PHP强制下载远程文件而不读入内存

这是我的代码：

if($url = getRemoteFileURL($file_id))
{
  header('Content-Type: application/octet-stream');
  header('Content-Disposition: attachment; filename="abc.zip"');
  header('Content-Transfer-Encoding: binary');
  header('Expires: 0');
  header('Cache-Control: must-revalidate,post-check=0,pre-check=0');
  header('Pragma: public');
  header('Pragma: no-cache');

  readfile($url);  // is there a better function ?
}

我不想做标题(“位置：”),因为这会显示URL