add using to sockets sample (dotnet#20301)

* add using to sockets sample

* Update aspnetcore/fundamentals/websockets/samples/2.x/WebSocketsSample/Startup2.cs

Co-authored-by: Brennan <[email protected]>

Co-authored-by: Brennan <[email protected]>

Author: Rick-Anderson

aspnetcore/fundamentals/websockets.md

@@ -5,7 +5,7 @@ description: Learn how to get started with WebSockets in ASP.NET Core.
 monikerRange: '>= aspnetcore-1.1'
 ms.author: riande
 ms.custom: mvc
-ms.date: 11/12/2019
+ms.date: 11/1/2020
 no-loc: ["ASP.NET Core Identity", cookie, Cookie, Blazor, "Blazor Server", "Blazor WebAssembly", "Identity", "Let's Encrypt", Razor, SignalR]
 uid: fundamentals/websockets
 ---
@@ -21,40 +21,26 @@ This article explains how to get started with WebSockets in ASP.NET Core. [WebSo
 
 [ASP.NET Core SignalR](xref:signalr/introduction) is a library that simplifies adding real-time web functionality to apps. It uses WebSockets whenever possible.
 
-For most applications, we recommend SignalR over raw WebSockets. SignalR provides transport fallback for environments where WebSockets is not available. It also provides a simple remote procedure call app model. And in most scenarios, SignalR has no significant performance disadvantage compared to using raw WebSockets.
+For most applications, we recommend SignalR over raw WebSockets. SignalR provides transport fallback for environments where WebSockets is not available. It also provides a basic remote procedure call app model. And in most scenarios, SignalR has no significant performance disadvantage compared to using raw WebSockets.
+
+For some apps, [gRPC on .NET](xref:grpc/index) provides an alternative to WebSockets.
 
 ## Prerequisites
 
-* ASP.NET Core 1.1 or later
-* Any OS that supports ASP.NET Core:
-  
+* Any OS that supports ASP.NET Core:  
   * Windows 7 / Windows Server 2008 or later
   * Linux
-  * macOS
-  
+  * macOS  
 * If the app runs on Windows with IIS:
-
   * Windows 8 / Windows Server 2012 or later
   * IIS 8 / IIS 8 Express
-  * WebSockets must be enabled (See the [IIS/IIS Express support](#iisiis-express-support) section.).
-  
+  * WebSockets must be enabled. See the [IIS/IIS Express support](#iisiis-express-support) section.  
 * If the app runs on [HTTP.sys](xref:fundamentals/servers/httpsys):
-
   * Windows 8 / Windows Server 2012 or later
-
 * For supported browsers, see https://caniuse.com/#feat=websockets.
 
-::: moniker range="< aspnetcore-2.1"
-
-## NuGet package
-
-Install the [Microsoft.AspNetCore.WebSockets](https://www.nuget.org/packages/Microsoft.AspNetCore.WebSockets/) package.
-
-::: moniker-end
-
 ## Configure the middleware
 
-
 Add the WebSockets middleware in the `Configure` method of the `Startup` class:
 
 [!code-csharp[](websockets/samples/2.x/WebSocketsSample/Startup.cs?name=UseWebSockets)]
@@ -99,19 +85,11 @@ Object name: 'HttpResponseStream'.
 
 If you're using a background service to write data to a WebSocket, make sure you keep the middleware pipeline running. Do this by using a <xref:System.Threading.Tasks.TaskCompletionSource%601>. Pass the `TaskCompletionSource` to your background service and have it call <xref:System.Threading.Tasks.TaskCompletionSource%601.TrySetResult%2A> when you finish with the WebSocket. Then `await` the <xref:System.Threading.Tasks.TaskCompletionSource%601.Task> property during the request, as shown in the following example:
 
-```csharp
-app.Use(async (context, next) => {
-    var socket = await context.WebSockets.AcceptWebSocketAsync();
-    var socketFinishedTcs = new TaskCompletionSource<object>();
-
-    BackgroundSocketProcessor.AddSocket(socket, socketFinishedTcs); 
+[!code-csharp[](websockets/samples/2.x/WebSocketsSample/Startup2.cs?name=AcceptWebSocket)]
 
-    await socketFinishedTcs.Task;
-});
-```
-The WebSocket closed exception can also happen if you return too soon from an action method. If you accept a socket in an action method, wait for the code that uses the socket to complete before returning from the action method.
+The WebSocket closed exception can also happen when returning too soon from an action method. When accepting a socket in an action method, wait for the code that uses the socket to complete before returning from the action method.
 
-Never use `Task.Wait()`, `Task.Result`, or similar blocking calls to wait for the socket to complete, as that can cause serious threading issues. Always use `await`.
+Never use `Task.Wait`, `Task.Result`, or similar blocking calls to wait for the socket to complete, as that can cause serious threading issues. Always use `await`.
 
 ## Send and receive messages
 

aspnetcore/fundamentals/websockets/samples/2.x/WebSocketsSample/Startup.cs

@@ -77,8 +77,10 @@ public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerF
                 {
                     if (context.WebSockets.IsWebSocketRequest)
                     {
-                        WebSocket webSocket = await context.WebSockets.AcceptWebSocketAsync();
-                        await Echo(context, webSocket);
+                        using (WebSocket webSocket = await context.WebSockets.AcceptWebSocketAsync())
+                        {
+                            await Echo(context, webSocket);
+                        }
                     }
                     else
                     {

aspnetcore/fundamentals/websockets/samples/2.x/WebSocketsSample/Startup2.cs

@@ -0,0 +1,66 @@
+#define UseOptions // or NoOptions or UseOptionsAO
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.WebSockets;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Console;
+using Microsoft.Extensions.Logging.Debug;
+
+namespace EchoApp
+{
+    public class Startup2
+    {
+        // This method gets called by the runtime. Use this method to add services to the container.
+        // For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=398940
+        public void ConfigureServices(IServiceCollection services)
+        {
+            services.AddLogging(builder =>
+            {
+                builder.AddConsole()
+                    .AddDebug()
+                    .AddFilter<ConsoleLoggerProvider>(category: null, level: LogLevel.Debug)
+                    .AddFilter<DebugLoggerProvider>(category: null, level: LogLevel.Debug);
+            });
+        }
+
+        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
+        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
+        {
+            if (env.IsDevelopment())
+            {
+                app.UseDeveloperExceptionPage();
+            }
+
+            #region AcceptWebSocket
+            app.Use(async (context, next) =>
+            {
+                using (WebSocket webSocket = await context.WebSockets.AcceptWebSocketAsync())
+                {
+                    var socketFinishedTcs = new TaskCompletionSource<object>();
+
+                    BackgroundSocketProcessor.AddSocket(webSocket, socketFinishedTcs);
+
+                    await socketFinishedTcs.Task;
+                }
+            });
+            #endregion
+            app.UseFileServer();
+        }
+    }
+
+    internal class BackgroundSocketProcessor
+    {
+        internal static void AddSocket(WebSocket socket, TaskCompletionSource<object> socketFinishedTcs)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}