Apache::Auth::Subrequest - Allow only if a Subrequest !
PerlModule Apache::Auth::Subrequest <LocationMatch "/z/style/[^/]+/xsl> PerlAccessHandler Apache::Auth::Subrequest </Location>
Restrict access control to a site/location/directory that
This is a very simple approach which allows access to systems from wihtin Apache only. This is useful for original images being resized or XSL being applied.
It is howerver not foolproof and should not be trusted. E.g. a module which runs XSL over XML could be used to grab the original XSL itself.
This module should also allow the opposite - can't think of a good reason now, but there will be one.