title: facebook PHP SDK cannot work in different PHP versions
body: <p>I have a sample code to test if my website can receive data from facebook.I ran this code locally on a webmatrix server running PHP 5.4 with no problems.I also ran that code on a machine running WAMP server with PHP 5.5 again without any problems.But when I ran it on a VM with ubuntu 12.04 and PHP 5.5.26 (according to phpinfo() function)or in a coding.io VM with PHP 5.9 it shows no output.Of course I have checked everywhere to keep the same path with the facebook sdk folder and that is ok.Any help would be appreciated on this strange problem.</p>
  
  <p>Here is my test code:</p>
  
  <pre><code>&lt;?php
  require_once( '/facebook-php-sdk-v4/src/Facebook/FacebookSession.php');
  require_once( '/facebook-php-sdk-v4/src/Facebook/FacebookRequest.php' );
  require_once( '/facebook-php-sdk-v4/src/Facebook/FacebookResponse.php' );
  require_once( '/facebook-php-sdk-v4/src/Facebook/FacebookSDKException.php' );
  require_once( '/facebook-php-sdk-v4/src/Facebook/FacebookRequestException.php' );
  require_once( '/facebook-php-sdk-v4/src/Facebook/FacebookRedirectLoginHelper.php');
  require_once( '/facebook-php-sdk-v4/src/Facebook/FacebookAuthorizationException.php' );
  require_once( '/facebook-php-sdk-v4/src/Facebook/GraphObject.php' );
  require_once( '/facebook-php-sdk-v4/src/Facebook/GraphUser.php' );
  require_once( '/facebook-php-sdk-v4/src/Facebook/GraphSessionInfo.php' );
  require_once( '/facebook-php-sdk-v4/src/Facebook/Entities/AccessToken.php');
  require_once( '/facebook-php-sdk-v4/src/Facebook/HttpClients/FacebookCurl.php' );
  require_once( '/facebook-php-sdk-v4/src/Facebook/HttpClients/FacebookHttpable.php');
  require_once( '/facebook-php-sdk-v4/src/Facebook/HttpClients/FacebookCurlHttpClient.php');
  
  use Facebook\FacebookSession;
  use Facebook\FacebookRequest;
  use Facebook\GraphUser;
  use Facebook\FacebookRequestException;
  use Facebook\FacebookCanvasLoginHelper;
  use Facebook\FacebookRedirectLoginHelper;
  
  
  $facebook = FacebookSession::setDefaultApplication('xxxxxxxxxxxxx','xxxxxxxxxxxxxx');
  FacebookSession::enableAppSecretProof(false);
  $session = new FacebookSession('xxxxxxxxxxxxxxxxxxxxxx');
  
  //from user
  $myurl = (isset($_POST['url']) ? $_POST['url'] : null); //not of any use here now
  $objRequest = '/461598630586060';
  
  
  try {
    $response = (new FacebookRequest($session, 'GET',$objRequest))-&gt;execute();
    $response='success';
  
    } catch (FacebookRequestException $ex) {
  
    $response='fail';
  } catch (\Exception $ex) {
  
    $response='fail';
  }
  
  echo $response;
  ?&gt;
  </code></pre>