Auth_OpenID_Server::decodeRequest PHP Method

    function decodeRequest($query = null)
    {
        if ($query === null) {
            $query = Auth_OpenID::getQuery();
        }
        return $this->decoder->decode($query);
    }

 /**
  * Receive an incoming request.
  *
  * This function never returns.
  */
 public function receiveRequest()
 {
     $request = $this->server->decodeRequest();
     if (!in_array($request->mode, array('checkid_immediate', 'checkid_setup'), TRUE)) {
         $this->sendResponse($this->server->handleRequest($request));
     }
     $state = array('request' => $request);
     $this->processRequest($state);
 }