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Re: Static? Dynamic?

From: Patrick McManus <mcmanus@appliedtheory.com>
Date: Tue, 6 Jul 1999 08:36:52 -0400 (EDT)
Message-Id: <199907061236.IAA26618@justice.atc-bos.com>
To: koen@win.tue.nl (Koen Holtman)
Cc: jmartin@netapp.com, connolly@w3.org, mcmanus@appliedtheory.com, roconnor@uwaterloo.ca, www-talk@w3.org, jigsaw@w3.org
In a previous episode Koen Holtman said...
:: John Martin:
:: >
:: >At 12:13 PM 30/06/99 -0500, Dan Connolly wrote:
:: >>I wonder what it would take to get the server installations
:: >>to have more cache-friendly defaults.
:: >
:: >I think the only way forward is to ensure that the default settings in all 
:: >server implementations are cache-friendly. (e.g. in the case of Apache, 
:: >that would mean that mod_expires became compiled in by default.)
:: 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 think I agree with what you mean, and disagree with what you said.

mod_expires actually has to be *both* compiled into apache (using a
refence on the ./configure line to a C file..) and turned on with the
ExpiresActive directive *and* have a value set for the file to be
served either via the ExpiresDefault or ExpiresByType directives.. 

for what passes for a 'webmaster' these days that's quite a hurdle and
the benefits of doing so aren't obvious.. Doing the first two
(compiling it in by default and implying ExpiresActive) would not
change any HTTP semantics unless the actual Expire rule was set by the

However, that's essentially the situation that Netscape and IIS leave
the admin in, and the option isn't widely used in those servers
either, so it really isn't that simple.

I'm not sure what can be done to teach content providers the value of
good expiry info. If they think of it at all, it's usually 'how do I
force a cache to skip over me?'.. and it's definitely a thing that
needs an economy of scale to be real worthwhile..

I suspect that it will come from pressure applied by access providers
as they enforce cache policies more and more the ramifications will
push content providers into thinking a little bit that way too.. the
irony is that the benefits are just as big (if not bigger) for the
content provider.

Received on Tuesday, 6 July 1999 08:37:01 UTC

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