Re: [Ltru] Issue 181, was: Issue 113 (language tag matching (Accept-Language) vs RFC4647), was: Proposed resolution for Issue 13 (language tags)

John Cowan <cowan@ccil.org> Mon, 27 July 2009 17:33 UTC

Return-Path: <cowan@ccil.org>
X-Original-To: ltru@core3.amsl.com
Delivered-To: ltru@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 0F8D23A6CE0 for <ltru@core3.amsl.com>; Mon, 27 Jul 2009 10:33:35 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3.949
X-Spam-Level:
X-Spam-Status: No, score=-3.949 tagged_above=-999 required=5 tests=[AWL=-1.350, BAYES_00=-2.599]
Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 0n58cXecC3kU for <ltru@core3.amsl.com>; Mon, 27 Jul 2009 10:33:33 -0700 (PDT)
Received: from earth.ccil.org (earth.ccil.org [192.190.237.11]) by core3.amsl.com (Postfix) with ESMTP id 4C8C93A6CC6 for <ltru@ietf.org>; Mon, 27 Jul 2009 10:33:30 -0700 (PDT)
Received: from cowan by earth.ccil.org with local (Exim 4.63) (envelope-from <cowan@ccil.org>) id 1MVU3i-0000zh-H5; Mon, 27 Jul 2009 13:32:22 -0400
Date: Mon, 27 Jul 2009 13:32:22 -0400
To: "Phillips, Addison" <addison@amazon.com>
Message-ID: <20090727173222.GF32524@mercury.ccil.org>
References: <48037FF9.9030103@gmx.de> <48049274.3090501@gmx.de> <4A61B8B7.7030200@gmx.de> <4D25F22093241741BC1D0EEBC2DBB1DA01AB843B4F@EX-SEA5-D.ant.amazon.com> <4A61F5C2.3050906@gmx.de> <4D25F22093241741BC1D0EEBC2DBB1DA01AB843BEE@EX-SEA5-D.ant.amazon.com> <4A6D9396.5020506@gmx.de> <4D25F22093241741BC1D0EEBC2DBB1DA01ABD5D45E@EX-SEA5-D.ant.amazon.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4D25F22093241741BC1D0EEBC2DBB1DA01ABD5D45E@EX-SEA5-D.ant.amazon.com>
User-Agent: Mutt/1.5.13 (2006-08-11)
From: John Cowan <cowan@ccil.org>
Cc: Julian Reschke <julian.reschke@gmx.de>, LTRU Working Group <ltru@ietf.org>, HTTP Working Group <ietf-http-wg@w3.org>
Subject: Re: [Ltru] Issue 181, was: Issue 113 (language tag matching (Accept-Language) vs RFC4647), was: Proposed resolution for Issue 13 (language tags)
X-BeenThere: ltru@ietf.org
X-Mailman-Version: 2.1.9
Precedence: list
List-Id: Language Tag Registry Update working group discussion list <ltru.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/listinfo/ltru>, <mailto:ltru-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/ltru>
List-Post: <mailto:ltru@ietf.org>
List-Help: <mailto:ltru-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ltru>, <mailto:ltru-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 27 Jul 2009 17:33:35 -0000

Phillips, Addison scripsit:

> I tend to think that HTTP's requirements are most like what the
> Lookup algorithm provides. That is, you can (and must) return
> exactly one result for a given request. 

Actually, no; that's an oversimplification of HTTP.  The whole point of
the error code 300 Multiple Choices is that the server has determined
that more than one resource satisfies the prescriptions of the Accept-*
headers as to the media types, charsets, content-encodings, and languages
specified as allowable by the client.  The body in that case will contain
hyperlinks to the original resources.

While this mechanism is not widely used in the Web today, it does serve
the intended purpose: servers can make different variants of pages
available, and clients see only the ones that they specify as meeting
their minimum requirements.

The question is, then, what to do if there is no resource that specifies
those minimum requirements.  Apache in this case applies the lookup algorithm
to loosen the client requirement in hopes of finding something usable.

-- 
Values of beeta will give rise to dom!          John Cowan
(5th/6th edition 'mv' said this if you tried    http://www.ccil.org/~cowan
to rename '.' or '..' entries; see              cowan@ccil.org
http://cm.bell-labs.com/cm/cs/who/dmr/odd.html)