JavaScript基础教程使用MQTT详解-职坐标

JavaScript基础教程使用MQTT详解

沉沙 2018-09-11 来源：阅读 5932 评论 0

摘要：本篇教程介绍了JavaScript基础教程使用MQTT详解，希望阅读本篇文章以后大家有所收获，帮助大家对JavaScript的理解更加深入。

本篇教程介绍了JavaScript基础教程使用MQTT详解，希望阅读本篇文章以后大家有所收获，帮助大家对JavaScript的理解更加深入。

1、MQTT Server使用EMQTTD开源库，自行安装配置；
2、JS使用Websocket连接通信。
3、JS的MQTT库为paho-mqtt，git地址：https://github.com/eclipse/paho.mqtt.javascript.git

代码如下：

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8" />
    <title></title>
    
    <script src="https://cdnjs.cloudflare.com/ajax/libs/paho-mqtt/1.0.1/mqttws31.min.js" type="text/javascript"></script>

    <script>
        var hostname = ‘127.0.0.1‘, //‘192.168.1.2‘,
            port = 8083,
            clientId = ‘client-mao2080‘,
            timeout = 5,
            keepAlive = 100,
            cleanSession = false,
            ssl = false,
            // userName = ‘mao2080‘,
            // password = ‘123‘,
            topic = ‘/World‘;
        client = new Paho.MQTT.Client(hostname, port, clientId);
        //建立客户端实例
        var options = {
            invocationContext: {
                host: hostname,
                port: port,
                path: client.path,
                clientId: clientId
            },
            timeout: timeout,
            keepAliveInterval: keepAlive,
            cleanSession: cleanSession,
            useSSL: ssl,
            // userName: userName,
            // password: password,
            onSuccess: onConnect,
            onFailure: function (e) {
                console.log(e);
                s = "{time:" + new Date().Format("yyyy-MM-dd hh:mm:ss") + ", onFailure()}";
                console.log(s);
            }
        };
        client.connect(options);
        //连接服务器并注册连接成功处理事件
        function onConnect() {
            console.log("onConnected");
            s = "{time:" + new Date().Format("yyyy-MM-dd hh:mm:ss") + ", onConnected()}";
            console.log(s);
            client.subscribe(topic);
        }

        client.onConnectionLost = onConnectionLost;

        //注册连接断开处理事件
        client.onMessageArrived = onMessageArrived;

        //注册消息接收处理事件
        function onConnectionLost(responseObject) {
            console.log(responseObject);
            s = "{time:" + new Date().Format("yyyy-MM-dd hh:mm:ss") + ", onConnectionLost()}";
            console.log(s);
            if (responseObject.errorCode !== 0) {
                console.log("onConnectionLost:" + responseObject.errorMessage);
                console.log("连接已断开");
            }
        }

        function onMessageArrived(message) {
            s = "{time:" + new Date().Format("yyyy-MM-dd hh:mm:ss") + ", onMessageArrived()}";
            console.log(s);
            console.log("收到消息:" + message.payloadString);
        }

        function send() {
            var s = document.getElementById("msg").value;
            if (s) {
                s = "{time:" + new Date().Format("yyyy-MM-dd hh:mm:ss") + ", content:" + (s) + ", from: web console}";
                message = new Paho.MQTT.Message(s);
                message.destinationName = topic;
                client.send(message);
                document.getElementById("msg").value = "";
            }
        }

        var count = 0;

        function start() {
            window.tester = window.setInterval(function () {
                if (client.isConnected) {
                    var s = "{time:" + new Date().Format("yyyy-MM-dd hh:mm:ss") + ", content:" + (count++) +
                        ", from: web console}";
                    message = new Paho.MQTT.Message(s);
                    message.destinationName = topic;
                    client.send(message);
                }
            }, 1000);
        }

        function stop() {
            window.clearInterval(window.tester);
        }

        Date.prototype.Format = function (fmt) { //author: meizz
            var o = {
                "M+": this.getMonth() + 1, //月份
                "d+": this.getDate(), //日
                "h+": this.getHours(), //小时
                "m+": this.getMinutes(), //分
                "s+": this.getSeconds(), //秒
                "q+": Math.floor((this.getMonth() + 3) / 3), //季度
                "S": this.getMilliseconds() //毫秒
            };
            if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
            for (var k in o)
                if (new RegExp("(" + k + ")").test(fmt)) fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[
                    k]) : (("00" + o[k]).substr(("" + o[k]).length)));
            return fmt;
        }
    </script>
</head>

<body>
    <input type="text" id="msg" />
    <input type="button" value="Send" onclick="send()" />
    <input type="button" value="Start" onclick="start()" />
    <input type="button" value="Stop" onclick="stop()" />
</body>

</html>