Re: A new HTTP response code say 209

John Arwe, who is one of the editors on the LDP spec, has proposed a solution
to the paging return code issue which the WG has endorsed.  Please take a look and comment:

We use 303; if the client doesn't do anything special, they get the second round trip, using base HTTP (2616 and/or bis).  If they add Prefer return=representation, then the client has specifically authorized new behavior, and (if honored) it can know that the response representation is a representation of the resource whose URI is given by the Location header.  The Preference-Applied response header would be Required in this case, because 303 already allows a response entity body (description in next "bullet").

Which gets me back to "why =representation instead of =minimal is important"... because a 'minimal' response to a 303 is no entity body (if you ignore the Should in 303) or an entity body that 2616 and bis describe this way: the entity of the response SHOULD contain a short hypertext note with a hyperlink to the new URI(s).  So a minimal response is not a representation; the excerpt above on modifications provides other similar examples.  We know we want a representation back, saying that seems like the better choice even though we've all been thinking of its LDP usage in terms of how to reduce the size of the representation.
All the best, Ashok

On 1/9/2014 11:08 AM, Julian Reschke wrote:
> On 2014-01-09 17:04, Henry S. Thompson wrote:
>> Julian Reschke writes:
>>
>>> On 2014-01-09 12:57, Henry S. Thompson wrote:
>>>> Right -- to short-circuit this, in the TAG f2f this morning, I offered
>>>> the following paraphrase for the 2xx proposal:
>>>>
>>>>     A 2xx response code signals all and only the short-circuiting of a
>>>>     303 response, with the content of what a GET to the Location header
>>>>     of the 303 would have had, and a Content-location header giving what
>>>>     would have been the Location of the 303.
>>>>
>>>> So no new 'semantics', in the sense that whatever you believe 303
>>>> means wrt what the relation between what you originally asked for, and
>>>> what you _eventually_ get, holds for 2xx between what you originally
>>>> asks for and what you get _immediately_.
>>>> ...
>>>
>>> I don't believe a new 2xx works for this case.
>>>
>>> Existing clients will interpret an unknown 2xx as 200 (at least that's
>>> what they should do), so they would interpret the response as being
>>> for the request-URI, not something else.
>>
>> Why, if there's a Content-location header?  They are supposed to
>> understand this wrt conneg, right?
>
> Content-Location just indicates that there is a more specific URI, but it doesn't change the fact that you got a representation of the resource identified by the request-URI.
>
> (see <http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p2-semantics-25.html#header.content-location>)
>
> Best regards, Julian
>
>