Force a file to download

woodeye

I've written a file transfer page that allows users to upload and download files. I'm having an issue when I try to download files like jpg's or txt files. They don't download, they just open in the browser. I guess this is probably more of an HTML question, but I'm writing in PHP, so I'll go ahead and ask....

I'm currently using a line like this:

<a href = "/upload/sample.jpg">sample.jpg</a>

Is there a better way of doing this?

Thanks in advance for all your help.
Brian

NogDog

Probably the most likely option would be to create a separate "file server" PHP script to use in the link, and have it set the necessary headers to force a download.

fileserver.php:

<?php
if(!empty($_GET['file']))
{
   $file = basename($_GET['file']); // strip any directory data
   $dir = $_SERVER['DOCUMENT_ROOT'].'/uploads/';
   if(is_readable($dir.$file))
   {
      header('Content-Length: '.filesize($dir.$file);
      header('Content-Disposition: attachment; filename="'.$file'"');
      header('Content-Transfer-Encoding: binary');
      header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
      readfile($dir.$file);
      exit;
   }
}
header('HTTP/1.0 404 Not Found');
?>

Then your link would be something like:

<a href='http://www.example.com/fileserver.php?file=sample.jpg'>sample.jpg</a>

woodeye

Thanks NogDog,
That gets me close. I have to work out the correct path to my files, but I tested that on a JPG in my root directory. It does transfer correctly, but when I opened it in Photoshop, I get a message "This document may be damaged (the file may be truncated or incomplete)."

I'm thinking that I need to increase the filesize slightly to accommodate any header info that is being sent with the file. Am I on the right path? If so, how would I know how much to increase the header allocation?

Thanks again. I never would have come up with that solution. Clearly I have a lot to learn!
Brian

BouncerFL

Hi,

I've had success using this type of script, (using, of course, some sort of obfuscation for filepaths) when working with smaller files. My problem is that I would like to pass an ISO file of about 160MB.

In my limited experience, the readfile(); function runs out of memory when dealing with a file of that size.

This one instance, IE seems to get it right...a direct link to the iso file prompts for 'download or open', whereas FF and Opera want to display the dang file in the browser! not much help there.

Is there a better method?

Thanks in advance for any replies,
BouncerFL