MQTT服务（C#）

MQTT服务（C#）

MQTT服务器（C#）

开启MQTT服务器，需要用到库MQTTnet，使用VS2019企业版。

1. 右键管理Nuget包，搜索下载MQTTnet（3.0.16版本）并安装，Install-Package MQTTNET，出现下列提示，安装成功；

   Successfully installed 'MQTTnet 3.0.16' to MQTTNET Executing nuget actions took 2.77 min Time Elapsed: 00:02:46.6697077 ========== Finished ==========

2. 对C#代码添加MQTTnet和MQTTnet.Server命名空间的引用；

3. 对构造函数里添加如下代码：

   public MqttServer()
   {
       server = new MqttFactory().CreateMqttServer();            
       // 客户端连接事件
       server.ClientConnectedHandler = new MqttServerClientConnectedHandlerDelegate(ClientConnectedHandler);
       //客户端断开连接事件
       server.ClientDisconnectedHandler = new MqttServerClientDisconnectedHandlerDelegate(ClientDisconnectedHandler);
       server.ApplicationMessageReceivedHandler = new MqttApplicationMessageReceivedHandlerDelegate(MessageReceivedHandler);
       server.UseApplicationMessageReceivedHandler(args =>
       {
           Console.WriteLine("===================================================");
           Console.WriteLine("收到消息:");
           Console.WriteLine($"客户端:{args.ClientId}");
           Console.WriteLine($"主题:{args.ApplicationMessage.Topic}");
           Console.WriteLine($"消息:{Encoding.UTF8.GetString(args.ApplicationMessage.Payload)}");
           Console.WriteLine("+++++++++++++++++++++++++++++++++++++++++++++++++++");
           Console.WriteLine();
       });
   }
   
   IMqttServer server;
   

4. 开启关闭MQTT服务如下，调用StartMqttServer方法即可开启特定端口服务

   /// <summary>
   /// 打开MQTT Server 服务
   /// </summary>
   /// <param name="port">端口号：默认为1883</param>
   public async void StartMqttServer(int port = 1883)
   {
       if (server.IsStarted)
           return;
       MqttServerOptionsBuilder serverOptions = new MqttServerOptionsBuilder();
       serverOptions.WithDefaultEndpointPort(port);
       await server.StartAsync(serverOptions.Build());
   }
   
   public async void CloseMqttServer(int port = 1883)
   {
       if (!server.IsStarted)
           return;
       MqttServerOptionsBuilder serverOptions = new MqttServerOptionsBuilder();
       serverOptions.WithDefaultEndpointPort(port);
       await server.StopAsync();
   }
   

5. 其余调用方法如下：

   private void StartedHandler(EventArgs obj)
   {
       Console.WriteLine("MQTT服务器已启动！");
   }
   
   private void StoppedHandler(EventArgs obj)
   {
       Console.WriteLine("MQTT服务器已停止！");
   }
   
   /// <summary>
   /// 客户端连接到服务器事件
   /// </summary>
   /// <param name="obj"></param>
   private void ClientConnectedHandler(MqttServerClientConnectedEventArgs obj)
   {
       Console.WriteLine($"{obj.ClientId}此客户端已连接至服务器！");
   }
   
   private void ClientDisconnectedHandler(MqttServerClientDisconnectedEventArgs obj)
   {
       Console.WriteLine($"断开连接的客户端:{obj.ClientId}");
       Console.WriteLine($"断开连接类型:{obj.DisconnectType.ToString()}");
   }
   
   /// <summary>
   /// 收到各个客户端发送的消息
   /// </summary>
   /// <param name="obj"></param>
   private void MessageReceivedHandler(MqttApplicationMessageReceivedEventArgs obj)
   {
       Console.WriteLine("===================================================");
       Console.WriteLine("收到消息:");
       Console.WriteLine($"客户端:{obj.ClientId}");
       Console.WriteLine($"主题:{obj.ApplicationMessage.Topic}");
       Console.WriteLine($"消息:{Encoding.UTF8.GetString(obj.ApplicationMessage.Payload)}");
       Console.WriteLine("+++++++++++++++++++++++++++++++++++++++++++++++++++");
       Console.WriteLine();
   }