gistfile1.php

<?php
// SET UP THESE VARIABLES;
$GOOGLE_ANALYTICS_ID = '';
$IOS_STORE_URL = '';
$PATH_TO_GOOGLE_ANALYTICS_FILE = '';// This is where the Google Analytics Helper Script is located

function loadGAN($id = null) {
	global $gan, $PATH_TO_GOOGLE_ANALYTICS_FILE;
	if($gan) {
		return $gan;
	}
	require_once($PATH_TO_GOOGLE_ANALYTICS_FILE);
	$gan = new GAN($id);
	return $gan;
}

//
// Detect's the user's mobile client
// If it is a matched client, creates a referral item in parse and returns a redirect URL for the AppStore
//
function createReferral($params = array()) {
  require_once 'Mobile_Detect.php';
  $detect = new Mobile_Detect;
  global $GOOGLE_ANALYTICS_ID, $IOS_STORE_URL;
  
  $clients = array('iPhone'=>$IOS_STORE_URL,
                   'iPod'=>$IOS_STORE_URL,
                   'iPad'=>$IOS_STORE_URL);
  $device = null;
  foreach($clients as $client => $url) {
    if($detect->is($client)) {
      $device = $client;
      break;
    }
  }
  $ganuid = isset($_COOKIE['ganuid']) ? $_COOKIE['ganuid'] : null;
  if(!$device) {
  	loadGAN()->pageview(array('page'=>'appstore-desktop'), $params, $ganuid);
    return $IOS_STORE_URL;
  }
  
  $v = $detect->version($device);
  $params['ip'] = sha1($_SERVER['REMOTE_ADDR']);
  $params['device'] = $device ? $device : 'OSX';
  $params['os_version'] = $v ? $v : '';
  $params['timestamp'] = time();
  $params['ganuid'] = $ganuid;
  
  // TODO:
  // 1. Store the $params as a new Referral object in a database
  // 2. Extract a unique $objId from the referral object...
  
	$gan = new GAN($GOOGLE_ANALYTICS_ID);
	$gan->pageview(array('page'=>'appstore-mobile?ref='.$objId,'title'=>$objId), $params, $ganuid);
  
  return $clients[$device];
}

$from = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '';
$from = explode('?', $from);
$from = sizeof($from) >= 2 ? $from[1] : '';
$qps = explode('&', $from);
$params = array();
foreach($qps as $qp) {
  $parts = explode('=', $qp);
  if(sizeof($parts)>=2 && strpos($parts[0], 'utm_')===0) {
    $params[substr($parts[0],4)] = $parts[1];
  }
}

header('location: '. createReferral($params));