Couldn't we add, in the documentation:
- a list of headers that cannot be added by mod_headers
- a list of headers that are stripped by mod_proxy (and mod_proxy_*)
I'm facing a practical case where it's a nightmare to find a correct
solution, even with (very contradicting) information found at several
places: proxying upgrade requests from http(s) to ws(s). There is no
place where it is documented when (in which modules) the Connection &
Upgrade request headers are discarded. There's also no indication that
these request headers cannot set/added/appended.
This kind of information would be invaluable for a lot of people.
I would be happy to help with the documentation obviously, but I'm not
very knowledgeable about this.
Thanks
