException) { Name = name; }
-        public TimelineNameBadFormatException(string name, Exception inner)
-            : base(Resources.Services.Exception.TimelineNameBadFormatException, inner) { Name = name; }
-
-        protected TimelineNameBadFormatException(
-          System.Runtime.Serialization.SerializationInfo info,
-          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
-
-        public string? Name { get; set; }
-    }
-}
diff --git a/Timeline/Services/TimelineService.cs b/Timeline/Services/TimelineService.cs
index f7b0e0e9..0ea68265 100644
--- a/Timeline/Services/TimelineService.cs
+++ b/Timeline/Services/TimelineService.cs
@@ -1,13 +1,15 @@
-using Microsoft.EntityFrameworkCore;
+using AutoMapper;
+using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Logging;
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Linq;
 using System.Threading.Tasks;
 using Timeline.Entities;
-using Timeline.Models;
 using Timeline.Models.Http;
 using Timeline.Models.Validation;
+using static Timeline.Resources.Services.TimelineService;
 
 namespace Timeline.Services
 {
@@ -28,12 +30,7 @@ namespace Timeline.Services
         /// <param name="name">Username or the timeline name. See remarks of <see cref="IBaseTimelineService"/>.</param>
         /// <returns>A list of all posts.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when timeline name is of bad format.
-        /// For normal timeline, it means name is an empty string.
-        /// For personal timeline, it means the username is of bad format,
-        /// the inner exception should be a <see cref="UsernameBadFormatException"/>.
-        /// </exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="name"/> is illegal. It is not a valid timeline name (for normal timeline service) or a valid username (for personal timeline service).</exception>
         /// <exception cref="TimelineNotExistException">
         /// Thrown when timeline does not exist.
         /// For normal timeline, it means the name does not exist.
@@ -46,26 +43,20 @@ namespace Timeline.Services
         /// Create a new post in timeline.
         /// </summary>
         /// <param name="name">Username or the timeline name. See remarks of <ssee cref="IBaseTimelineService"/>.</param>
-        /// <param name="author">The author's username.</param>
+        /// <param name="authorId">The author's id.</param>
         /// <param name="content">The content.</param>
         /// <param name="time">The time of the post. If null, then use current time.</param>
         /// <returns>The info of the created post.</returns>
-        /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> or <paramref name="author"/> or <paramref name="content"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when timeline name is of bad format.
-        /// For normal timeline, it means name is an empty string.
-        /// For personal timeline, it means the username is of bad format,
-        /// the inner exception should be a <see cref="UsernameBadFormatException"/>.
-        /// </exception>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> or <paramref name="content"/> is null.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="name"/> is illegal. It is not a valid timeline name (for normal timeline service) or a valid username (for personal timeline service).</exception>
         /// <exception cref="TimelineNotExistException">
         /// Thrown when timeline does not exist.
         /// For normal timeline, it means the name does not exist.
         /// For personal timeline, it means the user of that username does not exist
         /// and the inner exception should be a <see cref="UserNotExistException"/>.
         /// </exception>
-        /// <exception cref="UsernameBadFormatException">Thrown if <paramref name="author"/> is of bad format.</exception>
-        /// <exception cref="UserNotExistException">Thrown if <paramref name="author"/> does not exist.</exception>
-        Task<TimelinePostCreateResponse> CreatePost(string name, string author, string content, DateTime? time);
+        /// <exception cref="UserNotExistException">Thrown if user with <paramref name="authorId"/> does not exist.</exception>
+        Task<TimelinePostInfo> CreatePost(string name, long authorId, string content, DateTime? time);
 
         /// <summary>
         /// Delete a post
@@ -73,12 +64,7 @@ namespace Timeline.Services
         /// <param name="name">Username or the timeline name. See remarks of <see cref="IBaseTimelineService"/>.</param>
         /// <param name="id">The id of the post to delete.</param>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> or <paramref name="username"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when timeline name is of bad format.
-        /// For normal timeline, it means name is an empty string.
-        /// For personal timeline, it means the username is of bad format,
-        /// the inner exception should be a <see cref="UsernameBadFormatException"/>.
-        /// </exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="name"/> is illegal. It is not a valid timeline name (for normal timeline service) or a valid username (for personal timeline service).</exception>
         /// <exception cref="TimelineNotExistException">
         /// Thrown when timeline does not exist.
         /// For normal timeline, it means the name does not exist.
@@ -95,50 +81,22 @@ namespace Timeline.Services
         Task DeletePost(string name, long id);
 
         /// <summary>
-        /// Set the properties of a timeline. 
-        /// </summary>
-        /// <param name="name">Username or the timeline name. See remarks of <see cref="IBaseTimelineService"/>.</param>
-        /// <param name="newProperties">The new properties. Null member means not to change.</param>
-        /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> or <paramref name="newProperties"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when timeline name is of bad format.
-        /// For normal timeline, it means name is an empty string.
-        /// For personal timeline, it means the username is of bad format,
-        /// the inner exception should be a <see cref="UsernameBadFormatException"/>.
-        /// </exception>
-        /// <exception cref="TimelineNotExistException">
-        /// Thrown when timeline does not exist.
-        /// For normal timeline, it means the name does not exist.
-        /// For personal timeline, it means the user of that username does not exist
-        /// and the inner exception should be a <see cref="UserNotExistException"/>.
-        /// </exception>
-        Task ChangeProperty(string name, TimelinePropertyChangeRequest newProperties);
-
-        /// <summary>
         /// Remove members to a timeline.
         /// </summary>
         /// <param name="name">Username or the timeline name. See remarks of <see cref="IBaseTimelineService"/>.</param>
         /// <param name="add">A list of usernames of members to add. May be null.</param>
         /// <param name="remove">A list of usernames of members to remove. May be null.</param>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when timeline name is of bad format.
-        /// For normal timeline, it means name is an empty string.
-        /// For personal timeline, it means the username is of bad format,
-        /// the inner exception should be a <see cref="UsernameBadFormatException"/>.
-        /// </exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="name"/> is illegal. It is not a valid timeline name (for normal timeline service) or a valid username (for personal timeline service).</exception>
+        /// <exception cref="ArgumentException">Thrown when names in <paramref name="add"/> or <paramref name="remove"/> is not a valid username.</exception>
         /// <exception cref="TimelineNotExistException">
         /// Thrown when timeline does not exist.
         /// For normal timeline, it means the name does not exist.
         /// For personal timeline, it means the user of that username does not exist
         /// and the inner exception should be a <see cref="UserNotExistException"/>.
         /// </exception>
-        /// <exception cref="TimelineMemberOperationUserException">
-        /// Thrown when an exception occurs on the user list.
-        /// The inner exception is <see cref="UsernameBadFormatException"/>
-        /// when one of the username is invalid.
-        /// The inner exception is <see cref="UserNotExistException"/>
-        /// when one of the user to change does not exist.
+        /// <exception cref="UserNotExistException">
+        /// Thrown when one of the user to change does not exist.
         /// </exception>
         /// <remarks>
         /// Operating on a username that is of bad format or does not exist always throws.
@@ -153,42 +111,30 @@ namespace Timeline.Services
         /// Verify whether a visitor has the permission to read a timeline.
         /// </summary>
         /// <param name="name">Username or the timeline name. See remarks of <see cref="IBaseTimelineService"/>.</param>
-        /// <param name="username">The user to check on. Null means visitor without account.</param>
+        /// <param name="visitorId">The id of the user to check on. Null means visitor without account.</param>
         /// <returns>True if can read, false if can't read.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when timeline name is of bad format.
-        /// For normal timeline, it means name is an empty string.
-        /// For personal timeline, it means the username is of bad format,
-        /// the inner exception should be a <see cref="UsernameBadFormatException"/>.
-        /// </exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="name"/> is illegal. It is not a valid timeline name (for normal timeline service) or a valid username (for personal timeline service).</exception>
         /// <exception cref="TimelineNotExistException">
         /// Thrown when timeline does not exist.
         /// For normal timeline, it means the name does not exist.
         /// For personal timeline, it means the user of that username does not exist
         /// and the inner exception should be a <see cref="UserNotExistException"/>.
         /// </exception>
-        /// <exception cref="UsernameBadFormatException">
-        /// Thrown when <paramref name="username"/> is of bad format.
-        /// </exception>
-        /// <exception cref="UserNotExistException">
-        /// Thrown when <paramref name="username"/> does not exist.
-        /// </exception>
-        Task<bool> HasReadPermission(string name, string? username);
+        /// <remarks>
+        /// This method does not check whether visitor is administrator.
+        /// Return false if user with visitor id does not exist.
+        /// </remarks>
+        Task<bool> HasReadPermission(string name, long? visitorId);
 
         /// <summary>
         /// Verify whether a user has the permission to modify a post.
         /// </summary>
         /// <param name="name">Username or the timeline name. See remarks of <see cref="IBaseTimelineService"/>.</param>
-        /// <param name="username">The user to check on.</param>
+        /// <param name="modifierId">The id of the user to check on.</param>
         /// <returns>True if can modify, false if can't modify.</returns>
-        /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> or <paramref name="username"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when timeline name is of bad format.
-        /// For normal timeline, it means name is an empty string.
-        /// For personal timeline, it means the username is of bad format,
-        /// the inner exception should be a <see cref="UsernameBadFormatException"/>.
-        /// </exception>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> is null.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="name"/> is illegal. It is not a valid timeline name (for normal timeline service) or a valid username (for personal timeline service).</exception>
         /// <exception cref="TimelineNotExistException">
         /// Thrown when timeline does not exist.
         /// For normal timeline, it means the name does not exist.
@@ -198,47 +144,32 @@ namespace Timeline.Services
         /// <exception cref="TimelinePostNotExistException">
         /// Thrown when the post with given id does not exist or is deleted already.
         /// </exception>
-        /// <exception cref="UsernameBadFormatException">
-        /// Thrown when <paramref name="username"/> is of bad format.
-        /// </exception>
-        /// <exception cref="UserNotExistException">
-        /// Thrown when <paramref name="username"/> does not exist.
-        /// </exception>
         /// <remarks>
         /// This method does not check whether the user is administrator.
         /// It only checks whether he is the author of the post or the owner of the timeline.
+        /// Return false when user with modifier id does not exist.
         /// </remarks>
-        Task<bool> HasPostModifyPermission(string name, long id, string username);
+        Task<bool> HasPostModifyPermission(string name, long id, long modifierId);
 
         /// <summary>
         /// Verify whether a user is member of a timeline.
         /// </summary>
         /// <param name="name">Username or the timeline name. See remarks of <see cref="IBaseTimelineService"/>.</param>
-        /// <param name="username">The user to check on.</param>
+        /// <param name="userId">The id of user to check on.</param>
         /// <returns>True if it is a member, false if not.</returns>
-        /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> or <paramref name="username"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when timeline name is of bad format.
-        /// For normal timeline, it means name is an empty string.
-        /// For personal timeline, it means the username is of bad format,
-        /// the inner exception should be a <see cref="UsernameBadFormatException"/>.
-        /// </exception>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> is null.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="name"/> is illegal. It is not a valid timeline name (for normal timeline service) or a valid username (for personal timeline service).</exception>
         /// <exception cref="TimelineNotExistException">
         /// Thrown when timeline does not exist.
         /// For normal timeline, it means the name does not exist.
         /// For personal timeline, it means the user of that username does not exist
         /// and the inner exception should be a <see cref="UserNotExistException"/>.
         /// </exception>
-        /// <exception cref="UsernameBadFormatException">
-        /// Thrown when <paramref name="username"/> is not a valid username.
-        /// </exception>
-        /// <exception cref="UserNotExistException">
-        /// Thrown when user <paramref name="username"/> does not exist.
-        /// </exception>
         /// <remarks>
         /// Timeline owner is also considered as a member.
+        /// Return false when user with user id does not exist.
         /// </remarks>
-        Task<bool> IsMemberOf(string name, string username);
+        Task<bool> IsMemberOf(string name, long userId);
     }
 
     /// <summary>
@@ -252,7 +183,7 @@ namespace Timeline.Services
         /// <param name="name">The name of the timeline.</param>
         /// <returns>The timeline info.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
+        /// <exception cref="ArgumentException">
         /// Thrown when timeline name is invalid. Currently it means it is an empty string.
         /// </exception>
         /// <exception cref="TimelineNotExistException">
@@ -264,20 +195,12 @@ namespace Timeline.Services
         /// Create a timeline.
         /// </summary>
         /// <param name="name">The name of the timeline.</param>
-        /// <param name="owner">The owner of the timeline.</param>
+        /// <param name="owner">The id of owner of the timeline.</param>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> or <paramref name="owner"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when timeline name is invalid. Currently it means it is an empty string.
-        /// </exception>
-        /// <exception cref="TimelineAlreadyExistException">
-        /// Thrown when the timeline already exists.
-        /// </exception>
-        /// <exception cref="UsernameBadFormatException">
-        /// Thrown when the username of the owner is not valid.
-        /// </exception>
-        /// <exception cref="UserNotExistException">
-        /// Thrown when the owner user does not exist.</exception>
-        Task CreateTimeline(string name, string owner);
+        /// <exception cref="ArgumentException">Thrown when timeline name is invalid. Currently it means it is an empty string.</exception>
+        /// <exception cref="ConflictException">Thrown when the timeline already exists.</exception>
+        /// <exception cref="UserNotExistException">Thrown when the owner user does not exist.</exception>
+        Task CreateTimeline(string name, long owner);
     }
 
     public interface IPersonalTimelineService : IBaseTimelineService
@@ -290,21 +213,40 @@ namespace Timeline.Services
         /// <exception cref="ArgumentNullException">
         /// Thrown when <paramref name="username"/> is null.
         /// </exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when <paramref name="username"/> is of bad format. Inner exception MUST be <see cref="UsernameBadFormatException"/>.
+        /// <exception cref="ArgumentException">
+        /// Thrown when <paramref name="username"/> is of bad format.
         /// </exception>
         /// <exception cref="TimelineNotExistException">
         /// Thrown when the user does not exist. Inner exception MUST be <see cref="UserNotExistException"/>.
         /// </exception>
         Task<BaseTimelineInfo> GetTimeline(string username);
+
+        /// <summary>
+        /// Set the properties of a timeline. 
+        /// </summary>
+        /// <param name="name">Username or the timeline name. See remarks of <see cref="IBaseTimelineService"/>.</param>
+        /// <param name="newProperties">The new properties. Null member means not to change.</param>
+        /// <exception cref="ArgumentNullException">
+        /// Thrown when <paramref name="username"/> is null.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        /// Thrown when <paramref name="username"/> is of bad format.
+        /// </exception>
+        /// <exception cref="TimelineNotExistException">
+        /// Thrown when the user does not exist. Inner exception MUST be <see cref="UserNotExistException"/>.
+        /// </exception>
+        Task ChangeProperty(string name, TimelinePatchRequest newProperties);
+
     }
 
     public abstract class BaseTimelineService : IBaseTimelineService
     {
-        protected BaseTimelineService(ILoggerFactory loggerFactory, DatabaseContext database, IClock clock)
+        protected BaseTimelineService(ILoggerFactory loggerFactory, DatabaseContext database, IUserService userService, IMapper mapper, IClock clock)
         {
             Clock = clock;
             Database = database;
+            UserService = userService;
+            Mapper = mapper;
         }
 
         protected IClock Clock { get; }
@@ -313,6 +255,10 @@ namespace Timeline.Services
 
         protected DatabaseContext Database { get; }
 
+        protected IUserService UserService { get; }
+
+        protected IMapper Mapper { get; }
+
         /// <summary>
         /// Find the timeline id by the name.
         /// For details, see remarks.
@@ -320,12 +266,7 @@ namespace Timeline.Services
         /// <param name="name">The username or the timeline name. See remarks.</param>
         /// <returns>The id of the timeline entity.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="name"/> is null.</exception>
-        /// <exception cref="TimelineNameBadFormatException">
-        /// Thrown when timeline name is of bad format.
-        /// For normal timeline, it means name is an empty string.
-        /// For personal timeline, it means the username is of bad format,
-        /// the inner exception should be a <see cref="UsernameBadFormatException"/>.
-        /// </exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="name"/> is illegal. It is not a valid timeline name (for normal timeline service) or a valid username (for personal timeline service).</exception>
         /// <exception cref="TimelineNotExistException">
         /// Thrown when timeline does not exist.
         /// For normal timeline, it means the name does not exist.
@@ -347,66 +288,60 @@ namespace Timeline.Services
             if (name == null)
                 throw new ArgumentNullException(nameof(name));
 
+
             var timelineId = await FindTimelineId(name);
             var postEntities = await Database.TimelinePosts.OrderBy(p => p.Time).Where(p => p.TimelineId == timelineId && p.Content != null).ToListAsync();
+
             var posts = new List<TimelinePostInfo>();
             foreach (var entity in postEntities)
             {
-                posts.Add(new TimelinePostInfo
+                if (entity.Content != null) // otherwise it is deleted
                 {
-                    Id = entity.Id,
-                    Content = entity.Content,
-                    Author = (await Database.Users.Where(u => u.Id == entity.AuthorId).Select(u => new { u.Name }).SingleAsync()).Name,
-                    Time = entity.Time
-                });
+                    var author = Mapper.Map<UserInfo>(await UserService.GetUserById(entity.AuthorId));
+                    posts.Add(new TimelinePostInfo
+                    {
+                        Id = entity.Id,
+                        Content = entity.Content,
+                        Author = author,
+                        Time = entity.Time,
+                        LastUpdated = entity.LastUpdated
+                    });
+                }
             }
             return posts;
         }
 
-        public async Task<TimelinePostCreateResponse> CreatePost(string name, string author, string content, DateTime? time)
+        public async Task<TimelinePostInfo> CreatePost(string name, long authorId, string content, DateTime? time)
         {
             if (name == null)
                 throw new ArgumentNullException(nameof(name));
-            if (author == null)
-                throw new ArgumentNullException(nameof(author));
             if (content == null)
                 throw new ArgumentNullException(nameof(content));
 
-            {
-                var (result, message) = UsernameValidator.Validate(author);
-                if (!result)
-                {
-                    throw new UsernameBadFormatException(author, message);
-                }
-            }
-
             var timelineId = await FindTimelineId(name);
-
-            var authorEntity = Database.Users.Where(u => u.Name == author).Select(u => new { u.Id }).SingleOrDefault();
-            if (authorEntity == null)
-            {
-                throw new UserNotExistException(author);
-            }
-            var authorId = authorEntity.Id;
+            var author = Mapper.Map<UserInfo>(await UserService.GetUserById(authorId));
 
             var currentTime = Clock.GetCurrentTime();
+            var finalTime = time ?? currentTime;
 
             var postEntity = new TimelinePostEntity
             {
                 Content = content,
                 AuthorId = authorId,
                 TimelineId = timelineId,
-                Time = time ?? currentTime,
+                Time = finalTime,
                 LastUpdated = currentTime
             };
-
             Database.TimelinePosts.Add(postEntity);
             await Database.SaveChangesAsync();
 
-            return new TimelinePostCreateResponse
+            return new TimelinePostInfo
             {
                 Id = postEntity.Id,
-                Time = postEntity.Time
+                Content = content,
+                Author = author,
+                Time = finalTime,
+                LastUpdated = currentTime
             };
         }
 
@@ -415,6 +350,9 @@ namespace Timeline.Services
             if (name == null)
                 throw new ArgumentNullException(nameof(name));
 
+            // Currently we don't use the result. But we need to check the timeline.
+            var _ = await FindTimelineId(name);
+
             var post = await Database.TimelinePosts.Where(p => p.Id == id).SingleOrDefaultAsync();
 
             if (post == null)
@@ -426,7 +364,7 @@ namespace Timeline.Services
             await Database.SaveChangesAsync();
         }
 
-        public async Task ChangeProperty(string name, TimelinePropertyChangeRequest newProperties)
+        public async Task ChangeProperty(string name, TimelinePatchRequest newProperties)
         {
             if (name == null)
                 throw new ArgumentNullException(nameof(name));
@@ -455,27 +393,23 @@ namespace Timeline.Services
             if (name == null)
                 throw new ArgumentNullException(nameof(name));
 
-            // remove duplication and check the format of each username.
-            // Return a username->index map.
-            Dictionary<string, int>? RemoveDuplicateAndCheckFormat(IList<string>? list, TimelineMemberOperationUserException.MemberOperation operation)
+            List<string>? RemoveDuplicateAndCheckFormat(IList<string>? list, string paramName)
             {
                 if (list != null)
                 {
-                    Dictionary<string, int> result = new Dictionary<string, int>();
+                    List<string> result = new List<string>();
                     var count = list.Count;
                     for (var index = 0; index < count; index++)
                     {
                         var username = list[index];
-                        if (result.ContainsKey(username))
+                        if (result.Contains(username))
                         {
                             continue;
                         }
                         var (validationResult, message) = UsernameValidator.Validate(username);
                         if (!validationResult)
-                            throw new TimelineMemberOperationUserException(
-                                index, operation, username,
-                                new UsernameBadFormatException(username, message));
-                        result.Add(username, index);
+                            throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, ExceptionChangeMemberUsernameBadFormat, index), nameof(paramName));
+                        result.Add(username);
                     }
                     return result;
                 }
@@ -484,13 +418,13 @@ namespace Timeline.Services
                     return null;
                 }
             }
-            var simplifiedAdd = RemoveDuplicateAndCheckFormat(add, TimelineMemberOperationUserException.MemberOperation.Add);
-            var simplifiedRemove = RemoveDuplicateAndCheckFormat(remove, TimelineMemberOperationUserException.MemberOperation.Remove);
+            var simplifiedAdd = RemoveDuplicateAndCheckFormat(add, nameof(add));
+            var simplifiedRemove = RemoveDuplicateAndCheckFormat(remove, nameof(remove));
 
             // remove those both in add and remove
             if (simplifiedAdd != null && simplifiedRemove != null)
             {
-                var usersToClean = simplifiedRemove.Keys.Where(u => simplifiedAdd.ContainsKey(u));
+                var usersToClean = simplifiedRemove.Where(u => simplifiedAdd.Contains(u)).ToList();
                 foreach (var u in usersToClean)
                 {
                     simplifiedAdd.Remove(u);
@@ -500,26 +434,20 @@ namespace Timeline.Services
 
             var timelineId = await FindTimelineId(name);
 
-            async Task<List<long>?> CheckExistenceAndGetId(Dictionary<string, int>? map, TimelineMemberOperationUserException.MemberOperation operation)
+            async Task<List<long>?> CheckExistenceAndGetId(List<string>? list)
             {
-                if (map == null)
+                if (list == null)
                     return null;
 
                 List<long> result = new List<long>();
-                foreach (var (username, index) in map)
+                foreach (var username in list)
                 {
-                    var user = await Database.Users.Where(u => u.Name == username).Select(u => new { u.Id }).SingleOrDefaultAsync();
-                    if (user == null)
-                    {
-                        throw new TimelineMemberOperationUserException(index, operation, username,
-                            new UserNotExistException(username));
-                    }
-                    result.Add(user.Id);
+                    result.Add(await UserService.GetUserIdByUsername(username));
                 }
                 return result;
             }
-            var userIdsAdd = await CheckExistenceAndGetId(simplifiedAdd, TimelineMemberOperationUserException.MemberOperation.Add);
-            var userIdsRemove = await CheckExistenceAndGetId(simplifiedRemove, TimelineMemberOperationUserException.MemberOperation.Remove);
+            var userIdsAdd = await CheckExistenceAndGetId(simplifiedAdd);
+            var userIdsRemove = await CheckExistenceAndGetId(simplifiedRemove);
 
             if (userIdsAdd != null)
             {
@@ -536,30 +464,11 @@ namespace Timeline.Services
             await Database.SaveChangesAsync();
         }
 
-        public async Task<bool> HasReadPermission(string name, string? username)
+        public async Task<bool> HasReadPermission(string name, long? visitorId)
         {
             if (name == null)
                 throw new ArgumentNullException(nameof(name));
 
-            long? userId = null;
-            if (username != null)
-            {
-                var (result, message) = UsernameValidator.Validate(username);
-                if (!result)
-                {
-                    throw new UsernameBadFormatException(username);
-                }
-
-                var user = await Database.Users.Where(u => u.Name == username).Select(u => new { u.Id }).SingleOrDefaultAsync();
-
-                if (user == null)
-                {
-                    throw new UserNotExistException(username);
-                }
-
-                userId = user.Id;
-            }
-
             var timelineId = await FindTimelineId(name);
 
             var timelineEntity = await Database.Timelines.Where(t => t.Id == timelineId).Select(t => new { t.Visibility }).SingleAsync();
@@ -567,43 +476,24 @@ namespace Timeline.Services
             if (timelineEntity.Visibility == TimelineVisibility.Public)
                 return true;
 
-            if (timelineEntity.Visibility == TimelineVisibility.Register && username != null)
+            if (timelineEntity.Visibility == TimelineVisibility.Register && visitorId != null)
                 return true;
 
-            if (userId == null)
+            if (visitorId == null)
             {
                 return false;
             }
             else
             {
-                var memberEntity = await Database.TimelineMembers.Where(m => m.UserId == userId && m.TimelineId == timelineId).SingleOrDefaultAsync();
+                var memberEntity = await Database.TimelineMembers.Where(m => m.UserId == visitorId && m.TimelineId == timelineId).SingleOrDefaultAsync();
                 return memberEntity != null;
             }
         }
 
-        public async Task<bool> HasPostModifyPermission(string name, long id, string username)
+        public async Task<bool> HasPostModifyPermission(string name, long id, long modifierId)
         {
             if (name == null)
                 throw new ArgumentNullException(nameof(name));
-            if (username == null)
-                throw new ArgumentNullException(nameof(username));
-
-            {
-                var (result, message) = UsernameValidator.Validate(username);
-                if (!result)
-                {
-                    throw new UsernameBadFormatException(username);
-                }
-            }
-
-            var user = await Database.Users.Where(u => u.Name == username).Select(u => new { u.Id }).SingleOrDefaultAsync();
-
-            if (user == null)
-            {
-                throw new UserNotExistException(username);
-            }
-
-            var userId = user.Id;
 
             var timelineId = await FindTimelineId(name);
 
@@ -614,32 +504,13 @@ namespace Timeline.Services
             if (postEntity == null)
                 throw new TimelinePostNotExistException(id);
 
-            return timelineEntity.OwnerId == userId || postEntity.AuthorId == userId;
+            return timelineEntity.OwnerId == modifierId || postEntity.AuthorId == modifierId;
         }
 
-        public async Task<bool> IsMemberOf(string name, string username)
+        public async Task<bool> IsMemberOf(string name, long userId)
         {
             if (name == null)
                 throw new ArgumentNullException(nameof(name));
-            if (username == null)
-                throw new ArgumentNullException(nameof(username));
-
-            {
-                var (result, message) = UsernameValidator.Validate(username);
-                if (!result)
-                {
-                    throw new UsernameBadFormatException(username);
-                }
-            }
-
-            var user = await Database.Users.Where(u => u.Name == username).Select(u => new { u.Id }).SingleOrDefaultAsync();
-
-            if (user == null)
-            {
-                throw new UserNotExistException(username);
-            }
-
-            var userId = user.Id;
 
             var timelineId = await FindTimelineId(name);
 
@@ -648,38 +519,33 @@ namespace Timeline.Services
             if (userId == timelineEntity.OwnerId)
                 return true;
 
-            var timelineMemberEntity = await Database.TimelineMembers.Where(m => m.TimelineId == timelineId && m.UserId == userId).SingleOrDefaultAsync();
-
-            return timelineMemberEntity != null;
+            return await Database.TimelineMembers.AnyAsync(m => m.TimelineId == timelineId && m.UserId == userId);
         }
     }
 
     public class PersonalTimelineService : BaseTimelineService, IPersonalTimelineService
     {
-        public PersonalTimelineService(ILoggerFactory loggerFactory, DatabaseContext database, IClock clock)
-            : base(loggerFactory, database, clock)
+        public PersonalTimelineService(ILoggerFactory loggerFactory, DatabaseContext database, IUserService userService, IMapper mapper, IClock clock)
+            : base(loggerFactory, database, userService, mapper, clock)
         {
 
         }
 
         protected override async Task<long> FindTimelineId(string name)
         {
+            long userId;
+            try
             {
-                var (result, message) = UsernameValidator.Validate(name);
-                if (!result)
-                {
-                    throw new TimelineNameBadFormatException(name, new UsernameBadFormatException(name, message));
-                }
+                userId = await UserService.GetUserIdByUsername(name);
             }
-
-            var userEntity = await Database.Users.Where(u => u.Name == name).Select(u => new { u.Id }).SingleOrDefaultAsync();
-
-            if (userEntity == null)
+            catch (ArgumentException e)
             {
-                throw new TimelineNotExistException(name, new UserNotExistException(name));
+                throw new ArgumentException(ExceptionFindTimelineUsernameBadFormat, nameof(name), e);
+            }
+            catch (UserNotExistException e)
+            {
+                throw new TimelineNotExistException(name, e);
             }
-
-            var userId = userEntity.Id;
 
             var timelineEntity = await Database.Timelines.Where(t => t.OwnerId == userId && t.Name == null).Select(t => new { t.Id }).SingleOrDefaultAsync();
 
@@ -715,16 +581,20 @@ namespace Timeline.Services
 
             var timelineMemberEntities = await Database.TimelineMembers.Where(m => m.TimelineId == timelineId).Select(m => new { m.UserId }).ToListAsync();
 
-            var memberUsernameTasks = timelineMemberEntities.Select(m => Database.Users.Where(u => u.Id == m.UserId).Select(u => u.Name).SingleAsync()).ToArray();
+            var owner = Mapper.Map<UserInfo>(await UserService.GetUserById(timelineEntity.OwnerId));
 
-            var memberUsernames = await Task.WhenAll(memberUsernameTasks);
+            var members = new List<UserInfo>();
+            foreach (var memberEntity in timelineMemberEntities)
+            {
+                members.Add(Mapper.Map<UserInfo>(await UserService.GetUserById(memberEntity.UserId)));
+            }
 
             return new BaseTimelineInfo
             {
                 Description = timelineEntity.Description ?? "",
-                Owner = username,
+                Owner = owner,
                 Visibility = timelineEntity.Visibility,
-                Members = memberUsernames.ToList()
+                Members = members
             };
         }
 
diff --git a/Timeline/Services/User.cs b/Timeline/Services/User.cs
new file mode 100644
index 00000000..09a472e5
--- /dev/null
+++ b/Timeline/Services/User.cs
@@ -0,0 +1,18 @@
+namespace Timeline.Services
+{
+    public class User
+    {
+        public string? Username { get; set; }
+        public string? Nickname { get; set; }
+
+        #region adminsecret
+        public bool? Administrator { get; set; }
+        #endregion adminsecret
+
+        #region secret
+        public long? Id { get; set; }
+        public string? Password { get; set; }
+        public long? Version { get; set; }
+        #endregion secret
+    }
+}
diff --git a/Timeline/Services/UserAvatarService.cs b/Timeline/Services/UserAvatarService.cs
index 01201864..39b408e6 100644
--- a/Timeline/Services/UserAvatarService.cs
+++ b/Timeline/Services/UserAvatarService.cs
@@ -11,7 +11,6 @@ using System.Linq;
 using System.Threading.Tasks;
 using Timeline.Entities;
 using Timeline.Helpers;
-using Timeline.Models.Validation;
 
 namespace Timeline.Services
 {
@@ -61,36 +60,27 @@ namespace Timeline.Services
     public interface IUserAvatarService
     {
         /// <summary>
-        /// Get the etag of a user's avatar.
+        /// Get the etag of a user's avatar. Warning: This method does not check the user existence.
         /// </summary>
-        /// <param name="username">The username of the user to get avatar etag of.</param>
+        /// <param name="id">The id of the user to get avatar etag of.</param>
         /// <returns>The etag.</returns>
-        /// <exception cref="ArgumentNullException">Thrown if <paramref name="username"/> is null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown if the <paramref name="username"/> is of bad format.</exception>
-        /// <exception cref="UserNotExistException">Thrown if the user does not exist.</exception>
-        Task<string> GetAvatarETag(string username);
+        Task<string> GetAvatarETag(long id);
 
         /// <summary>
-        /// Get avatar of a user. If the user has no avatar set, a default one is returned.
+        /// Get avatar of a user. If the user has no avatar set, a default one is returned. Warning: This method does not check the user existence.
         /// </summary>
-        /// <param name="username">The username of the user to get avatar of.</param>
+        /// <param name="id">The id of the user to get avatar of.</param>
         /// <returns>The avatar info.</returns>
-        /// <exception cref="ArgumentNullException">Thrown if <paramref name="username"/> is null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown if the <paramref name="username"/> is of bad format.</exception>
-        /// <exception cref="UserNotExistException">Thrown if the user does not exist.</exception>
-        Task<AvatarInfo> GetAvatar(string username);
+        Task<AvatarInfo> GetAvatar(long id);
 
         /// <summary>
-        /// Set avatar for a user.
+        /// Set avatar for a user. Warning: This method does not check the user existence.
         /// </summary>
-        /// <param name="username">The username of the user to set avatar for.</param>
+        /// <param name="id">The id of the user to set avatar for.</param>
         /// <param name="avatar">The avatar. Can be null to delete the saved avatar.</param>
-        /// <exception cref="ArgumentNullException">Throw if <paramref name="username"/> is null.</exception>
         /// <exception cref="ArgumentException">Thrown if any field in <paramref name="avatar"/> is null when <paramref name="avatar"/> is not null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown if the <paramref name="username"/> is of bad format.</exception>
-        /// <exception cref="UserNotExistException">Thrown if the user does not exist.</exception>
         /// <exception cref="AvatarFormatException">Thrown if avatar is of bad format.</exception>
-        Task SetAvatar(string username, Avatar? avatar);
+        Task SetAvatar(long id, Avatar? avatar);
     }
 
     // TODO! : Make this configurable.
@@ -104,7 +94,6 @@ namespace Timeline.Services
         private DateTime _cacheLastModified;
         private string _cacheETag = default!;
 
-        [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods", Justification = "DI.")]
         public DefaultUserAvatarProvider(IWebHostEnvironment environment, IETagGenerator eTagGenerator)
         {
             _avatarPath = Path.Combine(environment.ContentRootPath, "default-avatar.png");
@@ -195,22 +184,18 @@ namespace Timeline.Services
             _clock = clock;
         }
 
-        public async Task<string> GetAvatarETag(string username)
+        public async Task<string> GetAvatarETag(long id)
         {
-            var userId = await DatabaseExtensions.CheckAndGetUser(_database.Users, username);
-
-            var eTag = (await _database.UserAvatars.Where(a => a.UserId == userId).Select(a => new { a.ETag }).SingleOrDefaultAsync())?.ETag;
+            var eTag = (await _database.UserAvatars.Where(a => a.UserId == id).Select(a => new { a.ETag }).SingleOrDefaultAsync())?.ETag;
             if (eTag == null)
                 return await _defaultUserAvatarProvider.GetDefaultAvatarETag();
             else
                 return eTag;
         }
 
-        public async Task<AvatarInfo> GetAvatar(string username)
+        public async Task<AvatarInfo> GetAvatar(long id)
         {
-            var userId = await DatabaseExtensions.CheckAndGetUser(_database.Users, username);
-
-            var avatarEntity = await _database.UserAvatars.Where(a => a.UserId == userId).Select(a => new { a.Type, a.Data, a.LastModified }).SingleOrDefaultAsync();
+            var avatarEntity = await _database.UserAvatars.Where(a => a.UserId == id).Select(a => new { a.Type, a.Data, a.LastModified }).SingleOrDefaultAsync();
 
             if (avatarEntity != null)
             {
@@ -240,7 +225,7 @@ namespace Timeline.Services
             return defaultAvatar;
         }
 
-        public async Task SetAvatar(string username, Avatar? avatar)
+        public async Task SetAvatar(long id, Avatar? avatar)
         {
             if (avatar != null)
             {
@@ -250,8 +235,7 @@ namespace Timeline.Services
                     throw new ArgumentException(Resources.Services.UserAvatarService.ExceptionAvatarTypeNullOrEmpty, nameof(avatar));
             }
 
-            var userId = await DatabaseExtensions.CheckAndGetUser(_database.Users, username);
-            var avatarEntity = await _database.UserAvatars.Where(a => a.UserId == userId).SingleOrDefaultAsync();
+            var avatarEntity = await _database.UserAvatars.Where(a => a.UserId == id).SingleOrDefaultAsync();
 
             if (avatar == null)
             {
@@ -275,13 +259,13 @@ namespace Timeline.Services
                 var create = avatarEntity == null;
                 if (create)
                 {
-                    avatarEntity = new UserAvatar();
+                    avatarEntity = new UserAvatarEntity();
                 }
                 avatarEntity!.Type = avatar.Type;
                 avatarEntity.Data = avatar.Data;
                 avatarEntity.ETag = await _eTagGenerator.Generate(avatar.Data);
                 avatarEntity.LastModified = _clock.GetCurrentTime();
-                avatarEntity.UserId = userId;
+                avatarEntity.UserId = id;
                 if (create)
                 {
                     _database.UserAvatars.Add(avatarEntity);
diff --git a/Timeline/Services/UserDetailService.cs b/Timeline/Services/UserDetailService.cs
deleted file mode 100644
index 0b24e4e2..00000000
--- a/Timeline/Services/UserDetailService.cs
+++ /dev/null
@@ -1,102 +0,0 @@
-using Microsoft.Extensions.Logging;
-using System;
-using System.Linq;
-using System.Threading.Tasks;
-using Timeline.Entities;
-using static Timeline.Resources.Services.UserDetailService;
-
-namespace Timeline.Services
-{
-    public interface IUserDetailService
-    {
-        /// <summary>
-        /// Get the nickname of the user with given username.
-        /// If the user does not set a nickname, the username is returned as the nickname.
-        /// </summary>
-        /// <param name="username">The username of the user to get nickname of.</param>
-        /// <returns>The nickname of the user.</returns>
-        /// <exception cref="ArgumentNullException">Thrown when <paramref name="username"/> is null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown when <paramref name="username"/> is of bad format.</exception>
-        /// <exception cref="UserNotExistException">Thrown when the user does not exist.</exception>
-        Task<string> GetNickname(string username);
-
-        /// <summary>
-        /// Set the nickname of the user with given username.
-        /// </summary>
-        /// <param name="username">The username of the user to set nickname of.</param>
-        /// <param name="nickname">The nickname. Pass null to unset.</param>
-        /// <exception cref="ArgumentNullException">Thrown when <paramref name="username"/> is null.</exception>
-        /// <exception cref="ArgumentException">Thrown when <paramref name="nickname"/> is not null but its length is bigger than 10.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown when <paramref name="username"/> is of bad format.</exception>
-        /// <exception cref="UserNotExistException">Thrown when the user does not exist.</exception>
-        Task SetNickname(string username, string? nickname);
-    }
-
-    public class UserDetailService : IUserDetailService
-    {
-        private readonly DatabaseContext _database;
-
-        private readonly ILogger<UserDetailService> _logger;
-
-        public UserDetailService(DatabaseContext database, ILogger<UserDetailService> logger)
-        {
-            _database = database;
-            _logger = logger;
-        }
-
-        public async Task<string> GetNickname(string username)
-        {
-            var userId = await DatabaseExtensions.CheckAndGetUser(_database.Users, username);
-            var nickname = _database.UserDetails.Where(d => d.UserId == userId).Select(d => new { d.Nickname }).SingleOrDefault()?.Nickname;
-            return nickname ?? username;
-        }
-
-        public async Task SetNickname(string username, string? nickname)
-        {
-            if (nickname != null && nickname.Length > 10)
-            {
-                throw new ArgumentException(ExceptionNicknameTooLong, nameof(nickname));
-            }
-            var userId = await DatabaseExtensions.CheckAndGetUser(_database.Users, username);
-            var userDetail = _database.UserDetails.Where(d => d.UserId == userId).SingleOrDefault();
-            if (nickname == null)
-            {
-                if (userDetail == null || userDetail.Nickname == null)
-                {
-                    return;
-                }
-                else
-                {
-                    userDetail.Nickname = null;
-                    await _database.SaveChangesAsync();
-                    _logger.LogInformation(LogEntityNicknameSetToNull, userId);
-                }
-            }
-            else
-            {
-                var create = userDetail == null;
-                if (create)
-                {
-                    userDetail = new UserDetail
-                    {
-                        UserId = userId
-                    };
-                }
-                userDetail!.Nickname = nickname;
-                if (create)
-                {
-                    _database.UserDetails.Add(userDetail);
-                }
-                await _database.SaveChangesAsync();
-                if (create)
-                {
-                    _logger.LogInformation(LogEntityNicknameCreate, userId, nickname);
-                }
-                else
-                {
-                    _logger.LogInformation(LogEntityNicknameSetNotNull, userId, nickname);
-                }
-            }
-        }
-    }
-}
diff --git a/Timeline/Services/UserNotExistException.cs b/Timeline/Services/UserNotExistException.cs
index c7317f56..fd0b5ecf 100644
--- a/Timeline/Services/UserNotExistException.cs
+++ b/Timeline/Services/UserNotExistException.cs
@@ -31,11 +31,11 @@ namespace Timeline.Services
         /// <summary>
         /// The username of the user that does not exist.
         /// </summary>
-        public string? Username { get; set; }
+        public string Username { get; set; } = "";
 
         /// <summary>
         /// The id of the user that does not exist.
         /// </summary>
-        public long? Id { get; set; }
+        public long Id { get; set; }
     }
 }
diff --git a/Timeline/Models/UserConvert.cs b/Timeline/Services/UserRoleConvert.cs
index 5b132421..f27ee1bb 100644
--- a/Timeline/Models/UserConvert.cs
+++ b/Timeline/Services/UserRoleConvert.cs
@@ -2,33 +2,9 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using Timeline.Entities;
-using Timeline.Services;
 
-namespace Timeline.Models
+namespace Timeline.Services
 {
-    public static class UserConvert
-    {
-        public static UserInfo CreateUserInfo(User user)
-        {
-            if (user == null)
-                throw new ArgumentNullException(nameof(user));
-            return new UserInfo(user.Name, UserRoleConvert.ToBool(user.RoleString));
-        }
-
-        internal static UserCache CreateUserCache(User user)
-        {
-            if (user == null)
-                throw new ArgumentNullException(nameof(user));
-            return new UserCache
-            {
-                Username = user.Name,
-                Administrator = UserRoleConvert.ToBool(user.RoleString),
-                Version = user.Version
-            };
-        }
-    }
-
-    [System.Diagnostics.CodeAnalysis.SuppressMessage("Design", "CA1062:Validate arguments of public methods", Justification = "No need.")]
     public static class UserRoleConvert
     {
         public const string UserRole = UserRoles.User;
diff --git a/Timeline/Services/UserService.cs b/Timeline/Services/UserService.cs
index 4012539f..7dc7159d 100644
--- a/Timeline/Services/UserService.cs
+++ b/Timeline/Services/UserService.cs
@@ -1,396 +1,462 @@
 using Microsoft.EntityFrameworkCore;
-using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Logging;
 using System;
+using System.Globalization;
 using System.Linq;
 using System.Threading.Tasks;
 using Timeline.Entities;
 using Timeline.Helpers;
-using Timeline.Models;
 using Timeline.Models.Validation;
+using static Timeline.Resources.Services.UserService;
 
 namespace Timeline.Services
 {
-    public class CreateTokenResult
-    {
-        public string Token { get; set; } = default!;
-        public UserInfo User { get; set; } = default!;
-    }
-
     public interface IUserService
     {
         /// <summary>
-        /// Try to anthenticate with the given username and password.
-        /// If success, create a token and return the user info.
+        /// Try to verify the given username and password.
         /// </summary>
-        /// <param name="username">The username of the user to anthenticate.</param>
-        /// <param name="password">The password of the user to anthenticate.</param>
-        /// <param name="expires">The expired time point. Null then use default. See <see cref="JwtService.GenerateJwtToken(TokenInfo, DateTime?)"/> for what is default.</param>
-        /// <returns>An <see cref="CreateTokenResult"/> containing the created token and user info.</returns>
+        /// <param name="username">The username of the user to verify.</param>
+        /// <param name="password">The password of the user to verify.</param>
+        /// <returns>The user info and auth info.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="username"/> or <paramref name="password"/> is null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown when username is of bad format.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="username"/> is of bad format or <paramref name="password"/> is empty.</exception>
         /// <exception cref="UserNotExistException">Thrown when the user with given username does not exist.</exception>
         /// <exception cref="BadPasswordException">Thrown when password is wrong.</exception>
-        Task<CreateTokenResult> CreateToken(string username, string password, DateTime? expires = null);
+        Task<User> VerifyCredential(string username, string password);
 
         /// <summary>
-        /// Verify the given token.
-        /// If success, return the user info.
+        /// Try to get a user by id.
         /// </summary>
-        /// <param name="token">The token to verify.</param>
-        /// <returns>The user info specified by the token.</returns>
-        /// <exception cref="ArgumentNullException">Thrown when <paramref name="token"/> is null.</exception>
-        /// <exception cref="JwtVerifyException">Thrown when the token is of bad format. Thrown by <see cref="JwtService.VerifyJwtToken(string)"/>.</exception>
-        /// <exception cref="UserNotExistException">Thrown when the user specified by the token does not exist. Usually it has been deleted after the token was issued.</exception>
-        Task<UserInfo> VerifyToken(string token);
+        /// <param name="id">The id of the user.</param>
+        /// <returns>The user info.</returns>
+        /// <exception cref="UserNotExistException">Thrown when the user with given id does not exist.</exception>
+        Task<User> GetUserById(long id);
 
         /// <summary>
         /// Get the user info of given username.
         /// </summary>
         /// <param name="username">Username of the user.</param>
-        /// <returns>The info of the user. Null if the user of given username does not exists.</returns>
+        /// <returns>The info of the user.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="username"/> is null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown when <paramref name="username"/> is of bad format.</exception>
-        Task<UserInfo> GetUser(string username);
+        /// <exception cref="ArgumentException">Thrown when <paramref name="username"/> is of bad format.</exception>
+        /// <exception cref="UserNotExistException">Thrown when the user with given username does not exist.</exception>
+        Task<User> GetUserByUsername(string username);
+
+        /// <summary>
+        /// Get the user id of given username.
+        /// </summary>
+        /// <param name="username">Username of the user.</param>
+        /// <returns>The id of the user.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="username"/> is null.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="username"/> is of bad format.</exception>
+        /// <exception cref="UserNotExistException">Thrown when the user with given username does not exist.</exception>
+        Task<long> GetUserIdByUsername(string username);
 
         /// <summary>
         /// List all users.
         /// </summary>
         /// <returns>The user info of users.</returns>
-        Task<UserInfo[]> ListUsers();
+        Task<User[]> GetUsers();
 
         /// <summary>
-        /// Create or modify a user with given username.
-        /// Username must be match with [a-zA-z0-9-_].
+        /// Create a user with given info.
         /// </summary>
-        /// <param name="username">Username of user.</param>
-        /// <param name="password">Password of user.</param>
-        /// <param name="administrator">Whether the user is administrator.</param>
-        /// <returns>
-        /// Return <see cref="PutResult.Create"/> if a new user is created.
-        /// Return <see cref="PutResult.Modify"/> if a existing user is modified.
-        /// </returns>
-        /// <exception cref="ArgumentNullException">Thrown when <paramref name="username"/> or <paramref name="password"/> is null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown when <paramref name="username"/> is of bad format.</exception>
-        Task<PutResult> PutUser(string username, string password, bool administrator);
+        /// <param name="info">The info of new user.</param>
+        /// <param name="password">The password, can't be null or empty.</param>
+        /// <returns>The the new user.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="info"/>is null.</exception>
+        /// <exception cref="ArgumentException">Thrown when some fields in <paramref name="info"/> is bad.</exception>
+        /// <exception cref="ConflictException">Thrown when a user with given username already exists.</exception>
+        /// <remarks>
+        /// <see cref="User.Username"/> must not be null and must be a valid username.
+        /// <see cref="User.Password"/> must not be null or empty.
+        /// <see cref="User.Administrator"/> is false by default (null).
+        /// <see cref="User.Nickname"/> must be a valid nickname if set. It is empty by default.
+        /// Other fields are ignored.
+        /// </remarks>
+        Task<User> CreateUser(User info);
 
         /// <summary>
-        /// Partially modify a user of given username.
+        /// Modify a user's info.
+        /// </summary>
+        /// <param name="id">The id of the user.</param>
+        /// <param name="info">The new info. May be null.</param>
+        /// <returns>The new user info.</returns>
+        /// <exception cref="ArgumentException">Thrown when some fields in <paramref name="info"/> is bad.</exception>
+        /// <exception cref="UserNotExistException">Thrown when user with given id does not exist.</exception>
+        /// <remarks>
+        /// Only <see cref="User.Username"/>, <see cref="User.Administrator"/>, <see cref="User.Password"/> and <see cref="User.Nickname"/> will be used.
+        /// If null, then not change.
+        /// Other fields are ignored.
+        /// Version will increase if password is changed.
+        /// 
+        /// <see cref="User.Username"/> must be a valid username if set.
+        /// <see cref="User.Password"/> can't be empty if set.
+        /// <see cref="User.Nickname"/> must be a valid nickname if set.
         /// 
-        /// Note that whether actually modified or not, Version of the user will always increase.
+        /// </remarks>
+        /// <seealso cref="ModifyUser(string, User)"/>
+        Task<User> ModifyUser(long id, User? info);
+
+        /// <summary>
+        /// Modify a user's info.
         /// </summary>
-        /// <param name="username">Username of the user to modify. Can't be null.</param>
-        /// <param name="password">New password. Null if not modify.</param>
-        /// <param name="administrator">Whether the user is administrator. Null if not modify.</param>
-        /// <exception cref="ArgumentNullException">Thrown if <paramref name="username"/> is null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown when <paramref name="username"/> is of bad format.</exception>
-        /// <exception cref="UserNotExistException">Thrown if the user with given username does not exist.</exception>
-        Task PatchUser(string username, string? password, bool? administrator);
+        /// <param name="username">The username of the user.</param>
+        /// <param name="info">The new info. May be null.</param>
+        /// <returns>The new user info.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="username"/> is null.</exception>
+        /// <exception cref="ArgumentException">Thrown when <paramref name="username"/> is of bad format or some fields in <paramref name="info"/> is bad.</exception>
+        /// <exception cref="UserNotExistException">Thrown when user with given id does not exist.</exception>
+        /// <exception cref="ConflictException">Thrown when user with the newusername already exist.</exception>
+        /// <remarks>
+        /// Only <see cref="User.Administrator"/>, <see cref="User.Password"/> and <see cref="User.Nickname"/> will be used.
+        /// If null, then not change.
+        /// Other fields are ignored.
+        /// After modified, even if nothing is changed, version will increase.
+        /// 
+        /// <see cref="User.Username"/> must be a valid username if set.
+        /// <see cref="User.Password"/> can't be empty if set.
+        /// <see cref="User.Nickname"/> must be a valid nickname if set.
+        /// 
+        /// Note: Whether <see cref="User.Version"/> is set or not, version will increase and not set to the specified value if there is one.
+        /// </remarks>
+        /// <seealso cref="ModifyUser(long, User)"/>
+        Task<User> ModifyUser(string username, User? info);
+
+        /// <summary>
+        /// Delete a user of given id.
+        /// </summary>
+        /// <param name="id">Id of the user to delete.</param>
+        /// <returns>True if user is deleted, false if user not exist.</returns>
+        Task<bool> DeleteUser(long id);
 
         /// <summary>
         /// Delete a user of given username.
         /// </summary>
-        /// <param name="username">Username of thet user to delete. Can't be null.</param>
+        /// <param name="username">Username of the user to delete. Can't be null.</param>
+        /// <returns>True if user is deleted, false if user not exist.</returns>
         /// <exception cref="ArgumentNullException">Thrown if <paramref name="username"/> is null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown when <paramref name="username"/> is of bad format.</exception>
-        /// <exception cref="UserNotExistException">Thrown if the user with given username does not exist.</exception>
-        Task DeleteUser(string username);
+        /// <exception cref="ArgumentException">Thrown when <paramref name="username"/> is of bad format.</exception>
+        Task<bool> DeleteUser(string username);
 
         /// <summary>
         /// Try to change a user's password with old password.
         /// </summary>
-        /// <param name="username">The name of user to change password of.</param>
-        /// <param name="oldPassword">The user's old password.</param>
-        /// <param name="newPassword">The user's new password.</param>
-        /// <exception cref="ArgumentNullException">Thrown if <paramref name="username"/> or <paramref name="oldPassword"/> or <paramref name="newPassword"/> is null.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown when <paramref name="username"/> is of bad format.</exception>
+        /// <param name="id">The id of user to change password of.</param>
+        /// <param name="oldPassword">Old password.</param>
+        /// <param name="newPassword">New password.</param>
+        /// <exception cref="ArgumentNullException">Thrown if <paramref name="oldPassword"/> or <paramref name="newPassword"/> is null.</exception>
+        /// <exception cref="ArgumentException">Thrown if <paramref name="oldPassword"/> or <paramref name="newPassword"/> is empty.</exception>
         /// <exception cref="UserNotExistException">Thrown if the user with given username does not exist.</exception>
         /// <exception cref="BadPasswordException">Thrown if the old password is wrong.</exception>
-        Task ChangePassword(string username, string oldPassword, string newPassword);
-
-        /// <summary>
-        /// Change a user's username.
-        /// </summary>
-        /// <param name="oldUsername">The user's old username.</param>
-        /// <param name="newUsername">The new username.</param>
-        /// <exception cref="ArgumentNullException">Thrown if <paramref name="oldUsername"/> or <paramref name="newUsername"/> is null.</exception>
-        /// <exception cref="UserNotExistException">Thrown if the user with old username does not exist.</exception>
-        /// <exception cref="UsernameBadFormatException">Thrown if the <paramref name="oldUsername"/> or <paramref name="newUsername"/> is of bad format.</exception>
-        /// <exception cref="UsernameConfictException">Thrown if user with the new username already exists.</exception>
-        Task ChangeUsername(string oldUsername, string newUsername);
-    }
-
-    internal class UserCache
-    {
-        public string Username { get; set; } = default!;
-        public bool Administrator { get; set; }
-        public long Version { get; set; }
-
-        public UserInfo ToUserInfo()
-        {
-            return new UserInfo(Username, Administrator);
-        }
+        Task ChangePassword(long id, string oldPassword, string newPassword);
     }
 
     public class UserService : IUserService
     {
         private readonly ILogger<UserService> _logger;
 
-        private readonly IMemoryCache _memoryCache;
         private readonly DatabaseContext _databaseContext;
 
-        private readonly IJwtService _jwtService;
         private readonly IPasswordService _passwordService;
 
-        private readonly UsernameValidator _usernameValidator;
-
-        public UserService(ILogger<UserService> logger, IMemoryCache memoryCache, DatabaseContext databaseContext, IJwtService jwtService, IPasswordService passwordService)
+        private readonly UsernameValidator _usernameValidator = new UsernameValidator();
+        private readonly NicknameValidator _nicknameValidator = new NicknameValidator();
+        public UserService(ILogger<UserService> logger, DatabaseContext databaseContext, IPasswordService passwordService)
         {
             _logger = logger;
-            _memoryCache = memoryCache;
             _databaseContext = databaseContext;
-            _jwtService = jwtService;
             _passwordService = passwordService;
-
-            _usernameValidator = new UsernameValidator();
         }
 
-        private static string GenerateCacheKeyByUserId(long id) => $"user:{id}";
+        private void CheckUsernameFormat(string username, string? paramName)
+        {
+            if (!_usernameValidator.Validate(username, out var message))
+            {
+                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, ExceptionUsernameBadFormat, message), paramName);
+            }
+        }
 
-        private void RemoveCache(long id)
+        private static void CheckPasswordFormat(string password, string? paramName)
         {
-            var key = GenerateCacheKeyByUserId(id);
-            _memoryCache.Remove(key);
-            _logger.LogInformation(Log.Format(Resources.Services.UserService.LogCacheRemove, ("Key", key)));
+            if (password.Length == 0)
+            {
+                throw new ArgumentException(ExceptionPasswordEmpty, paramName);
+            }
         }
 
-        private void CheckUsernameFormat(string username, string? additionalMessage = null)
+        private void CheckNicknameFormat(string nickname, string? paramName)
         {
-            var (result, message) = _usernameValidator.Validate(username);
-            if (!result)
+            if (!_nicknameValidator.Validate(nickname, out var message))
             {
-                if (additionalMessage == null)
-                    throw new UsernameBadFormatException(username, message);
-                else
-                    throw new UsernameBadFormatException(username, additionalMessage + message);
+                throw new ArgumentException(string.Format(CultureInfo.CurrentCulture, ExceptionNicknameBadFormat, message), paramName);
             }
         }
 
-        public async Task<CreateTokenResult> CreateToken(string username, string password, DateTime? expires)
+        private static void ThrowUsernameConflict()
+        {
+            throw new ConflictException(ExceptionUsernameConflict);
+        }
+
+        private static User CreateUserFromEntity(UserEntity entity)
+        {
+            return new User
+            {
+                Username = entity.Username,
+                Administrator = UserRoleConvert.ToBool(entity.Roles),
+                Nickname = string.IsNullOrEmpty(entity.Nickname) ? entity.Username : entity.Nickname,
+                Id = entity.Id,
+                Version = entity.Version
+            };
+        }
+
+        public async Task<User> VerifyCredential(string username, string password)
         {
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
             if (password == null)
                 throw new ArgumentNullException(nameof(password));
-            CheckUsernameFormat(username);
 
-            // We need password info, so always check the database.
-            var user = await _databaseContext.Users.Where(u => u.Name == username).SingleOrDefaultAsync();
+            CheckUsernameFormat(username, nameof(username));
+            CheckPasswordFormat(password, nameof(password));
 
-            if (user == null)
+            var entity = await _databaseContext.Users.Where(u => u.Username == username).SingleOrDefaultAsync();
+
+            if (entity == null)
                 throw new UserNotExistException(username);
 
-            if (!_passwordService.VerifyPassword(user.EncryptedPassword, password))
+            if (!_passwordService.VerifyPassword(entity.Password, password))
                 throw new BadPasswordException(password);
 
-            var token = _jwtService.GenerateJwtToken(new TokenInfo
-            {
-                Id = user.Id,
-                Version = user.Version
-            }, expires);
-
-            return new CreateTokenResult
-            {
-                Token = token,
-                User = UserConvert.CreateUserInfo(user)
-            };
+            return CreateUserFromEntity(entity);
         }
 
-        public async Task<UserInfo> VerifyToken(string token)
+        public async Task<User> GetUserById(long id)
         {
-            if (token == null)
-                throw new ArgumentNullException(nameof(token));
+            var user = await _databaseContext.Users.Where(u => u.Id == id).SingleOrDefaultAsync();
 
-            TokenInfo tokenInfo;
-            tokenInfo = _jwtService.VerifyJwtToken(token);
+            if (user == null)
+                throw new UserNotExistException(id);
 
-            var id = tokenInfo.Id;
-            var key = GenerateCacheKeyByUserId(id);
-            if (!_memoryCache.TryGetValue<UserCache>(key, out var cache))
-            {
-                // no cache, check the database
-                var user = await _databaseContext.Users.Where(u => u.Id == id).SingleOrDefaultAsync();
+            return CreateUserFromEntity(user);
+        }
 
-                if (user == null)
-                    throw new UserNotExistException(id);
+        public async Task<User> GetUserByUsername(string username)
+        {
+            if (username == null)
+                throw new ArgumentNullException(nameof(username));
 
-                // create cache
-                cache = UserConvert.CreateUserCache(user);
-                _memoryCache.CreateEntry(key).SetValue(cache);
-                _logger.LogInformation(Log.Format(Resources.Services.UserService.LogCacheCreate, ("Key", key)));
-            }
+            CheckUsernameFormat(username, nameof(username));
 
-            if (tokenInfo.Version != cache.Version)
-                throw new JwtVerifyException(new JwtBadVersionException(tokenInfo.Version, cache.Version), JwtVerifyException.ErrorCodes.OldVersion);
+            var entity = await _databaseContext.Users.Where(user => user.Username == username).SingleOrDefaultAsync();
 
-            return cache.ToUserInfo();
+            if (entity == null)
+                throw new UserNotExistException(username);
+
+            return CreateUserFromEntity(entity);
         }
 
-        public async Task<UserInfo> GetUser(string username)
+        public async Task<long> GetUserIdByUsername(string username)
         {
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
-            CheckUsernameFormat(username);
 
-            return await _databaseContext.Users
-                .Where(user => user.Name == username)
-                .Select(user => UserConvert.CreateUserInfo(user))
-                .SingleOrDefaultAsync();
+            CheckUsernameFormat(username, nameof(username));
+
+            var entity = await _databaseContext.Users.Where(user => user.Username == username).Select(u => new { u.Id }).SingleOrDefaultAsync();
+
+            if (entity == null)
+                throw new UserNotExistException(username);
+
+            return entity.Id;
         }
 
-        public async Task<UserInfo[]> ListUsers()
+        public async Task<User[]> GetUsers()
         {
-            return await _databaseContext.Users
-                .Select(user => UserConvert.CreateUserInfo(user))
-                .ToArrayAsync();
+            var entities = await _databaseContext.Users.ToArrayAsync();
+            return entities.Select(user => CreateUserFromEntity(user)).ToArray();
         }
 
-        public async Task<PutResult> PutUser(string username, string password, bool administrator)
+        public async Task<User> CreateUser(User info)
         {
-            if (username == null)
-                throw new ArgumentNullException(nameof(username));
-            if (password == null)
-                throw new ArgumentNullException(nameof(password));
-            CheckUsernameFormat(username);
+            if (info == null)
+                throw new ArgumentNullException(nameof(info));
 
-            var user = await _databaseContext.Users.Where(u => u.Name == username).SingleOrDefaultAsync();
+            if (info.Username == null)
+                throw new ArgumentException(ExceptionUsernameNull, nameof(info));
+            CheckUsernameFormat(info.Username, nameof(info));
 
-            if (user == null)
-            {
-                var newUser = new User
-                {
-                    Name = username,
-                    EncryptedPassword = _passwordService.HashPassword(password),
-                    RoleString = UserRoleConvert.ToString(administrator),
-                    Avatar = null
-                };
-                await _databaseContext.AddAsync(newUser);
-                await _databaseContext.SaveChangesAsync();
-                _logger.LogInformation(Log.Format(Resources.Services.UserService.LogDatabaseCreate,
-                    ("Id", newUser.Id), ("Username", username), ("Administrator", administrator)));
-                return PutResult.Create;
-            }
+            if (info.Password == null)
+                throw new ArgumentException(ExceptionPasswordNull, nameof(info));
+            CheckPasswordFormat(info.Password, nameof(info));
+
+            if (info.Nickname != null)
+                CheckNicknameFormat(info.Nickname, nameof(info));
+
+            var username = info.Username;
+
+            var conflict = await _databaseContext.Users.AnyAsync(u => u.Username == username);
+            if (conflict)
+                ThrowUsernameConflict();
 
-            user.EncryptedPassword = _passwordService.HashPassword(password);
-            user.RoleString = UserRoleConvert.ToString(administrator);
-            user.Version += 1;
+            var administrator = info.Administrator ?? false;
+            var password = info.Password;
+            var nickname = info.Nickname;
+
+            var newEntity = new UserEntity
+            {
+                Username = username,
+                Password = _passwordService.HashPassword(password),
+                Roles = UserRoleConvert.ToString(administrator),
+                Nickname = nickname,
+                Version = 1
+            };
+            _databaseContext.Users.Add(newEntity);
             await _databaseContext.SaveChangesAsync();
-            _logger.LogInformation(Log.Format(Resources.Services.UserService.LogDatabaseUpdate,
-                ("Id", user.Id), ("Username", username), ("Administrator", administrator)));
 
-            //clear cache
-            RemoveCache(user.Id);
+            _logger.LogInformation(Log.Format(LogDatabaseCreate,
+                ("Id", newEntity.Id), ("Username", username), ("Administrator", administrator)));
 
-            return PutResult.Modify;
+            return CreateUserFromEntity(newEntity);
         }
 
-        public async Task PatchUser(string username, string? password, bool? administrator)
+        private void ValidateModifyUserInfo(User? info)
         {
-            if (username == null)
-                throw new ArgumentNullException(nameof(username));
-            CheckUsernameFormat(username);
+            if (info != null)
+            {
+                if (info.Username != null)
+                    CheckUsernameFormat(info.Username, nameof(info));
 
-            var user = await _databaseContext.Users.Where(u => u.Name == username).SingleOrDefaultAsync();
-            if (user == null)
-                throw new UserNotExistException(username);
+                if (info.Password != null)
+                    CheckPasswordFormat(info.Password, nameof(info));
 
-            if (password != null)
-            {
-                user.EncryptedPassword = _passwordService.HashPassword(password);
+                if (info.Nickname != null)
+                    CheckNicknameFormat(info.Nickname, nameof(info));
             }
+        }
 
-            if (administrator != null)
+        private async Task UpdateUserEntity(UserEntity entity, User? info)
+        {
+            if (info != null)
             {
-                user.RoleString = UserRoleConvert.ToString(administrator.Value);
+                var username = info.Username;
+                if (username != null)
+                {
+                    var conflict = await _databaseContext.Users.AnyAsync(u => u.Username == username);
+                    if (conflict)
+                        ThrowUsernameConflict();
+
+                    entity.Username = username;
+                }
+
+                var password = info.Password;
+                if (password != null)
+                {
+                    entity.Password = _passwordService.HashPassword(password);
+                    entity.Version += 1;
+                }
+
+                var administrator = info.Administrator;
+                if (administrator.HasValue)
+                {
+                    entity.Roles = UserRoleConvert.ToString(administrator.Value);
+                }
+
+                var nickname = info.Nickname;
+                if (nickname != null)
+                {
+                    entity.Nickname = nickname;
+                }
             }
+        }
+
+
+        public async Task<User> ModifyUser(long id, User? info)
+        {
+            ValidateModifyUserInfo(info);
+
+            var entity = await _databaseContext.Users.Where(u => u.Id == id).SingleOrDefaultAsync();
+            if (entity == null)
+                throw new UserNotExistException(id);
+
+            await UpdateUserEntity(entity, info);
 
-            user.Version += 1;
             await _databaseContext.SaveChangesAsync();
-            _logger.LogInformation(Resources.Services.UserService.LogDatabaseUpdate, ("Id", user.Id));
+            _logger.LogInformation(LogDatabaseUpdate, ("Id", id));
 
-            //clear cache
-            RemoveCache(user.Id);
+            return CreateUserFromEntity(entity);
         }
 
-        public async Task DeleteUser(string username)
+        public async Task<User> ModifyUser(string username, User? info)
         {
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
-            CheckUsernameFormat(username);
+            CheckUsernameFormat(username, nameof(username));
 
-            var user = await _databaseContext.Users.Where(u => u.Name == username).SingleOrDefaultAsync();
-            if (user == null)
+            ValidateModifyUserInfo(info);
+
+            var entity = await _databaseContext.Users.Where(u => u.Username == username).SingleOrDefaultAsync();
+            if (entity == null)
                 throw new UserNotExistException(username);
 
-            _databaseContext.Users.Remove(user);
+            await UpdateUserEntity(entity, info);
+
             await _databaseContext.SaveChangesAsync();
-            _logger.LogInformation(Log.Format(Resources.Services.UserService.LogDatabaseRemove,
-                ("Id", user.Id)));
+            _logger.LogInformation(LogDatabaseUpdate, ("Username", username));
+
+            return CreateUserFromEntity(entity);
+        }
+
+        public async Task<bool> DeleteUser(long id)
+        {
+            var user = await _databaseContext.Users.Where(u => u.Id == id).SingleOrDefaultAsync();
+            if (user == null)
+                return false;
 
-            //clear cache
-            RemoveCache(user.Id);
+            _databaseContext.Users.Remove(user);
+            await _databaseContext.SaveChangesAsync();
+            _logger.LogInformation(Log.Format(LogDatabaseRemove, ("Id", id), ("Username", user.Username)));
+            return true;
         }
 
-        public async Task ChangePassword(string username, string oldPassword, string newPassword)
+        public async Task<bool> DeleteUser(string username)
         {
             if (username == null)
                 throw new ArgumentNullException(nameof(username));
-            if (oldPassword == null)
-                throw new ArgumentNullException(nameof(oldPassword));
-            if (newPassword == null)
-                throw new ArgumentNullException(nameof(newPassword));
-            CheckUsernameFormat(username);
+            CheckUsernameFormat(username, nameof(username));
 
-            var user = await _databaseContext.Users.Where(u => u.Name == username).SingleOrDefaultAsync();
+            var user = await _databaseContext.Users.Where(u => u.Username == username).SingleOrDefaultAsync();
             if (user == null)
-                throw new UserNotExistException(username);
-
-            var verifyResult = _passwordService.VerifyPassword(user.EncryptedPassword, oldPassword);
-            if (!verifyResult)
-                throw new BadPasswordException(oldPassword);
+                return false;
 
-            user.EncryptedPassword = _passwordService.HashPassword(newPassword);
-            user.Version += 1;
+            _databaseContext.Users.Remove(user);
             await _databaseContext.SaveChangesAsync();
-            _logger.LogInformation(Log.Format(Resources.Services.UserService.LogDatabaseUpdate,
-                ("Id", user.Id), ("Operation", "Change password")));
-            //clear cache
-            RemoveCache(user.Id);
+            _logger.LogInformation(Log.Format(LogDatabaseRemove, ("Id", user.Id), ("Username", username)));
+            return true;
         }
 
-        public async Task ChangeUsername(string oldUsername, string newUsername)
+        public async Task ChangePassword(long id, string oldPassword, string newPassword)
         {
-            if (oldUsername == null)
-                throw new ArgumentNullException(nameof(oldUsername));
-            if (newUsername == null)
-                throw new ArgumentNullException(nameof(newUsername));
-            CheckUsernameFormat(oldUsername, Resources.Services.UserService.ExceptionOldUsernameBadFormat);
-            CheckUsernameFormat(newUsername, Resources.Services.UserService.ExceptionNewUsernameBadFormat);
-
-            var user = await _databaseContext.Users.Where(u => u.Name == oldUsername).SingleOrDefaultAsync();
-            if (user == null)
-                throw new UserNotExistException(oldUsername);
+            if (oldPassword == null)
+                throw new ArgumentNullException(nameof(oldPassword));
+            if (newPassword == null)
+                throw new ArgumentNullException(nameof(newPassword));
+            CheckPasswordFormat(oldPassword, nameof(oldPassword));
+            CheckPasswordFormat(newPassword, nameof(newPassword));
+
+            var entity = await _databaseContext.Users.Where(u => u.Id == id).SingleOrDefaultAsync();
 
-            var conflictUser = await _databaseContext.Users.Where(u => u.Name == newUsername).SingleOrDefaultAsync();
-            if (conflictUser != null)
-                throw new UsernameConfictException(newUsername);
+            if (entity == null)
+                throw new UserNotExistException(id);
+
+            if (!_passwordService.VerifyPassword(entity.Password, oldPassword))
+                throw new BadPasswordException(oldPassword);
 
-            user.Name = newUsername;
-            user.Version += 1;
+            entity.Password = _passwordService.HashPassword(newPassword);
+            entity.Version += 1;
             await _databaseContext.SaveChangesAsync();
-            _logger.LogInformation(Log.Format(Resources.Services.UserService.LogDatabaseUpdate,
-                ("Id", user.Id), ("Old Username", oldUsername), ("New Username", newUsername)));
-            RemoveCache(user.Id);
+            _logger.LogInformation(Log.Format(LogDatabaseUpdate, ("Id", id), ("Operation", "Change password")));
         }
     }
 }
diff --git a/Timeline/Services/UserTokenException.cs b/Timeline/Services/UserTokenException.cs
new file mode 100644
index 00000000..ed0bae1a
--- /dev/null
+++ b/Timeline/Services/UserTokenException.cs
@@ -0,0 +1,68 @@
+using System;
+
+namespace Timeline.Services
+{
+
+    [Serializable]
+    public class UserTokenException : Exception
+    {
+        public UserTokenException() { }
+        public UserTokenException(string message) : base(message) { }
+        public UserTokenException(string message, Exception inner) : base(message, inner) { }
+        public UserTokenException(string token, string message) : base(message) { Token = token; }
+        public UserTokenException(string token, string message, Exception inner) : base(message, inner) { Token = token; }
+        protected UserTokenException(
+          System.Runtime.Serialization.SerializationInfo info,
+          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+
+        public string Token { get; private set; } = "";
+    }
+
+
+    [Serializable]
+    public class UserTokenTimeExpireException : UserTokenException
+    {
+        public UserTokenTimeExpireException() : base(Resources.Services.Exception.UserTokenTimeExpireException) { }
+        public UserTokenTimeExpireException(string message) : base(message) { }
+        public UserTokenTimeExpireException(string message, Exception inner) : base(message, inner) { }
+        public UserTokenTimeExpireException(string token, DateTime expireTime, DateTime verifyTime) : base(token, Resources.Services.Exception.UserTokenTimeExpireException) { ExpireTime = expireTime; VerifyTime = verifyTime; }
+        public UserTokenTimeExpireException(string token, DateTime expireTime, DateTime verifyTime, Exception inner) : base(token, Resources.Services.Exception.UserTokenTimeExpireException, inner) { ExpireTime = expireTime; VerifyTime = verifyTime; }
+        protected UserTokenTimeExpireException(
+          System.Runtime.Serialization.SerializationInfo info,
+          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+
+        public DateTime ExpireTime { get; private set; } = default;
+
+        public DateTime VerifyTime { get; private set; } = default;
+    }
+
+    [Serializable]
+    public class UserTokenBadVersionException : UserTokenException
+    {
+        public UserTokenBadVersionException() : base(Resources.Services.Exception.UserTokenBadVersionException) { }
+        public UserTokenBadVersionException(string message) : base(message) { }
+        public UserTokenBadVersionException(string message, Exception inner) : base(message, inner) { }
+        public UserTokenBadVersionException(string token, long tokenVersion, long requiredVersion) : base(token, Resources.Services.Exception.UserTokenBadVersionException) { TokenVersion = tokenVersion; RequiredVersion = requiredVersion; }
+        public UserTokenBadVersionException(string token, long tokenVersion, long requiredVersion, Exception inner) : base(token, Resources.Services.Exception.UserTokenBadVersionException, inner) { TokenVersion = tokenVersion; RequiredVersion = requiredVersion; }
+        protected UserTokenBadVersionException(
+          System.Runtime.Serialization.SerializationInfo info,
+          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+
+        public long TokenVersion { get; set; }
+
+        public long RequiredVersion { get; set; }
+    }
+
+    [Serializable]
+    public class UserTokenBadFormatException : UserTokenException
+    {
+        public UserTokenBadFormatException() : base(Resources.Services.Exception.UserTokenBadFormatException) { }
+        public UserTokenBadFormatException(string token) : base(token, Resources.Services.Exception.UserTokenBadFormatException) { }
+        public UserTokenBadFormatException(string token, string message) : base(token, message) { }
+        public UserTokenBadFormatException(string token, Exception inner) : base(token, Resources.Services.Exception.UserTokenBadFormatException, inner) { }
+        public UserTokenBadFormatException(string token, string message, Exception inner) : base(token, message, inner) { }
+        protected UserTokenBadFormatException(
+          System.Runtime.Serialization.SerializationInfo info,
+          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+    }
+}
diff --git a/Timeline/Services/UserTokenManager.cs b/Timeline/Services/UserTokenManager.cs
new file mode 100644
index 00000000..3e9ef3d4
--- /dev/null
+++ b/Timeline/Services/UserTokenManager.cs
@@ -0,0 +1,93 @@
+using Microsoft.Extensions.Logging;
+using System;
+using System.Threading.Tasks;
+using Timeline.Models;
+
+namespace Timeline.Services
+{
+    public class UserTokenCreateResult
+    {
+        public string Token { get; set; } = default!;
+        public User User { get; set; } = default!;
+    }
+
+    public interface IUserTokenManager
+    {
+        /// <summary>
+        /// Try to create a token for given username and password.
+        /// </summary>
+        /// <param name="username">The username.</param>
+        /// <param name="password">The password.</param>
+        /// <param name="expireAt">The expire time of the token.</param>
+        /// <returns>The created token and the user info.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="username"/> or <paramref name="password"/> is null.</exception>
+        /// <exception cref="UsernameBadFormatException">Thrown when <paramref name="username"/> is of bad format.</exception>
+        /// <exception cref="UserNotExistException">Thrown when the user with <paramref name="username"/> does not exist.</exception>
+        /// <exception cref="BadPasswordException">Thrown when <paramref name="password"/> is wrong.</exception>
+        public Task<UserTokenCreateResult> CreateToken(string username, string password, DateTime? expireAt = null);
+
+        /// <summary>
+        /// Verify a token and get the saved user info. This also check the database for existence of the user.
+        /// </summary>
+        /// <param name="token">The token.</param>
+        /// <returns>The user stored in token.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="token"/> is null.</exception>
+        /// <exception cref="UserTokenTimeExpireException">Thrown when the token is expired.</exception>
+        /// <exception cref="UserTokenBadVersionException">Thrown when the token is of bad version.</exception>
+        /// <exception cref="UserTokenBadFormatException">Thrown when the token is of bad format.</exception>
+        /// <exception cref="UserNotExistException">Thrown when the user specified by the token does not exist. Usually the user had been deleted after the token was issued.</exception>
+        public Task<User> VerifyToken(string token);
+    }
+
+    public class UserTokenManager : IUserTokenManager
+    {
+        private readonly ILogger<UserTokenManager> _logger;
+        private readonly IUserService _userService;
+        private readonly IUserTokenService _userTokenService;
+        private readonly IClock _clock;
+
+        public UserTokenManager(ILogger<UserTokenManager> logger, IUserService userService, IUserTokenService userTokenService, IClock clock)
+        {
+            _logger = logger;
+            _userService = userService;
+            _userTokenService = userTokenService;
+            _clock = clock;
+        }
+
+        public async Task<UserTokenCreateResult> CreateToken(string username, string password, DateTime? expireAt = null)
+        {
+            if (username == null)
+                throw new ArgumentNullException(nameof(username));
+            if (password == null)
+                throw new ArgumentNullException(nameof(password));
+
+            var user = await _userService.VerifyCredential(username, password);
+            var token = _userTokenService.GenerateToken(new UserTokenInfo { Id = user.Id!.Value, Version = user.Version!.Value, ExpireAt = expireAt });
+
+            return new UserTokenCreateResult { Token = token, User = user };
+        }
+
+
+        public async Task<User> VerifyToken(string token)
+        {
+            if (token == null)
+                throw new ArgumentNullException(nameof(token));
+
+            var tokenInfo = _userTokenService.VerifyToken(token);
+
+            if (tokenInfo.ExpireAt.HasValue)
+            {
+                var currentTime = _clock.GetCurrentTime();
+                if (tokenInfo.ExpireAt < currentTime)
+                    throw new UserTokenTimeExpireException(token, tokenInfo.ExpireAt.Value, currentTime);
+            }
+
+            var user = await _userService.GetUserById(tokenInfo.Id);
+
+            if (tokenInfo.Version < user.Version)
+                throw new UserTokenBadVersionException(token, tokenInfo.Version, user.Version.Value);
+
+            return user;
+        }
+    }
+}
diff --git a/Timeline/Services/JwtService.cs b/Timeline/Services/UserTokenService.cs
index bf92966a..cf7286f4 100644
--- a/Timeline/Services/JwtService.cs
+++ b/Timeline/Services/UserTokenService.cs
@@ -9,50 +9,59 @@ using Timeline.Configs;
 
 namespace Timeline.Services
 {
-    public class TokenInfo
+    public class UserTokenInfo
     {
         public long Id { get; set; }
         public long Version { get; set; }
+        public DateTime? ExpireAt { get; set; }
     }
 
-    public interface IJwtService
+    public interface IUserTokenService
     {
         /// <summary>
-        /// Create a JWT token for a given token info.
+        /// Create a token for a given token info.
         /// </summary>
         /// <param name="tokenInfo">The info to generate token.</param>
-        /// <param name="expires">The expire time. If null then use current time with offset in config.</param>
         /// <returns>Return the generated token.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="tokenInfo"/> is null.</exception>
-        string GenerateJwtToken(TokenInfo tokenInfo, DateTime? expires = null);
+        string GenerateToken(UserTokenInfo tokenInfo);
 
         /// <summary>
-        /// Verify a JWT token.
-        /// Return null is <paramref name="token"/> is null.
+        /// Verify a token and get the saved info.
         /// </summary>
-        /// <param name="token">The token string to verify.</param>
-        /// <returns>Return the saved info in token.</returns>
+        /// <param name="token">The token to verify.</param>
+        /// <returns>The saved info in token.</returns>
         /// <exception cref="ArgumentNullException">Thrown when <paramref name="token"/> is null.</exception>
-        /// <exception cref="JwtVerifyException">Thrown when the token is invalid.</exception>
-        TokenInfo VerifyJwtToken(string token);
-
+        /// <exception cref="UserTokenBadFormatException">Thrown when the token is of bad format.</exception>
+        /// <remarks>
+        /// If this method throw <see cref="UserTokenBadFormatException"/>, it usually means the token is not created by this service.
+        /// </remarks>
+        UserTokenInfo VerifyToken(string token);
     }
 
-    public class JwtService : IJwtService
+    public class JwtUserTokenService : IUserTokenService
     {
         private const string VersionClaimType = "timeline_version";
 
         private readonly IOptionsMonitor<JwtConfig> _jwtConfig;
-        private readonly JwtSecurityTokenHandler _tokenHandler = new JwtSecurityTokenHandler();
         private readonly IClock _clock;
 
-        public JwtService(IOptionsMonitor<JwtConfig> jwtConfig, IClock clock)
+        private readonly JwtSecurityTokenHandler _tokenHandler = new JwtSecurityTokenHandler();
+        private SymmetricSecurityKey _tokenSecurityKey;
+
+        public JwtUserTokenService(IOptionsMonitor<JwtConfig> jwtConfig, IClock clock)
         {
             _jwtConfig = jwtConfig;
             _clock = clock;
+
+            _tokenSecurityKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(jwtConfig.CurrentValue.SigningKey));
+            jwtConfig.OnChange(config =>
+            {
+                _tokenSecurityKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(config.SigningKey));
+            });
         }
 
-        public string GenerateJwtToken(TokenInfo tokenInfo, DateTime? expires = null)
+        public string GenerateToken(UserTokenInfo tokenInfo)
         {
             if (tokenInfo == null)
                 throw new ArgumentNullException(nameof(tokenInfo));
@@ -71,7 +80,7 @@ namespace Timeline.Services
                 SigningCredentials = new SigningCredentials(
                     new SymmetricSecurityKey(Encoding.ASCII.GetBytes(config.SigningKey)), SecurityAlgorithms.HmacSha384),
                 IssuedAt = _clock.GetCurrentTime(),
-                Expires = expires.GetValueOrDefault(_clock.GetCurrentTime().AddSeconds(config.DefaultExpireOffset)),
+                Expires = tokenInfo.ExpireAt.GetValueOrDefault(_clock.GetCurrentTime().AddSeconds(config.DefaultExpireOffset)),
                 NotBefore = _clock.GetCurrentTime() // I must explicitly set this or it will use the current time by default and mock is not work in which case test will not pass.
             };
 
@@ -82,7 +91,7 @@ namespace Timeline.Services
         }
 
 
-        public TokenInfo VerifyJwtToken(string token)
+        public UserTokenInfo VerifyToken(string token)
         {
             if (token == null)
                 throw new ArgumentNullException(nameof(token));
@@ -95,37 +104,42 @@ namespace Timeline.Services
                     ValidateIssuer = true,
                     ValidateAudience = true,
                     ValidateIssuerSigningKey = true,
-                    ValidateLifetime = true,
+                    ValidateLifetime = false,
                     ValidIssuer = config.Issuer,
                     ValidAudience = config.Audience,
-                    IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(config.SigningKey))
-                }, out _);
+                    IssuerSigningKey = _tokenSecurityKey
+                }, out var t);
 
                 var idClaim = principal.FindFirstValue(ClaimTypes.NameIdentifier);
                 if (idClaim == null)
-                    throw new JwtVerifyException(JwtVerifyException.ErrorCodes.NoIdClaim);
+                    throw new JwtUserTokenBadFormatException(token, JwtUserTokenBadFormatException.ErrorKind.NoIdClaim);
                 if (!long.TryParse(idClaim, out var id))
-                    throw new JwtVerifyException(JwtVerifyException.ErrorCodes.IdClaimBadFormat);
+                    throw new JwtUserTokenBadFormatException(token, JwtUserTokenBadFormatException.ErrorKind.IdClaimBadFormat);
 
                 var versionClaim = principal.FindFirstValue(VersionClaimType);
                 if (versionClaim == null)
-                    throw new JwtVerifyException(JwtVerifyException.ErrorCodes.NoVersionClaim);
+                    throw new JwtUserTokenBadFormatException(token, JwtUserTokenBadFormatException.ErrorKind.NoVersionClaim);
                 if (!long.TryParse(versionClaim, out var version))
-                    throw new JwtVerifyException(JwtVerifyException.ErrorCodes.VersionClaimBadFormat);
+                    throw new JwtUserTokenBadFormatException(token, JwtUserTokenBadFormatException.ErrorKind.VersionClaimBadFormat);
+
+                var decodedToken = (JwtSecurityToken)t;
+                var exp = decodedToken.Payload.Exp;
+                DateTime? expireAt = null;
+                if (exp.HasValue)
+                {
+                    expireAt = EpochTime.DateTime(exp.Value);
+                }
 
-                return new TokenInfo
+                return new UserTokenInfo
                 {
                     Id = id,
-                    Version = version
+                    Version = version,
+                    ExpireAt = expireAt
                 };
             }
-            catch (SecurityTokenExpiredException e)
-            {
-                throw new JwtVerifyException(e, JwtVerifyException.ErrorCodes.Expired);
-            }
-            catch (Exception e)
+            catch (Exception e) when (e is SecurityTokenException || e is ArgumentException)
             {
-                throw new JwtVerifyException(e, JwtVerifyException.ErrorCodes.Others);
+                throw new JwtUserTokenBadFormatException(token, JwtUserTokenBadFormatException.ErrorKind.Other, e);
             }
         }
     }
diff --git a/Timeline/Services/UsernameBadFormatException.cs b/Timeline/Services/UsernameBadFormatException.cs
deleted file mode 100644
index d82bf962..00000000
--- a/Timeline/Services/UsernameBadFormatException.cs
+++ /dev/null
@@ -1,27 +0,0 @@
-using System;
-
-namespace Timeline.Services
-{
-    /// <summary>
-    /// Thrown when username is of bad format.
-    /// </summary>
-    [Serializable]
-    public class UsernameBadFormatException : Exception
-    {
-        public UsernameBadFormatException() : base(Resources.Services.Exception.UsernameBadFormatException) { }
-        public UsernameBadFormatException(string username) : this() { Username = username; }
-        public UsernameBadFormatException(string username, Exception inner) : base(Resources.Services.Exception.UsernameBadFormatException, inner) { Username = username; }
-
-        public UsernameBadFormatException(string username, string message) : base(message) { Username = username; }
-        public UsernameBadFormatException(string username, string message, Exception inner) : base(message, inner) { Username = username; }
-
-        protected UsernameBadFormatException(
-          System.Runtime.Serialization.SerializationInfo info,
-          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
-
-        /// <summary>
-        /// Username of bad format.
-        /// </summary>
-        public string? Username { get; private set; }
-    }
-}
diff --git a/Timeline/Services/UsernameConfictException.cs b/Timeline/Services/UsernameConfictException.cs
deleted file mode 100644
index fde1eda6..00000000
--- a/Timeline/Services/UsernameConfictException.cs
+++ /dev/null
@@ -1,25 +0,0 @@
-using System;
-using Timeline.Helpers;
-
-namespace Timeline.Services
-{
-    /// <summary>
-    /// Thrown when the user already exists.
-    /// </summary>
-    [Serializable]
-    public class UsernameConfictException : Exception
-    {
-        public UsernameConfictException() : base(Resources.Services.Exception.UsernameConfictException) { }
-        public UsernameConfictException(string username) : base(Log.Format(Resources.Services.Exception.UsernameConfictException, ("Username", username))) { Username = username; }
-        public UsernameConfictException(string username, string message) : base(message) { Username = username; }
-        public UsernameConfictException(string message, Exception inner) : base(message, inner) { }
-        protected UsernameConfictException(
-          System.Runtime.Serialization.SerializationInfo info,
-          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
-
-        /// <summary>
-        /// The username that already exists.
-        /// </summary>
-        public string? Username { get; set; }
-    }
-}
diff --git a/Timeline/Startup.cs b/Timeline/Startup.cs
index 5b6499a4..86349a27 100644
--- a/Timeline/Startup.cs
+++ b/Timeline/Startup.cs
@@ -1,14 +1,16 @@
+using AutoMapper;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.HttpOverrides;
-using Microsoft.AspNetCore.Localization;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Hosting;
+using Pomelo.EntityFrameworkCore.MySql.Infrastructure;
+using Pomelo.EntityFrameworkCore.MySql.Storage;
 using System;
-using System.Collections.Generic;
-using System.Globalization;
 using System.Text.Json.Serialization;
 using Timeline.Auth;
 using Timeline.Configs;
@@ -50,7 +52,6 @@ namespace Timeline
             });
 
             services.Configure<JwtConfig>(Configuration.GetSection(nameof(JwtConfig)));
-            var jwtConfig = Configuration.GetSection(nameof(JwtConfig)).Get<JwtConfig>();
             services.AddAuthentication(AuthenticationConstants.Scheme)
                 .AddScheme<MyAuthenticationOptions, MyAuthenticationHandler>(AuthenticationConstants.Scheme, AuthenticationConstants.DisplayName, o => { });
             services.AddAuthorization();
@@ -78,20 +79,20 @@ namespace Timeline
                 });
             }
 
-            services.AddLocalization(options =>
-            {
-                options.ResourcesPath = "Resources";
-            });
+            services.AddAutoMapper(GetType().Assembly);
 
-            services.AddScoped<IUserService, UserService>();
-            services.AddScoped<IJwtService, JwtService>();
-            services.AddTransient<IPasswordService, PasswordService>();
             services.AddTransient<IClock, Clock>();
+
+            services.AddTransient<IPasswordService, PasswordService>();
+            services.AddScoped<IUserService, UserService>();
+            services.AddScoped<IUserTokenService, JwtUserTokenService>();
+            services.AddScoped<IUserTokenManager, UserTokenManager>();
             services.AddUserAvatarService();
-            services.AddScoped<IUserDetailService, UserDetailService>();
 
             services.AddScoped<IPersonalTimelineService, PersonalTimelineService>();
 
+            services.TryAddSingleton<IActionContextAccessor, ActionContextAccessor>();
+
             var databaseConfig = Configuration.GetSection(nameof(DatabaseConfig)).Get<DatabaseConfig>();
 
             if (databaseConfig.UseDevelopment)
@@ -109,11 +110,10 @@ namespace Timeline
                 {
                     if (databaseConfig.ConnectionString == null)
                         throw new InvalidOperationException("DatabaseConfig.ConnectionString is not set. Please set it as a mysql connection string.");
-                    options.UseMySql(databaseConfig.ConnectionString);
+                    options.UseMySql(databaseConfig.ConnectionString,
+                        mySqlOptions => mySqlOptions.ServerVersion(new ServerVersion(new Version(5, 7), ServerType.MySql)));
                 });
             }
-
-            services.AddMemoryCache();
         }
 
 
@@ -127,19 +127,6 @@ namespace Timeline
 
             app.UseRouting();
 
-            var supportedCultures = new List<CultureInfo>
-            {
-                new CultureInfo("en"),
-                new CultureInfo("zh")
-            };
-
-            app.UseRequestLocalization(new RequestLocalizationOptions
-            {
-                DefaultRequestCulture = new RequestCulture("en"),
-                SupportedCultures = supportedCultures,
-                SupportedUICultures = supportedCultures
-            });
-
             app.UseCors();
 
             app.UseAuthentication();
diff --git a/Timeline/Timeline.csproj b/Timeline/Timeline.csproj
index 681f49cb..1a3a07cd 100644
--- a/Timeline/Timeline.csproj
+++ b/Timeline/Timeline.csproj
@@ -15,38 +15,39 @@
     </ItemGroup>
 
     <ItemGroup>
+        <PackageReference Include="AutoMapper" Version="9.0.0" />
+        <PackageReference Include="AutoMapper.Extensions.Microsoft.DependencyInjection" Version="7.0.0" />
         <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="2.9.8">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>
-        <PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.1.0" />
-        <PackageReference Include="Microsoft.EntityFrameworkCore.Analyzers" Version="3.1.0" />
-        <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="3.1.0" />
-        <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.0">
+        <PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.1.1" />
+        <PackageReference Include="Microsoft.EntityFrameworkCore.Analyzers" Version="3.1.1" />
+        <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="3.1.1" />
+        <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="3.1.1">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>
-        <PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="3.1.0" />
+        <PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="3.1.1" />
         <PackageReference Include="Pomelo.EntityFrameworkCore.MySql.Design" Version="1.1.2" />
         <PackageReference Include="SixLabors.ImageSharp" Version="1.0.0-dev002868" />
         <PackageReference Include="System.IdentityModel.Tokens.Jwt" Version="5.6.0" />
     </ItemGroup>
 
     <ItemGroup>
+        <ProjectReference Include="..\Timeline.ErrorCodes\Timeline.ErrorCodes.csproj" />
+    </ItemGroup>
+
+    <ItemGroup>
         <Compile Update="Resources\Authentication\AuthHandler.Designer.cs">
             <DesignTime>True</DesignTime>
             <AutoGen>True</AutoGen>
             <DependentUpon>AuthHandler.resx</DependentUpon>
         </Compile>
-        <Compile Update="Resources\Common.Designer.cs">
-            <DesignTime>True</DesignTime>
-            <AutoGen>True</AutoGen>
-            <DependentUpon>Common.resx</DependentUpon>
-        </Compile>
-        <Compile Update="Resources\Controllers\Testing\TestingI18nController.Designer.cs">
-            <DesignTime>True</DesignTime>
-            <AutoGen>True</AutoGen>
-            <DependentUpon>TestingI18nController.resx</DependentUpon>
+        <Compile Update="Resources\Controllers\ControllerAuthExtensions.Designer.cs">
+          <DesignTime>True</DesignTime>
+          <AutoGen>True</AutoGen>
+          <DependentUpon>ControllerAuthExtensions.resx</DependentUpon>
         </Compile>
         <Compile Update="Resources\Controllers\TimelineController.Designer.cs">
             <DesignTime>True</DesignTime>
@@ -73,11 +74,21 @@
             <AutoGen>True</AutoGen>
             <DependentUpon>Filters.resx</DependentUpon>
         </Compile>
+        <Compile Update="Resources\Messages.Designer.cs">
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>Messages.resx</DependentUpon>
+        </Compile>
         <Compile Update="Resources\Models\Http\Common.Designer.cs">
             <DesignTime>True</DesignTime>
             <AutoGen>True</AutoGen>
             <DependentUpon>Common.resx</DependentUpon>
         </Compile>
+        <Compile Update="Resources\Models\Validation\NicknameValidator.Designer.cs">
+            <DesignTime>True</DesignTime>
+            <AutoGen>True</AutoGen>
+            <DependentUpon>NicknameValidator.resx</DependentUpon>
+        </Compile>
         <Compile Update="Resources\Models\Validation\UsernameValidator.Designer.cs">
             <DesignTime>True</DesignTime>
             <AutoGen>True</AutoGen>
@@ -93,16 +104,16 @@
             <AutoGen>True</AutoGen>
             <DependentUpon>Exception.resx</DependentUpon>
         </Compile>
+        <Compile Update="Resources\Services\TimelineService.Designer.cs">
+          <DesignTime>True</DesignTime>
+          <AutoGen>True</AutoGen>
+          <DependentUpon>TimelineService.resx</DependentUpon>
+        </Compile>
         <Compile Update="Resources\Services\UserAvatarService.Designer.cs">
             <DesignTime>True</DesignTime>
             <AutoGen>True</AutoGen>
             <DependentUpon>UserAvatarService.resx</DependentUpon>
         </Compile>
-        <Compile Update="Resources\Services\UserDetailService.Designer.cs">
-            <DesignTime>True</DesignTime>
-            <AutoGen>True</AutoGen>
-            <DependentUpon>UserDetailService.resx</DependentUpon>
-        </Compile>
         <Compile Update="Resources\Services\UserService.Designer.cs">
             <DesignTime>True</DesignTime>
             <AutoGen>True</AutoGen>
@@ -115,13 +126,9 @@
             <Generator>ResXFileCodeGenerator</Generator>
             <LastGenOutput>AuthHandler.Designer.cs</LastGenOutput>
         </EmbeddedResource>
-        <EmbeddedResource Update="Resources\Common.resx">
-            <Generator>ResXFileCodeGenerator</Generator>
-            <LastGenOutput>Common.Designer.cs</LastGenOutput>
-        </EmbeddedResource>
-        <EmbeddedResource Update="Resources\Controllers\Testing\TestingI18nController.resx">
-            <Generator>ResXFileCodeGenerator</Generator>
-            <LastGenOutput>TestingI18nController.Designer.cs</LastGenOutput>
+        <EmbeddedResource Update="Resources\Controllers\ControllerAuthExtensions.resx">
+          <Generator>ResXFileCodeGenerator</Generator>
+          <LastGenOutput>ControllerAuthExtensions.Designer.cs</LastGenOutput>
         </EmbeddedResource>
         <EmbeddedResource Update="Resources\Controllers\TimelineController.resx">
             <Generator>ResXFileCodeGenerator</Generator>
@@ -144,10 +151,18 @@
             <Generator>ResXFileCodeGenerator</Generator>
             <LastGenOutput>Filters.Designer.cs</LastGenOutput>
         </EmbeddedResource>
+        <EmbeddedResource Update="Resources\Messages.resx">
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>Messages.Designer.cs</LastGenOutput>
+        </EmbeddedResource>
         <EmbeddedResource Update="Resources\Models\Http\Common.resx">
             <Generator>ResXFileCodeGenerator</Generator>
             <LastGenOutput>Common.Designer.cs</LastGenOutput>
         </EmbeddedResource>
+        <EmbeddedResource Update="Resources\Models\Validation\NicknameValidator.resx">
+            <Generator>ResXFileCodeGenerator</Generator>
+            <LastGenOutput>NicknameValidator.Designer.cs</LastGenOutput>
+        </EmbeddedResource>
         <EmbeddedResource Update="Resources\Models\Validation\UsernameValidator.resx">
             <Generator>ResXFileCodeGenerator</Generator>
             <LastGenOutput>UsernameValidator.Designer.cs</LastGenOutput>
@@ -160,14 +175,14 @@
             <Generator>ResXFileCodeGenerator</Generator>
             <LastGenOutput>Exception.Designer.cs</LastGenOutput>
         </EmbeddedResource>
+        <EmbeddedResource Update="Resources\Services\TimelineService.resx">
+          <Generator>ResXFileCodeGenerator</Generator>
+          <LastGenOutput>TimelineService.Designer.cs</LastGenOutput>
+        </EmbeddedResource>
         <EmbeddedResource Update="Resources\Services\UserAvatarService.resx">
             <Generator>ResXFileCodeGenerator</Generator>
             <LastGenOutput>UserAvatarService.Designer.cs</LastGenOutput>
         </EmbeddedResource>
-        <EmbeddedResource Update="Resources\Services\UserDetailService.resx">
-            <Generator>ResXFileCodeGenerator</Generator>
-            <LastGenOutput>UserDetailService.Designer.cs</LastGenOutput>
-        </EmbeddedResource>
         <EmbeddedResource Update="Resources\Services\UserService.resx">
             <Generator>ResXFileCodeGenerator</Generator>
             <LastGenOutput>UserService.Designer.cs</LastGenOutput>