drupal.google.urlshortener.php

<?php

/**
 * Google Url Shortener http://goo.gl/xxxxx
 */
function MYMODULE_urlshortener_get_short_url($url) {
  
  $api_key = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';
  $api_url = 'https://www.googleapis.com/urlshortener/v1/url/?key=' . $api_key;

  $post = json_encode(array("longUrl" => $url));
  
  $ch = curl_init(); 
  curl_setopt($ch, CURLOPT_URL, $api_url); 
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($ch, CURLOPT_POST, true);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $post); 
  curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type: application/json"));
  $result = curl_exec($ch); 
  curl_close($ch); 

  $result = json_decode($result);  

  return $result->id;
}

?>