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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: <4.2.0.58.19990706140225.00cc0340@pop.netapp.com>
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
>trusted.

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 
common)]

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).

John

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

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