Metadata Reference

Warning

This page describes the metadata currently deployed on CC Network and consumed by the license deeds. A draft specification has been published which simplifies some portions of this.

New implementers should consult Describing Work Registrations.

This section describes the metadata published by Commoner. For the purposes of this document, we assume the following namespaces are defined:

Prefix	Name	URL
cc	Creative Commons (ccREL)	http://creativecommons.org/ns#
ccnet	creativecommons.net (Commoner)	http://creativecommons.net/n#
sioc	SIOC	http://rdfs.org/sioc/ns#
foaf	FOAF	http://xmlns.com/foaf/0.1/“
rdf	RDF Syntax	http://www.w3.org/1999/02/22-rdf-syntax-ns#
dct	DC Terms	http://purl.org/dc/terms/
xsd	XML Schema	http://www.w3.org/2001/XMLSchema#
sioc_service	SIOC Service Module	http://rdfs.org/sioc/services#
powder	POWDER	http://www.w3.org/2007/05/powder#

Work Registration

Work registration relies reciprocal metadata published on the work page and on the registry.

Asserting Ownership

The work page publishes sioc:has_owner information pointing at the registry page. Commoner implements this in the network “badge” using RDFa. The triples published on the work page are:

<WORK_PAGE> <http://rdfs.org/sioc/ns#has_owner> <OWNER_PAGE> .
<WORK_PAGE> <http://www.w3.org/1999/xhtml/vocab#license> <LICENSE_URL> .

The registry must publish triples describing a reciprocal relationship. Commoner publishes these triples on the profile page, the full work list and the individual work pages. Clients should traverse rdf:seeAlso and sioc:has_owner to ensure full discovery. The reciprocal relationship is described by sioc:owner_of. For example:

<OWNER_PAGE> <http://rdfs.org/sioc/ns#owner_of> <WORK_PAGE> .

In addition to the reciprocal ownership information, the registry may publish metadata connecting the work page to the individual registation page. This is done using sioc:parent_of and sioc:has_parent. The registration page is declared as the sioc:parent_of the work page. The work page is declared to sioc:has_parent the registration page.

Wildcards

Registries may also indicate that a registration is applicable to a group of works, indicated by one or more powder:iriset. The iriset is a property of the registration page. Each powder:iriset includes zero or more powder:includeregex and zero or more powder:excluderegex statements. If a work page publishes ownership information which leads to the discovery of a work parent, the work page must pass all statements (inclusion and exclusion) in a powder:iriset of the parent to verify the claim.

See the POWDER Grouping of Resources documentation for more details on the regular expression usage.

For example:

<http://example.org/work> <http://rdfs.org/sioc/ns#has_parent>
   <http://registry.example.org/registration/page/> .

<http://registry.example.org/registration/page/>
  <http://rdfs.org/sioc/ns#parent_of> <http://example.org/work> .
<http://registry.example.org/registration/page/>
   <http://www.w3.org/2007/05/powder#iriset> _:n1 .

_:n1 <http://www.w3.org/2007/05/powder#includeregex>
   "\\:\\/\\/(([^\\/\\?\\#]*)\\@)?([^\\:\\/\\?\\#\\@]*)(\\:([0-9]+))?(\\/work)"@en .
_:n1 <http://www.w3.org/2007/05/powder#includeregex> "\\:\\/\\/(([^\\/\\?\\#]*)\\@)?([^\\:\\/\\?\\#\\@]+\\.)?(example\\.org)(\\:([0-9]+))?\\/"@en .
_:n1 <http://www.w3.org/2007/05/powder#includeregex> "^(http)\\:\\/\\/"@en .

Describes a relationship which would verify a claim that http://example.org/work/sub-page is registered in a group registration.

POWDER Compliance

Commoner and the specification in this document DOES NOT comply with POWDER or the POWDER RDF schema. We have attempted to reuse vocabulary where appropriate without introducing complexity for consumers. This feature may change dramatically in the future to become compliant.

Registration Details

Details regarding the registration may be published on the registration page. This includes – but is not limited to – the registration date (dct:created) and any powder:iriset.

Owner Information

Registries should publish sioc:name information for work owners. sioc:name should be the most accurate name available. For example, the owner’s legal name as opposed to their screen name.

Registry Information

Registries should publish information regarding the site. The minimum information is the registry name, dct:title.

Work Lookup Service

Registries may provide a work lookup service which redirects the user agent to the specific work registration page, if available. Commoner implements this service as a URL taking a single query-string parameter, the URI to look up.

For example:

GET /r/lookup?uri=http://example.org/work/

would redirect to a work registration page, if it exists. If one does not exist, the HTTP status code is set to 404.

Registries may advertise this service using the SIOC Service module. The service is advertised using sioc_service:has_service and is differentiated from other services by sioc_service:service_protocol. The protocol for work lookup is identified by the URI http://wiki.creativecommons.org/work-lookup.

For example, creativecommons.net publishes the following two triples:

<https://creativecommons.net/> <http://rdfs.org/sioc/services#has_service> <https://creativecommons.net/r/lookup/> .
<https://creativecommons.net/r/lookup/> <http://rdfs.org/sioc/services#service_protocol> <http://wiki.creativecommons.org/work-lookup> .