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Date: Tue, 22 Jul 2008 11:06:47 +0200
Old-From: Stephane Bortzmeyer <bortzmeyer@nic.fr>
To: Michelle Cotton <michelle.cotton@icann.org>, iana@iana.org
Cc: bortzmeyer@nic.fr
Old-Subject: Modification date of IANA registries now misleading (Was: IANA
	Update: Project to convert registries to XML
Message-ID: <20080722090647.GA31384@nic.fr>
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Subject: Modification date of IANA registries now misleading (Was: IANA
	Update: Project to convert registries to XML
From: Stephane Bortzmeyer <bortzmeyer@nic.fr>

On Mon, Jul 14, 2008 at 03:04:07PM -0700,
 Michelle Cotton <michelle.cotton@icann.org> wrote 
 a message of 115 lines which said:

> As first announced in April 2008, IANA is improving the formatting
> of its protocol registries by migrating the source format of these
> registries to structured XML format.

The change had an unexpected side-effect: registries which have *not*
been modified (such as the Language Subtag Registry,
http://www.iana.org/assignments/language-subtag-registry) now have a
Last-Modified of today (the file seems to be recreated each day).

For instance, the Language Subtag Registry has:

  Last-Modified: Tue, 22 Jul 2008 08:10:08 GMT

while its last modification is from 2008-05-07.

This breaks "conditional GET", a feature of HTTP which is very useful
to avoid overloading the IANA servers. For instance, this requests
used to download the registry only if it were new:

curl --silent --output language-subtag-registry.TMP --compressed \
  --referer http://ltru.generic-nic.net/ --proxy '' --time-cond 20080507
  -- http://www.iana.org/assignments/language-subtag-registry

but it now downloads it each time I run it.

Do note that the successor of RFC 4646 will make this registry ten
times bigger and so the issue is serious.

]