Nick, I'm moving from from a -.9 to a -1 of trunk on this because altering the semantics of ALL of the existing ProxyPass[Reverse] directives in one misplaced or poorly understood directive seems highly hazardous.
On any server with more than one administrator, this can be very toxic and cause all sorts of ill will as Joe turns on the directive, breaking James' mappings. Similar issues occur when ProxyPass directives are scattered throughout many .conf'lets. Can this please be reverted, and replace if you like with a second set of unambiguous ProxyPassEnv[Reverse|CookieDomain|CookiePath] directives which triggers honoring the env var interpolation on a per-mapping basis? My suggestion is to simply add a boolean to the stored ProxyPass entries which is set for ProxyPassEnv* and otherwise left unset. The existing ProxyPass* becomes conditional on the per-entry boolean instead of a global setting. Thanks, Bill * mod_proxy: Support variable interpolation in reverse proxy configuration http://svn.apache.org/viewvc?view=rev&revision=421686 (code) http://svn.apache.org/viewvc?view=rev&revision=422178 (code) http://svn.apache.org/viewvc/httpd/httpd/trunk/docs/manual/mod/mod_proxy.xml?r1=420990&r2=421725 (docs) +1: niq, mturk -.9: wrowe notes; modifying the existing syntax seems inappropriate, new ProxyPassSubstitute or similarly named directives would seem to make more sense, permit direct Reverse'als when appropriate and restrict the Substitutions to be parsed only when required.