mqtt使用方法

1、mqtt一些配置（oss和c4代码里有）

 /**
  * 使用中的配置 
  */
 import * as qiniu from 'qiniu-js'
 export const globalConfig = {
         qiniu: {
             getToken: '',
             qiniuUrl: "",
             qiniu_file: "",
             versionList: [],
             qiniuRegion: 
         },
         mqtt: {
             connectTimeout: 40000,
             clientId: '',
             username: '',
             password: '',
             clean: true,
             url: "ws://io.st.com/mqtt",
             port: 8083
         },
         lang: "en"
 
     }
     /**
      * 国内配置
      */
 export const cn_config = {
         qiniu: {
             getToken: '',
             qiniuUrl: ",
             qiniu_file: "",
             versionList: [],
             qiniuRegion: 
         },
         mqtt: {
             connectTimeout: 40000,
             clientId: '',
             username: '',
             password: '',
             clean: true,
             url: "ws://io.s.com/mqtt",
             port: 8083
         },
         lang: "zh"
 
     }

2、使用mqtt接收信息的文件 ，即以上第一步的文件

	import {
		globalConfig
	} from '@/config/cnSgConfig'

data() {
			return {
				mqtt: {
					config: globalConfig.mqtt
				},
				deviceId: "",
				cmdList: [],
				client2: '',
				gatewayId2: "",}}

    subscrib(topic) {
      // topic = 'aibox/trash-ai-edge-02/event'
      let that = this
      let mqtt = require('mqtt')
      let now = new Date()
      let number = now.getTime()
      let clientId = 'cid_' + number
      //开启mqtt链接
      this.client2 = mqtt.connect(this.mqtt.config.url, {
        port: this.mqtt.config.port,
        clientId: clientId,
        username: this.mqtt.config.username,
        password: this.mqtt.config.password,
        clean: false
      })
        //监听是否连接成功
      this.client2.on('connect', () => {
        console.log('连接成功!')
      })
      //订阅后端给你发的字段 在on里面接收
      that.client2.unsubscribe([topic])//先取消订阅，防止重复
      that.client2.subscribe([topic], (error, res) => {
        if (error) {
          console.log('订阅失败', error)
        }
        console.log('订阅成功', res)
      })
      //接收消息
      console.log('订阅topic是', topic)
 
      let messagearr = []//该数组要在接收数据前定义，不然容易每次只有最新的数据
 
        //监听订阅的消息，当有消息发过来，该函数便执行 ，回调函数中message则是收到的数据
      that.client2.on('message', (topic, message) => {
        // debugger
        let messageitem = {}
        messageitem = JSON.parse(message.toString())//收到的数据是一堆数字，要toString才能变成想要的样子，如果需要的是对象格式，记得JSON.parse
        console.log('接收到的信息是', messageitem, message.toString())
        //将收到的对象 处理message
        messageitem.time = formatDate(new Date(messageitem.time), 'yyyy-MM-dd HH:mm:ss')
        for (let i = 0; i < that.eventtypes.length; i++) {
          if (that.eventtypes[i].event == messageitem.event[0]) {
            messageitem.event = that.eventtypes[i].eventName
          }
        }
 
        messagearr.push(messageitem)//由于数据是实时的，每次发过来一个对象，需将他们放入数组中使用
        console.log('messageitem', messageitem, 'messagearr', messagearr)
        console.log('arr', messagearr)
        that.message = messagearr
      })
    },