Re: Last-Modified vs. Expires

dgaudet@arctic.org writes:

>Hi folks, this may be a bit off-topic.
>
>I'm trying to decide on how to weight some additions to features in Apache
>which assist in generating Last-Modified headers for dynamic html content.
>Others in the group argue that it's better to just use mod_expires and
>generate Expires: headers than it is to try to get a sane Last-Modified
>header.
>
>I'm curious, what works better with squid?

I think Expires would be preferable, and especially
if you can get long Expires values (e.g. days instead of minutes).

To turn the question around a bit, how does Apache handle IMS requests
for dynamic content? Would it use the same Last-Modified timestamp
to return 'not modified?'

On a similar subject, I would like to propose something....

I have recently been thinking it would be very good to be able
to mark a URL as "absolutely static." That is, the origin server
guarantees that the content will never change. So even if the
client issued a 'pragma: no-cache' or 'max-stale=0' in the request,
the cache could ALWAYS immediately return a hit for the object.
Of course, we would generally have HTML remain dynamic as it is
now, and apply the static feature to images and such.

This is one big difference between NNTP and HTTP. Usenet has quite
efficient distribution because each artcile is only transmitted once
between a pair of NNTP servers. Its certainly not the case with
the Web. This was all became very apparent during the Mars pathfinder
mission. It would have been so nice to be able to have JPL mark
all their images as static, which I'm quite sure they were anyway.

Duane W.
Received on Tue Jul 29 2003 - 13:15:42 MDT