if-none-match status

[Joe Williams]

Thanks Rogério, I am totally aware that it currently is "client <->
varnish" communication that deals with if-none-match. My question is
whether it was considered making an option for doing this on "varnish
<-> backend" communication as well since it seems like a reasonable way
to validate objects in the cache during lookups. Does the varnish
project have a (official or unofficial) policy regarding doing
backend communication with conditions?

Thanks.

-Joe


On Fri, 9 Oct 2009 19:06:55 -0300
Rogério Schneider <stockrt at gmail.com> wrote:

> 2009/10/9 Joe Williams <joe at joetify.com>:
> >
> > Has is been considered doing this with the backend servers rather
> > than the client? Basically to re-validate objects in the cache? A
> > request hits varnish, varnish requests the backend with an
> > if-none-match header and the backend replies with either a 200 or
> > 304. This way the client does not need to know anything of etags,
> > the cache is always up to date for commonly requested objects and
> > the backend won't need to produce the content if the object in the
> > cache is the most recent.
> 
> Take a look at:
> 
> http://varnish.projects.linpro.no/changeset/4294
> 
> The change was made to the "client <-> varnish" communication, not
> "varnish <-> backend". This later communication is, AFAIK, always done
> without conditionals.
> 
> Regards,


-- 
Name: Joseph A. Williams
Email: joe at joetify.com
Blog: http://www.joeandmotorboat.com/