rdf.api.php

<?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".
 */