Not knowing anything about how your scripts work, I might be shooting blanks here.
You might see if you can do a HTTP HEAD request against the torrent file and see what date information the server returns. I believe this is how most proxies (like Squid) determine whether a file has been changed since it was last downloaded. HEAD is the same as GET except the actual file contents are not transferred, just the HTTP header information. Take a look at section 9.2 of the
HTTP RFC 2616.
You also might want to look at
http://www.squid-cache.org/mail-arch...9904/0688.html, which discusses how Squid uses "If-Modified-Since."