php force download on mobile browsers

Question

Hi, I'm trying to force download a image file (jpg for example) using php. So I have a script here force.php and here would be the code:

header("Pragma: public"); // required
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: private",false); // required for certain browsers
header('Content-Description: File Transfer');
header("Content-Type: image/jpeg");
header('Content-Length: ' . filesize($file));
header('Content-Disposition: attachment; filename=test.jpg');
readfile($file);

Now the problem is for some browsers (mobile phone browsers especially), it'll work properly and prompt test.jpg for the user to save. However on some browser, it'll prompt force.php as download. Any solution?

Thank you!

Answer 1

Content disposition header highly depends on how a particular browser implements it. Sometimes there are encoding issues (I do not see in your case).

The document at Test Cases for HTTP Content-Disposition shows behavior for various browsers.

Answer 2

To be safe with mobile browsers you should consider having the http request's last part be equal to the actual filename of the attachment, for example http://some.url/download/test.jpg .

Use apache mod_rewrite or similar to route such requests to your download script.