Use internal class instead of interface

src/Microsoft.Azure.SignalR/HubHost/ServiceLifetimeManager.cs

@@ -53,11 +53,11 @@ public ServiceLifetimeManager(
 
         public override Task OnConnectedAsync(HubConnectionContext connection)
         {
-            var userIdFeature = connection.Features.Get<IServiceUserIdFeature>();
+            var userIdFeature = connection.Features.Get<ServiceUserIdFeature>();
             if (userIdFeature != null)
             {
                 connection.UserIdentifier = userIdFeature.UserId;
-                connection.Features.Set<IServiceUserIdFeature>(null);
+                connection.Features.Set<ServiceUserIdFeature>(null);
             }
             return base.OnConnectedAsync(connection);
         }

src/Microsoft.Azure.SignalR/Internals/ServiceUserIdFeature.cs

@@ -1,9 +1,16 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using Microsoft.AspNetCore.SignalR;
+
 namespace Microsoft.Azure.SignalR
 {
-    internal class ServiceUserIdFeature : IServiceUserIdFeature
+    /// <summary>
+    /// When clients negotiate with Management SDK and connect to SignalR server, the <see cref="IUserIdProvider"/> might not work as the user Id is set directly in the Management SDK.
+    /// To make <see cref="HubConnectionContext.UserIdentifier"/> have the valid value in this case, we should set it before the server can access it. <see cref="HubLifetimeManager{THub}.OnConnectedAsync(HubConnectionContext)"/> is the only chance we can set the value. However, we cannot access the <see cref="Constants.ClaimType.UserId"/> as ASRS system claims're trimmed there. <see cref="HubConnectionContext.Features"/> is the place where we can store the user Id.
+    /// https://github.com/dotnet/aspnetcore/blob/v6.0.9/src/SignalR/server/Core/src/HubConnectionHandler.cs#L132-L141
+    /// </summary>
+    internal class ServiceUserIdFeature
     {
         public string UserId { get; }
 

src/Microsoft.Azure.SignalR/ServerConnections/ClientConnectionContext.cs

@@ -248,7 +248,7 @@ private FeatureCollection BuildFeatures(OpenConnectionMessage serviceMessage)
             var userIdClaim = serviceMessage.Claims.FirstOrDefault(c => c.Type == Constants.ClaimType.UserId);
             if (userIdClaim != default)
             {
-                features.Set<IServiceUserIdFeature>(new ServiceUserIdFeature(userIdClaim.Value));
+                features.Set(new ServiceUserIdFeature(userIdClaim.Value));
             }
             return features;
         }

test/Microsoft.Azure.SignalR.Tests/ClientConnectionContextFacts.cs

@@ -14,7 +14,7 @@ public void SetUserIdFeatureTest()
         {
             var claims = new Claim[] { new(Constants.ClaimType.UserId, "testUser") };
             var connection = new ClientConnectionContext(new("connectionId", claims));
-            var feature = connection.Features.Get<IServiceUserIdFeature>();
+            var feature = connection.Features.Get<ServiceUserIdFeature>();
             Assert.NotNull(feature);
             Assert.Equal("testUser", feature.UserId);
         }
@@ -23,7 +23,7 @@ public void SetUserIdFeatureTest()
         public void DoNotSetUserIdFeatureWithoutUserIdClaimTest()
         {
             var connection = new ClientConnectionContext(new("connectionId", Array.Empty<Claim>()));
-            var feature = connection.Features.Get<IServiceUserIdFeature>();
+            var feature = connection.Features.Get<ServiceUserIdFeature>();
             Assert.Null(feature);
         }
     }

test/Microsoft.Azure.SignalR.Tests/ServiceLifetimeManagerFacts.cs

@@ -21,17 +21,17 @@ namespace Microsoft.Azure.SignalR.Tests
 {
     public class ServiceLifetimeManagerFacts
     {
-        private static readonly List<string> TestUsers = new List<string> {"user1", "user2"};
+        private static readonly List<string> TestUsers = new List<string> { "user1", "user2" };
 
-        private static readonly List<string> TestGroups = new List<string> {"group1", "group2"};
+        private static readonly List<string> TestGroups = new List<string> { "group1", "group2" };
 
         private const string MockProtocol = "blazorpack";
 
         private const string TestMethod = "TestMethod";
 
-        private static readonly object[] TestArgs = {"TestArgs"};
+        private static readonly object[] TestArgs = { "TestArgs" };
 
-        private static readonly List<string> TestConnectionIds = new List<string> {"connection1", "connection2"};
+        private static readonly List<string> TestConnectionIds = new List<string> { "connection1", "connection2" };
 
         private static readonly IHubProtocolResolver HubProtocolResolver =
             new DefaultHubProtocolResolver(new IHubProtocol[]
@@ -229,7 +229,7 @@ public async void TestSendConnectionAsyncisOverwrittenWhenClientConnectionExiste
         public async void SetUserIdTest()
         {
             var connectionContext = new TestConnectionContext();
-            connectionContext.Features.Set<IServiceUserIdFeature>(new ServiceUserIdFeature("testUser"));
+            connectionContext.Features.Set(new ServiceUserIdFeature("testUser"));
 
             var hubConnectionContext = new HubConnectionContext(connectionContext, new(), NullLoggerFactory.Instance);
             var serviceLifetimeManager = MockLifetimeManager(new TestServiceConnectionManager<TestHub>());
@@ -248,6 +248,7 @@ public async void DoNotSetUserIdWithoutFeatureTest()
             await serviceLifetimeManager.OnConnectedAsync(hubConnectionContext);
 
             Assert.Null(hubConnectionContext.UserIdentifier);
+            Assert.Null(hubConnectionContext.Features.Get<ServiceUserIdFeature>());
         }
 
         private HubLifetimeManager<TestHub> MockLifetimeManager(IServiceConnectionManager<TestHub> serviceConnectionManager, IClientConnectionManager clientConnectionManager = null, IBlazorDetector blazorDetector = null)
@@ -324,41 +325,41 @@ private static void VerifyServiceMessage(string methodName, ServiceMessage servi
             switch (methodName)
             {
                 case "SendAllAsync":
-                    Assert.Null(((BroadcastDataMessage) serviceMessage).ExcludedList);
+                    Assert.Null(((BroadcastDataMessage)serviceMessage).ExcludedList);
                     break;
                 case "SendAllExceptAsync":
-                    Assert.Equal(TestConnectionIds, ((BroadcastDataMessage) serviceMessage).ExcludedList);
+                    Assert.Equal(TestConnectionIds, ((BroadcastDataMessage)serviceMessage).ExcludedList);
                     break;
                 case "SendConnectionAsync":
-                    Assert.Equal(TestConnectionIds[0], ((MultiConnectionDataMessage) serviceMessage).ConnectionList[0]);
+                    Assert.Equal(TestConnectionIds[0], ((MultiConnectionDataMessage)serviceMessage).ConnectionList[0]);
                     break;
                 case "SendConnectionsAsync":
-                    Assert.Equal(TestConnectionIds, ((MultiConnectionDataMessage) serviceMessage).ConnectionList);
+                    Assert.Equal(TestConnectionIds, ((MultiConnectionDataMessage)serviceMessage).ConnectionList);
                     break;
                 case "SendGroupAsync":
-                    Assert.Equal(TestGroups[0], ((GroupBroadcastDataMessage) serviceMessage).GroupName);
-                    Assert.Null(((GroupBroadcastDataMessage) serviceMessage).ExcludedList);
+                    Assert.Equal(TestGroups[0], ((GroupBroadcastDataMessage)serviceMessage).GroupName);
+                    Assert.Null(((GroupBroadcastDataMessage)serviceMessage).ExcludedList);
                     break;
                 case "SendGroupsAsync":
-                    Assert.Equal(TestGroups, ((MultiGroupBroadcastDataMessage) serviceMessage).GroupList);
+                    Assert.Equal(TestGroups, ((MultiGroupBroadcastDataMessage)serviceMessage).GroupList);
                     break;
                 case "SendGroupExceptAsync":
-                    Assert.Equal(TestGroups[0], ((GroupBroadcastDataMessage) serviceMessage).GroupName);
-                    Assert.Equal(TestConnectionIds, ((GroupBroadcastDataMessage) serviceMessage).ExcludedList);
+                    Assert.Equal(TestGroups[0], ((GroupBroadcastDataMessage)serviceMessage).GroupName);
+                    Assert.Equal(TestConnectionIds, ((GroupBroadcastDataMessage)serviceMessage).ExcludedList);
                     break;
                 case "SendUserAsync":
-                    Assert.Equal(TestUsers[0], ((UserDataMessage) serviceMessage).UserId);
+                    Assert.Equal(TestUsers[0], ((UserDataMessage)serviceMessage).UserId);
                     break;
                 case "SendUsersAsync":
-                    Assert.Equal(TestUsers, ((MultiUserDataMessage) serviceMessage).UserList);
+                    Assert.Equal(TestUsers, ((MultiUserDataMessage)serviceMessage).UserList);
                     break;
                 case "AddToGroupAsync":
-                    Assert.Equal(TestConnectionIds[0], ((JoinGroupWithAckMessage) serviceMessage).ConnectionId);
-                    Assert.Equal(TestGroups[0], ((JoinGroupWithAckMessage) serviceMessage).GroupName);
+                    Assert.Equal(TestConnectionIds[0], ((JoinGroupWithAckMessage)serviceMessage).ConnectionId);
+                    Assert.Equal(TestGroups[0], ((JoinGroupWithAckMessage)serviceMessage).GroupName);
                     break;
                 case "RemoveFromGroupAsync":
-                    Assert.Equal(TestConnectionIds[0], ((LeaveGroupWithAckMessage) serviceMessage).ConnectionId);
-                    Assert.Equal(TestGroups[0], ((LeaveGroupWithAckMessage) serviceMessage).GroupName);
+                    Assert.Equal(TestConnectionIds[0], ((LeaveGroupWithAckMessage)serviceMessage).ConnectionId);
+                    Assert.Equal(TestGroups[0], ((LeaveGroupWithAckMessage)serviceMessage).GroupName);
                     break;
                 default:
                     break;