app.js

## app.js
var cfenv = require( 'cfenv' );
var express = require( 'express' );
var jsonfile = require( 'jsonfile' );
var parser = require( 'body-parser' );
var Particle = require( 'particle-api-js' );
var request = require( 'request' );

// External configuration
config = jsonfile.readFileSync( __dirname + '/config.json' );

// Application
var app = express();

// Middleware
app.use( parser.json() );
app.use( parser.urlencoded( {
  extended: false
} ) );

// Per-request actions
app.use( function( req, res, next ) {
  // Configuration
  req.config = config;

  // Just keep swimming
  next();
} );

// Static for main files
app.use( '/', express.static( 'public' ) );

// Bluemix
var env = cfenv.getAppEnv();

// Listen
var server = app.listen( env.port, env.bind, function() {
  // Debug
  console.log( 'Started on: ' + env.port );
} );

// Socket
var io = require( 'socket.io' )( server );

// Paricle
var particle = new Particle();

// Login
particle.login( {
  username: config.particle_username,
  password: config.particle_password
} ).then(
  function( data ) {
    // Listen to event stream
    // Specific to my devices
    // Can use device ID if known
    particle.getEventStream( {
      auth: data.body.access_token,
      deviceId: 'mine',
    } ).then( function( stream ) {
      // Stream event arrived
      stream.on( 'event', function( evt ) {
        // Look for location-specific event
        if( evt.name.startsWith( 'hook-response/' + config.event_name ) ) {
          // Parse out location details
          var parts = evt.data.split( ',' );

          // Assemble message
          var msg = JSON.stringify( {
            id: evt.name.split( '/' )[2],
            published: evt.published_at,
            position: {
              lat: parseFloat( parts[0] ),
              lng: parseFloat( parts[1] ),
            },
            accuracy: parseInt( parts[2] )
          } );

          // Send to clients
          io.emit( 'location', msg );
        }
      } );
    } );
  },
  function( err ) {
    console.log( err );
  }
);

## config.json
{
  "location_api_key": "AIzaSyBLfo4g4C8Wzo2gqZy6rFkYLORIBAXakPw",
  "map_api_key": "AIzaS2AVdZUkJcTZlcBr3xdidBgCBA55q4jjbXg",
  "event_name": "deviceLocator",
  "particle_username": "_YOUR_PARTICLE_USERNAME_",
  "particle_password": "_YOUR_PARTICLE_PASSWORD_",
  "particle_device": "240023000f4d343436313031"
}

## index.html
<html>
<head>

<title>Location</title>

<!-- Styles -->
<!-- Just fill with map -->
<style>
body {
  margin: 0;
  overflow: hidden;
  padding: 0;
}

#map {
  height: 100%;
  width: 100%;
}
</style>

</head>
<body>

<!-- Map placeholder -->
<div id="map"></div>

<!-- Google Maps -->
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCHSq9HBd3Q-ar2zbCUnB4HwdD64IgNl3M"></script>

<!-- Socket IO -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/1.7.2/socket.io.js"></script>

<!-- Application -->
<script>
class Location {
  constructor() {
    // Create the map instance
    // Set default location
    // Set default zoom level
    this._map = new google.maps.Map( document.querySelector( '#map' ), {
      center: {lat: 41.1106266, lng: -73.7248718},
      zoom: 14
    } );

    // Marker showing location
    // Wait for first location event
    this._marker = null;

    // Socket
    // Listen for location events
    this._socket = io();
    this._socket.on( 'location', evt => this.doLocation( evt ) );
  }

  // Location event
  // Position marker and map
  doLocation( evt ) {
    // Parse JSON
    var data = JSON.parse( evt );
    console.log( data );

    // First location event
    // Instantiate marker
    if( this._marker == null ) {
        this._marker = new google.maps.Marker( {
            map: this._map
        } );
    }

    // Position marker
    // Center map
    this._marker.setPosition( data.position );
    this._map.setCenter( data.position );
  }
};

// Here we go!
let app = new Location();
</script>

</body>
</html>

## location.ino
#include <google-maps-device-locator.h>

// Google Maps
GoogleMapsDeviceLocator locator;

// Setup
void setup() {
  // Scan for visible networks
  // Publish to the cloud every thirty seconds
  locator.withSubscribe( locationCallback ).withLocatePeriodic( 30 );
}

void locationCallback( float lat, float lng, float accuracy ) {
  // Do stuff if you want
}

// Loop
void loop() {
  // Keep on looping
  locator.loop();
}

## package.json
{
  "name": "Locator",
  "version": "0.1.0",
  "description": "Listen for geolocation from Particle Cloud.",
  "private": true,
  "scripts": {
    "start": "node app.js"
  },
  "dependencies": {
    "body-parser": "^1.15.2",
    "cfenv": "^1.0.3",
    "express": "^4.14.0",
    "jsonfile": "^2.4.0",
    "particle-api-js": "^6.5.0",
    "request": "^2.78.0",
    "socket.io": "^1.5.1"
  },
  "repository": {},
  "engines": {
    "node": "4.x"
  }
}