React to Mono WebAssembly changes for 3.1 preview 3

Author: SteveSandersonMS

src/Components/Blazor/Blazor/ref/Microsoft.AspNetCore.Blazor.netstandard2.0.cs

@@ -54,13 +54,9 @@ public enum FetchCredentialsOption
         SameOrigin = 1,
         Include = 2,
     }
-    public partial class WebAssemblyHttpMessageHandler : System.Net.Http.HttpMessageHandler
+    public static partial class WebAssemblyHttpMessageHandlerOptions
     {
-        public const string FetchArgs = "WebAssemblyHttpMessageHandler.FetchArgs";
-        public WebAssemblyHttpMessageHandler() { }
-        public static Microsoft.AspNetCore.Blazor.Http.FetchCredentialsOption DefaultCredentials { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } [System.Runtime.CompilerServices.CompilerGeneratedAttribute]set { } }
-        [System.Diagnostics.DebuggerStepThroughAttribute]
-        protected override System.Threading.Tasks.Task<System.Net.Http.HttpResponseMessage> SendAsync(System.Net.Http.HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) { throw null; }
+        public static Microsoft.AspNetCore.Blazor.Http.FetchCredentialsOption DefaultCredentials { get { throw null; } set { } }
     }
 }
 namespace Microsoft.AspNetCore.Blazor.Rendering

src/Components/Blazor/Blazor/src/Hosting/WebAssemblyHost.cs

@@ -2,11 +2,8 @@
 // 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.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Blazor.Http;
 using Microsoft.AspNetCore.Blazor.Rendering;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.JSInterop;
@@ -30,16 +27,6 @@ public WebAssemblyHost(IServiceProvider services, IJSRuntime runtime)
 
         public Task StartAsync(CancellationToken cancellationToken = default)
         {
-            // We need to do this as early as possible, it eliminates a bunch of problems. Note that what we do
-            // is a bit fragile. If you see things breaking because JSRuntime.Current isn't set, then it's likely
-            // that something on the startup path went wrong.
-            //
-            // We want to the JSRuntime created here to be the 'ambient' runtime when JS calls back into .NET. When
-            // this happens in the browser it will be a direct call from Mono. We effectively needs to set the
-            // JSRuntime in the 'root' execution context which implies that we want to do as part of a direct
-            // call from Program.Main, and before any 'awaits'.
-            SetBrowserHttpMessageHandlerAsDefault();
-
             return StartAsyncAwaited();
         }
 
@@ -102,35 +89,5 @@ public void Dispose()
         {
             (Services as IDisposable)?.Dispose();
         }
-
-        private static void SetBrowserHttpMessageHandlerAsDefault()
-        {
-            // Within the Mono WebAssembly BCL, this is a special private static field
-            // that can be assigned to override the default handler
-            const string getHttpMessageHandlerFieldName = "GetHttpMessageHandler";
-            var getHttpMessageHandlerField = typeof(HttpClient).GetField(
-                getHttpMessageHandlerFieldName,
-                BindingFlags.Static | BindingFlags.NonPublic);
-
-            // getHttpMessageHandlerField will be null in tests, but nonnull when actually
-            // running under Mono WebAssembly
-            if (getHttpMessageHandlerField != null)
-            {
-                // Just in case you're not actually using HttpClient, defer the construction
-                // of the WebAssemblyHttpMessageHandler
-                var handlerSingleton = new Lazy<HttpMessageHandler>(
-                    () => new WebAssemblyHttpMessageHandler());
-                Func<HttpMessageHandler> handlerFactory = () => handlerSingleton.Value;
-                getHttpMessageHandlerField.SetValue(null, handlerFactory);
-            }
-            else
-            {
-                // We log a warning in case this ever happens at runtime (even though there's
-                // no obvious way it could be possible), but don't actually throw because that
-                // would break unit tests
-                Console.WriteLine("WARNING: Could not set default HttpMessageHandler because " +
-                    $"'{getHttpMessageHandlerFieldName}' was not found on '{typeof(HttpClient).FullName}'.");
-            }
-        }
     }
 }

src/Components/Blazor/Blazor/src/Http/WebAssemblyHttpMessageHandler.cs

@@ -0,0 +1,59 @@
+// 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.Reflection;
+
+namespace Microsoft.AspNetCore.Blazor.Http
+{
+    /// <summary>
+    /// Configures options for the WebAssembly HTTP message handler.
+    /// </summary>
+    public static class WebAssemblyHttpMessageHandlerOptions
+    {
+        /// <summary>
+        /// Gets or sets the default value of the 'credentials' option on outbound HTTP requests.
+        /// Defaults to <see cref="FetchCredentialsOption.SameOrigin"/>.
+        /// </summary>
+        public static FetchCredentialsOption DefaultCredentials
+        {
+            get
+            {
+                var valueString = MonoDefaultCredentialsGetter.Value();
+                var result = default(FetchCredentialsOption);
+                if (valueString != null)
+                {
+                    Enum.TryParse(valueString, out result);
+                }
+                return result;
+            }
+
+            set
+            {
+                MonoDefaultCredentialsSetter.Value(value.ToString());
+            }
+        }
+
+        static Func<Type> MonoWasmHttpMessageHandlerType = ()
+            => Assembly.Load("WebAssembly.Net.Http")
+                .GetType("WebAssembly.Net.Http.HttpClient.WasmHttpMessageHandler");
+
+        static Func<Type> MonoFetchCredentialsOptionType = ()
+            => Assembly.Load("WebAssembly.Net.Http")
+                .GetType("WebAssembly.Net.Http.HttpClient.FetchCredentialsOption");
+
+        static Lazy<PropertyInfo> MonoDefaultCredentialsProperty = new Lazy<PropertyInfo>(
+            () => MonoWasmHttpMessageHandlerType()?.GetProperty("DefaultCredentials", BindingFlags.Public | BindingFlags.Static));
+
+        static Lazy<Func<string>> MonoDefaultCredentialsGetter = new Lazy<Func<string>>(() =>
+        {
+            return () => MonoDefaultCredentialsProperty.Value?.GetValue(null).ToString();
+        });
+
+        static Lazy<Action<string>> MonoDefaultCredentialsSetter = new Lazy<Action<string>>(() =>
+        {
+            var fetchCredentialsOptionsType = MonoFetchCredentialsOptionType();
+            return value => MonoDefaultCredentialsProperty.Value?.SetValue(null, Enum.Parse(fetchCredentialsOptionsType, value));
+        });
+    }
+}

src/Components/Blazor/Blazor/src/Http/WebAssemblyHttpMessageHandlerOptions.cs

@@ -422,7 +422,7 @@
     4) Add the file we just created to the list of file writes, to support incremental builds.
     -->
     <ItemGroup>
-      <_MonoBaseClassLibraryFolder Include="$(MonoBaseClassLibraryPath);$(MonoBaseClassLibraryFacadesPath)" />
+      <_MonoBaseClassLibraryFolder Include="$(MonoBaseClassLibraryPath);$(MonoBaseClassLibraryFacadesPath);$(MonoWasmFrameworkPath)" />
       <_BlazorAssembliesToLink Include="@(_BlazorDependencyInput->'-a &quot;%(Identity)&quot;')" />
       <_BlazorAssembliesToLink Include="@(IntermediateAssembly->'-a &quot;%(FullPath)&quot;')" />
       <_BlazorFolderLookupPaths Include="@(_MonoBaseClassLibraryFolder->'-d &quot;%(Identity)&quot;')" />
@@ -522,7 +522,7 @@
 
     <PropertyGroup>
       <_ReferencesArg Condition="'@(_BlazorDependencyInput)' != ''">--references &quot;$(BlazorResolveDependenciesFilePath)&quot;</_ReferencesArg>
-      <_BclParameter>--base-class-library &quot;$(MonoBaseClassLibraryPath)&quot; --base-class-library &quot;$(MonoBaseClassLibraryFacadesPath)&quot;</_BclParameter>
+      <_BclParameter>--base-class-library &quot;$(MonoBaseClassLibraryPath)&quot; --base-class-library &quot;$(MonoBaseClassLibraryFacadesPath)&quot; --base-class-library &quot;$(MonoWasmFrameworkPath)&quot;</_BclParameter>
     </PropertyGroup>
 
     <WriteLinesToFile

src/Components/Blazor/Build/src/targets/Blazor.MonoRuntime.targets

@@ -18,4 +18,10 @@
     <type fullname="System.ComponentModel.GuidConverter" />
     <type fullname="System.ComponentModel.TimeSpanConverter" />
   </assembly>
+
+  <assembly fullname="WebAssembly.Net.Http">
+    <!-- Without this, the setter for DefaultCredentials would be removed, but we need it -->
+    <type fullname="WebAssembly.Net.Http.HttpClient.FetchCredentialsOption" />
+    <type fullname="WebAssembly.Net.Http.HttpClient.WasmHttpMessageHandler" />
+  </assembly>
 </linker>

src/Components/Blazor/Build/src/targets/BuiltInBclLinkerDescriptor.xml

@@ -40,6 +40,7 @@
     <ItemGroup>
       <_BclDirectory Include="$(MonoBaseClassLibraryPath)" />
       <_BclDirectory Include="$(MonoBaseClassLibraryFacadesPath)" />
+      <_BclDirectory Include="$(MonoWasmFrameworkPath)" />
     </ItemGroup>
 
     <WriteLinesToFile Lines="@(ReferencePath)" File="$(TargetDir)referenceHints.txt" WriteOnlyWhenDifferent="true" Overwrite="true" />

src/Components/Blazor/Build/test/Microsoft.AspNetCore.Blazor.Build.Tests.csproj

@@ -488,7 +488,7 @@ async Task GetScopeProperties (int msg_id, int scope_id, CancellationToken token
 			// Trying to inspect the stack frame for DotNetDispatcher::InvokeSynchronously
 			// results in a "Memory access out of bounds", causing 'values' to be null,
 			// so skip returning variable values in that case.
-			while (values != null && i < var_ids.Length && i < values.Length) {
+			while (values != null && i < vars.Length && i < values.Length) {
 				var value = values [i] ["value"];
 				if (((string)value ["description"]) == null)
 					value ["description"] = value ["value"]?.ToString();