proxy_store help requested

[nginx_newbie_too]

Maxim, one last piece of advice requested. Would it be more proper to turn
off i-m-s in the request body (by setting proxy_pass_request_headers to off
in the downstream server configuration) instead of turning it off on the
upstream server?  I think that's more correct behavior, but I'm not sure.

Yes, proxy_cache simply works out of the box, and it's awesome. But I
couldn't understand how to use it so that the downstream server doesn't
naively GET content again from the upstream after the expiration time period
had passed. I would have wanted instead to only have the cache refreshed if
i-m-s suggested that the upstream content had changed.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,248241,248283#msg-248283