dcat: updated serializer for subject info

site/zenodo_rdm/serializers/dcat.py

@@ -20,6 +20,51 @@ def __init__(self, **options):
         """Constructor."""
         super().__init__(**options)
 
+    def add_subjects_uri(self, rdf_tree, subjects):
+        """Add valueURI of subjects to the corresponding dct:subject elements in the RDF tree."""
+        namespaces = rdf_tree.nsmap
+        for subject in subjects:
+            value_uri = subject.get("valueURI")
+            subject_label = subject.get("subject")
+            subject_scheme = subject.get("subjectScheme")
+            subject_props = subject.get("subjectProps", {})
+
+            if value_uri and subject_label and subject_scheme:
+                # Find the corresponding dct:subject element by prefLabel and subjectScheme
+                subject_element = rdf_tree.xpath(
+                    f"""
+                    //dct:subject[
+                        skos:Concept[
+                            skos:prefLabel[text()='{subject_label}']
+                            and skos:inScheme/skos:ConceptScheme/dct:title[text()='{subject_scheme}']
+                        ]
+                    ]
+                    """,
+                    namespaces=namespaces,
+                )[0]
+
+                if subject_element:
+                    # Add the valueURI to the dct:subject element as rdf:about
+                    subject_element.set(
+                        "{http://www.w3.org/1999/02/22-rdf-syntax-ns#}about", value_uri
+                    )
+
+                # Check if
+                #  subject has a definition in its props
+                definition = subject_props.get("definition")
+                if definition:
+                    concept_elem = subject_element.find(
+                        ".//skos:Concept", namespaces=namespaces
+                    )
+                    if concept_elem is not None:
+                        skos_definition = etree.Element(
+                            "{http://www.w3.org/2004/02/skos/core#}definition"
+                        )
+                        skos_definition.text = definition
+                        concept_elem.append(skos_definition)
+
+        return rdf_tree
+
     def add_missing_creator_link(self, rdf_tree):
         """Add `rdf:about` attributes to <rdf:Description> within <dct:creator> if missing."""
         namespaces = rdf_tree.nsmap
@@ -55,6 +100,11 @@ def transform_with_xslt(self, dc_record, **kwargs):
         dc_etree.tag = "{{{0}}}resource".format(dc_namespace)
         dcat_etree = self.xslt_transform_func(dc_etree).getroot()
 
+        # Add valueURI to subjects
+        subjects = dc_record.get("subjects", [])
+        if subjects:
+            dcat_etree = self.add_subjects_uri(dcat_etree, subjects)
+
         # Add the identifier links for creators if missing
         dcat_etree = self.add_missing_creator_link(dcat_etree)