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From "Graham Leggett" <>
Subject Re: mod_cache responsibilities vs mod_xxx_cache provider responsibilities
Date Thu, 21 Sep 2006 10:50:56 GMT
On Thu, September 21, 2006 11:05 am, Issac Goldstand wrote:

> Based on that, it seems to me that the sensible thing to do would be to
> update the header file to include trailers after the response is
> complete (and send them as-is as trailers to the initial client).  If
> we're already doing that, then it would probably also make sense to
> calculate the entity-length to update the headers afterwards.

This makes sense - once completely cached, all cached entities should have
a content length header added, even if its done after the entry is
finished being cached.

mod_proxy would need to cooperate by passing the trailers somehow up the
filter stack if a trailer is present, cache_save would then add the
trailer to the existing headers.

In theory, all mod_proxy needs to do is add the trailer to the headers
list when one is received. Once mod_cache has finished caching an entity,
mod_cache could then check and see if the length of the header list has
changed from when the request started - if so, it means a trailer was
present and the headers must be updated.

> However,
> I'm not even sure as to where such things should be implemented, in
> mod_cache, mod_proxy(_http), or http filters, or somewhere else entirely?

mod_proxy definitely needs to be involved by it not ignoring trailers.
mod_cache can however cache anything in the server (CGI, anything), so it
cannot be assumed that mod_proxy will always be involved when caching.


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