In this article i will explain you how you can work with MQTT in NodeJS application
Step 1: Install MQTT package
npm install mqtt --save
Step 2: Add the following code to your Nodejs application
const mqtt = require("mqtt");
const client = mqtt.connect("mqtt://test.mosquitto.org");
client.on("connect", function () {
client.subscribe("presence", function (err) {
if (!err) {
client.publish("presence", "Hello mqtt");
}
});
});
client.on("message", function (topic, message) {
// message is Buffer
console.log(message.toString());
client.end();
});
-In this code we are connecting with IOT application and subscribing and publishing to the topic
In MQTT we generally communicate with IOT application using topic where application publish message to the topic and other application who have subscribed to this topic get the message
client.on("connect", function () {
client.subscribe("presence", function (err) {
if (!err) {
client.publish("presence", "Hello mqtt");
}
});
});
- Getting message from the topic
This is the code where we get message from the topic
client.on("message", function (topic, message) {
// message is Buffer
console.log(message.toString());
client.end();
});