diff -r 07239de796bb -r e756a8c72c3d cms/drupal/modules/rdf/rdf.api.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cms/drupal/modules/rdf/rdf.api.php	Fri Sep 08 12:04:06 2017 +0200
@@ -0,0 +1,106 @@
+<?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".
+ */