nixfilter-mqtt/mqtt_subscribe.coffee

Filters for publishing and subscribing to MQTT topics, similar to "mosquitto_pub" and "mosquitto_sub"

`#!/usr/bin/env node

'use strict'`

# Require the "nixfilter" module
nixfilter = require('nixfilter')

# Require the "./utils" module
utils = require('./utils')

# Define the filter and register it on the module
nixfilter.filter module,
	description: 'Subscribe to a MQTT topic and output messages published to the topic'

	input_reader: null

	add_arguments: (argument_parser) ->
		utils.add_common_arguments(argument_parser)
		argument_parser.addArgument ['subscribe_topic'],
			help: 'The MQTT topic to subscribe to'
		return

	setup: (args) ->
		utils.connect_to_mqtt_broker(args)
		.then (@mqtt_client) =>
			@mqtt_client.on 'message', (topic, message) =>
				@output(message)
			@mqtt_client.subscribe(args.subscribe_topic)

	terminate: ->
		utils.disconnect_from_mqtt_broker(@mqtt_client)