mqtt-dispatcher

MQTT dispatcher is a library that extends MQTT.js and allows to route incoming messages on a specific handler, according to defined routing rules.

Why this library?

The implementation for MQTT in Javascript is MQTT.js. It is able to handle MQTT messages but it doesn't have a built-in message dispatcher. You can subscribe different topics, but all messages are handled by a single event listener on('message', cb).

This library provides a dispatch system that connects a subscribe operation with a specific callback. A callback is called only when an incoming message matches the provided pattern.

Documentation

• APIs

Install

npm install mqtt-dispatcher

Example

const mqtt = require('mqtt')
const MqttDispatcher = require('mqtt-dispatcher')

const client = mqtt.connect('mqtt://broker.hivemq.com:1883')
const dispatcher = new MqttDispatcher(client)

client.on('connect', () => console.log('connected'));

(async () => {
  await dispatcher.addRule('mqtt-dispatcher/command/logout', (topic, message) => {
    console.log('RECEIVED MESSAGE', message.toString())
  })

  await dispatcher.addRule('mqtt-dispatcher/command/restart', (topic, message) => {
    console.log('RECEIVED MESSAGE', message.toString())
  })

  await dispatcher.addRule('mqtt-dispatcher/command/shutdown', (topic, message) => {
    console.log('RECEIVED MESSAGE', message.toString())
  })

  client.publish('mqtt-dispatcher/command/logout', 'logout command')
  client.publish('mqtt-dispatcher/command/restart', 'restart command')
  client.publish('mqtt-dispatcher/command/shutdown', 'shutdown command')

  await new Promise(resolve => setTimeout(resolve, 5000))

  await dispatcher.removeRule('mqtt-dispatcher/command/logout')
  await dispatcher.removeRule('mqtt-dispatcher/command/restart')
  await dispatcher.removeRule('mqtt-dispatcher/command/shutdown')

  client.end(() => console.log('end'))
})()

Changelog

• 0.x - Preview version
• 1.0 - First stable version
• 1.1 - Upgrades libraries
• 1.2 - Migrates to codecov
• 2.0 - Upgrades deps; migrates to npm, chrvadala/github-actions and coveralls; improves documentation

Contributors

• chrvadala (author)

Related projects

• mqtt-router