From 4b6460e7d564eebff7a79df475a702dbd3f009b9 Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Fri, 23 Apr 2021 19:06:11 +0800
Subject: feat: Fix #51.

---
 BackEnd/Timeline/Auth/MyAuthenticationHandler.cs | 63 ++++++++++++++++++++++--
 1 file changed, 60 insertions(+), 3 deletions(-)

(limited to 'BackEnd/Timeline/Auth/MyAuthenticationHandler.cs')

diff --git a/BackEnd/Timeline/Auth/MyAuthenticationHandler.cs b/BackEnd/Timeline/Auth/MyAuthenticationHandler.cs
index e4122c65..f1f71b20 100644
--- a/BackEnd/Timeline/Auth/MyAuthenticationHandler.cs
+++ b/BackEnd/Timeline/Auth/MyAuthenticationHandler.cs
@@ -1,13 +1,18 @@
 using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using Microsoft.Net.Http.Headers;
 using System;
+using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
 using System.Security.Claims;
 using System.Text.Encodings.Web;
+using System.Text.Json;
 using System.Threading.Tasks;
+using Timeline.Models;
+using Timeline.Models.Http;
 using Timeline.Services;
 using static Timeline.Resources.Authentication.AuthHandler;
 
@@ -30,16 +35,33 @@ namespace Timeline.Auth
 
     public class MyAuthenticationHandler : AuthenticationHandler<MyAuthenticationOptions>
     {
+        private const string TokenErrorCodeKey = "TokenErrorCode";
+
+        private static CommonResponse CreateChallengeResponseBody(int errorCode)
+        {
+            return new CommonResponse(errorCode, errorCode switch
+            {
+                ErrorCodes.Common.Token.TimeExpired => "The token is out of date and expired. Please create a new one.",
+                ErrorCodes.Common.Token.VersionExpired => "The token is of old version and expired. Please create a new one.",
+                ErrorCodes.Common.Token.BadFormat => "The token is of bad format. It might not be created by this server.",
+                ErrorCodes.Common.Token.UserNotExist => "The owner of the token does not exist. It might have been deleted.",
+                _ => "Unknown error."
+            });
+        }
+
         private readonly ILogger<MyAuthenticationHandler> _logger;
         private readonly IUserTokenManager _userTokenManager;
         private readonly IUserPermissionService _userPermissionService;
 
-        public MyAuthenticationHandler(IOptionsMonitor<MyAuthenticationOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock, IUserTokenManager userTokenManager, IUserPermissionService userPermissionService)
+        private readonly IOptionsMonitor<JsonOptions> _jsonOptions;
+
+        public MyAuthenticationHandler(IOptionsMonitor<MyAuthenticationOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock, IUserTokenManager userTokenManager, IUserPermissionService userPermissionService, IOptionsMonitor<JsonOptions> jsonOptions)
             : base(options, logger, encoder, clock)
         {
             _logger = logger.CreateLogger<MyAuthenticationHandler>();
             _userTokenManager = userTokenManager;
             _userPermissionService = userPermissionService;
+            _jsonOptions = jsonOptions;
         }
 
         // return null if no token is found
@@ -49,7 +71,7 @@ namespace Timeline.Auth
             string header = Request.Headers[HeaderNames.Authorization];
             if (!string.IsNullOrEmpty(header) && header.StartsWith("Bearer ", StringComparison.OrdinalIgnoreCase))
             {
-                var token = header.Substring("Bearer ".Length).Trim();
+                var token = header["Bearer ".Length..].Trim();
                 _logger.LogInformation(LogTokenFoundInHeader, token);
                 return token;
             }
@@ -98,8 +120,43 @@ namespace Timeline.Auth
             catch (Exception e) when (!(e is ArgumentException))
             {
                 _logger.LogInformation(e, LogTokenValidationFail);
-                return AuthenticateResult.Fail(e);
+                return AuthenticateResult.Fail(e, new AuthenticationProperties(new Dictionary<string, string?>()
+                {
+                    [TokenErrorCodeKey] = (e switch
+                    {
+                        UserTokenTimeExpiredException => ErrorCodes.Common.Token.TimeExpired,
+                        UserTokenVersionExpiredException => ErrorCodes.Common.Token.VersionExpired,
+                        UserTokenBadFormatException => ErrorCodes.Common.Token.BadFormat,
+                        UserTokenUserNotExistException => ErrorCodes.Common.Token.UserNotExist,
+                        _ => ErrorCodes.Common.Token.Unknown
+                    }).ToString(CultureInfo.InvariantCulture)
+                }));
             }
         }
+
+        protected override async Task HandleChallengeAsync(AuthenticationProperties properties)
+        {
+            Response.StatusCode = 401;
+
+            CommonResponse body;
+
+            if (properties.Items.TryGetValue(TokenErrorCodeKey, out var tokenErrorCode))
+            {
+                if (!int.TryParse(tokenErrorCode, out var errorCode))
+                    errorCode = ErrorCodes.Common.Token.Unknown;
+                body = CreateChallengeResponseBody(errorCode);
+            }
+            else
+            {
+                body = new CommonResponse(ErrorCodes.Common.Unauthorized, "You must use a token to authenticate.");
+            }
+
+
+            var bodyData = JsonSerializer.SerializeToUtf8Bytes(body, typeof(CommonResponse), _jsonOptions.CurrentValue.JsonSerializerOptions);
+
+            Response.ContentType = MimeTypes.ApplicationJson;
+            Response.ContentLength = bodyData.Length;
+            await Response.Body.WriteAsync(bodyData);
+        }
     }
 }
-- 
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