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Re: Static? Dynamic?

From: John Martin <jmartin@netapp.com>
Date: Tue, 6 Jul 1999 08:18:28 -0400 (EDT)
Message-Id: <>
To: koen@win.tue.nl (Koen Holtman), www-talk@w3.org
At 12:21 PM 06/07/99 +0200, Koen Holtman wrote:
>I disagree.  Expires information being sent by servers is only
>cache-friendly if the server operator actually spent some time
>thinking about what the expires value should be.

I'm suggesting that the mod_expires module is compiled in as my 
understanding is that it will allow Apache to at least send an Expires 
header. The content of that header is another matter.

>Preconfiguring some Expires default into Apache is worse than useless.
>It will probably lead to proxy cache operators having to distinguish
>between a) Expires headers that were configured explicitely by server
>operators, which can thus be trusted, and b) Expires headers sent by
>default with the server operators unaware of it, which can thus not be

So the issue is whether you would prefer the proxy to guess based on 
default information or no information at all. I would prefer default, so 
long as the defaults were set correctly. E.g. in most* cases, URIs ending 
'.gif' are cacheable for some period of time.

[*If they are not, e.g. for stock-ticker applications, they usually already 
have an Expires header OR the URI itself changes. (The latter appears most 

Since, as a cache operator, most of my hits come from a relatively small 
number of objects, and the highest byte hit rate comes from gif/jpg 
objects, a default would at least let me cache the object for a short 
period of time. If the object is popular, I don't mind needing to verify it 
- or re-retrieve it - even fairly regularly.

>If the server operator does not configure anything explicitely, then
>proxy cache operators are in a better position to make up an
>appropriate default than the Apache group.

Well, this does not conflict with my desire to have the *option* compiled 
in. (i.e. it currently doesn't even appear in the config file unless it is 
compiled in).


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Received on Tuesday, 6 July 1999 08:31:46 UTC

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