Re: [apps-discuss] HTTP header field for "URI lifetime"
Herbert Van de Sompel <hvdsomp@gmail.com> Wed, 20 May 2015 14:42 UTC
Return-Path: <hvdsomp@gmail.com>
X-Original-To: apps-discuss@ietfa.amsl.com
Delivered-To: apps-discuss@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 265901A8789 for <apps-discuss@ietfa.amsl.com>; Wed, 20 May 2015 07:42:42 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: 0.7
X-Spam-Level:
X-Spam-Status: No, score=0.7 tagged_above=-999 required=5 tests=[BAYES_50=0.8, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, SPF_PASS=-0.001] autolearn=ham
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id inClR-EKIPvZ for <apps-discuss@ietfa.amsl.com>; Wed, 20 May 2015 07:42:40 -0700 (PDT)
Received: from mail-oi0-x22c.google.com (mail-oi0-x22c.google.com [IPv6:2607:f8b0:4003:c06::22c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id EFA031A8787 for <apps-discuss@ietf.org>; Wed, 20 May 2015 07:42:39 -0700 (PDT)
Received: by oica37 with SMTP id a37so37637547oic.0 for <apps-discuss@ietf.org>; Wed, 20 May 2015 07:42:39 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=26bvRDDhEcGW+5uSDSn4WWBH7AztjIFhht2eLiqbMYo=; b=zA4p8h7zTWF7zRkwY5FUKCwHy0IjU5D7rXkSrf82IGchvp1S4zG//ngHnrpF/rKzcc +M03zdRaGb/hpl2fSKEUctkmw6vNOVRQYpJfiWpLRdzRWbUk/zo5Yijyfz0EYGXySleJ kTVbqXkKXU+fHaWZTtmIIAKNz3FQ+IMrvFR8vFOrmlt/64JzEVTcbnD7/rfhH1R0Zbr3 itLqeIGZrg3IFch9SLUxZZPVUawskP5kcMo8FRsFK6xYawtvJ6ZmzdxV1YQ+fVMxDYOc 7BLCE6jTMMauTY1EFVWMNSkox/eJKiaul/haz4NEFgUZMZ09w40kZzqcZlKK9rp9+lL8 QJGg==
MIME-Version: 1.0
X-Received: by 10.60.39.65 with SMTP id n1mr29204075oek.31.1432132959327; Wed, 20 May 2015 07:42:39 -0700 (PDT)
Received: by 10.202.192.137 with HTTP; Wed, 20 May 2015 07:42:39 -0700 (PDT)
In-Reply-To: <555C46AD.2080006@berkeley.edu>
References: <555C284E.1030208@berkeley.edu> <0AD556BB-614D-47D0-8509-C8670E01E82B@mnot.net> <555C46AD.2080006@berkeley.edu>
Date: Wed, 20 May 2015 08:42:39 -0600
Message-ID: <CAOywMHd1zv2rG-YC+733kVHP=-+zB+AeiMFDUaGQ-7L89m1YtA@mail.gmail.com>
From: Herbert Van de Sompel <hvdsomp@gmail.com>
To: Erik Wilde <dret@berkeley.edu>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Archived-At: <http://mailarchive.ietf.org/arch/msg/apps-discuss/Xu7KT2Zs4CJKoJubw8Ryv3fFRlA>
Cc: Mark Nottingham <mnot@mnot.net>, Herbert Van de Sompel <hvdsomp@gmail.com>, IETF Apps Discuss <apps-discuss@ietf.org>
Subject: Re: [apps-discuss] HTTP header field for "URI lifetime"
X-BeenThere: apps-discuss@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: General discussion of application-layer protocols <apps-discuss.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/apps-discuss>, <mailto:apps-discuss-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/apps-discuss/>
List-Post: <mailto:apps-discuss@ietf.org>
List-Help: <mailto:apps-discuss-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/apps-discuss>, <mailto:apps-discuss-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 20 May 2015 14:42:42 -0000
hi, (Thanks for cc-ing me) Rather interesting. Indeed, it is not directly related to Memento; the Memento-Datetime header is for expressing that a resource has been "frozen" at the datetime that is conveyed as the header value, i.e. it entails a promise that the resource will not change beyond the expressed datetime. The way I understand what you are discussing, this is about a header that indicates that a URI will no longer be existent starting at a certain date, ie past that date one can expect a 404 or similar bad news. But there is a relation with a possible web archiving use case: if a web archiving client comes across a URI-R that indicates its extinction datetime, then the client could make it a priority to crawl that URI-R and archive its representation at URI-M in a web archive. Using Memento, URI-M would then have a HTTP link with relation type "original" pointing at URI-R. Even when URI-R is gone, using Memento, URI-R could still be used to access archived snapshots of URI-R such as URI-M. Magic :-) I am thinking that this could be particularly useful for shortened URIs, many of which - as we know - aren't long lasting and the minters of those URIs are very much aware of that. If these minters would convey their short term URI retention strategy using a header, then applications that consume/mine tweets and resources linked in tweets (there's a lot of research in this realm) could optimize their data collecting strategy by taking the URI expiration date into account. Cheers Herbert On Wed, May 20, 2015 at 2:32 AM, Erik Wilde <dret@berkeley.edu> wrote: > hello mark. > > On 2015-05-20 08:50, Mark Nottingham wrote: >> >> On 20 May 2015, at 4:23 pm, Erik Wilde <dret@berkeley.edu> wrote: >>> >>> we had some discussions at www2015 about a possible HTTP header for >>> exposing a URI's "lifetime". please do not get hung up on any terminology, >>> but the scenarios we discussed included: >> >> Hm. It's come up before, and there's a legitimate distinction between this >> (which is about the resource) and Expires (which is about a specific >> representation). > > > we were specifically not interested in the caching mechanisms, because like > you say, these are about the "lifetime of the resource state", and not about > the resource as such. > >> However, I'm having trouble seeing how it would be useful to clients — can >> you illustrate the use cases a little more fully? > > > so, one thing from my own experience is retention in content management: > there are many scenarios where some data needs to be kept around for > regulatory reasons for a certain period of time, and then it can and maybe > will be removed. that's a fairly large category of scenarios. > > another one was decommissioning of services: at some point, a decision may > be made to take down a service at some point in time. if this could be made > visible in the uniform interface, then clients having awareness of this > would have an easier time to maybe alert users. for some time, these > services may still operate but redirect, and that at some time they may > disappear completely. > >> What will a client do with that information? > > > that depends on the client. services might simply raise alarms that some of > the resources they are using are about to disappear. clients such as > browsers may alert users that bookmarks are going to expire and encourage > users to maybe check for redirects, or archive the page before it > disappears. > >> Given that this necessarily requires someone to predict the future and >> make some level of commitment to that, it may be that the information it >> conveys is of very limited use — i.e., people won't trust it :) > > > retention and decommissioning are relatively reliable ways to predict the > future, but of course in many other cases there is no such mechanism. and of > course this is more a hint than anything else, but it may be a hint worth > having in the uniform interface. > >>> - a service doing archiving and wanting to expose that resources will >>> only be kept until a certain time, and then disposed. >> >> This seems somewhat related to Memento; CC:ing Herbert for his comment / >> information. > > > yes, we did talk about memento. this just seemed to be way more than what we > were discussing, and mostly revolve around the scenario of how to expose > archived information ("looking into the past"), and not so much about just > looking, as you said it, "into the future", > > thanks and cheers, > > > dret. > > -- > erik wilde | mailto:dret@berkeley.edu - tel:+1-510-2061079 | > | UC Berkeley - School of Information (ISchool) | > | http://dret.net/netdret http://twitter.com/dret | -- Herbert Van de Sompel Digital Library Research & Prototyping Los Alamos National Laboratory, Research Library http://public.lanl.gov/herbertv/ ==
- [apps-discuss] HTTP header field for "URI lifetim… Erik Wilde
- Re: [apps-discuss] HTTP header field for "URI lif… Mark Nottingham
- Re: [apps-discuss] HTTP header field for "URI lif… Karl Dubost
- Re: [apps-discuss] HTTP header field for "URI lif… Erik Wilde
- Re: [apps-discuss] HTTP header field for "URI lif… Erik Wilde
- Re: [apps-discuss] HTTP header field for "URI lif… Graham Klyne
- Re: [apps-discuss] HTTP header field for "URI lif… Erik Wilde
- Re: [apps-discuss] HTTP header field for "URI lif… Graham Klyne
- Re: [apps-discuss] HTTP header field for "URI lif… Herbert Van de Sompel