Network Working GroupM. Amundsen
Internet-DraftAugust 9, 2011
Intended status: Informational
Expires: February 10, 2012

The Item and Collection Link Relations
draft-amundsen-item-and-collection-link-relations-00

Abstract

RFC 5988 [RFC5988] defined the way of indicating resources on the Web. This specification defines a pair of reciprocal link relation types that may be used to express the relationship between a collection and its members.

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1. Introduction

RFC 5988 [RFC5988] defined the way of indicating resources on the Web. This specification defines a pair of reciprocal link relation types that may be used to express the relationship between a collection and its members.

These link relation types can be applied to a wide range of use cases across multiple media types. For example, the 'collection' and 'item' link relation types are used in these media types:

  1. OpenSearch 1.1: see <http://www.opensearch.org/Specifications/OpenSearch/1.1#Url_rel_values>
  2. Maze+XML: see <http://amundsen.com/media-types/maze/format/#link-relations>
  3. Collection+JSON: see <http://amundsen.com/media-types/collection/format/#link-relations>

2. Link Relations

The following link relations are defined.

2.1 'item'

When included in a resource which represents a collection, the 'item' link relation identifies a target resource that represents a member of that collection.

For example, if a resource represents a catalog of products, that same representation may include one or more links to resources which represent members of that catalog.

<html>
...
  <h1>Product Group X Listing</h1>
  ...
  <a href="..." rel="item">View Product X001</a>
  <a href="..." rel="item">View Product X002</a>
  ...
</html>

or

Link: <...>; rel="item"; title="View Product X001"
Link: <...>; rel="item"; title="View Product X002"

2.2 'collection'

When included in a resource which represents a member of a collection, the 'collection' link relation identifies a target resource that represents a collection of which the context resource is a member.

For example, if a resource represents a single product in a catalog, that same representation may include a link to a resource which represents a product group to which this single product belongs:

<a href="..." rel="collection">Return to Product Group X</a>

or

Link: <...>; rel="collection"; title="Return to Product Group X"

Since it is possible that a resource could be a member of multiple collections, multiple 'collection' link relations may appear within the same representation:

<a href="..." rel="collection">View other widgets</a>
<a href="..." rel="collection">View all discontinued items</a>

The target resource representation need not be restricted to representing a list. It may simply be a document that provides details on the collection of which the context resource is a member:

Link: <...>; rel="collection"; 
      title="Shakespeare's Collected Works - A History"

3. IANA Considerations

IANA is asked to register the 'collection' and 'item' Link Relations below as per [RFC5988].

3.1 'item' Link Relation Registration

Relation Name:

Description:

Reference:

Notes:

Application Data:

3.2 'collection' Link Relation Registration

Relation Name:

Description:

Reference:

Notes:

Application Data:

4. Security Considerations

See Section 7 of RFC5988 [RFC5988].

5. Internationalisation Considerations

See Section 8 of RFC5988 [RFC5988].

6. Normative References

[RFC5988]Nottingham, M., “Web Linking”, RFC 5988, October 2010.

Author's Address

Mike AmundsenEmail: URI: http://amundsen.com