关于mqtt:MQTT实战

` // const MQTT_URL = "ws://192.168.50.221:8083/mqtt";

        // const MQTT_PORT = 8083;        const MQTT_TIMEOUT  = 4000;        // const MQTT_TOPIC = "device/field/update/CR-7iA/WS01_PL04_01/INP_CURRENT";        try {            if(item.url?.length){            let url = new URL(item.url);            let port = url.port;            if(port?.length){                let c = mqtt.connect(`${item.url}`, {                    port: `${port}`,                    connectTimeout: MQTT_TIMEOUT,                    keepalive: 5,                    clientId: "mqtt_t_sub" + new Date().valueOf()                });                c.on("connect", e => {                    console.info("========= SUBSCRIBER CONNECTED");                    c.subscribe(`${item.topicUrl}`, {}, (err, granted) => {                        // console.info(err, granted);                        if (granted) {                            c.on("message", (topic, payload, packet) => {                                // console.info(">> " + payload.toString());                                let stringData = payload.toString(),objData;                                if(stringData.includes('{') || stringData.includes('[')){                                    objData = JSON.parse(stringData);                                }                                else if(payload.buffer){                                    objData = new Int32Array(new Uint8Array(payload).buffer);                                }                                // console.info(">>JSON.parse(stringData) ", objData);                                _this.callbackFun(item, objData);                            });                        }                    });                });                c.on("disconnect", e=>{                    console.info("========= DISCONNECTED", e);                })                c.on("error", e=>{                    console.info("========= SUBSCRIBER ERROR...", e);                })            }        }        }        catch (e) {            console.log(e);        }

`
先上代码
MQTT(websocket)类型

入门教程【http://blog.itpub.net/6995813...】