Re: 2NN Contents Of Related (303 Shortcut)

[Mark Nottingham <[e-mail]>]

On 2 Sep 2014, at 6:00 pm, Eric Prud'hommeaux <[e-mail]> wrote:

> Sorry for the delayed response; moving house. Will try to be more
> attentive now.
> 
> * Mark Nottingham <[e-mail]> [2014-08-26 12:20+1000]
>> Eric,
>> 
>> We’re happy to discuss it here, but can’t commit to a schedule before that discussion has begun. 
>> 
>> For my part, I’m still not sure what the difference between the proposed status code is from 200 + Content-Location.
> 
> I think there are two ways this discussion could go:
> 
> We could ask questions like "Is /Index?page=1 a representation of
> /Index ?" and "What is the subject of the metadata in a 200+CL, the
> effective request URI or the CL?" The end result of these is that we
> evaluate the use cases for 303.
> 
> Another is that we say 303's exist and people use them and want to
> streamline their use. I believe that any approach to do so will find
> some way to say that the metadata in the response is about the target
> of the redirect. Is there a more graceful way to do that than 2NN?

Eric,

You haven’t answered the question; you’ve speculated on two different ways that the question might be answered.

Choose.




> 
>> Cheers,
>> 
>> 
>> On 26 Aug 2014, at 10:11 am, Eric Prud'hommeaux <[e-mail]> wrote:
>> 
>>> I understand people are busy, but is there a chance we can move forward
>>> on this? The subject has been extensively discussed on
>>> www-tag (as detailed below). The June I-D is at:
>>> http://tools.ietf.org/html/draft-prudhommeaux-http-status-2nn-00
>>> 
>>> Technical Summary:
>>> [[
>>> 2NN provides a shorcut the GET X->303 Location:Y, GET Y->200 pattern.
>>> For responses where the server would have responded with a Location
>>> header, it can instead respond with the payload of a notional GET on
>>> that location. The notional GET has all of the headers of the original
>>> request. This defines the behavior for conneg, Vary headers, caching,
>>> etc.
>>> ]]
>>> 
>>> There's a fairly thorough summary in the TAG's draft review:
>>> https://github.com/w3ctag/spec-reviews/blob/master/2014/04/http-209.md
>>> The issues in that document have been addressed in the I-D, but it
>>> does contain motivation for 2NN (especially with respect to Server
>>> Push).
>>> 
>>> The urgency here is that the W3C Linked Data Platform (LDP) Working
>>> Group, which first surfaced the need for this, will be ready to issue
>>> its formal "Call for Implementations" in mid-September.  At that
>>> point, people outside the LDP Working Group will begin writing code
>>> that uses this response code.
>>> 
>>> I understand there may still be some concerns. In the next few weeks,
>>> we'd like to try to address them or resolve that they are truly
>>> insurmountable. Is that reasonable?
>>> 
>>> I went throught the www-tag archives and added my own summary,
>>> underneath, for each message:
>>> -------------------------------------------------------------------------
>>> A new HTTP response code say 209                Dec 19 Tim Berners-Lee
>>> │                   use case for a 209
>>> ├─>Re: A new HTTP response code say 209         Dec 19 Daniel Appelquist
>>> │                   London f2f logistics
>>> ├─>Re: A new HTTP response code say 209         Dec 19 Julian Reschke
>>> │ │                 299 as placeholder
>>> │ │                 why not 303 or 202?
>>> │ └─>                                           Dec 20 Tim Berners-Lee
>>> │                   payload conflict of 303
>>> │                   202 for asynchronous
>>> │                   303 fine logically but requires round trip
>>> ├─>Re: A new HTTP response code say 209         Dec 20 Mark Nottingham
>>> │ │                 use media type instead?
>>> │ │                 HTTPbis 8.2.2.  Considerations for New Status Codes
>>> │ └─>                                           Jan 09 Henry Story
>>> │   │               media types describe representation, not resource
>>> │   ├─>                                         Jan 09 Henry S. Thompson
>>> │   │ │             define in terms of 303+200
>>> │   │ ├─>                                       Jan 09 Henry Story
>>> │   │ │ │           +1 but propose 3xx instead of 2xx
>>> │   │ │ └─>                                     Jan 09 David Sheets
>>> │   │ │   │         respond with message/http
>>> │   │ │   ├─>                                   Jan 09 David Booth
>>> │   │ │   │ │       broaden 209 to cover 300, 301, 302 and 307
>>> │   │ │   │ └─>                                 Jan 09 David Booth
>>> │   │ │   │         or 300, 301, 302 or 307 + multipart body
>>> │   │ │   └─>                                   Feb 13 Reto Gmür
>>> │   │ │             confuses clients interpreting 2xx as 200
>>> │   │ │             could work in 303
>>> │   │ ├─>Fwd: A new HTTP response code say 209  Jan 09 Jonathan A Reese
>>> │   │ │             no evidence that 200 has intended semantics in practice
>>> │   │ └─>                                       Jan 09 Julian Reschke
>>> │   │   │           use 3xx code. 2xx response would apply to request-URI
>>> │   │   └─>                                     Jan 09 Henry S. Thompson
>>> │   │     │         Content-location understood wrt conneg
>>> │   │     └─>                                   Jan 09 Julian Reschke
>>> │   │       │       says there's a more specific URI
>>> │   │       └─>                                 Feb 10 Ashok Malhotra
>>> │   │         │     Arwe: propose: 303 + Prefer: return=representation
>>> │   │         └─>                               Feb 13 Yves Lafon
>>> │   │               dangerous, changes 303, would need Vary: Prefer. 2xx more applicable
>>> │   └─>                                         Jan 09 Julian Reschke
>>> │                   wording of 303
>>> ├─>Re: A new HTTP response code say 209         Dec 19 Jonathan A Reese
>>> │                   note http://www.w3.org/2001/tag/doc/urls-in-data-2013-04-27/
>>> └─>draft of                                     Feb 24 Eric Prud'hommeaux
>>> │                 draft <http://localhost/2014/02/2xx/draft-prudhommeaux-http-status-209>
>>> ├─>Re: draft of 209 proposal                  Feb 24 David Booth
>>> │ │               URL correction
>>> │ └─>                                         Feb 24 Eric Prud'hommeaux
>>> │   │             ack
>>> │   └─>                                       Mar 17 Julian Reschke
>>> │     │           Conflates "see elsewhere" with "too large", how can client know which applies
>>> │     └─>                                     Mar 17 Eric Prud'hommeaux
>>> │                 all that HTTP cares is that the client requested X and got something other than X
>>> └─>                                           Mar 07 Mark Nottingham
>>>   │               why is 209 better than 200 with Content-Location for e.g. POST->303 and GET->303?
>>>   │               partial feeds is addressed in RFC5005
>>>   │               how does HTTP software behave differently?
>>>   ├─>                                         Mar 07 Julian Reschke
>>>   │               offer to help submit I-D
>>>   ├─>                                         Mar 07 Eric Prud'hommeaux
>>>   │ │             GET->303 requires a round trip
>>>   │ │             RFC5005 re-uses URL for a page of resource. requires syndication format (Atom)
>>>   │ │             ack, same-origin constraint insufficient for shared caches
>>>   │ ├─>                                       Mar 08 Julian Reschke
>>>   │ │             submit I-D via http://www.ietf.org/id-info/
>>>   │ ├─>                                       Mar 08 Jeni Tennison
>>>   │ │             TAGs use of URLs http://www.w3.org/TR/urls-in-data/ includes 303s
>>>   │ └─>                                       Mar 13 Mark Nottingham
>>>   │   │           not really a redirect so 200 with Content-Location should suffice
>>>   │   │           RFC5005 doesn't require URL re-use
>>>   │   │           why not embed paging info in served representations?
>>>   │   ├─>                                     Mar 13 Jonathan A Rees
>>>   │   │ │         Content-Location is a representation of requested resource
>>>   │   │ ├─>                                   Mar 16 Mark Nottingham
>>>   │   │ │ │       more details [on why Content-Location won't suffice]
>>>   │   │ │ └─>                                 Mar 15 Jonathan A Rees
>>>   │   │ │         [discussion of non-information resources]
>>>   │   │ └─>                                   Mar 17 Julian Reschke
>>>   │   │   │       is it OK that naive clients will treat 209 as 200?
>>>   │   │   └─>                                 Mar 17 Eric Prud'hommeaux
>>>   │   │           small survey examining behavior of such clients
>>>   │   └─>                                     Mar 15 Eric Prud'hommeaux
>>>   │     │         example differentiating page of resource from representation of resource
>>>   │     └─>                                   Mar 16 Mark Nottingham
>>>   │               HTTP doesn't enable one representation to make an authoritative assertion about another
>>>   └─>                                         Mar 07 Sandro Hawke
>>>     │             propose same-origin requirements for trusting 209 response
>>>     └─>                                       Mar 07 Eric Prud'hommeaux
>>>                   there are apparently different security reqs for client vs. proxies
>>>                   proxies may not be content with same-origin, client proxies likely more liberal
>>> 
>>> I believe Mark Nottingham remains concerned that 2NN's assertion about
>>> the representation of the Location resource is counter to HTTP.  The
>>> Linked Data Platform's paging spec presumes that clients will take
>>> advantage of the improved efficiency.
>>> -- 
>>> -ericP
>>> 
>>> 
>>> * Julian Reschke <[e-mail]> [2014-06-30 19:40+0200]
>>>> (FYI)
>>>> 
>>>> 
>>>> -------- Original Message --------
>>>> Subject: I-D Action: draft-prudhommeaux-http-status-2nn-00.txt
>>>> Date: Mon, 30 Jun 2014 09:08:17 -0700
>>>> From: [e-mail]
>>>> Reply-To: [e-mail]
>>>> To: [e-mail]
>>>> X-ArchivedAt: http://www.w3.org/mid/[e-mail]
>>>> 
>>>> 
>>>> A New Internet-Draft is available from the on-line Internet-Drafts
>>>> directories.
>>>> 
>>>> 
>>>>       Title           : The Hypertext Transfer Protocol (HTTP)
>>>> Status Code 2NN (Contents of Related)
>>>>       Author          : Eric G. Prud'hommeaux
>>>> 	Filename        : draft-prudhommeaux-http-status-2nn-00.txt
>>>> 	Pages           : 9
>>>> 	Date            : 2014-06-30
>>>> 
>>>> Abstract:
>>>>  This document specifies the additional HyperText Transfer Protocol
>>>>  (HTTP) Status Code 2NN (Contents of Related).  It also specified a
>>>>  Prefer header value "contents-of-related" which clients can use to
>>>>  indicate that they can accept 2NN responses.
>>>> 
>>>> 
>>>> The IETF datatracker status page for this draft is:
>>>> https://datatracker.ietf.org/doc/draft-prudhommeaux-http-status-2nn/
>>>> 
>>>> There's also a htmlized version available at:
>>>> http://tools.ietf.org/html/draft-prudhommeaux-http-status-2nn-00
>>>> 
>>>> 
>>>> Please note that it may take a couple of minutes from the time of submission
>>>> until the htmlized version and diff are available at tools.ietf.org.
>>>> 
>>>> Internet-Drafts are also available by anonymous FTP at:
>>>> ftp://ftp.ietf.org/internet-drafts/
>>>> 
>>>> _______________________________________________
>>>> I-D-Announce mailing list
>>>> [e-mail]
>>>> https://www.ietf.org/mailman/listinfo/i-d-announce
>>>> Internet-Draft directories: http://www.ietf.org/shadow.html
>>>> or ftp://ftp.ietf.org/ietf/1shadow-sites.txt
>>>> 
>>>> 
>>>> 
>>>> 
>>> 
>>> -- 
>>> -ericP
>>> 
>>> office: +1.617.599.3509
>>> mobile: [phone]
>>> 
>>> ([e-mail])
>>> Feel free to forward this message to any list for any purpose other than
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>>> 
>>> There are subtle nuances encoded in font variation and clever layout
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>>> 
>> 
>> --
>> Mark Nottingham   http://www.mnot.net/
>> 
>> 
>> 
> 
> -- 
> -ericP
> 
> office: +1.617.599.3509
> mobile: [phone]
> 
> ([e-mail])
> Feel free to forward this message to any list for any purpose other than
> email address distribution.
> 
> There are subtle nuances encoded in font variation and clever layout
> which can only be seen by printing this message on high-clay paper.

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