本文是对改良：vue3+ts 封装mqtt_你的微笑、暖暖的的博客-CSDN博客近期在vue3的项目中使用到了mqtt，再次记录下，供大家学习。https://blog.csdn.net/wangyuiba1314/article/details/126307598

服务器采用，RabbitMQ3.9，开启rabbitmq_web_mqtt，部署方法参考http://t.csdn.cn/Xe6Vg

0.安装相关组件

mqtt：用于连接

npm i "mqtt"

uuid：用于确定客户端唯一（非必须）

npm i "vue-uuid"

1.新建Mqtt.ts

import type { MqttClient, OnMessageCallback } from 'mqtt';
import * as mqtt from 'mqtt/dist/mqtt.min.js';
import { uuid } from 'vue-uuid';

class MQTT {
  type: string; // 客户端分类（非必须）
  url: string; // mqtt地址
  client!: MqttClient;

  constructor(type: string) {
    this.type= type;
    this.url = 'ws://192.168.x.x:15675/ws';// ws方式必须ws结尾
  }

  //初始化mqtt
  init() {
    const options = {
      clean: true,
      clientId: this.type+ "_" + uuid.v1(), // 客户端分类唯一
      username: 'xxx',
      password: 'xxx',
      connectTimeout: 3000, // 超时时间
    };

    this.client = mqtt.connect(this.url, options);

    this.client.on('error', (error: any) => {
      console.log(this.url + "异常中断");
    });

    this.client.on('reconnect', (error: Error) => {
      console.log(this.url + "重新连接");
    });
  }

  //取消订阅
  unsubscribes(topic: string) {
    this.client.unsubscribe(topic, (error: Error) => {
      if (!error) {
        console.log(topic + '取消订阅成功');
      } else {
        console.log(topic + '取消订阅失败');
      }
    });
  }

  //连接
  link(topic: string) {
    this.client.on('connect', () => {
      this.client.subscribe(topic, (error: any) => {
        if (!error) {
          console.log(topic + '订阅成功');
        } else {
          console.log(topic + '订阅失败');
        }
      });
    });
  }

  //收到的消息
  get(callback: OnMessageCallback) {
    this.client.on('message', callback);
  }

  //结束链接
  over() {
    this.client.end();
  }
}
export default MQTT;

2.新建UseMqtt.ts

import MQTT from './Mqtt';
import type { OnMessageCallback } from 'mqtt';
import {
  ref,
  onUnmounted
} from 'vue';

export default function useMqtt() {
  const PublicMqtt = ref<MQTT | null>(null);
  const linkList = Array<string>(); // 长连接的列表

  const startMqtt = (type: string, callback: OnMessageCallback) => {
    PublicMqtt.value = new MQTT(type);//创建连接
    PublicMqtt.value.init();//初始化mqtt
    linkList.forEach((topic) => { PublicMqtt.value?.unsubscribes(topic); PublicMqtt.value?.link(topic) });//订阅主题
    getMessage(callback);
  };

  const addLink = (topic: string) => {
    if (!linkList.includes(topic)) { // 简单地去重
      linkList.push(topic);
      PublicMqtt.value?.link(topic);
    }
  }

  const Uint8ArrayToString = (fileData: Uint8Array) => {
    var dataString = "";
    for (var i = 0; i < fileData.length; i++) {
      dataString += String.fromCharCode(fileData[i]);
    }
    return dataString
  }

  const getMessage = (callback: Function) => {
    PublicMqtt.value?.get((t, m) => { callback(t, Uint8ArrayToString(m)); });
  };

  onUnmounted(() => {//页面销毁结束订阅
    linkList.forEach((topic) => { PublicMqtt.value?.unsubscribes(topic) });
    PublicMqtt.value?.over();
  });

  return {
    startMqtt,
    addLink
  };
}

3.使用vue

<script setup lang="ts">
  import UseMqtt from './UseMqtt';

  const {
    startMqtt,
    addLink
  } = UseMqtt();

 // 创建一个连接
 startMqtt("A", (topic, data) => {
    console.log(topic);
    console.log(data);
 });

 // 订阅多主题
 addLink('a001');
 addLink('a002');
</script>