Difference between revisions of "License Properties"

In addition to the human readable license deeds and legal code, Creative Commons provides machine readable metadata for licenses. This page describes how to begin with a license URI and map it to license properties.

Properties Overview

License Properties describe the permissions, prohibitions and requirements of a license. Permissions declare a permission given by the license, above and beyond what default copyright law allows. Prohibitions prohibit a particular use of the work, specifically affecting the scope of the permissions provided by a permission. Requirements describe actions required of user when making use of the permissions.

Inspecting the URL

Creative Commons license deed URLs have the following format:

 http://creativecommons.org/licenses/{license-properties}/{version}/{jurisdiction}/

The jurisdiction is optional. For example:

 http://creativecommons.org/licenses/by/3.0/

Is the URL for the Attribution 3.0 (Unported) license. The license is Unported as there is no jurisdiction element present. The Attribution 2.0 (France) license has the following URL:

 http://creativecommons.org/licenses/by/2.0/fr/

Mapping Individual Properties

The license properties portion of the URL is a sequence a two letter codes separated by dashes ("-"). These map to the following license properties:

• by: Attribution: Attribution is required with any reuse or redistribution, in the manner specified by the licensor.
• nc: Non-Commercial: Commercial use is prohibited.
• nd: No Derivatives: Only verbatim reproduction is permitted.
• sa: Share-Alike: Derivative works are allowed, but must also be licensed under the same license.

Using RDFa

RDFa is an editor's draft at W3 which describes a way to serialize RDF triples in HTML. Creative Commons includes the appropriate RDFa When selecting a license from http://creativecommons.org/license to indicate that a page is licensed. For example:

 <a href="http://creativecommons.org/licenses/by/3.0/" rel="license">Attribution 3.0</a>

The rel="license" attribute indicates that the link specified (the license URL in this case) has special semantic meaning.

With the license URI, an RDFa parser may be used to extract license attributes from the human readable deed. RDFa parsers are available for many languages, including Python (RdfaDict, rdflib), Ruby (ruby-rdfa) and PHP (RDFa Monkey).

Passing the Attribution 3.0 Unported deed (http://creativecommons.org/licenses/by/3.0/) through an RDFa parser yields the following triples:

 @prefix cc: <http://creativecommons.org/ns#> .
 http://creativecommons.org/licenses/by/3.0/ cc:requires cc:Attribution .
 http://creativecommons.org/licenses/by/3.0/ cc:requires cc:Notice .
 http://creativecommons.org/licenses/by/3.0/ cc:permits cc:Reproduction .
 http://creativecommons.org/licenses/by/3.0/ cc:permits cc:Distribution .
 http://creativecommons.org/licenses/by/3.0/ cc:permits cc:DerivativeWorks .

For a complete list of Permissions, Prohibitions and Requirements defined by Creative Commons see http://creativecommons.org/ns.