前端结合MQTT实现连接订阅发送信息等操作 VUE3-编程知识

MQTT客户端下载使用测试在我之前文章中 MQTT下载基础使用

下面记录一下前端使用的话的操作

1.安装

npm i mqtt

引入

import * as mqtt from "mqtt/dist/mqtt.min"; //VUE3
import mqtt from 'mqtt'   //VUE2

一、MQTT协议中的方法

Connect。等待与服务器建立连接。
Disconnect。等待MQTT客户端完成所做的工作，并与服务器断开TCP/IP会话。
Subscribe。等待完成订阅。
UnSubscribe。等待服务器取消客户端的一个或多个topics订阅。
Publish。MQTT客户端发送消息请求，发送完成后返回应用程序线程。

二,简单使用基础使用(VUE2)

下面代码中， options 是客户端连接选项，以下是主要参数说明，其余参数详见https://www.npmjs.com/package/mqtt#connect。
keepalive：心跳时间，默认 60秒，设置 0 为禁用；
clientId：客户端 ID ，默认通过 ‘mqttjs_’ + Math.random().toString(16).substr(2, 8) 随机生成；
username：连接用户名（如果有）；
password：连接密码（如果有）；
clean：true，设置为 false 以在离线时接收 QoS 1 和 2 消息；
reconnectPeriod：默认 1000 毫秒，两次重新连接之间的间隔，客户端 ID 重复、认证失败等客户端会重新连接；
connectTimeout：默认 30 * 1000毫秒，收到 CONNACK 之前等待的时间，即连接超时时间。

import mqtt from 'mqtt'// 连接选项
const options = {connectTimeout: 4000, // 超时时间// 认证信息clientId: 'emqx-connect-via-websocket',username: 'emqx-connect-via-websocket',password: 'emqx-connect-via-websocket',
}const client = mqtt.connect('wss://iot.actorcloud.io:8084/mqtt', options)client.on('reconnect', (error) => {console.log('正在重连:', error)
})client.on('error', (error) => {console.log('连接失败:', error)
})client.on('connect', (e) => {console.log('成功连接服务器')// 订阅一个主题client.subscribe('hello', { qos: 1 }, (error) => {if (!error) {cosnole.log('订阅成功')client.publish('hello', 'Hello EMQ', { qos: 1, rein: false }, (error) => {cosnole.log(error || '发布成功')})}})// 订阅多个主题client.subscribe(['hello', 'one/two/three/#', '#'], { qos: 1 },  onSubscribeSuccess)// 订阅不同 qos 的不同主题client.subscribe([{ hello: 1 }, { 'one/two/three': 2 }, { '#': 0 }], onSubscribeSuccess,)
})// 取消订阅
client.unubscribe(// topic, topic Array, topic Array-Onject'hello',onUnubscribeSuccess,
)// 监听接收消息事件
client.on('message', (topic, message) => {console.log('收到来自', topic, '的消息', message.toString())
})// 发布消息
if (!client.connected) {console.log('客户端未连接')return
}client.publish('hello', 'hello EMQ', (error) => {console.log(error || '消息发布成功')
})

三,项目中示例 (VUE3)

//项目中示例这只是一个简单的链接订阅断开链接的案例

import * as mqtt from "mqtt/dist/mqtt.min";
import { onUnmounted, ref, reactive } from 'vue';
import { ElNotification } from 'element-plus'export default function useMqtt() {let client = ref({connected: false});const notifyPromise = ref(Promise.resolve())const qosList = [0, 1, 2];// 订阅const topic = ref('rscu/alertpush/participant/up')const qos = ref(1)// 链接地址const hostUrl = ref('101.37.163.199')const connection = reactive({// 指明协议类型protocol: "ws",host: hostUrl.value,// ws: 8083; wss: 8084//端口号port: 8083,endpoint: "/mqtt",// for more options, please refer to https://github.com/mqttjs/MQTT.js#mqttclientstreambuilder-optionsclean: true,connectTimeout: 30 * 1000, // msreconnectPeriod: 4000, // msclientId: "emqx_benYing_" + Math.random().toString(16).substring(2, 8),// 账号密码username: "admin",password: "root",});const messageValue = ref(false)// 订阅的信息const receiveNews = ref('')const time = ref(null)const startMqtt = () => {try {const { protocol, host, port, endpoint, ...options } = connection;const connectUrl = `${protocol}://${host}:${port}${endpoint}`;client.value = mqtt.connect(connectUrl, options);if (client.value.on) {// 连接client.value.on("connect", () => {console.log("连接成功 successful");});// 重连client.value.on("reconnect", handleOnReConnect);client.value.on("error", (error) => {console.log("重连失败 error:", error);});// 收到信息client.value.on("message", (topic, message) => {// receiveNews.value = receiveNews.value.concat(message.toString());let { phaseValue } = JSON.parse(message)phaseValue.forEach((value, index, array) => {notifyPromise.value = notifyPromise.value.then(() => {ElNotification({type: 'warning',title: '警告',message: value.msg,position: 'bottom-right',offset: 10})})})console.log(`收到信息 message: ${message} from topic: ${topic}`);});}} catch (error) {console.log("mqtt.connect error:", error);}};// 订阅const link = () => {let qosValue = qos.valueclient.value.subscribe(topic.value,{ qosValue },(error, granted) => {if (error) {console.log("订阅失败 error:", error);return;}console.log("订阅成功 successfully:", granted);});};// 取消订阅const UnSubscribe = () => {let qosValue = qos.valueclient.value.unsubscribe(topic.value, { qosValue }, (error) => {if (error) {console.log("取消订阅失败 error:", error);return;}console.log(`取消订阅成功 topic: ${topic}`);});};// 取消连接const destroyConnection = () => {if (client.value.connected) {try {client.value.end(false, () => {console.log("断开连接成功 successfully");});} catch (error) {console.log("断开连接失败 error:", error);}}};//发送信息  sendMsg //发送的信息const SendMessage =(topic, sendMsg)=> {let qosValue = qos.valueclient.value.publish(this.topic, JSON.stringify(sendMsg), {qosValue }, (err, a) => {if (!err) {console.log('发送信息成功');} else {console.log('发送信息失败');}})}const retryTimes = ref(0);const handleOnReConnect = () => {retryTimes.value += 1;if (retryTimes.value > 5) {try {client.value.end();initData();console.log("connection maxReconnectTimes limit, stop retry");} catch (error) {console.log("handleOnReConnect catch error:", error);}}};const initData = () => {client.value = {connected: false,};retryTimes.value = 0;};return {startMqtt,link,UnSubscribe,destroyConnection};
}