Nagłówki do wysłania pliku csv

header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Last-Modified: ".gmdate("D, d M Y H:i:s")." GMT");
header("Content-Type: unknown");
header("Content-Disposition: attachment; filename=".urlencode($filename));
header("Content-Length: ".strlen($content)."");
header('Pragma: public');
echo $content;
exit();