View source for Mihini/mqtt

== MQTT ==
This example demonstrates the ON/OFF of LED lights via GPIO's pin 17 

'''Variables'''
 local sched = require 'sched'
 local mqtt   = require 'mqtt_library' //import MQTT Lib
 local gpio = require 'gpio'
 local log = require 'log'


 local MQTT_BROKER       = 'iot.eclipse.org'  //sandbox broker hosted @Eclipse
 local MQTT_PORT         = 1883               //Port number
 local MQTT_LOG_NAME     = 'MQTT_LED'        
-- ---------------------------
 local MQTT_LED_RECEIVE = "/MQTT/LED/"         //Topic that we subscribe for, to receive an event
 local MQTT_LED_PUBLISH="/MQTT/PUBDATA/"       // topic that we publish in this example
 local mqtt_client

'''Call back that will be called on a publish to a subscribed topic /MQTT/LED'''
  local function callback(topic, val)
    sched.wait(2)  //wait
     if( topic == '/MQTT/LED') then
         local val2 = gpio.configure(17,{direction="out", edge="both", activelow="0"})
         if(val=='on')then
           gpio.write(17,0)  
           mqtt_client:publish(MQTT_LED_PUBLISH, "Light's ON")
         elseif(val=='off') then
           gpio.write(17,1)
           mqtt_client:publish(MQTT_LED_PUBLISH, "Light's OFF")        -- publish data to a topic
    end
   end
 end

'''Main Function''' 
 local function main()
    log(LOG_NAME, "INFO", "Application started")
   -- Connect to mqtt
     mqtt_client = mqtt.client.create(MQTT_BROKER, MQTT_PORT, callback)    --Create MQTT client
     log(LOG_NAME, "INFO", "MQTT Client is created")
      mqtt_client:connect(MQTT_LOG_NAME)                          --Connect to the server
      log(LOG_NAME, "INFO", "Connected to:" .. MQTT_LOG_NAME)
  sched.wait(2)
    mqtt_client:subscribe({MQTT_LED_RECEIVE})          --MQTT Subscribe to a topic
   while(true) do 
    -- print('INside main')
      mqtt_client:handler()           --MQTT handler continously calls sub and pub
  
     end--
   end
   sched.run(main)
   sched.loop()