For CGI programs that want to use "ETag" values (e.g. MD5 hashes) to avoid re-sending dynamically-generated content that hasn't changed since the last time the client requested it, it's useful to have access to the HTTP header "If-None-Match".
This HTTP header isn't passed in the environment from Mathopd at present. I don't know the Mathopd source, but I'm guessing it should be easy to patch Mathopd to provide it? Perhaps a more general solution would be useful, so that mathopd.conf can say which HTTP headers we want to have passed to CGI programs: possibly, all of them, at least for debugging... Thanks, - Martin.
