Re: Delta Compression and UTF-8 Header Values

"Poul-Henning Kamp" <phk@phk.freebsd.dk> Fri, 08 February 2013 19:51 UTC

Return-Path: <ietf-http-wg-request@listhub.w3.org>
X-Original-To: ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com
Delivered-To: ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 41C5021F8B96 for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Fri, 8 Feb 2013 11:51:58 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -10.514
X-Spam-Level:
X-Spam-Status: No, score=-10.514 tagged_above=-999 required=5 tests=[AWL=-0.067, BAYES_00=-2.599, RCVD_IN_DNSWL_HI=-8, SARE_SUB_ENC_UTF8=0.152]
Received: from mail.ietf.org ([64.170.98.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Gboq6+0ezFzZ for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Fri, 8 Feb 2013 11:51:57 -0800 (PST)
Received: from frink.w3.org (frink.w3.org [128.30.52.56]) by ietfa.amsl.com (Postfix) with ESMTP id 8ABB421F8B81 for <httpbisa-archive-bis2Juki@lists.ietf.org>; Fri, 8 Feb 2013 11:51:57 -0800 (PST)
Received: from lists by frink.w3.org with local (Exim 4.72) (envelope-from <ietf-http-wg-request@listhub.w3.org>) id 1U3tyX-0006Cf-DP for ietf-http-wg-dist@listhub.w3.org; Fri, 08 Feb 2013 19:51:09 +0000
Resent-Date: Fri, 08 Feb 2013 19:51:09 +0000
Resent-Message-Id: <E1U3tyX-0006Cf-DP@frink.w3.org>
Received: from lisa.w3.org ([128.30.52.41]) by frink.w3.org with esmtp (Exim 4.72) (envelope-from <phk@phk.freebsd.dk>) id 1U3tyQ-0006C0-PT for ietf-http-wg@listhub.w3.org; Fri, 08 Feb 2013 19:51:02 +0000
Received: from phk.freebsd.dk ([130.225.244.222]) by lisa.w3.org with esmtp (Exim 4.72) (envelope-from <phk@phk.freebsd.dk>) id 1U3tyP-00076U-TL for ietf-http-wg@w3.org; Fri, 08 Feb 2013 19:51:02 +0000
Received: from critter.freebsd.dk (critter.freebsd.dk [192.168.61.3]) by phk.freebsd.dk (Postfix) with ESMTP id D43EA89FCD; Fri, 8 Feb 2013 19:50:40 +0000 (UTC)
Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.14.5/8.14.5) with ESMTP id r18JoeKH006527; Fri, 8 Feb 2013 19:50:40 GMT (envelope-from phk@phk.freebsd.dk)
To: James M Snell <jasnell@gmail.com>
cc: "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
In-reply-to: <CABP7Rbd7bck4czG9c84hLeAHMnbeqb1mYhS+-DKKtZYEyia=6A@mail.gmail.com>
From: Poul-Henning Kamp <phk@phk.freebsd.dk>
References: <CABP7RbfRLXPpL4=wip=FvqD3DM7BM8PXi7uRswHAusXUmPO_xw@mail.gmail.com> <6372.1360352116@critter.freebsd.dk> <CABP7Rbd7bck4czG9c84hLeAHMnbeqb1mYhS+-DKKtZYEyia=6A@mail.gmail.com>
Date: Fri, 08 Feb 2013 19:50:40 +0000
Message-ID: <6526.1360353040@critter.freebsd.dk>
Received-SPF: none client-ip=130.225.244.222; envelope-from=phk@phk.freebsd.dk; helo=phk.freebsd.dk
X-W3C-Hub-Spam-Status: No, score=-3.4
X-W3C-Hub-Spam-Report: AWL=-3.372, RP_MATCHES_RCVD=-0.001
X-W3C-Scan-Sig: lisa.w3.org 1U3tyP-00076U-TL 5a694f8b6f42eff908d5a1079311f762
X-Original-To: ietf-http-wg@w3.org
Subject: Re: Delta Compression and UTF-8 Header Values
Archived-At: <http://www.w3.org/mid/6526.1360353040@critter.freebsd.dk>
Resent-From: ietf-http-wg@w3.org
X-Mailing-List: <ietf-http-wg@w3.org> archive/latest/16470
X-Loop: ietf-http-wg@w3.org
Resent-Sender: ietf-http-wg-request@w3.org
Precedence: list
List-Id: <ietf-http-wg.w3.org>
List-Help: <http://www.w3.org/Mail/>
List-Post: <mailto:ietf-http-wg@w3.org>
List-Unsubscribe: <mailto:ietf-http-wg-request@w3.org?subject=unsubscribe>

Content-Type: text/plain; charset=ISO-8859-1
--------
In message <CABP7Rbd7bck4czG9c84hLeAHMnbeqb1mYhS+-DKKtZYEyia=6A@mail.gmail.com>
, James M Snell writes:
>On Fri, Feb 8, 2013 at 11:35 AM, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:

>>>So the question is: do we want to allow UTF-8 header values?
>>
>> Jim Gettys famously laid down some principles for X11 development,
>> number 1 and 3 of which are:
>>
>>         1.Do not add new functionality unless an implementor cannot
>>           complete a real application without it.

>AFAIC, the main motivation for allowing UTF-8 headers is to reduce
>(and *eventually* eliminate) the need for
>punycode/pct-encoding/B-codec/Q-codec/RFC5987.

I guess the relevant question then is: Are these headers where it
is necessary for HTTP entities to understand the value (ie:
"Cache-Control", "Location" etc, ) or headers which are just
transported transparently from end to end ("X-FOObar", "Cookie"
etc.)

In the latter case, supporting UTF-8 is merely a matter of letting
another bit through per byte, in the former case it opens a major
bucket of worms IMO.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.