Re: p6: Returning the freshest response

Mark Nottingham <mnot@mnot.net> Fri, 29 March 2013 22:12 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 63C9421F9593 for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Fri, 29 Mar 2013 15:12:58 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -9.219
X-Spam-Level:
X-Spam-Status: No, score=-9.219 tagged_above=-999 required=5 tests=[AWL=1.380, BAYES_00=-2.599, RCVD_IN_DNSWL_HI=-8]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Z2qpMQzXgkVx for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Fri, 29 Mar 2013 15:12:57 -0700 (PDT)
Received: from frink.w3.org (frink.w3.org [128.30.52.56]) by ietfa.amsl.com (Postfix) with ESMTP id D8F3421F9015 for <httpbisa-archive-bis2Juki@lists.ietf.org>; Fri, 29 Mar 2013 15:12:56 -0700 (PDT)
Received: from lists by frink.w3.org with local (Exim 4.72) (envelope-from <ietf-http-wg-request@listhub.w3.org>) id 1ULhX2-0008RA-0E for ietf-http-wg-dist@listhub.w3.org; Fri, 29 Mar 2013 22:12:20 +0000
Resent-Date: Fri, 29 Mar 2013 22:12:20 +0000
Resent-Message-Id: <E1ULhX2-0008RA-0E@frink.w3.org>
Received: from maggie.w3.org ([128.30.52.39]) by frink.w3.org with esmtp (Exim 4.72) (envelope-from <mnot@mnot.net>) id 1ULhWq-0008PB-VT for ietf-http-wg@listhub.w3.org; Fri, 29 Mar 2013 22:12:08 +0000
Received: from mxout-07.mxes.net ([216.86.168.182]) by maggie.w3.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.72) (envelope-from <mnot@mnot.net>) id 1ULhWo-0007gB-Dk for ietf-http-wg@w3.org; Fri, 29 Mar 2013 22:12:08 +0000
Received: from [192.168.1.80] (unknown [118.209.42.8]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by smtp.mxes.net (Postfix) with ESMTPSA id 83F2E22E253; Fri, 29 Mar 2013 18:11:43 -0400 (EDT)
Content-Type: text/plain; charset="us-ascii"
Mime-Version: 1.0 (Mac OS X Mail 6.3 \(1503\))
From: Mark Nottingham <mnot@mnot.net>
In-Reply-To: <CABkgnnVtiRV0HNAY04nyD+h=0BEWt1ACCtGZSPNxgZ-cS9M=xA@mail.gmail.com>
Date: Sat, 30 Mar 2013 09:11:38 +1100
Cc: Ken Murchison <murch@andrew.cmu.edu>, HTTP Working Group <ietf-http-wg@w3.org>, Roy Fielding <fielding@gbiv.com>, "Julian F. Reschke" <julian.reschke@gmx.de>
Content-Transfer-Encoding: quoted-printable
Message-Id: <458FCCFB-E5B0-4A9A-8CCD-BEFCBA8E1BC2@mnot.net>
References: <E56A5FA7-555D-4283-95A1-FD0030D4616A@mnot.net> <5155B23A.2050002@andrew.cmu.edu> <CABkgnnUc+CxTUfVvxsyJnG6pemkTpC9Z+3bQeaZbfnAdALZEtQ@mail.gmail.com> <5155BB1C.1020703@andrew.cmu.edu> <CABkgnnVtiRV0HNAY04nyD+h=0BEWt1ACCtGZSPNxgZ-cS9M=xA@mail.gmail.com>
To: Martin Thomson <martin.thomson@gmail.com>
X-Mailer: Apple Mail (2.1503)
Received-SPF: pass client-ip=216.86.168.182; envelope-from=mnot@mnot.net; helo=mxout-07.mxes.net
X-W3C-Hub-Spam-Status: No, score=-3.4
X-W3C-Hub-Spam-Report: AWL=-3.363, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001
X-W3C-Scan-Sig: maggie.w3.org 1ULhWo-0007gB-Dk 96aa6527bfffee85f97fe7507b941c02
X-Original-To: ietf-http-wg@w3.org
Subject: Re: p6: Returning the freshest response
Archived-At: <http://www.w3.org/mid/458FCCFB-E5B0-4A9A-8CCD-BEFCBA8E1BC2@mnot.net>
Resent-From: ietf-http-wg@w3.org
X-Mailing-List: <ietf-http-wg@w3.org> archive/latest/17181
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>

On 30/03/2013, at 3:39 AM, Martin Thomson <martin.thomson@gmail.com> wrote:

> On 29 March 2013 09:02, Ken Murchison <murch@andrew.cmu.edu> wrote:
>> The current language in
>> https://svn.tools.ietf.org/svn/wg/httpbis/draft-ietf-httpbis/latest/p2-semantics.html#proactive.negotiation
>> (MAY) and
>> https://svn.tools.ietf.org/svn/wg/httpbis/draft-ietf-httpbis/latest/p2-semantics.html#header.vary
>> (SHOULD)
>> don't seem to make it a requirement.  However, the SHOULD certainly suggests
>> best practice.
> 
> I think that this might trigger a review comment:
> 
> The MAY is spurious, no 2119 language is needed here: the text need
> only highlight that it is possible (as opposed to permissible) for a
> Vary header to be present.

There seem to be a lot of MAYs in p2; some of them are mostly harmless, but this one seems to be actively misleading. Roy, Julian?


> The SHOULD is qualified sufficiently that I believe that a MUST is
> more appropriate.

The requirement is of the form "SHOULD... unless...", with the clause:

> , unless the variance cannot be crossed or the origin server has been deliberately configured to prevent cache transparency.

so I think this one is OK.


Cheers,


--
Mark Nottingham   http://www.mnot.net/