vue 连接mqtt

1. 下载mqtt服务：npm install mqtt

2. const mqttConfig = {  
     // 你的 MQTT 服务器配置  
     protocolId: 'MQTT',
     protocolVersion: 4,
     clean: true,
     clientId: 'xxxx',
     reconnectPeriod: 1000,
     connectTimeout: 60 * 1000,
     // will: {
     //   topic: 'WillTopic',
     //   payload: 'Connection Closed Unexpectedly!',
     //   qos: 0,
     //   retain: false
     // },
     username: 'xxxx', // 如果需要
     password: 'xxxxx', // 如果需要
     // 其他配置...  
   };  
   export function useMqtt() {
     const client = ref(null);
     const listeners = ref({});
     // 连接到 MQTT 服务器  
    function connect() {
     console.log('2**********');
       if (client.value) return;  
       client.value = mqtt.connect('地址',mqttConfig);  
       client.value.on('connect', () => {  
         console.log('Connected to MQTT');
         return true
         // 这里可以添加默认的订阅
         // client.value.subscribe('xxxx')
       });  
       client.value.on('message', (topic, message) => {
         if (listeners.value[topic]) {
           listeners.value[topic].forEach(callback => callback(message.toString()))
         }  
       });
       // 处理错误和断开连接的情况  
       client.value.on('error', (error) => {  
         console.error('MQTT error:', error);  
       });  
       client.value.on('close', () => {  
         console.log('MQTT connection closed');  
         client.value = null; // 断开连接后重置 client  
       });  
     }  
     // 断开 MQTT 连接  
     function disconnect() {  
       if (client.value) {  
         client.value.end();  
         client.value = null;  
       }  
     }  
     // 订阅 MQTT 主题  
     function subscribe(topic, callback) {  
       console.log(topic)
       if (client.value && client.value.connected) {  
         client.value.subscribe(topic);  
     
         if (!listeners.value[topic]) {  
           listeners.value[topic] = [];  
         }  
         listeners.value[topic].push(callback);  
       }
     }
     // 取消订阅 MQTT 主题  
     function unsubscribe(topic, callback) {  
       if (client.value && client.value.connected && listeners.value[topic]) {  
         const index = listeners.value[topic].indexOf(callback);  
         if (index > -1) {  
           listeners.value[topic].splice(index, 1);  
     
           // 如果没有监听者了，可以取消订阅  
           if (listeners.value[topic].length === 0) {  
             client.value.unsubscribe(topic);  
           }  
         }  
       }  
     }  
     // 发布 MQTT 消息  
     function publish(topic, message) {  
       if (client.value && client.value.connected) {  
         client.value.publish(topic, message);  
       }  
     }