2 Legged OAuth in PHP

Google Apps Premier/Education administrators can take advantage of 2 legged OAuth to communicate with the Google Data APIs. This sample makes use of the PHP OAuth library from oauth.net.

<?php
require_once('OAuth.php');

// Establish an OAuth consumer based on our admin 'credentials'
$CONSUMER_KEY = 'yourdomain.com'; 
$CONSUMER_SECRET = 'YOUR_CONSUMER_SECRET'; 
$consumer = new OAuthConsumer($CONSUMER_KEY, $CONSUMER_SECRET, NULL);

// Setup OAuth request based our previous credentials and query
$user= 'any.user@yourdomain.com';
$base_feed = 'http://www.google.com/m8/feeds/contacts/default/full/';
$params = array('max-results' => 10, 'xoauth_requestor_id' => $user);
$request = OAuthRequest::from_consumer_and_token($consumer, NULL, 'GET', $base_feed, $params);

// Sign the constructed OAuth request using HMAC-SHA1
$request->sign_request(new OAuthSignatureMethod_HMAC_SHA1(), $consumer, NULL);

// Make signed OAuth request to the Contacts API server
$url = $base_feed . '?' . implode_assoc('=', '&', $params);
echo send_request($request->get_normalized_http_method(), $url, $request->to_header());
 
/**
 * Makes an HTTP request to the specified URL
 * @param string $http_method The HTTP method (GET, POST, PUT, DELETE)
 * @param string $url Full URL of the resource to access
 * @param string $auth_header (optional) Authorization header
 * @param string $postData (optional) POST/PUT request body
 * @return string Response body from the server
 */
function send_request($http_method, $url, $auth_header=null, $postData=null) {
  $curl = curl_init($url);
  curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
  curl_setopt($curl, CURLOPT_FAILONERROR, false);
  curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);

  switch($http_method) {
    case 'GET':
      if ($auth_header) {
        curl_setopt($curl, CURLOPT_HTTPHEADER, array($auth_header)); 
      }
      break;
    case 'POST':
      curl_setopt($curl, CURLOPT_HTTPHEADER, array('Content-Type: application/atom+xml', 
                                                   $auth_header)); 
      curl_setopt($curl, CURLOPT_POST, 1);                                       
      curl_setopt($curl, CURLOPT_POSTFIELDS, $postData);
      break;
    case 'PUT':
      curl_setopt($curl, CURLOPT_HTTPHEADER, array('Content-Type: application/atom+xml', 
                                                   $auth_header)); 
      curl_setopt($curl, CURLOPT_CUSTOMREQUEST, $http_method);
      curl_setopt($curl, CURLOPT_POSTFIELDS, $postData);
      break;
    case 'DELETE':
      curl_setopt($curl, CURLOPT_HTTPHEADER, array($auth_header)); 
      curl_setopt($curl, CURLOPT_CUSTOMREQUEST, $http_method); 
      break;
  }
  $response = curl_exec($curl);
  if (!$response) {
    $response = curl_error($curl);
  }
  curl_close($curl);
  return $response;
}

/**
 * Joins key:value pairs by inner_glue and each pair together by outer_glue
 * @param string $inner_glue The HTTP method (GET, POST, PUT, DELETE)
 * @param string $outer_glue Full URL of the resource to access
 * @param array $array Associative array of query parameters
 * @return string Urlencoded string of query parameters
 */
function implode_assoc($inner_glue, $outer_glue, $array) {
  $output = array();
  foreach($array as $key => $item) {
    $output[] = $key . $inner_glue . urlencode($item);
  }
  return implode($outer_glue, $output);
}
?>