Psr7Middlewares\Middleware\ReadResponse::range PHP Метод

    private static function range(ServerRequestInterface $request, ResponseInterface $response)
    {
        $response = $response->withHeader('Accept-Ranges', 'bytes');
        $range = $request->getHeaderLine('Range');
        if (empty($range) || !($range = self::parseRangeHeader($range))) {
            return $response;
        }
        list($first, $last) = $range;
        $size = $response->getBody()->getSize();
        if ($last === null) {
            $last = $size - 1;
        }
        return $response->withStatus(206)->withHeader('Content-Length', (string) ($last - $first + 1))->withHeader('Content-Range', sprintf('bytes %d-%d/%d', $first, $last, $size));
    }