Implement IHttpUpgradeFeature.IsUpgradableRequest in IIS #23172 (#28121)

Author: Tratcher

src/Servers/IIS/IIS/src/Core/IISHttpContext.FeatureCollection.cs

@@ -250,7 +250,10 @@ private async Task CompleteInitializeResponseAwaited(Task initializeTask)
             await _writeBodyTask;
         }
 
-        bool IHttpUpgradeFeature.IsUpgradableRequest => true;
+        // Http/2 does not support the upgrade mechanic.
+        // Http/1.x upgrade requests may have a request body, but that's not allowed in our main scenario (WebSockets) and much
+        // more complicated to support. See https://tools.ietf.org/html/rfc7230#section-6.7, https://tools.ietf.org/html/rfc7540#section-3.2
+        bool IHttpUpgradeFeature.IsUpgradableRequest => !RequestCanHaveBody && HttpVersion < System.Net.HttpVersion.Version20;
 
         bool IFeatureCollection.IsReadOnly => false;
 

src/Servers/IIS/IIS/test/IISExpress.FunctionalTests/InProcess/WebSocketTests.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Globalization;
 using System.Linq;
+using System.Net.Http;
 using System.Net.WebSockets;
 using System.Text;
 using System.Threading;
@@ -17,11 +18,30 @@ namespace Microsoft.AspNetCore.Server.IIS.FunctionalTests
     [MinimumOSVersion(OperatingSystems.Windows, WindowsVersions.Win8, SkipReason = "No WebSocket supported on Win7")]
     public class WebSocketsTests
     {
+        private readonly string _requestUri;
         private readonly string _webSocketUri;
 
         public WebSocketsTests(IISTestSiteFixture fixture)
         {
-            _webSocketUri = fixture.DeploymentResult.ApplicationBaseUri.Replace("http:", "ws:");
+            _requestUri = fixture.DeploymentResult.ApplicationBaseUri;
+            _webSocketUri = _requestUri.Replace("http:", "ws:");
+        }
+
+        [ConditionalFact]
+        public async Task RequestWithBody_NotUpgradable()
+        {
+            using var client = new HttpClient();
+            using var response = await client.PostAsync(_requestUri + "WebSocketNotUpgradable", new StringContent("Hello World"));
+            response.EnsureSuccessStatusCode();
+        }
+
+        [ConditionalFact]
+        public async Task RequestWithoutBody_Upgradable()
+        {
+            using var client = new HttpClient();
+            // POST with Content-Length: 0 counts as not having a body.
+            using var response = await client.PostAsync(_requestUri + "WebSocketUpgradable", new StringContent(""));
+            response.EnsureSuccessStatusCode();
         }
 
         [ConditionalFact]
@@ -38,7 +58,7 @@ public async Task OnStartedCalledForWebSocket()
         public async Task WebReadBeforeUpgrade()
         {
             var cws = new ClientWebSocket();
-            await cws.ConnectAsync(new Uri(_webSocketUri + "WebReadBeforeUpgrade"), default);
+            await cws.ConnectAsync(new Uri(_webSocketUri + "WebSocketReadBeforeUpgrade"), default);
 
             await ReceiveMessage(cws, "Yay");
         }

src/Servers/IIS/IIS/test/testassets/InProcessWebSite/Startup.WebSockets.cs

@@ -21,16 +21,27 @@ namespace TestSite
 {
     public partial class Startup
     {
+        private void WebSocketNotUpgradable(IApplicationBuilder app)
+        {
+            app.Run(context => {
+
+                var upgradeFeature = context.Features.Get<IHttpUpgradeFeature>();
+                Assert.False(upgradeFeature.IsUpgradableRequest);
+                return Task.CompletedTask;
+            });
+        }
 
-        private void WebsocketRequest(IApplicationBuilder app)
+        private void WebSocketUpgradable(IApplicationBuilder app)
         {
-            app.Run(async context =>
-            {
-                await context.Response.WriteAsync("test");
+            app.Run(context => {
+
+                var upgradeFeature = context.Features.Get<IHttpUpgradeFeature>();
+                Assert.True(upgradeFeature.IsUpgradableRequest);
+                return Task.CompletedTask;
             });
         }
 
-        private void WebReadBeforeUpgrade(IApplicationBuilder app)
+        private void WebSocketReadBeforeUpgrade(IApplicationBuilder app)
         {
             app.Run(async context => {
 

src/Servers/IIS/IIS/test/testassets/InProcessWebSite/Startup.cs

@@ -1488,6 +1488,8 @@ public Task Http2_MethodsRequestWithoutData_Success(HttpContext httpContext)
             Assert.Equal("HTTP/2", httpContext.Request.Protocol);
 #if !FORWARDCOMPAT
             Assert.False(httpContext.Request.CanHaveBody());
+            var feature = httpContext.Features.Get<IHttpUpgradeFeature>();
+            Assert.False(feature.IsUpgradableRequest);
 #endif
             Assert.Null(httpContext.Request.ContentLength);
             Assert.False(httpContext.Request.Headers.ContainsKey(HeaderNames.TransferEncoding));