Node

本文主要介绍如何在 Node.js 项目中使用 MQTT.js 客户端库，实现 SX-IOT设备与 MQTT 服务器的连接、订阅、收发消息等功能。

前提条件

安装依赖包

sudo apt install nodejs npm -y
npm install mqtt

连接使用

连接设置

本文将使用自定义的接入认证方式，服务器接入信息如下： -Broker: mqtt.geek-smart.cn -TCP Port: 1883 -WebSocket Port: 8083

导入依赖包

 const mqtt = require('mqtt')
 /**
   choose which protocol to use for connection here
    * TCP Port: 1883
    * WebSocket port: 8083
 */
 // tcp
 const { connectOptions } = require('./use_mqtt.js')
 // ws
 // const { connectOptions } = require('./use_ws.js')

定义连接地址、认证信息以及消息发布主题

 // tcp
 const connectOptions = {
   protocol: 'mqtt',
   port: 1883,
   host: 'mqtt.geek-smart.cn',
 }
 
 // ws
 // const connectOptions = {
 //   protocol: 'ws',
 //   port: 8083,
 //   host: 'mqtt.geek-smart.cn',
 // }
 
 module.exports = {
   connectOptions,
 }
 const pub_topic = '/HYUGHV/lVtAcHuorFDJ/4cebd60bfada/publish'
 const sub_topic = '/HYUGHV/lVtAcHuorFDJ/4cebd60bfada/subscribe'
 // tcp
 const clientId = 'nodejs-mqtt-tcp-client'
 // ws
 // const clientId = 'nodejs-mqtt-ws-client'
 const options = {
     clientId,
     clean: true,
     connectTimeout: 4000,
     username: 'OGVkSlBrskPY',
     password: 'XaIkqRXwcNuuQjXGPi',
     reconnectPeriod: 1000,
 }

定义消息发布函数

 client.publish(pub_topic, payload, { qos }, (error) => {
     if (error) {
         console.error(error)
     }
 })

定义 on_message 回调函数，用于打印订阅主题接收的消息内容

 client.on('message', (sub_topic, payload) => {
     console.log('Received Message:', sub_topic, payload.toString())
 })

连接 MQTT

client.on('connect', () => {
     console.log(`${protocol}: Connected`)
 })

完整代码

 const mqtt = require('mqtt')
     /**
       choose which protocol to use for connection here
        * TCP Port: 1883
        * WebSocket port: 8083
     */
     // tcp
 const { connectOptions } = require('./use_mqtt.js')
     // ws
     // const { connectOptions } = require('./use_ws.js')
 
 const clientId = 'nodejs-mqtt-tcp-client'
     // const clientId = 'nodejs-mqtt-ws-client'
 const options = {
     clientId,
     clean: true,
     connectTimeout: 4000,
     username: 'OGVkSlBrskPY',
     password: 'XaIkqRXwcNuuQjXGPi',
     reconnectPeriod: 1000,
 }
 
 const { protocol, host, port } = connectOptions
 /**
  * if protocol is "mqtt", connectUrl = "mqtt://mqtt.geek-smart.cn:1883"
  * if protocol is "ws", connectUrl = "ws://mqtt.geek-smart.cn:8083/mqtt"
  *
  * for more details about "mqtt.connect" method & options,
  * please refer to https://github.com/mqttjs/MQTT.js#mqttconnecturl-options
  */
 let connectUrl = `${protocol}://${host}:${port}`
 if (['ws', 'wss'].includes(protocol)) {
     // mqtt: MQTT-WebSocket uniformly uses /path as the connection path,
     // which should be specified when connecting, and the path used on EMQX is /mqtt.
     connectUrl += '/mqtt'
 }
 
 const client = mqtt.connect(connectUrl, options)
 
 const pub_topic = '/HYUGHV/lVtAcHuorFDJ/4cebd60bfada/publish'
 const sub_topic = '/HYUGHV/lVtAcHuorFDJ/4cebd60bfada/subscribe'
 const payload = '{"type":"info"}'
     // https://github.com/mqttjs/MQTT.js#qos
 const qos = 0
 
 // https://github.com/mqttjs/MQTT.js#event-connect
 client.on('connect', () => {
     console.log(`${protocol}: Connected`)
 
     // subscribe topic
     // https://github.com/mqttjs/MQTT.js#mqttclientsubscribetopictopic-arraytopic-object-options-callback
     client.subscribe(sub_topic, { qos }, (error) => {
         if (error) {
             console.log('subscribe error:', error)
             return
         }
         console.log(`${protocol}: Subscribe to topic '${sub_topic}'`)
             // publish message
             // https://github.com/mqttjs/MQTT.js#mqttclientpublishtopic-message-options-callback
         client.publish(pub_topic, payload, { qos }, (error) => {
             if (error) {
                 console.error(error)
             }
         })
     })
 })
 
 // https://github.com/mqttjs/MQTT.js#event-reconnect
 client.on('reconnect', (error) => {
     console.log(`Reconnecting(${protocol}):`, error)
 })
 
 // https://github.com/mqttjs/MQTT.js#event-error
 client.on('error', (error) => {
     console.log(`Cannot connect(${protocol}):`, error)
 })
 
 // https://github.com/mqttjs/MQTT.js#event-message
 client.on('message', (sub_topic, payload) => {
     console.log('Received Message:', sub_topic, payload.toString())
 })
 
 /**
  * If you need to unsubscribe from a topic, you can use the following code.
  */
 // // unsubscribe topic
 // // https://github.com/mqttjs/MQTT.js#mqttclientunsubscribetopictopic-array-options-callback
 // client.unsubscribe(sub_topic, { qos }, (error) => {
 //   if (error) {
 //     console.log('unsubscribe error:', error)
 //     return
 //   }
 //   console.log(`unsubscribed topic: ${sub_topic}`)
 // })
 
 /**
  * If you need to disconnect, you can use the following code.
  */
 // if (client.connected) {
 //   try {
 //     // disconnect
 //     // https://github.com/mqttjs/MQTT.js#mqttclientendforce-options-callback
 //     client.end(false, () => {
 //       console.log('disconnected successfully')
 //     })
 //   } catch (error) {
 //     console.log('disconnect error:', error)
 //   }
 // }

测试验证

运行

npm start

PHP VUE3