Re: pragma no-cache -- Can we make it more useful?
karl@cavebear.com
Thu, 14 Jul 94 12:54:10 PDT
> Assuming all of these optimizations:
>
> client GETs document, but this is routed via proxy cache
>
> if expired(cached_document)
> then
> proxy GETs/If-Modified "/cgi-bin/changes" at original server
>
> if (original_mod_date > cached_mod_date)
> then
> proxy GETs/If-Modified document at original server
> put it in cache
> endif
> endif
>
> 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.
--karl--