nextHandler = $nextHandler; } public function __invoke(CommandInterface $command, RequestInterface $request = null) { $next = $this->nextHandler; return $next($command, $request)->then(function (ResultInterface $result) { if (empty($result['Expires']) && !empty($result['ExpiresString'])) { \trigger_error("Failed to parse the `expires` header as a timestamp due to " . " an invalid timestamp format.\nPlease refer to `ExpiresString` " . "for the unparsed string format of this header.\n", \E_USER_WARNING); } return $result; }); } }