Add new Microsoft.AspNetCore.SpaServices.Extensions package to host new runtime functionality needed for updated templates until 2.1 ships

src/Microsoft.AspNetCore.SpaServices.Extensions/Proxying/SpaProxyingExtensions.cs

@@ -0,0 +1,92 @@
+// 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 Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.SpaServices;
+using Microsoft.AspNetCore.SpaServices.Extensions.Proxy;
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.Builder
+{
+    /// <summary>
+    /// Extension methods for proxying requests to a local SPA development server during
+    /// development. Not for use in production applications.
+    /// </summary>
+    public static class SpaProxyingExtensions
+    {
+        /// <summary>
+        /// Configures the application to forward incoming requests to a local Single Page
+        /// Application (SPA) development server. This is only intended to be used during
+        /// development. Do not enable this middleware in production applications.
+        /// </summary>
+        /// <param name="spaBuilder">The <see cref="ISpaBuilder"/>.</param>
+        /// <param name="baseUri">The target base URI to which requests should be proxied.</param>
+        public static void UseProxyToSpaDevelopmentServer(
+            this ISpaBuilder spaBuilder,
+            string baseUri)
+        {
+            UseProxyToSpaDevelopmentServer(
+                spaBuilder,
+                new Uri(baseUri));
+        }
+
+        /// <summary>
+        /// Configures the application to forward incoming requests to a local Single Page
+        /// Application (SPA) development server. This is only intended to be used during
+        /// development. Do not enable this middleware in production applications.
+        /// </summary>
+        /// <param name="spaBuilder">The <see cref="ISpaBuilder"/>.</param>
+        /// <param name="baseUri">The target base URI to which requests should be proxied.</param>
+        public static void UseProxyToSpaDevelopmentServer(
+            this ISpaBuilder spaBuilder,
+            Uri baseUri)
+        {
+            UseProxyToSpaDevelopmentServer(
+                spaBuilder,
+                Task.FromResult(baseUri));
+        }
+
+        /// <summary>
+        /// Configures the application to forward incoming requests to a local Single Page
+        /// Application (SPA) development server. This is only intended to be used during
+        /// development. Do not enable this middleware in production applications.
+        /// </summary>
+        /// <param name="spaBuilder">The <see cref="ISpaBuilder"/>.</param>
+        /// <param name="baseUriTask">A <see cref="Task"/> that resolves with the target base URI to which requests should be proxied.</param>
+        public static void UseProxyToSpaDevelopmentServer(
+            this ISpaBuilder spaBuilder,
+            Task<Uri> baseUriTask)
+        {
+            var applicationBuilder = spaBuilder.ApplicationBuilder;
+            var applicationStoppingToken = GetStoppingToken(applicationBuilder);
+
+            // Since we might want to proxy WebSockets requests (e.g., by default, AngularCliMiddleware
+            // requires it), enable it for the app
+            applicationBuilder.UseWebSockets();
+
+            // It's important not to time out the requests, as some of them might be to
+            // server-sent event endpoints or similar, where it's expected that the response
+            // takes an unlimited time and never actually completes
+            var neverTimeOutHttpClient =
+                SpaProxy.CreateHttpClientForProxy(Timeout.InfiniteTimeSpan);
+
+            // Proxy all requests into the Angular CLI server
+            applicationBuilder.Use(async (context, next) =>
+            {
+                var didProxyRequest = await SpaProxy.PerformProxyRequest(
+                    context, neverTimeOutHttpClient, baseUriTask, applicationStoppingToken,
+                    proxy404s: true);
+            });
+        }
+
+        private static CancellationToken GetStoppingToken(IApplicationBuilder appBuilder)
+        {
+            var applicationLifetime = appBuilder
+                .ApplicationServices
+                .GetService(typeof(IApplicationLifetime));
+            return ((IApplicationLifetime)applicationLifetime).ApplicationStopping;
+        }
+    }
+}