Re: pragma no-cache -- Can we make it more useful?
Mon, 18 Jul 1994 16:18:20 +0200
> Assuming all of these optimizations:
> client GETs document, but this is routed via proxy cache
> if expired(cached_document)
> proxy GETs/If-Modified "/cgi-bin/changes" at original server
> if (original_mod_date > cached_mod_date)
> proxy GETs/If-Modified document at original server
> put it in cache
> return cached_document
> This algorithm works against all servers.
It doesn't always work.
1. The proxy/cache may be a firewall and the original server is not reachable.
(or the original server may be down because it crashed under the load ;-)
2. It is inefficient, unnecessarily bothering the original server when all the
user wants is recent, but not necessarily the absolute latest version.