(1) I have a site that serves up MP3 files:

http://domain/files/1234567890.mp3

(2) I have a php script that tracks file download counts:

http://domain/modules/download_counter.php?file=/files/1234567890.mp3

After download_counter.php records the download, it redirects to the original file: Header("Location: $FQDN_url");

(3) I'd like all my public links to be presented as the direct file urls from (1). I'm trying to use Apache to redirect the requests to download_counter.php:

RewriteRule ^files/(.+\.mp3)$ /modules/download_counter.php?file=/files/$1 [L]

I'm currently stuck on (3), as it results in a redirect loop, since download_counter.php simply redirects the request back to the original file (rather than streaming the file contents).

I'm also motivated to use download_counter.php as is (without modifying it's redirect behaviour). This is because the script is part of a larger CMS module, and I'd like to avoid complicating my upgrade path.

Perhaps there is no solution to my problem (other than modifying the download_counter script). WDYT?