/**
  * Get a hash of data identifying this MW installation.
  *
  * This is used by mw-config/index.php to prevent multiple installations of MW
  * on the same cookie domain from interfering with each other.
  *
  * @return string
  */
 public function getFingerprint()
 {
     // Get the base URL of the installation
     $url = $this->request->getFullRequestURL();
     if (preg_match('!^(.*\\?)!', $url, $m)) {
         // Trim query string
         $url = $m[1];
     }
     if (preg_match('!^(.*)/[^/]*/[^/]*$!', $url, $m)) {
         // This... seems to try to get the base path from
         // the /mw-config/index.php. Kinda scary though?
         $url = $m[1];
     }
     return md5(serialize(array('local path' => dirname(__DIR__), 'url' => $url, 'version' => $GLOBALS['wgVersion'])));
 }