How to send changes to a lever in Minecraft to a MQTT broker - and listen for changes in an Arduino

lever_pulled_mqtt.js

var mqtt = require('sc-mqtt');  
var client = mqtt.client(); // local host is default. Otherwise use host, user/pwd
client.connect();

//Subscribe to changes in the state of the Arduino
client.subscribe('/arduino/1/status');
var player; // To remember who pulled the switch

// Here we tell Minecraft to give us control after certain events
events.on('player.PlayerInteractEvent', function (listener, event) { 
	var block = event.getClickedBlock(); // Which block?
	var type = block.getType();			 // What type is it?
 	player = event.player; 				 // Note who shall be alerted

	if(type==org.bukkit.Material.LEVER) {
		var loc = block.location;	//We need to find the location
		
		// Compose a MQTT Topic which contains the world name and location of the block
		var mqttTopic='minecraft/'+loc.world.name+'/lever/'+loc.x+','+loc.y+','+loc.z+'/status';

		// Is the lever up or down?
		var state='';
		if (block.data==3){
			state='DOWN'
		}
		else
		{
			state='UP'
		} 	    

		// Now publish it
  		client.publish(mqttTopic, 	// which topic
  		state,				// the status
  		1,				// QoS 1 ( deliver at least once )
  		true); 				// broker should retain message

	}
})

//Give the player a notification if a message arrives
client.onMessageArrived(function(topic, message){
	var bytes = message.payload;	
	var javaString = new java.lang.String(bytes);	// Using the Java libraries, we can convert from binary
	player.sendMessage(javaString.slice(0, - 1));	
});