Make RequestServices work for cloned longpolling HttpContext (dotnet#23014)

Author: BrennanConroy

src/SignalR/common/Http.Connections/src/Internal/HttpConnectionContext.cs

@@ -16,6 +16,7 @@
 using Microsoft.AspNetCore.Http.Connections.Internal.Transports;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Internal;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNetCore.Http.Connections.Internal
@@ -99,6 +100,9 @@ public HttpConnectionContext(string connectionId, string connectionToken, ILogge
         // Used for testing only
         internal Task DisposeAndRemoveTask { get; set; }
 
+        // Used for LongPolling because we need to create a scope that spans the lifetime of multiple requests on the cloned HttpContext
+        internal IServiceScope ServiceScope { get; set; }
+
         public Task TransportTask { get; set; }
 
         public Task PreviousPollTask { get; set; } = Task.CompletedTask;
@@ -251,6 +255,8 @@ public async Task DisposeAsync(bool closeGracefully = false)
                         (identity as IDisposable)?.Dispose();
                     }
                 }
+
+                ServiceScope?.Dispose();
             }
 
             await disposeTask;

src/SignalR/common/Http.Connections/src/Internal/HttpConnectionDispatcher.cs

@@ -14,6 +14,7 @@
 using Microsoft.AspNetCore.Http.Connections.Internal.Transports;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Internal;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Primitives;
 
@@ -537,8 +538,7 @@ private async Task<bool> EnsureConnectionStateAsync(HttpConnectionContext connec
                 var existing = connection.HttpContext;
                 if (existing == null)
                 {
-                    var httpContext = CloneHttpContext(context);
-                    connection.HttpContext = httpContext;
+                    CloneHttpContext(context, connection);
                 }
                 else
                 {
@@ -606,7 +606,7 @@ private static void CloneUser(HttpContext newContext, HttpContext oldContext)
             }
         }
 
-        private static HttpContext CloneHttpContext(HttpContext context)
+        private static void CloneHttpContext(HttpContext context, HttpConnectionContext connection)
         {
             // The reason we're copying the base features instead of the HttpContext properties is
             // so that we can get all of the logic built into DefaultHttpContext to extract higher level
@@ -660,14 +660,13 @@ private static HttpContext CloneHttpContext(HttpContext context)
 
             CloneUser(newHttpContext, context);
 
-            // Making request services function property could be tricky and expensive as it would require
-            // DI scope per connection. It would also mean that services resolved in middleware leading up to here
-            // wouldn't be the same instance (but maybe that's fine). For now, we just return an empty service provider
-            newHttpContext.RequestServices = EmptyServiceProvider.Instance;
+            connection.ServiceScope = context.RequestServices.CreateScope();
+            newHttpContext.RequestServices = connection.ServiceScope.ServiceProvider;
 
             // REVIEW: This extends the lifetime of anything that got put into HttpContext.Items
             newHttpContext.Items = new Dictionary<object, object>(context.Items);
-            return newHttpContext;
+
+            connection.HttpContext = newHttpContext;
         }
 
         private async Task<HttpConnectionContext> GetConnectionAsync(HttpContext context)