How to monitor the status of devices using MQTT?

To monitor the device status, you can utilize MQTT’s subscription feature.

First, you need to create an MQTT client and then use the client to connect to an MQTT broker. Once the connection is successful, you can use the client to subscribe to a specific topic in order to receive messages on that topic.

Devices will periodically send status messages on the topics you subscribe to. You can take appropriate actions when receiving these messages, such as updating the device’s status or triggering other logic.

Here is a simple example code implementing MQTT subscription using the MQTT.js library.

const mqtt = require('mqtt');

const brokerUrl = 'mqtt://mqtt.example.com'; // MQTT 代理服务器的地址
const topic = 'devices/status'; // 要监听的主题

// 创建 MQTT 客户端
const client = mqtt.connect(brokerUrl);

// 连接成功后订阅主题
client.on('connect', () => {
  console.log('Connected to MQTT broker');
  client.subscribe(topic);
});

// 收到消息时执行的操作
client.on('message', (topic, message) => {
  console.log(`Received message on topic ${topic}: ${message}`);
  // 在这里执行相应的设备状态更新操作或其他逻辑
});

Please note that the brokerUrl and topic in the above example need to be modified according to your actual situation.