Re: minimum-cache time?+

From: Christian Balzer <>
Date: Sun, 27 Oct 1996 11:39:08 +0100 (MET)

Miguel A.L. Paraz wrote:
>> Yup, that would be very nice, but to make any really intelligent guesses
>> as to how often you want these to be refreshed, you need Last Modified
>> headers for calculations and/or IMS requests.
>But if you honor the Expires: immediately, you should never cache it.
>And, the Microsoft header doesn't have Last-Modified.
Well, I guess there are two things to consider here:

1. Objects with short expire values, which can be quite reasonable in
fast changing page. For these I'd like to see an option which changes
the forcible reload into an IMS request, so if nothing changed, nothing
has to be fetched. ^_^
Of course this fails if no Last Modified headers are available, so we
also need...

2. If there are sites which make caching really hard on us, even if
they don't change (all) their date so frequently, we need some ways to
define sensible TTL/Refresh values for them, which should be fairly
easy with the current pattern mechanism.

>How about
>these Squid configuration directives:
>acl noncacheable
>must_cache noncacheable
>Which will ignore cache-control, Expires: immediately, and the like.
>Or, is it a HTTP protocol violation?
It might be a violation, but so is this foul game for hits they play.
Alas your suggestion lacks a method to define how long you want to
chache these... ^_-

>> Which reminds me to ask (and to point this out to Duane, as his
>> URL is affected by this as
>> well), how does one get Apache to generate valid Last Modified headers
>> for directory listings like these? CERN does it right and uses the
>> directory date, but Apache just leaves things blank, thus resulting in
>> stale data ever so often. :(
>Yeah, I checked it out, and that is so. I'll see how easy/hard it is
>to add it to Apache, so it could be out before 1.2. Great way to
>exercise my C skills... :)
Hehehehehe, thank you!

Mata ne,


  // <CB> aka Christian Balzer, Tannenstr. 23c, D-64342 Seeheim, Germany
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Received on Sun Oct 27 1996 - 02:40:09 MST

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