public function getUserId()
    {
        try {
            $parameters = $this->getParameters();
            if (!isset($parameters[self::LTI_USER_ID])) {
                throw new \common_exception_MissingParameter(self::LTI_USER_ID, __FUNCTION__);
            }
            if (!isset($parameters[self::LTI_CONSUMER_KEY])) {
                throw new \common_exception_MissingParameter(self::LTI_CONSUMER_KEY, __FUNCTION__);
            }

            $id = $parameters[self::LTI_USER_ID];
            $key = $parameters[self::LTI_CONSUMER_KEY];

            $data = $this->getCrudService->getUserId($id, $key);
            if (!$data) {
                \common_Logger::i('Id ' . $id . ' is not found.');
                throw new \common_exception_NotFound('No data found for the given id.');
            }

            $this->returnSuccess($data);
        } catch (\Exception $e) {
            \common_Logger::w($e->getMessage());
            $this->returnFailure($e);
        }
    }