6 files changed, 86 insertions, 65 deletions
diff --git a/Timeline/Models/Http/User.cs b/Timeline/Models/Http/User.cs
index 98406fec..516c1329 100644
--- a/Timeline/Models/Http/User.cs
+++ b/Timeline/Models/Http/User.cs
@@ -20,9 +20,11 @@ namespace Timeline.Models.Http
     public class ChangeUsernameRequest
     {
         [Required]
+        [Username]
         public string OldUsername { get; set; } = default!;
 
-        [Required, ValidateWith(typeof(UsernameValidator))]
+        [Required]
+        [Username]
         public string NewUsername { get; set; } = default!;
     }
 
diff --git a/Timeline/Models/UserConvert.cs b/Timeline/Models/UserConvert.cs
new file mode 100644
index 00000000..5b132421
--- /dev/null
+++ b/Timeline/Models/UserConvert.cs
@@ -0,0 +1,67 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Timeline.Entities;
+using Timeline.Services;
+
+namespace Timeline.Models
+{
+    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;
+        public const string AdminRole = UserRoles.Admin;
+
+        public static string[] ToArray(bool administrator)
+        {
+            return administrator ? new string[] { UserRole, AdminRole } : new string[] { UserRole };
+        }
+
+        public static string[] ToArray(string s)
+        {
+            return s.Split(',').ToArray();
+        }
+
+        public static bool ToBool(IReadOnlyCollection<string> roles)
+        {
+            return roles.Contains(AdminRole);
+        }
+
+        public static string ToString(IReadOnlyCollection<string> roles)
+        {
+            return string.Join(',', roles);
+        }
+
+        public static string ToString(bool administrator)
+        {
+            return administrator ? UserRole + "," + AdminRole : UserRole;
+        }
+
+        public static bool ToBool(string s)
+        {
+            return s.Contains("admin", StringComparison.InvariantCulture);
+        }
+    }
+}
diff --git a/Timeline/Models/UserInfo.cs b/Timeline/Models/UserInfo.cs
index e502855b..b60bdfa2 100644
--- a/Timeline/Models/UserInfo.cs
+++ b/Timeline/Models/UserInfo.cs
@@ -12,8 +12,8 @@ namespace Timeline.Models
             Administrator = administrator;
         }
 
-        public string Username { get; set; }
-        public bool Administrator { get; set; }
+        public string Username { get; set; } = default!;
+        public bool Administrator { get; set; } = default!;
 
         public override string ToString()
         {
diff --git a/Timeline/Models/UserUtility.cs b/Timeline/Models/UserUtility.cs
deleted file mode 100644
index 405987b5..00000000
--- a/Timeline/Models/UserUtility.cs
+++ /dev/null
@@ -1,60 +0,0 @@
-using System;
-using System.Linq;
-using Timeline.Entities;
-using Timeline.Services;
-
-namespace Timeline.Models
-{
-    public static class UserUtility
-    {
-        public const string UserRole = UserRoles.User;
-        public const string AdminRole = UserRoles.Admin;
-
-        public static string[] UserRoleArray { get; } = new string[] { UserRole };
-        public static string[] AdminRoleArray { get; } = new string[] { UserRole, AdminRole };
-
-        public static string[] IsAdminToRoleArray(bool isAdmin)
-        {
-            return isAdmin ? AdminRoleArray : UserRoleArray;
-        }
-
-        public static bool RoleArrayToIsAdmin(string[] roles)
-        {
-            return roles.Contains(AdminRole);
-        }
-
-        public static string[] RoleStringToRoleArray(string roleString)
-        {
-            return roleString.Split(',').ToArray();
-        }
-
-        public static string RoleArrayToRoleString(string[] roles)
-        {
-            return string.Join(',', roles);
-        }
-
-        public static string IsAdminToRoleString(bool isAdmin)
-        {
-            return RoleArrayToRoleString(IsAdminToRoleArray(isAdmin));
-        }
-
-        public static bool RoleStringToIsAdmin(string roleString)
-        {
-            return RoleArrayToIsAdmin(RoleStringToRoleArray(roleString));
-        }
-
-        public static UserInfo CreateUserInfo(User user)
-        {
-            if (user == null)
-                throw new ArgumentNullException(nameof(user));
-            return new UserInfo(user.Name, RoleStringToIsAdmin(user.RoleString));
-        }
-
-        internal static UserCache CreateUserCache(User user)
-        {
-            if (user == null)
-                throw new ArgumentNullException(nameof(user));
-            return new UserCache { Username = user.Name, Administrator = RoleStringToIsAdmin(user.RoleString), Version = user.Version };
-        }
-    }
-}
diff --git a/Timeline/Models/Validation/UsernameValidator.cs b/Timeline/Models/Validation/UsernameValidator.cs
index 65d4da71..dc237add 100644
--- a/Timeline/Models/Validation/UsernameValidator.cs
+++ b/Timeline/Models/Validation/UsernameValidator.cs
@@ -1,4 +1,5 @@
-using System.Linq;
+using System;
+using System.Linq;
 
 namespace Timeline.Models.Validation
 {
@@ -36,4 +37,15 @@ namespace Timeline.Models.Validation
             return (true, SuccessMessageGenerator);
         }
     }
+
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter,
+        AllowMultiple = false)]
+    public class UsernameAttribute : ValidateWithAttribute
+    {
+        public UsernameAttribute()
+            : base(typeof(UsernameValidator))
+        {
+
+        }
+    }
 }
diff --git a/Timeline/Models/Validation/Validator.cs b/Timeline/Models/Validation/Validator.cs
index 606ba7b4..d2c7c377 100644
--- a/Timeline/Models/Validation/Validator.cs
+++ b/Timeline/Models/Validation/Validator.cs
@@ -8,7 +8,7 @@ namespace Timeline.Models.Validation
 {
     /// <summary>
     /// Generate a message from a localizer factory.
-    /// If localizerFactory is null, it should return a neutral-cultural message.
+    /// If localizerFactory is null, it should return a culture-invariant message.
     /// </summary>
     /// <param name="localizerFactory">The localizer factory. Could be null.</param>
     /// <returns>The message.</returns>