PHP - Change file name from url when user downloads file - php

Question

File links are all http://website.com/f/xxx.png/zip/txt and so on.
I need to set it up so that if a user downloads that file it would download with a different name.
I have seen how to do this on a normal page, but I have no clue how making it work when the image itself is linked to is done.
Appreciate any help :)
Edit: Using the rewrite Steven Jeffries posted,
header('Content-Disposition: inline; filename=' . $originalFileName . "'");
header("Content-Type:" . $mimeType);
$im = imagecreatefrompng($filePathOnServer);
imagepng($im);
to display images and
header('Content-Disposition: attachment; filename=' . $originalFileName . "'");
header("Content-Type:" . $mimeType);
to make other files download solved the issues I had.

Answer 1

I think an easy way to do this would be to redirect download links to another script that handles what to download, etc. Basically, I'd set up a download dir, add some rewrite rules, and then create a script to handle what gets output.
Something like this (untested):
/path-to-web-root/download/.htaccess
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^.* /downloads/handle-downloads.php
/path-to-web-root/download/handle-downloads.php
$url = trim($_SERVER['REQUEST_URI'], '/');
if (preg_match('^#downloads/(?<real_filename>.*?)/(?<options>.*)/(?<fake_filename>.*)$#', $url, $matches)) {
// Double check my regex, but basically pull the real filename from the url here
$actual_file = "/path-to-webroot/f/{$matches['real_filename']}";
$options = explode('/', $matches['options']);
if (in_array('zip', $options)) {
// Handle zip, etc.
}
$fake_filename = $matches['fake_filename'];
if (file_exists($actual_file)) {
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="'.basename($fake_filename).'"');
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($actual_file));
readfile($file);
exit;
}
}
Then, instead of having the download link being website.com/f/xxx.png/zip/txt, you could instead do website.com/download/xxx.png/zip/txt/new-filename.png. This would allow you to set the filename to whatever you wanted since the browser will just take what's at the end of the url.
Edit: I've included the relevant code from readfile's manual page.

Answer 2

You can set the file response file name by setting header parameter.
For example:
<?php
header('Content-Type: image/png');
header('Content-Disposition: attachment; filename="xyz.png"');
header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
...
More on PHP header function here: http://php.net/manual/en/function.header.php