SweoIG/TaskForces/CommunityProjects/LinkingOpenData/AutoDiscovery
Triggered by a discussion on public-lod ML this page is about Patterns of Linked Data Auto-Discovery, and is meant to gather good practices in connecting information resources with non-information resources, with a special focus on (X)HTML.
The Problem
Assume the following exemplary situation: there is a person, Jane, and an HTML document that describes Jane:
The question now is: how should this HTML document (an information resource) be connected (i.e., linked) to the Real World Object (a non-information resource) that it describes, in a machine readable manner?
Good Practices
The following are a collection of good practices found on the Web:
Link element with primaryTopic
(X)HTML documents use a <link>
element in the header with the @rel
attribute and the @href
attribute to associate the document with the entities its describes. The value of @href
should be a generic HTTP URI; the value of @rel
may be:
- the string
"primaryTopic"
, for example:<link rel="primaryTopic" href="http://dbpedia.org/resource/Mogwai_(band)"/>
- the RDF property CURIe
"foaf:primaryTopic"
(DEF), for example:<link rel="foaf:primaryTopic" href="http://dbpedia.org/resource/Mogwai_(band)"/>
(note: this is RDFa 1.x-friendly, if thefoaf
namespace is also set in the header) - the RDF property URI
"http://xmlns.com/foaf/0.1/primaryTopic"
, for example:<link rel="http://xmlns.com/foaf/0.1/primaryTopic" href="http://dbpedia.org/resource/Mogwai_(band)"/>
(note: this is RDFa 1.x- and 2.x-friendly) (Michael: not sure about this one ...)
OPEN: need to register @rel
value with IANA, see Link Relation Type Registry
Link element with describedby
RDF model-based information resources such as (X)HTML+RDFa, Turtle, RDF-JSON, RDF/XML, etc. should include assertions that connect them to the entities that they describe via the RDF property wdr:describedby. Note that this property is defined in POWDER DR and also in the initially proposed content of the IANA Link Relation Type Registry.
Relevant Standards and References
- Web Linking, IETF draft, M. Nottingham
- Section 3 and section 4.2 of LRDD (Link-based Resource Descriptor Discovery), IETF draft, E. Hammer-Lahav
- FOAF spec
- RelExtensions, WHATWG HTML5 (note: will likely be moved to Web Linking as of ISSUE-27 of the HTML WG.)
- FOAF Autodiscovery