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claimed completion of ACTION-97 - proposal for pure-HTTP paging

From: Eric Prud'hommeaux <eric@w3.org>
Date: Sat, 21 Sep 2013 21:40:57 -0400
To: public-ldp-wg@w3.org
Message-ID: <20130922014055.GA19832@w3.org>
Find the <PROPOSAL/> 44 lines down.

TimBL's comment LC-2836 proposed moving page control out of the body
of an LDPR and into headers.
<https://www.w3.org/2006/02/lc-comments-tracker/55082/ldp/2836?cid=2836>

This buys us:
  • Potential reuse outside of LDPRs.
  • Unrestricted data in an LDPR (screw case: an LDPR which includes a
    page from another LDPR).

The first example in the LDP LC decribes how a GET on <resourceURL>
303's (now 208½'s?) to e.g. <resourceURL>?firstPage, or OPTIONS on
<resourceURL> yields:
  Link: <resourceURL>?firstPage; rel="first"
The content of <resourceURL>?firstPage includes client data plus this
paging data:

[[
<http://example.org/customer-relations?firstPage>
   a ldp:Page;
   ldp:pageOf <http://example.org/customer-relations>;
   ldp:nextPage <http://example.org/customer-relations?p=2>.
]] <http://www.w3.org/TR/ldp/#ldpr-PagingIntro> (can we have an anchor
   on the <div class="example"/> elements?)

The paging in this example is a singly-linked list split across HTTP
and the payload. We can move it all into HTTP (for the reasons above)
using link types defined in RFC5988 Web Linking:

first      - An IRI that refers to the furthest preceding resource in a
             series of resources.
last       - An IRI that refers to the furthest following resource in a
             series of resources.
previous   - Refers to the previous resource in an ordered series of
             resources
next       - Refers to the next resource in a ordered series of resources.

The type arc can come from RFC6903 Additional Link Relation Types:
type      - Refers to a resource identifying the abstract semantic
            type of which the link's context is considered to be an
            instance.


<PROPOSAL>
• GETs and OPTIONS on <resourceURL> remain the same.

• GET/HEAD on <resourceURL>?firstPage returns purely user content with:
    Link: http://www.w3.org/ns/ldp#Page; rel=type
    Link: <resourceURL>?page2; rel=next

• Lack of a Link: rel=next means you're at the end (closed HTTP world).

• GET/OPTIONS on "doubly-linked servers" return an addtional last linl:
  Link: <resourceURL>?page2; rel="last"

• GET/HEAD on <resourceURL>?page2 on "doubly-linked servers" includes
    Link: <resourceURL>?firstPage; rel=previous
</PROPOSAL>


I prefer these link types to others in the IANA registry:
<http://www.iana.org/assignments/link-relations/link-relations.xhtml>

RFC6903 Additional Link Relation Types:
about      - Refers to a resource that is the subject of the link's context.

RFC6573 The Item and Collection Link Relations:
collection - The target IRI points to a resource which represents the
             collection resource for the context IRI.
item       - The target IRI points to a resource that is a member of
             the collection represented by the context IRI.

POWDER:
describedBy
RFC6892 The 'describes' Link Relation Type:
describes

RFC6906 The 'profile' Link Relation Type:
profile    - Identifying that a resource representation conforms to
             a certain profile, without affecting the non-profile
             semantics of the resource representation.
-- 
-ericP
Received on Sunday, 22 September 2013 01:41:29 UTC

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