I have a project that need to solve ASAP. This project requirest these conditions.

1. If user purchased membership, he/she can download media (over 2GB)
from Linux download server. Therefore, we have latest Apache version
2.2 which support over 2GB files.
2. when user request a file by http://down1.example.com/12345.wmv,
first the download server must authenticate the user then update the
download counting to database if it is new file. Since I do not know
anything about Apache modules, I created cgi script that authenticate
and update the database.

Now my question is how can download server Apache can call cgi script
before it deliver the media file? I was thinking about mod_rewriterule
but my friend said I'm on wrong track. He said I should use custom
Apache module to authenticate/update database.

Let me know if you have any good answers :)