Fix AccessTokenFactory not being called with each request (#1880)

src/Microsoft.AspNetCore.Http.Connections.Client/HttpConnection.cs

@@ -399,9 +399,15 @@ namespace Microsoft.AspNetCore.Http.Connections.Client
                         throw new InvalidOperationException("Configured HttpMessageHandlerFactory did not return a value.");
                     }
                 }
+
+                // Apply the authorization header in a handler instead of a default header because it can change with each request
+                if (_httpOptions.AccessTokenFactory != null)
+                {
+                    httpMessageHandler = new AccessTokenHttpMessageHandler(httpMessageHandler, _httpOptions.AccessTokenFactory);
+                }
             }
 
-            // Wrap message handler in a logging handler last to ensure it is always present
+            // Wrap message handler after HttpMessageHandlerFactory to ensure not overriden
             httpMessageHandler = new LoggingHttpMessageHandler(httpMessageHandler, _loggerFactory);
 
             var httpClient = new HttpClient(httpMessageHandler);
@@ -410,21 +416,12 @@ namespace Microsoft.AspNetCore.Http.Connections.Client
             // Start with the user agent header
             httpClient.DefaultRequestHeaders.UserAgent.Add(Constants.UserAgentHeader);
 
-            if (_httpOptions != null)
+            // Apply any headers configured on the HttpOptions
+            if (_httpOptions?.Headers != null)
             {
-                // Apply any headers configured on the HttpOptions
-                if (_httpOptions.Headers != null)
+                foreach (var header in _httpOptions.Headers)
                 {
-                    foreach (var header in _httpOptions.Headers)
-                    {
-                        httpClient.DefaultRequestHeaders.Add(header.Key, header.Value);
-                    }
-                }
-
-                // Apply the authorization header
-                if (_httpOptions.AccessTokenFactory != null)
-                {
-                    httpClient.DefaultRequestHeaders.Add("Authorization", $"Bearer {_httpOptions.AccessTokenFactory()}");
+                    httpClient.DefaultRequestHeaders.Add(header.Key, header.Value);
                 }
             }
 

src/Microsoft.AspNetCore.Http.Connections.Client/Internal/AccessTokenHttpMessageHandler.cs

@@ -0,0 +1,28 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Net.Http;
+using System.Net.Http.Headers;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.Http.Connections.Client.Internal
+{
+    public class AccessTokenHttpMessageHandler : DelegatingHandler
+    {
+        private readonly Func<string> _accessTokenFactory;
+
+        public AccessTokenHttpMessageHandler(HttpMessageHandler inner, Func<string> accessTokenFactory) : base(inner)
+        {
+            _accessTokenFactory = accessTokenFactory ?? throw new ArgumentNullException(nameof(accessTokenFactory));
+        }
+
+        protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", _accessTokenFactory());
+
+            return base.SendAsync(request, cancellationToken);
+        }
+    }
+}

test/Microsoft.AspNetCore.SignalR.Client.Tests/HttpConnectionTests.Helpers.cs

@@ -13,11 +13,19 @@ namespace Microsoft.AspNetCore.SignalR.Client.Tests
 {
     public partial class HttpConnectionTests
     {
-        private static HttpConnection CreateConnection(HttpMessageHandler httpHandler = null, ILoggerFactory loggerFactory = null, string url = null, ITransport transport = null, ITransportFactory transportFactory = null, HttpTransportType transportType = HttpTransportType.LongPolling)
+        private static HttpConnection CreateConnection(
+            HttpMessageHandler httpHandler = null,
+            ILoggerFactory loggerFactory = null,
+            string url = null,
+            ITransport transport = null,
+            ITransportFactory transportFactory = null,
+            HttpTransportType transportType = HttpTransportType.LongPolling,
+            Func<string> accessTokenFactory = null)
         {
-            var httpOptions = new HttpOptions()
+            var httpOptions = new HttpOptions
             {
                 HttpMessageHandlerFactory = (httpMessageHandler) => httpHandler ?? TestHttpMessageHandler.CreateDefault(),
+                AccessTokenFactory = accessTokenFactory,
             };
 
             return CreateConnection(httpOptions, loggerFactory, url, transport, transportFactory, transportType);

test/Microsoft.AspNetCore.SignalR.Client.Tests/HttpConnectionTests.Transport.cs

@@ -19,6 +19,55 @@ namespace Microsoft.AspNetCore.SignalR.Client.Tests
     {
         public class Transport
         {
+            [Theory]
+            [InlineData(HttpTransportType.LongPolling)]
+            [InlineData(HttpTransportType.ServerSentEvents)]
+            public async Task HttpConnectionSetsAccessTokenOnAllRequests(HttpTransportType transportType)
+            {
+                var testHttpHandler = new TestHttpMessageHandler(autoNegotiate: false);
+                var requestsExecuted = false;
+                var callCount = 0;
+
+                testHttpHandler.OnRequest((request, next, token) =>
+                {
+                    return Task.FromResult(ResponseUtils.CreateResponse(HttpStatusCode.NoContent));
+                });
+
+                testHttpHandler.OnNegotiate((_, cancellationToken) =>
+                {
+                    return ResponseUtils.CreateResponse(HttpStatusCode.OK, ResponseUtils.CreateNegotiationContent());
+                });
+
+                testHttpHandler.OnRequest(async (request, next, token) =>
+                {
+                    Assert.Equal("Bearer", request.Headers.Authorization.Scheme);
+
+                    // Call count increments with each call and is used as the access token
+                    Assert.Equal(callCount.ToString(), request.Headers.Authorization.Parameter);
+
+                    requestsExecuted = true;
+
+                    return await next();
+                });
+
+                string AccessTokenFactory()
+                {
+                    callCount++;
+                    return callCount.ToString();
+                }
+
+                await WithConnectionAsync(
+                    CreateConnection(testHttpHandler, transportType: transportType, accessTokenFactory: AccessTokenFactory),
+                    async (connection) =>
+                    {
+                        await connection.StartAsync(TransferFormat.Text).OrTimeout();
+                        await connection.Transport.Output.WriteAsync(Encoding.UTF8.GetBytes("Hello world 1"));
+                        await connection.Transport.Output.WriteAsync(Encoding.UTF8.GetBytes("Hello world 2"));
+                    });
+                // Fail safe in case the code is modified and some requests don't execute as a result
+                Assert.True(requestsExecuted);
+            }
+
             [Theory]
             [InlineData(HttpTransportType.LongPolling)]
             [InlineData(HttpTransportType.ServerSentEvents)]