开始在 .NET 中使用中继混合连接 WebSocket

在本快速入门中，请创建 .NET 发送者和接收者应用程序，以便在 Azure 中继中通过混合连接 WebSocket 发送和接收消息。 若要了解 Azure 中继的常规信息，请参阅 Azure 中继。

在本快速入门中，你将执行以下步骤：

1. 使用 Azure 门户创建中继命名空间。
2. 使用 Azure 门户在该命名空间中创建混合连接。
3. 编写服务器（侦听器）控制台应用程序，用于接收消息。
4. 编写客户端（发送方）控制台应用程序，用于发送消息。
5. 运行应用程序。

先决条件

若要完成本教程，需要满足以下先决条件：

• Visual Studio 2015 或更高版本。 本教程中的示例使用 Visual Studio 2017。
• Azure 订阅。 如果没有 Azure 订阅，请在开始之前创建一个试用版订阅。

创建命名空间

1. 登录 Azure 门户。

2. 在左侧菜单中，选择“所有服务” 。 选择“集成”，搜索“中继”，将鼠标移到“中继”上方，然后选择“创建”。

   

3. 在“创建命名空间”页上，执行以下步骤：

   1. 选择要在其中创建命名空间的 Azure 订阅。

   2. 对于资源组，选择一个要在其中放置命名空间的现有资源组，或创建一个新资源组。

   3. 输入中继命名空间的名称。

   4. 选择应托管该命名空间的区域。

   5. 在页面底部选择查看 + 创建。

      

   6. 在“查看 + 创建”页面上，选择“创建”。

   7. 几分钟后，将看到该命名空间的“中继”页面。

      

获取管理凭据

1. 在“中继”页上，选择左侧菜单的“共享访问策略”。

2. 在“共享访问策略”页，选择“RootManageSharedAccessKey” 。

3. 在“SAS 策略:RootManageSharedAccessKey”下，选择“主连接字符串”旁边的“复制”按钮。 此操作会将连接字符串复制到剪贴板，供以后使用。 将此值粘贴到记事本或其他某个临时位置。

4. 重复上述步骤，将主密钥的值复制和粘贴到临时位置，供以后使用。

   

创建混合连接

在命名空间的“中继”页上，按照以下步骤创建混合连接。

1. 请在左侧菜单中的“实体”下选择“混合连接”，然后选择“+ 混合连接”。

   

2. 在“创建混合连接”页上，输入混合连接的名称，然后选择“创建”。

   

创建服务器应用程序（侦听程序）

在 Visual Studio 中编写可侦听和接收来自中继的消息的 C# 控制台应用程序。

创建控制台应用程序

在 Visual Studio 中创建新的控制台应用 (.NET Framework) 项目。

添加中继 NuGet 包

1. 右键单击新创建的项目，然后选择“管理 NuGet 包”。

2. 选择“浏览”，然后搜索 Microsoft.Azure.Relay。 在搜索结果中，选择“Microsoft Azure 中继”。

3. 选择“安装”即可完成安装。 关闭对话框。

编写接收消息的代码

1. 将 Program.cs 文件顶部的现有 using 语句替换为以下 using 语句：

   using System;
   using System.IO;
   using System.Threading;
   using System.Threading.Tasks;
   using System.Net;
   using Microsoft.Azure.Relay;
   

2. 将常量添加到 Program 类，用于保存混合连接的连接详细信息。 将占位符替换为在创建混合连接时获得的值。 请务必使用完全限定的命名空间名称。

   // replace {RelayNamespace} with the name of your namespace
   private const string RelayNamespace = "YOUR-RELAY-NAMESPACE-NAME.servicebus.chinacloudapi.cn";
   
   // replace {HybridConnectionName} with the name of your hybrid connection
   private const string ConnectionName = "HYBRID-CONNECTION-NAME";
   
   // replace {SAKKeyName} with the name of your Shared Access Policies key, which is RootManageSharedAccessKey by default
   private const string KeyName = "SAS-KEY-NAME";
   
   // replace {SASKey} with the primary key of the namespace you saved earlier
   private const string Key = "SAS-KEY-VALUE";
   

3. 将 ProcessMessagesOnConnection 方法添加到 Program 类：

   // The method initiates the connection.
   private static async void ProcessMessagesOnConnection(HybridConnectionStream relayConnection, CancellationTokenSource cts)
   {
       Console.WriteLine("New session");
   
       // The connection is a fully bidrectional stream. 
       // Put a stream reader and a stream writer over it.  
       // This allows you to read UTF-8 text that comes from 
       // the sender, and to write text replies back.
       var reader = new StreamReader(relayConnection);
       var writer = new StreamWriter(relayConnection) { AutoFlush = true };
       while (!cts.IsCancellationRequested)
       {
           try
           {
               // Read a line of input until a newline is encountered.
               var line = await reader.ReadLineAsync();
   
               if (string.IsNullOrEmpty(line))
               {
                   // If there's no input data, signal that 
                   // you will no longer send data on this connection,
                   // and then break out of the processing loop.
                   await relayConnection.ShutdownAsync(cts.Token);
                   break;
               }
   
               // Write the line on the console.
               Console.WriteLine(line);
   
               // Write the line back to the client, prepended with "Echo:"
               await writer.WriteLineAsync($"Echo: {line}");
           }
           catch (IOException)
           {
               // Catch an I/O exception. This likely occurred when
               // the client disconnected.
               Console.WriteLine("Client closed connection");
               break;
           }
       }
   
       Console.WriteLine("End session");
   
       // Close the connection.
       await relayConnection.CloseAsync(cts.Token);
   }
   

4. 将 RunAsync 方法添加到 Program 类：

   private static async Task RunAsync()
   {
       var cts = new CancellationTokenSource();
   
       var tokenProvider = TokenProvider.CreateSharedAccessSignatureTokenProvider(KeyName, Key);
       var listener = new HybridConnectionListener(new Uri(string.Format("sb://{0}/{1}", RelayNamespace, ConnectionName)), tokenProvider);
   
       // Subscribe to the status events.
       listener.Connecting += (o, e) => { Console.WriteLine("Connecting"); };
       listener.Offline += (o, e) => { Console.WriteLine("Offline"); };
       listener.Online += (o, e) => { Console.WriteLine("Online"); };
   
       // Opening the listener establishes the control channel to
       // the Azure Relay service. The control channel is continuously 
       // maintained, and is reestablished when connectivity is disrupted.
       await listener.OpenAsync(cts.Token);
       Console.WriteLine("Server listening");
   
       // Provide callback for the cancellation token that will close the listener.
       cts.Token.Register(() => listener.CloseAsync(CancellationToken.None));
   
       // Start a new thread that will continuously read the console.
       new Task(() => Console.In.ReadLineAsync().ContinueWith((s) => { cts.Cancel(); })).Start();
   
       // Accept the next available, pending connection request. 
       // Shutting down the listener allows a clean exit. 
       // This method returns null.
       while (true)
       {
           var relayConnection = await listener.AcceptConnectionAsync();
           if (relayConnection == null)
           {
               break;
           }
   
           ProcessMessagesOnConnection(relayConnection, cts);
       }
   
       // Close the listener after you exit the processing loop.
       await listener.CloseAsync(cts.Token);
   }
   

5. 在 Program 类的 Main 方法中添加以下代码行：

   RunAsync().GetAwaiter().GetResult();
   

   完成的 Program.cs 文件应如下所示：

   namespace Server
   {
       using System;
       using System.IO;
       using System.Threading;
       using System.Threading.Tasks;
       using Microsoft.Azure.Relay;
   
       public class Program
       {
           private const string RelayNamespace = "{RelayNamespace}.servicebus.chinacloudapi.cn";
           private const string ConnectionName = "{HybridConnectionName}";
           private const string KeyName = "{SASKeyName}";
           private const string Key = "{SASKey}";
   
           public static void Main(string[] args)
           {
               RunAsync().GetAwaiter().GetResult();
           }
   
           private static async Task RunAsync()
           {
               var cts = new CancellationTokenSource();
   
               var tokenProvider = TokenProvider.CreateSharedAccessSignatureTokenProvider(KeyName, Key);
               var listener = new HybridConnectionListener(new Uri(string.Format("sb://{0}/{1}", RelayNamespace, ConnectionName)), tokenProvider);
   
               // Subscribe to the status events.
               listener.Connecting += (o, e) => { Console.WriteLine("Connecting"); };
               listener.Offline += (o, e) => { Console.WriteLine("Offline"); };
               listener.Online += (o, e) => { Console.WriteLine("Online"); };
   
               // Opening the listener establishes the control channel to
               // the Azure Relay service. The control channel is continuously 
               // maintained, and is reestablished when connectivity is disrupted.
               await listener.OpenAsync(cts.Token);
               Console.WriteLine("Server listening");
   
               // Provide callback for a cancellation token that will close the listener.
               cts.Token.Register(() => listener.CloseAsync(CancellationToken.None));
   
               // Start a new thread that will continuously read the console.
               new Task(() => Console.In.ReadLineAsync().ContinueWith((s) => { cts.Cancel(); })).Start();
   
               // Accept the next available, pending connection request. 
               // Shutting down the listener allows a clean exit. 
               // This method returns null.
               while (true)
               {
                   var relayConnection = await listener.AcceptConnectionAsync();
                   if (relayConnection == null)
                   {
                       break;
                   }
   
                   ProcessMessagesOnConnection(relayConnection, cts);
               }
   
               // Close the listener after you exit the processing loop.
               await listener.CloseAsync(cts.Token);
           }
   
           private static async void ProcessMessagesOnConnection(HybridConnectionStream relayConnection, CancellationTokenSource cts)
           {
               Console.WriteLine("New session");
   
               // The connection is a fully bidrectional stream. 
               // Put a stream reader and a stream writer over it.  
               // This allows you to read UTF-8 text that comes from 
               // the sender, and to write text replies back.
               var reader = new StreamReader(relayConnection);
               var writer = new StreamWriter(relayConnection) { AutoFlush = true };
               while (!cts.IsCancellationRequested)
               {
                   try
                   {
                       // Read a line of input until a newline is encountered.
                       var line = await reader.ReadLineAsync();
   
                       if (string.IsNullOrEmpty(line))
                       {
                           // If there's no input data, signal that 
                           // you will no longer send data on this connection.
                           // Then, break out of the processing loop.
                           await relayConnection.ShutdownAsync(cts.Token);
                           break;
                       }
   
                       // Write the line on the console.
                       Console.WriteLine(line);
   
                       // Write the line back to the client, prepended with "Echo:"
                       await writer.WriteLineAsync($"Echo: {line}");
                   }
                   catch (IOException)
                   {
                       // Catch an I/O exception. This likely occurred when
                       // the client disconnected.
                       Console.WriteLine("Client closed connection");
                       break;
                   }
               }
   
               Console.WriteLine("End session");
   
               // Close the connection.
               await relayConnection.CloseAsync(cts.Token);
           }
       }
   }
   

创建客户端应用程序（发送程序）

在 Visual Studio 中编写可将消息发送到中继的 C# 控制台应用程序。

创建控制台应用程序

在 Visual Studio 中创建新的控制台应用 (.NET Framework) 项目。

添加中继 NuGet 包

1. 右键单击新创建的项目，然后选择“管理 NuGet 包”。

2. 选择“浏览”，然后搜索 Microsoft.Azure.Relay。 在搜索结果中，选择“Microsoft Azure 中继”。

3. 选择“安装”即可完成安装。 关闭对话框。

编写发送消息的代码

1. 将 Program.cs 文件顶部的现有 using 语句替换为以下 using 语句：

   using System;
   using System.IO;
   using System.Threading;
   using System.Threading.Tasks;
   using Microsoft.Azure.Relay;
   

2. 将常量添加到 Program 类，用于保存混合连接的连接详细信息。 将占位符替换为在创建混合连接时获得的值。 请务必使用完全限定的命名空间名称。

   // replace {RelayNamespace} with the name of your namespace
   private const string RelayNamespace = "YOUR-RELAY-NAMESPACE-NAME.servicebus.chinacloudapi.cn";
   
   // replace {HybridConnectionName} with the name of your hybrid connection
   private const string ConnectionName = "HYBRID-CONNECTION-NAME";
   
   // replace {SAKKeyName} with the name of your Shared Access Policies key, which is RootManageSharedAccessKey by default
   private const string KeyName = "SAS-KEY-NAME";
   
   // replace {SASKey} with the primary key of the namespace you saved earlier
   private const string Key = "SAS-KEY-VALUE";
   

3. 将以下方法添加到 Program 类：

   private static async Task RunAsync()
   {
       Console.WriteLine("Enter lines of text to send to the server with ENTER");
   
       // Create a new hybrid connection client.
       var tokenProvider = TokenProvider.CreateSharedAccessSignatureTokenProvider(KeyName, Key);
       var client = new HybridConnectionClient(new Uri(String.Format("sb://{0}/{1}", RelayNamespace, ConnectionName)), tokenProvider);
   
       // Initiate the connection.
       var relayConnection = await client.CreateConnectionAsync();
   
       // Run two concurrent loops on the connection. One 
       // reads input from the console and writes it to the connection 
       // with a stream writer. The other reads lines of input from the 
       // connection with a stream reader and writes them to the console. 
       // Entering a blank line shuts down the write task after 
       // sending it to the server. The server then cleanly shuts down
       // the connection, which terminates the read task.
   
       var reads = Task.Run(async () => {
           // Initialize the stream reader over the connection.
           var reader = new StreamReader(relayConnection);
           var writer = Console.Out;
           do
           {
               // Read a full line of UTF-8 text up to newline.
               string line = await reader.ReadLineAsync();
               // If the string is empty or null, you are done.
               if (String.IsNullOrEmpty(line))
                   break;
               // Write to the console.
               await writer.WriteLineAsync(line);
           }
           while (true);
       });
   
       // Read from the console and write to the hybrid connection.
       var writes = Task.Run(async () => {
           var reader = Console.In;
           var writer = new StreamWriter(relayConnection) { AutoFlush = true };
           do
           {
               // Read a line from the console.
               string line = await reader.ReadLineAsync();
               // Write the line out, also when it's empty.
               await writer.WriteLineAsync(line);
               // Quit when the line is empty,
               if (String.IsNullOrEmpty(line))
                   break;
           }
           while (true);
       });
   
       // Wait for both tasks to finish.
       await Task.WhenAll(reads, writes);
       await relayConnection.CloseAsync(CancellationToken.None);
   }
   

4. 在 Program 类的 Main 方法中添加以下代码行。

   RunAsync().GetAwaiter().GetResult();
   

   Program.cs 应如下所示：

   using System;
   using System.IO;
   using System.Threading;
   using System.Threading.Tasks;
   using Microsoft.Azure.Relay;
   
   namespace Client
   {
       class Program
       {
           private const string RelayNamespace = "{RelayNamespace}.servicebus.chinacloudapi.cn";
           private const string ConnectionName = "{HybridConnectionName}";
           private const string KeyName = "{SASKeyName}";
           private const string Key = "{SASKey}";
   
           static void Main(string[] args)
           {
               RunAsync().GetAwaiter().GetResult();
           }
   
           private static async Task RunAsync()
           {
               Console.WriteLine("Enter lines of text to send to the server with ENTER");
   
               // Create a new hybrid connection client.
               var tokenProvider = TokenProvider.CreateSharedAccessSignatureTokenProvider(KeyName, Key);
               var client = new HybridConnectionClient(new Uri(String.Format("sb://{0}/{1}", RelayNamespace, ConnectionName)), tokenProvider);
   
               // Initiate the connection.
               var relayConnection = await client.CreateConnectionAsync();
   
               // Run two concurrent loops on the connection. One 
               // reads input from the console and then writes it to the connection 
               // with a stream writer. The other reads lines of input from the 
               // connection with a stream reader and then writes them to the console. 
               // Entering a blank line shuts down the write task after 
               // sending it to the server. The server then cleanly shuts down
               // the connection, which terminates the read task.
   
               var reads = Task.Run(async () => {
                   // Initialize the stream reader over the connection.
                   var reader = new StreamReader(relayConnection);
                   var writer = Console.Out;
                   do
                   {
                       // Read a full line of UTF-8 text up to newline.
                       string line = await reader.ReadLineAsync();
                       // If the string is empty or null, you are done.
                       if (String.IsNullOrEmpty(line))
                           break;
                       // Write to the console.
                       await writer.WriteLineAsync(line);
                   }
                   while (true);
               });
   
               // Read from the console and write to the hybrid connection.
               var writes = Task.Run(async () => {
                   var reader = Console.In;
                   var writer = new StreamWriter(relayConnection) { AutoFlush = true };
                   do
                   {
                       // Read a line from the console.
                       string line = await reader.ReadLineAsync();
                       // Write the line out, also when it's empty.
                       await writer.WriteLineAsync(line);
                       // Quit when the line is empty.
                       if (String.IsNullOrEmpty(line))
                           break;
                   }
                   while (true);
               });
   
               // Wait for both tasks to finish.
               await Task.WhenAll(reads, writes);
               await relayConnection.CloseAsync(CancellationToken.None);
           }
       }
   }
   

运行应用程序

1. 运行服务器应用程序。

2. 运行客户端应用程序并输入一些文本。

3. 确保服务器应用程序控制台显示了客户端应用程序中输入的文本。

   

祝贺你，你已创建了一个完整的混合连接应用程序！

后续步骤

在本快速入门中，你创建了 .NET 客户端和服务器应用程序，此类程序使用 WebSocket 来发送和接收消息。 Azure 中继的混合连接功能也支持使用 HTTP 发送和接收消息。 若要了解如何将 HTTP 与 Azure 中继混合连接配合使用，请参阅 HTTP 快速入门。

在本快速入门中，你使用了 .NET Framework 来创建客户端和服务器应用程序。 若要了解如何使用 Node.js 编写客户端和服务器应用程序，请参阅 Node.js WebSocket 快速入门或 Node.js HTTP 快速入门。