Re: Apache's CacheNegotiatedDocs?

From: Marc Slemko <marcs@dont-contact.us>
Date: Sun, 15 Mar 1998 22:45:39 -0700 (MST)

On Mon, 16 Mar 1998, Dancer wrote:

> From: http://www.apache.org/docs/content-negotiation.html
> (This isn't the reference I was thinking of, but there you go)
>
> Note on Caching
>
> When a cache stores a document, it associates it with the request URL.
> The next time that URL is requested, the cache can use the stored
> document, provided it is still
> within date. But if the resource is subject to content negotiation at
> the server, this would result in only the first requested variant being
> cached, and subsequent cache hits
> could return the wrong response. To prevent this, Apache normally marks
> all responses that are returned after content negotiation as
> non-cacheable by HTTP/1.0
> clients. Apache also supports the HTTP/1.1 protocol features to allow
> caching of negotiated responses.
>
> For requests which come from a HTTP/1.0 compliant client (either a
> browser or a cache), the directive CacheNegotiatedDocs can be used to
> allow caching of
> responses which were subject to negotiation. This directive can be given
> in the server config or virtual host, and takes no arguments. It has no
> effect on requests from
> HTTP/1.1 clients.

This does _not_ claim that the Last-Modified will be the same, nor does it
claim that Apache doesn't send Vary: headers. Both suggestions are
incorrect.

>
>
> Marc Slemko wrote:
> >
> > On Sat, 14 Mar 1998, Dancer wrote:
> >
> > > Henrik Nordstrom wrote:
> > > >
> > > > Dancer wrote:
> > > > > If you fetch one version of a document under (say) content
> > > > > negotiation, then another version fetched under content
> > > > > negotiation will appear to have the same last-modified time,
> > > > > regardless of reality. S'just how Apache does it.
> > > >
> > > > I assume that Apache sends Vary: headers when doing content-negotiation
> > > > (it should, at least when there is more than possible object for the
> > > > URL)?
> > >
> > > Apparently not. This was from the Apache FAQ.
> >
> > Erm... no. Please provide an exact citation for that in the FAQ since I'm
> > sure not aware of it being there.
> >
> > Apache does send Vary: headers.
[...]
Received on Sun Mar 15 1998 - 21:54:54 MST

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