/**
  * Initialize a Facebook Application.
  *
  * The configuration:
  * - appId: the application ID
  * - secret: the application secret
  * - fileUpload: (optional) boolean indicating if file uploads are enabled
  * - allowSignedRequest: (optional) boolean indicating if signed_request is
  *                       allowed in query parameters or POST body.  Should be
  *                       false for non-canvas apps.  Defaults to true.
  *
  * @param array $config The application configuration
  */
 public static function setAuth($config)
 {
     self::setAppId($config['appId']);
     self::setAppSecret($config['secret']);
     if (isset($config['fileUpload'])) {
         self::setFileUploadSupport($config['fileUpload']);
     }
     if (isset($config['trustForwarded']) && $config['trustForwarded']) {
         self::$trustForwarded = true;
     }
     if (isset($config['allowSignedRequest']) && !$config['allowSignedRequest']) {
         self::$allowSignedRequest = false;
     }
     $state = self::getPersistentData('state');
     if (!empty($state)) {
         self::$state = $state;
     }
 }