NodeJS MQTT Proxy

index.js

const mqtt = require('mqtt');
const fs = require('fs');

// Source broker details
const sourceBrokerUrl = "mqtts://somebroker.com"; 
const sourceOptions = {
    port: 8883,
    ca: [fs.readFileSync('/home/ubuntu/keys/server/server.crt')],
    key: fs.readFileSync('/home/ubuntu/keys/client.key'),
    cert: fs.readFileSync('/home/ubuntu/keys/client.crt'),
    rejectUnauthorized: true
};

// Destination broker details
const destBrokerUrl = "mqtt://localhost:1883"; 

const sourceClient = mqtt.connect(sourceBrokerUrl, sourceOptions);
const destClient = mqtt.connect(destBrokerUrl);

sourceClient.on('connect', () => {
    console.log('Connected to source broker');
    sourceClient.subscribe('topic/of/interest/#'); 
});

sourceClient.on('message', (topic, message) => {
    console.log(`Received message on topic '${topic}': ${message.toString()}`);
    destClient.publish(topic, message);
});

destClient.on('connect', () => {
    console.log('Connected to destination broker');
});

// Handle errors (optional but recommended)
sourceClient.on('error', (err) => {
    console.error('Source broker error:', err);
});

destClient.on('error', (err) => {
    console.error('Destination broker error:', err);
});