web.js

var connect = require( 'connect' );
var mongo = require( 'mongodb' );

var port = process.env.PORT || 3000;
var mongoUri = process.env.MONGOLAB_URI;

var database = null;
var contactsCollection = null;

var contacts = {
    add: function( firstName, lastName, requestCallback )
    {
        if ( contactsCollection != null )
        {
            contactsCollection.insert( { "firstName": firstName, "lastName": lastName }, function(error, result)
            {
                requestCallback( null, "success" );
            });
        }
    }
};

mongo.connect( mongoUri, {}, dbConnectCallback );

connect.createServer(

    require( 'connect-jsonrpc' )( contacts )
).listen( port );

function dbConnectCallback( error, db )
{
    database = db;

    database.addListener( "error", handleError );
    database.createCollection( "contacts", createCollectionCallback );
};

function handleError( error )
{
    console.log( "Error connecting to MongoLab" );
};

function createCollectionCallback( error, collection )
{
    database.collection( "contacts", collectionCallback )
};

function collectionCallback( error, collection )
{
    contactsCollection = collection;
};