Introduce CustomJwtPayload to fix 'cnf' serialization issue

Author: cnblogs-dudu

src/IdentityServer4/src/Extensions/CustomJwtPayload.cs

@@ -0,0 +1,21 @@
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+
+namespace IdentityServer4.Extensions
+{
+    internal class CustomJwtPayload : JwtPayload
+    {
+        public CustomJwtPayload(string issuer, string audience, IEnumerable<Claim> claims, DateTime? notBefore, DateTime? expires) :
+            base(issuer, audience, claims, notBefore, expires)
+        {
+        }
+
+        public override string SerializeToJson()
+        {
+            return JsonConvert.SerializeObject(this);
+        }
+    }
+}

src/IdentityServer4/src/Extensions/TokenExtensions.cs

@@ -33,7 +33,7 @@ public static class TokenExtensions
         /// </exception>
         public static JwtPayload CreateJwtPayload(this Token token, ISystemClock clock, IdentityServerOptions options, ILogger logger)
         {
-            var payload = new JwtPayload(
+            var payload = new CustomJwtPayload(
                 token.Issuer,
                 null,
                 null,
@@ -48,7 +48,7 @@ public static JwtPayload CreateJwtPayload(this Token token, ISystemClock clock,
             var amrClaims = token.Claims.Where(x => x.Type == JwtClaimTypes.AuthenticationMethod).ToArray();
             var scopeClaims = token.Claims.Where(x => x.Type == JwtClaimTypes.Scope).ToArray();
             var jsonClaims = token.Claims.Where(x => x.ValueType == IdentityServerConstants.ClaimValueTypes.Json).ToList();
-            
+
             // add confirmation claim if present (it's JSON valued)
             if (token.Confirmation.IsPresent())
             {
@@ -83,7 +83,7 @@ public static JwtPayload CreateJwtPayload(this Token token, ISystemClock clock,
                 var amrValues = amrClaims.Select(x => x.Value).Distinct().ToArray();
                 payload.Add(JwtClaimTypes.AuthenticationMethod, amrValues);
             }
-            
+
             // deal with json types
             // calling ToArray() to trigger JSON parsing once and so later 
             // collection identity comparisons work for the anonymous type
@@ -125,7 +125,7 @@ public static JwtPayload CreateJwtPayload(this Token token, ISystemClock clock,
                     var newArr = new List<JToken>();
                     foreach (var arrays in group)
                     {
-                        var arr = (JArray)arrays.JsonValue;
+                        var arr = (JArray) arrays.JsonValue;
                         newArr.AddRange(arr);
                     }