前端使用mqtt，用于接收消息

主要是用vue 安装mqtt npm i mqtt

import mqtt from 'mqtt' 
let client = ''
export default {
  created () {
    let options = {
      connectTimeout: 40000,
      clientId: `id`,
      username: `定义的用户名`,
      password: `密码`,
      path: '/mqtt',
      clean: true,
      useSSL: true/false,
      port: '端口号',
      topic: '通信'
    }
    client = mqtt.connect(`链接的地址`, options)
    this.mqttMsg()
  },
  methods: {
    mqttMsg () {
      client.on('connect', () => {
        client.subscribe(`通信`, { qos: 0 }, (error) => {
          if (!error) {
            console.log('success')
          } else {
            console.log('fail')
          }
        })
      })
      // 接收消息处理
      client.on('message', (topic, message) => {
        let msg = message.toString()
        if (msg && JSON.parse(msg).content === 'ok') {
           console.log('信息成功')
        }
      })
      client.on('reconnect', (error) => {
        console.log('正在重连:', error)
      })
      // 链接异常处理
      client.on('error', (error) => {
        console.log('连接失败:', error)
      })
    },
  }
}