/** * Override used to allow pre-signed URLs to be created for an * in-determinate request payload. */ protected function getPresignedPayload(RequestInterface $request) { $result = parent::getPresignedPayload($request); // If the body is empty, then sign with 'UNSIGNED-PAYLOAD' if ($result === self::DEFAULT_PAYLOAD) { $result = 'UNSIGNED-PAYLOAD'; } return $result; }