feat(serializers.dcat): Add checksum to dcat serializer

consider checksums in the dcat serializer for oai-sets as per W3 dcat version 3

Author: MahmoudMHassan

invenio_rdm_records/resources/serializers/dcat/__init__.py

@@ -75,12 +75,15 @@ def access_url(file):
             url = file.get("access_url")
             return {"{{{rdf}}}resource".format(**ns): url} if url else None
 
+        def checksum(file):
+            return file["checksum"] if file.get("checksum") else None
+        
         files_fields = {
             "{{{dcat}}}downloadURL": download_url,
             "{{{dcat}}}mediaType": media_type,
             "{{{dcat}}}byteSize": byte_size,
             "{{{dcat}}}accessURL": access_url,
-            # TODO: there's also "spdx:checksum", but it's not in the W3C spec yet
+            "{{{dcat}}}checksum": checksum,
         }
 
         for f in files:

invenio_rdm_records/resources/serializers/dcat/schema.py

@@ -50,6 +50,7 @@ def get_files(self, obj):
                     access_url=access_url,
                     download_url=url,
                     key=value["key"],
+                    checksum=value["checksum"],
                 )
             )
 

tests/resources/serializers/test_dcat_serializer.py

@@ -251,6 +251,7 @@ def test_dcat_serializer(running_app, full_record_to_dict):
         'rdf:resource="https://127.0.0.1:5000/records/12345-abcde/files/test.txt"/>\n'
         "        <dcat:mediaType>text/plain</dcat:mediaType>\n"
         "        <dcat:byteSize>9</dcat:byteSize>\n"
+        "        <dcat:checksum>md5:e795abeef2c38de2b064be9f6364ceae</dcat:checksum>\n"
         "        <dcat:accessURL "
         'rdf:resource="https://doi.org/10.1234/12345-abcde"/>\n'
         "      </dcat:Distribution>\n"