[RFC] remove X-Cache and X-Cache-Lookup headers

These two headers are marked as experimental, but have been in there so
long they seem to have become defacto standards for HIT/MISS debugging.

1) they are not necessary on 99% (or more) of traffic.
2) they *actualy* present bogus information, and most of the blog /
tutorial / how-to I have found document some strange behaviour which is
*not* how Squid has aways used them.
3) X-Cache-Lookup, when it works at all it is redundant behind X-Cache.
When it does not work presents "MISS", always.

X-Cache-Lookup I think we can just drop.

X-Cache is trickier due to the defacto nature it has gained. I think we
can suppress its addition unless TRACE method or Max-Forwards header are
present as a sign of manual debugging. Alternatively we could make it
configurable. Either way the minor information leak and bandwidth waste
that it presents can be resolved.
  PS. if X-Cache remains I think we should extend it slightly to
indicate REFRESH operations not just HIT/MISS.

Amos
Received on Mon May 20 2013 - 14:23:07 MDT