初步完成Mqtt后台服务的改造

DMS.Infrastructure/Interfaces/Services/IMqttService.cs

@@ -0,0 +1,52 @@
+using DMS.Core.Models;
+using MQTTnet.Client;
+using System;
+using System.Threading.Tasks;
+
+namespace DMS.Infrastructure.Interfaces.Services
+{
+    /// <summary>
+    /// MQTT服务接口，定义MQTT客户端的基本操作
+    /// </summary>
+    public interface IMqttService
+    {
+        /// <summary>
+        /// 获取MQTT客户端连接状态
+        /// </summary>
+        bool IsConnected { get; }
+
+        /// <summary>
+        /// 异步连接到MQTT服务器
+        /// </summary>
+        /// <param name="serverUrl">MQTT服务器URL</param>
+        /// <param name="port">端口号</param>
+        /// <param name="clientId">客户端ID</param>
+        /// <param name="username">用户名</param>
+        /// <param name="password">密码</param>
+        Task ConnectAsync(string serverUrl, int port, string clientId, string username, string password);
+
+        /// <summary>
+        /// 异步断开MQTT连接
+        /// </summary>
+        Task DisconnectAsync();
+
+        /// <summary>
+        /// 异步发布消息
+        /// </summary>
+        /// <param name="topic">主题</param>
+        /// <param name="payload">消息内容</param>
+        Task PublishAsync(string topic, string payload);
+
+        /// <summary>
+        /// 异步订阅主题
+        /// </summary>
+        /// <param name="topic">要订阅的主题</param>
+        Task SubscribeAsync(string topic);
+
+        /// <summary>
+        /// 设置消息接收处理程序
+        /// </summary>
+        /// <param name="handler">消息处理回调函数</param>
+        void SetMessageHandler(Func<string, string, Task> handler);
+    }
+}