工业互联-基于C#的MQTT服务器开发

安装MQTTnet包，这我用的版本是3.1.2

public static IMqttServer server = null;

基于C#的MQTT服务器开发：

        /// <summary>
        /// 开启mqtt服务
        /// </summary>
        private static async void ServerStart()
        {
            server = new MqttFactory().CreateMqttServer();
            // 初始化Sever对象
            server.ClientConnectedHandler = new MqttServerClientConnectedHandlerDelegate(Server_ClientConnected);
            server.ClientSubscribedTopicHandler = new MqttServerClientSubscribedHandlerDelegate(Server_ClientSubscribedTopic);
            server.ApplicationMessageReceivedHandler = new MqttApplicationMessageReceivedHandlerDelegate(Server_ApplicationMessageReceived);
            MqttServerOptionsBuilder msob = new MqttServerOptionsBuilder()
                .WithDefaultEndpointBoundIPAddress(IPAddress.Any) // 任意ip地址，相当于0.0.0.0
                .WithDefaultEndpointPort(1121)// 客户端连接服务器如果使用其他端口号，无法连接
                .WithConnectionValidator(ConnectionValidator); // 匹配客户端设置用户名和密码
            IMqttServerOptions serverOptions = msob.Build(); // 配置对象生成
            await server.StartAsync(serverOptions); // 根据配置信息启动服务器
            Console.WriteLine("MQTT服务端已启动完成！");
        }

        /// <summary>
        /// 用户名和密码匹配
        /// </summary>
        /// <param name="context"></param>
        private static void ConnectionValidator(MqttConnectionValidatorContext context)
        {
            if (context.Username != "admin" || context.Password != "123456")
            {
                context.ReturnCode = MqttConnectReturnCode.ConnectionRefusedBadUsernameOrPassword;
            }
            context.ReturnCode = MqttConnectReturnCode.ConnectionAccepted;
        }

        /// <summary>
        /// topic，订阅消息
        /// </summary>
        /// <param name="e"></param>
        private static void Server_ClientSubscribedTopic(MqttServerClientSubscribedTopicEventArgs e)
        {
            Console.WriteLine(">>> 客户端:" + e.ClientId + "  订阅topic:" + e.TopicFilter.Topic);
        }

        /// <summary>
        /// 客户端连接服务器
        /// </summary>
        /// <param name="e"></param>
        private static void Server_ClientConnected(MqttServerClientConnectedEventArgs e)
        {
            Console.WriteLine(">>> 客户端:" + e.ClientId + " 连接");
        }

        /// <summary>
        /// 客户端接收消息
        /// </summary>
        /// <param name="e"></param>
        private static void Server_ApplicationMessageReceived(MqttApplicationMessageReceivedEventArgs e)
        {
            if (e.ClientId != null)
            {
                ushort value = BitConverter.ToUInt16(new byte[] { e.ApplicationMessage.Payload[1],e.ApplicationMessage.Payload[0] });
                Console.WriteLine(value);
                // 接收从客户端发到服务器的消息，将这个消息分发下去
                Console.WriteLine(">>> 收到消息:" + e.ApplicationMessage.ConvertPayloadToString() + ",来自客户端" + e.ClientId + ",topic:" + e.ApplicationMessage.Topic);
                // 将客户端发过来的消息，根据topic进行分发
                server.PublishAsync(e.ApplicationMessage);
            }
        }

服务端监听：

客户端连接mqtt服务器端：

 

客户端1发送消息给客户端2：