[blazor-wasm] Pass access token as query string when running SignalR in the browser

eng/Build.props

@@ -52,7 +52,7 @@
 
   <PropertyGroup>
     <!-- For the Blazor WASM branch, only build a subset of projects -->
-    <ProjectToBuild>$(RepoRoot)src\Components\**\*.csproj;$(RepoRoot)src\ProjectTemplates\**\*.csproj</ProjectToBuild>
+    <ProjectToBuild>$(RepoRoot)src\Components\**\*.csproj;$(RepoRoot)src\ProjectTemplates\**\*.csproj;$(RepoRoot)src\SignalR\clients\csharp\Http.Connections.Client\**\*.csproj</ProjectToBuild>
   </PropertyGroup>
 
   <Choose>

eng/ProjectReferences.props

@@ -13,5 +13,6 @@
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.Components.WebAssembly.Authentication" ProjectPath="$(RepoRoot)src\Components\WebAssembly\WebAssembly.Authentication\src\Microsoft.AspNetCore.Components.WebAssembly.Authentication.csproj"  />
     <ProjectReferenceProvider Include="Microsoft.Authentication.WebAssembly.Msal" ProjectPath="$(RepoRoot)src\Components\WebAssembly\Authentication.Msal\src\Microsoft.Authentication.WebAssembly.Msal.csproj"  />
     <ProjectReferenceProvider Include="Microsoft.AspNetCore.Components.WebAssembly" ProjectPath="$(RepoRoot)src\Components\WebAssembly\WebAssembly\src\Microsoft.AspNetCore.Components.WebAssembly.csproj" RefProjectPath="$(RepoRoot)src\Components\WebAssembly\WebAssembly\ref\Microsoft.AspNetCore.Components.WebAssembly.csproj" />
+    <ProjectReferenceProvider Include="Microsoft.AspNetCore.Http.Connections.Client" ProjectPath="$(RepoRoot)src\SignalR\clients\csharp\Http.Connections.Client\src\Microsoft.AspNetCore.Http.Connections.Client.csproj" />
   </ItemGroup>
 </Project>

src/SignalR/clients/csharp/Http.Connections.Client/src/HttpConnection.Log.cs

@@ -66,6 +66,9 @@ private static class Log
             private static readonly Action<ILogger, HttpTransportType, Exception> _transportStarted =
                 LoggerMessage.Define<HttpTransportType>(LogLevel.Debug, new EventId(18, "TransportStarted"), "Transport '{Transport}' started.");
 
+            private static readonly Action<ILogger, Exception> _serverSentEventsNotSupportedByBrowser =
+                LoggerMessage.Define(LogLevel.Debug, new EventId(19, "ServerSentEventsNotSupportedByBrowser"), "Skipping ServerSentEvents because they are not supported by the browser.");
+
             public static void Starting(ILogger logger)
             {
                 _starting(logger, null);
@@ -167,6 +170,11 @@ public static void TransportStarted(ILogger logger, HttpTransportType transportT
             {
                 _transportStarted(logger, transportType, null);
             }
+
+            public static void ServerSentEventsNotSupportedByBrowser(ILogger logger)
+            {
+                _serverSentEventsNotSupportedByBrowser(logger, null);
+            }
         }
     }
 }

src/SignalR/clients/csharp/Http.Connections.Client/src/HttpConnection.cs

@@ -37,6 +37,7 @@ public partial class HttpConnection : ConnectionContext, IConnectionInherentKeep
         private bool _started;
         private bool _disposed;
         private bool _hasInherentKeepAlive;
+        private bool _isRunningInBrowser;
 
         private readonly HttpClient _httpClient;
         private readonly HttpConnectionOptions _httpConnectionOptions;
@@ -150,6 +151,14 @@ public HttpConnection(HttpConnectionOptions httpConnectionOptions, ILoggerFactor
                 _httpClient = CreateHttpClient();
             }
 
+            _isRunningInBrowser = Utils.IsRunningInBrowser();
+
+
+            if (httpConnectionOptions.Transports == HttpTransportType.ServerSentEvents && _isRunningInBrowser)
+            {
+                throw new ArgumentException("ServerSentEvents can not be the only transport specified when running in the browser.", nameof(httpConnectionOptions));
+            }
+
             _transportFactory = new DefaultTransportFactory(httpConnectionOptions.Transports, _loggerFactory, _httpClient, httpConnectionOptions, GetAccessTokenAsync);
             _logScope = new ConnectionLogScope();
 
@@ -365,6 +374,13 @@ private async Task SelectAndStartTransport(TransferFormat transferFormat, Cancel
                         continue;
                     }
 
+                    if (transportType == HttpTransportType.ServerSentEvents && _isRunningInBrowser)
+                    {
+                        Log.ServerSentEventsNotSupportedByBrowser(_logger);
+                        transportExceptions.Add(new TransportFailedException("ServerSentEvents", "The transport is not supported in the browser."));
+                        continue;
+                    }
+
                     try
                     {
                         if ((transportType & _httpConnectionOptions.Transports) == 0)

src/SignalR/clients/csharp/Http.Connections.Client/src/Internal/Utils.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Runtime.InteropServices;
 
 namespace Microsoft.AspNetCore.Http.Connections.Client.Internal
 {
@@ -41,5 +42,10 @@ internal static Uri AppendQueryString(Uri url, string qs)
             builder.Query = newQueryString;
             return builder.Uri;
         }
+
+        internal static bool IsRunningInBrowser()
+        {
+            return RuntimeInformation.IsOSPlatform(OSPlatform.Create("WEBASSEMBLY"));
+        }
     }
 }