<?php

/**

 * @file

 * Hooks provided by the RDF module.

 */

/**

 * @addtogroup hooks

 * @{

 */

/**

 * Allow modules to define RDF mappings for field bundles.

 *

 * Modules defining their own field bundles can specify which RDF semantics

 * should be used to annotate these bundles. These mappings are then used for

 * automatic RDFa output in the HTML code.

 *

 * @return

 *   A list of mapping structures, where each mapping is an associative array:

 *   - type: The name of an entity type (e.g., 'node', 'comment', and so on.)

 *   - bundle: The name of the bundle (e.g., 'page', 'blog', or

 *     RDF_DEFAULT_BUNDLE for default mappings.)

 *   - mapping: The mapping structure which applies to the entity type and

 *     bundle. A mapping structure is an array with keys corresponding to

 *     existing field instances in the bundle. Each field is then described in

 *     terms of the RDF mapping:

 *     - predicates: An array of RDF predicates which describe the relation

 *       between the bundle (RDF subject) and the value of the field (RDF

 *       object). This value is either some text, another bundle, or a URI in

 *       general.

 *     - datatype: Is used along with 'callback' to format data so that it is

 *       readable by machines. A typical example is a date which can be written

 *       in many different formats but should be translated into a uniform

 *       format for machine consumption.

 *     - callback: A function name to invoke for 'datatype'.

 *     - type: A string used to determine the type of RDFa markup which will be

 *       used in the final HTML output, depending on whether the RDF object is a

 *       literal text or another RDF resource.

 *     - rdftype: A special property used to define the type of the instance.

 *       Its value should be an array of RDF classes.

 *

 *       @ingroup rdf

 */

function hook_rdf_mapping() {

  return array(

    array(

      'type' => 'node',

      'bundle' => 'blog',

      'mapping' => array(

        'rdftype' => array('sioct:Weblog'),

        'title' => array(

          'predicates' => array('dc:title'),

        ),

        'created' => array(

          'predicates' => array('dc:date', 'dc:created'),

          'datatype' => 'xsd:dateTime',

          'callback' => 'date_iso8601',

        ),

        'body' => array(

          'predicates' => array('content:encoded'),

        ),

        'uid' => array(

          'predicates' => array('sioc:has_creator'),

          'type' => 'rel',

        ),

        'name' => array(

          'predicates' => array('foaf:name'),

        ),

      ),

    ),

  );

}

/**

 * Allow modules to define namespaces for RDF mappings.

 *

 * Many common namespace prefixes are defined in rdf_rdf_namespaces(). However,

 * if a module implements hook_rdf_mapping() and uses a prefix that is not

 * defined in rdf_rdf_namespaces(), this hook should be used to define the new

 * namespace prefix.

 *

 * @return

 *   An associative array of namespaces where the key is the namespace prefix

 *   and the value is the namespace URI.

 *

 * @ingroup rdf

 */

function hook_rdf_namespaces() {

  return array(

    'content'  => 'http://purl.org/rss/1.0/modules/content/',

    'dc'       => 'http://purl.org/dc/terms/',

    'foaf'     => 'http://xmlns.com/foaf/0.1/',

    'og'       => 'http://ogp.me/ns#',

    'rdfs'     => 'http://www.w3.org/2000/01/rdf-schema#',

    'sioc'     => 'http://rdfs.org/sioc/ns#',

    'sioct'    => 'http://rdfs.org/sioc/types#',

    'skos'     => 'http://www.w3.org/2004/02/skos/core#',

    'xsd'      => 'http://www.w3.org/2001/XMLSchema#',

  );

}

/**

 * @} End of "addtogroup hooks".

 */