index.js

const express = require('express');
const mqtt = require('mqtt');      // Using MQTT.js npm
const app = express();

app.get('/', (req, res) => {
  res.send('Hello WISE-PaaS!');
});

// Typically in the hosting environment for node application, there's an env variable called 'PORT'
const port = process.env.PORT || 3030;
const server = app.listen(port, () => console.log(`Listening on port ${port}...`));

// Start Config
var config = {};
config.mqtt = {};

/** Modify this config ***/
// SYS
config.timeout = 120 * 1000;
// Local environment MQTT configuration
config.mqtt.broker = "MODIFY_BROKER_HOST";     // mqtt://broker-host
config.mqtt.username = "MODIFY_YOUR_USERNAME";
config.mqtt.port = 1883;
config.mqtt.password = "MODIFY_YOUR_PASSWORD";
/*****/

config.mqtt.serviceName = "p-rabbitmq"; // 'p-rabbitmq'

var vcap_services = {
  "p-rabbitmq": [
    {
      "credentials": {
        "protocols": {
          "mqtt": {
            "username": config.mqtt.username,
            "password": config.mqtt.password,
            "port": config.mqtt.port,
            "host": config.mqtt.broker
          }
        }
      }
    }
  ]
};

if (process.env.VCAP_SERVICES != null) {
  console.log("Using VCAP_SERVICES");
  vcap_services = JSON.parse(process.env.VCAP_SERVICES);
}

// Parsing credentials from VCAP_SERVICES for binding service
if (vcap_services[config.mqtt.serviceName]) {
  console.log("Parsing " + config.mqtt.serviceName);
  config.mqtt.broker = "mqtt://" + vcap_services[config.mqtt.serviceName][0].credentials.protocols.mqtt.host;
  config.mqtt.username = vcap_services[config.mqtt.serviceName][0].credentials.protocols.mqtt.username.trim();
  config.mqtt.password = vcap_services[config.mqtt.serviceName][0].credentials.protocols.mqtt.password.trim();
  config.mqtt.port = vcap_services[config.mqtt.serviceName][0].credentials.protocols.mqtt.port;
}

config.mqtt.options = {
  broker: config.mqtt.broker,
  reconnectPeriod: 1000,
  port: config.mqtt.port,
  username: config.mqtt.username,
  password: config.mqtt.password
};

console.log(config.mqtt.options);

config.mqtt.topic = "#";
config.mqtt.retain = true; // MQTT Publish Retain

// Start MQTT
var client = mqtt.connect(config.mqtt.broker, config.mqtt.options);

client.on('connect', function () {
  client.subscribe(config.mqtt.topic);
  console.log("[MQTT]:", "Connected.");
});

client.on('message', function (topic, message) {
  console.log("[" + topic + "]:" + message.toString());
});

client.on('error', function (err) {
  console.log(err);
});

client.on('close', function () {
  console.log("[MQTT]: close");
});

client.on('offline', function () {
  console.log("[MQTT]: offline");
});