pack to gz and return archive file download

function pack_and_download($file){

  //  pack the file 
  $gzfile = gzopen($file.".gz", "w9");
  gzwrite($gzfile, file_get_contents($file));
  gzclose($gzfile);
	
  //  download the file
  header('Content-Description: File Transfer');
  header('Content-Type: application/octet-stream');
  header('Content-Disposition: attachment; filename="'.basename($file).'.gz"');
  header('Expires: 0');
  header('Cache-Control: must-revalidate');
  header('Pragma: public');
  header('Content-Length: ' . filesize($file.".gz"));
  ob_clean();
  flush();
  readfile($file.".gz");
  unlink($file.".gz"); 
  exit;
}