I think I didn't explain myself good enough and after playing with varnish I realized that by default varnish won't forward to the backend If-None-Match and If-Modified-Since headers. Right now my backend is prepared to answer 304 when the resource hasn't been modified, so I would like varnish to cache an object for X seconds and after that use the ETag and Last-Modified sent by the backend to verify if the expired resource is still the same and not ask directly for a fresh one. Right now it always asks for a new one.
On Tue, Sep 7, 2010 at 1:34 AM, Bedis 9 <[email protected]> wrote: > Hi, > > What kind of Vary header your webserver sends? > If no, there is no reason to cache 3 versions of this object unless > your conditionnal request does not match any header of the cached > object. > > cheers > > On Mon, Sep 6, 2010 at 4:40 PM, Jonathan Leibiusky <[email protected]> > wrote: > > Hi! > > I'm playing with If-None-Match and Cache-Control: max-age headers and I > > have a doubt. Maybe it is more related to HTTP than Varnish, but it worth > > asking. > > > > Imagine that I have 3 user-agents, a varnish and my webserver. > > When the clients ask the first time for /example, varnish doesn't have > > anything cached so he ask the webserver for it. The webserver response > has > > Cache-Control: max-age=180 and ETag: 123 (for example). > > So Varnish will cache the response for 180 seconds as well as the > > user-agents. > > After 180 seconds, the 3 user-agents will request /example for a > conditional > > If-None-Match header because they got the ETag. Since it is a conditional > > request varnish will ask the webserver and will get a fresh response with > > all the caching headers. When the other 2 user-agent make the same > > conditional request they will generate another request to the webserver > > unless varnish has some mechanism to answer himself. > > Is that right? Does varnish has this mechanism? > > > > Thanks! > > > > Jonathan > > > > _______________________________________________ > > varnish-misc mailing list > > [email protected] > > http://lists.varnish-cache.org/mailman/listinfo/varnish-misc > > >
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