DF13 Raspberry Pi Node JS Base Station

/*
Requires npm installs for 
* nforce (handles salesforce API)
* faye (handles streaming API -- there's an old version in nforce, but install a new one)
* serialport (this handles serial communication and will do a little compiling on your machine)

Configure Salesforce as follows
* Start with a standard developer org -- http://developer.force.com/join
* Install the package for the simple Streaming API demo here
https://github.com/ReidCarlberg/LAB-Streaming-API-Demo
(Link in the read me.)
* Configure a new connected app in your developer org.
Setup (top) > Create (side) > Apps > Connected Apps (scroll down) > New
* Check "Enable Oauth Settings"
* Add all permissions
* Use "http://localhost:3000/oauth/_callback" as your callback URL
* You'll be using the Oauth2 web server flow
https://help.salesforce.com/apex/HTViewHelpDoc?id=remoteaccess_oauth_web_server_flow.htm&language=en
* You need your personal security code.
Setup > My Personal Information > Reset My Security Code
* Use your passwork in the field below as PASSWORDsecurityCode (concatenated, no space)

* For bi-directional communication, this package has the Device, Device Reading and Device Message objects.
https://login.salesforce.com/packaging/installPackage.apexp?p0=04tE00000001XSP

Configure this app
* Ensure your oauth settings are correct at the bottom
* Client ID, Secret, Username, Password and Callback URL.
* Note that your secret, username and password should be set as environment variables, not encapsulated in code.

Raspberry Pi notes
* Node is not part of the Wheeze Distro.  You can install it using these instructions.
http://www.raspberrypi.org/phpBB3/viewtopic.php?f=66&t=54817
* The Pi has a single serial port that is in use by default.  You need to disable it following these instructions
http://www.hobbytronics.co.uk/raspberry-pi-serial-port
* The Pi comes with a UK keyboard layout that will be confusing.  You can update it following these instructions
http://raspberrypi.stackexchange.com/questions/10060/raspbian-keyboard-layout

Testing
* Note that new Oauth connected app id's take up to 10 minutes to become usable.
You will get authentication errors until then.

Versions 
* 11/11/13 - Updated to check for existence of an outbound message before inserting one into the array.

*/

var SerialPort = require("serialport");

var AckCounter = 0;

var serialPort = new SerialPort.SerialPort("/dev/ttyAMA0", {
  baudrate: 9600,
  parser: SerialPort.parsers.readline('\r\n')
}, false); // this is the openImmediately flag [default is true]

var nforce = require('nforce');
var http = require('http'),
    faye = require('faye');
var client;

var outboundMessages = [];

function handleStreamingAPI(_oauth, _serialPort) {
    client = new faye.Client(_oauth.instance_url + '/cometd/28.0');
    client.setHeader("Authorization", "OAuth " + _oauth.access_token);
    var subscription = client.subscribe('/topic/LAB_OutboundSample', function(message) {
	//V1 was JSON
	//var simpleMessage = { "addr": message.sobject.Device_Address__c, "msg" : message.sobject.Message__c };
	//var simpleMessageString = JSON.stringify(simpleMessage);
	var simpleMessageString = "^" + message.sobject.Device_Address__c + ":" + message.sobject.Message__c;
	console.log(simpleMessageString + "\n");
	if (outboundMessages.indexOf(simpleMessageString) < 0) {
		outboundMessages.push(simpleMessageString);
	}
     });
     console.log("Streaming API Connected...");    
}



function handleSerialPort(_oauth) {
	serialPort.open(function() {
		serialPort.on('data', function(data) {
  			var myData;
			try {
				myData = JSON.parse(data);
			} catch (e) {
				console.log("JSON Parse failed " + e);
				console.log("==============");
				console.log(data);
				console.log("==============");
			}
			if (myData) {
				org.apexRest({uri:'DeviceReport', method: 'POST', body: myData}, _oauth, function(err,resp){
					if(!err) {
      						console.log(resp);
    					}else{
      						console.log(err);
    					}
  				});				
			}
		});
	});
}

function processOutboundMessages() {
	console.log(outboundMessages);
	if (outboundMessages && outboundMessages.length > 0) {
		var targetOutboundMessage = outboundMessages[0];
		outboundMessages.splice(0,1);
		serialPort.write(targetOutboundMessage + "\n", function(err, results) {
        		if (err) {
                		console.log(err);
                	}
        	});

	} else { 
		//console.log("no messages");
	}
	setTimeout(function(){processOutboundMessages();},1000);
}

var sfuser = "reid@labs.551";
var sfpass = "PASSWORDsecuritycode";

var query = 'SELECT Id, FirstName, LastName, Email FROM Lead LIMIT 10';

var org = nforce.createConnection({
  clientId: '3MVG9y6x0357Hlefg7ne7tiUmhOZad6PLdNH8ljsB0UbY9OTJcx2Qp.c2xUVzXxBCV0xBjuFXYp0Ro4uS1mWV',
  clientSecret: '1909279409156583445',
  redirectUri: 'http://localhost:3000/oauth/_callback'
});




org.authenticate({ username: sfuser, password: sfpass}, function(err, oauth) {
  if(err) {
    console.error('unable to authenticate to sfdc');
    console.log(err);
    process.exit(code=0);
  } else {
    console.log("authenticated");
    console.log("oauth");
    console.log(oauth);
    handleStreamingAPI(oauth, serialPort);
    handleSerialPort(oauth);
    processOutboundMessages();
 }
});