Drupal: Send file programmatically

Here is a handy, general function for Drupal 6 that takes as an argument a file id and returns the file for downloading.


filepath;
       
    header("Pragma: public");
    header("Expires: 0");
    header('Cache-Control: no-store, no-cache, must-revalidate');
    header('Cache-Control: pre-check=0, post-check=0, max-age=0', false);
    header('Last-Modified: '.gmdate('D, d M Y H:i:s') . ' GMT');
    $browser = $_SERVER['HTTP_USER_AGENT'];
     
    if(preg_match('/MSIE 5.5/', $browser) || preg_match('/MSIE 6.0/', $browser))
    {
      header('Pragma: private');
      // the c in control is lowercase, didnt work for me with uppercase
      header('Cache-control: private, must-revalidate');
      // MUST be a number for IE
      header("Content-Length: ".filesize($my_path)); 
      header('Content-Type: application/x-download');
      header('Content-Disposition: attachment; filename="'.$file->filename.'"');
    }
    else
    {
      header("Content-Length: ".(string)(filesize($my_path)));
      header('Content-Type: application/x-download');
      header('Content-Disposition: attachment; filename="'.$file->filename.'"');
    }
     
    header('Content-Transfer-Encoding: binary');
     
  if ($file = fopen($my_path, 'rb')) {
      while(!feof($file) and (connection_status()==0))
      {
        ob_clean();
        print fread($file, filesize($my_path));
        flush();
      }
      fclose($file);
    }
    exit(0);
  }  
}
?>