[Lula] Squid configuration/groking

[TheBlueSage]

Hi Folks,

Is there anyone out there with Squid knowledge, specifically using squid
as an accelerated caching web-server ? I am having .. understanding ..
issues ..

I have setup Squid in the following manner, to act as a caching
accelerator in front of our web server. We serve a lot of mashup pages
that take a lot of time to put together, but once constructed, never
change. Thus serving from a cached page should make the page delivery
really quick after the first request.

1. Put squid in front of the web server, have it answer the incoming
requests on port 80
2. If squid has a copy of a requested page, then send the copy. 
3. if not, then request it from the real domain server (apache on port
81), send the page, and cache it at the same time

Conundrum 
-----------------
The basic setup seems to be cool, but I run into issues with the fact
that some of my content has varying expire times. For example, we take
XML feeds from some supplier, and output content derived from the feeds.
However the feeds come in bursts. This means that for several days there
is no change, and the cache should spit out the copy it has,. Then, when
the feed comes, it updates the pages on an 'every 30 second' basis. I
still want those pages cached, with 30 second expirt times, as we will
serve it many times in that 30 second gap.Then, once the feed stops, the
last page should be cached until the feed starts again... at some
undetermined time in the future.
Most of what I have read says to use ACLs for what should and should not
be cached, but not much explains how to do the above .....

anyone out there hit this before ? Or if there is a better solution that
Squid, I am all ears. I have no special attachment to squid, it was
chosen through familiarity with its name as much as any other reason,

thanks for any help,

Richard