mqtt job for dashing.io with publish and subscribe support

README.md

#Description This files will enable you to directly connect your widgets with your mqtt broker. It consists of a job, which will manage the connection to your project. It will over a rest api to publish, subscribe and unsubscribe from your widgets.

#Installation Add the mqtt.rb to your dashing jobs.

#Usage To connect a widget to mqtt use a post on 'mqtt/subscribe' on your constructor. As parameters you need to post the topic to subscribe and the widget id. E.g.:

    $.post 'mqtt/subscribe',
      topic: @get('subscribe'),
      widgetId: @get('id'),
      (data) =>
        console.log data

example.erb

<% content_for :title do %>Home Automation: Main Dashboard<% end %>
<div class="gridster">
  <ul>
    <li data-row="2" data-col="4" data-sizex="1" data-sizey="1">
      <div data-id="testWidget" data-view="Test" data-icon="android" data-title="Luigi" data-publish="some/topic/pub" data-subscribe="some/topic/sub"></div>
    </li>
  </ul>
</div>

mqtt.rb

require 'mqtt'
require 'pry'

module JSON
  def self.is_json?(foo)
    begin
      return false unless foo.is_a?(String)
      JSON.parse(foo).all?
    rescue JSON::ParserError
      false
    end
  end
end

subscriptions = Hash.new{|h,k| h[k] = []}

client = MQTT::Client.connect('mqtt://localhost:1883')

Thread.new {
  client.get do |topic,message|
    message = JSON.parse(message) if JSON.is_json?(message)
    subscriptions[topic].each do |tag|
      send_event( tag, { value: message, current: message })
    end
  end
}

post '/mqtt/publish' do
  client.publish(params['topic'], params['message'])
end

post '/mqtt/subscribe' do
  if subscriptions[params['topic']].empty?
    client.subscribe(params['topic'])
  end
  unless subscriptions[params['topic']].include? params['widgetId']
    subscriptions[params['topic']] << params['widgetId']
  end
end

post '/mqtt/unsubscribe' do
  subscriptions[params['topic']].delete(params['widgetId'])
  if subscriptions[params['topic']].empty
    client.unsubscribe(params['topic'])
  end
end

Test.coffee

class Dashing.Test extends Dashing.ClickableWidget

  constructor: ->
    super
    $.post 'mqtt/subscribe',
      topic: @get('subscribe'),
      widgetId: @get('id'),
      (data) =>
        console.log data

  ready: ->

  onData: (data) ->

  onClick: (node, event) ->
    $.post '/mqtt/publish',
      topic: @get('publish'),
      message: 'message',
      (data) =>
        alert(data)

Really interesting gist, I'm trying to create a widget with a list of events that will come from a mqtt topic, any idea how this would be potentially archived?

Thanks in advance!

Briliant piece of code! Do you know how I can remember the state on a page refresh? I am thing on outputting the state and widget name to txt file that is read directly in the widget constructor. What do you think, @mapero ?