Re: very rough caching change patch - centralize vary/http knowledge

[Roy T. Fielding]

On May 7, 2008, at 9:25 AM, Dirk-Willem van Gulik wrote:

But to me allowing caching modules some knowledge of HTTP is  
probably good - as
optimizing the generic case is simply not worthwhile - the very  
point of caches
is that they understand something of the biz-processes to go beyond  
what a the
operating system and what not can yield.

Please keep in mind that Vary is an instruction from the origin  
server to
external caches that it does not control.  A cache within an origin  
server
or reverse proxy/gateway is free to ignore Vary if so configured.   
Thus, an
internal cache may have two sets of instructions -- one "internal vary"
that guides its operation and another Vary header field that is intended
for external recipients of a message.

....Roy