fix: allow for sameAs links

resolves #819

apis_core/apis_metainfo/models.py

@@ -22,6 +22,8 @@ class RootObject(GenericModel, models.Model):
     By having one overarching super class we gain the advantage of unique identifiers.
     """
 
+    _sameas = None  # Internal storage for sameas property
+
     # self_contenttype: a foreign key to the respective contenttype comes in handy when querying for
     # triples where the subject's or object's contenttype must be respected (e.g. get all triples
     # where the subject is a Person)
@@ -35,10 +37,24 @@ class RootObject(GenericModel, models.Model):
     objects = models.Manager()
     objects_inheritance = InheritanceManager()
 
+    @property
+    def sameas(self):
+        uri = [u.uri for u in Uri.objects.filter(root_object=self)]
+        return uri if len(uri) > 0 else None
+
+    @sameas.setter
+    def sameas(self, value):
+        self._sameas = value
+
     def save(self, *args, **kwargs):
         self.self_contenttype = ContentType.objects.get_for_model(self)
         super().save(*args, **kwargs)
 
+        if self._sameas is not None:
+            for uri in self._sameas:
+                Uri.objects.create(root_object=self, uri=uri)
+            self._sameas = None
+
     def duplicate(self):
         origin = self.__class__
         signals.pre_duplicate.send(sender=origin, instance=self)

apis_core/generic/importers.py

@@ -4,6 +4,7 @@
 from functools import cache
 
 from django.core.exceptions import ImproperlyConfigured
+from django.db.utils import IntegrityError
 
 from apis_core.utils.normalize import clean_uri
 from apis_core.utils.rdf import get_definition_and_attributes_from_uri
@@ -42,16 +43,16 @@ def request(self, uri):
         # we first try to use the RDF parser
         try:
             defn, data = get_definition_and_attributes_from_uri(uri, self.model)
-            return data
+            return data, defn
         except Exception as e:
             logger.debug(e)
         # if everything else fails, try parsing json
         # if even that does not help, return an empty dict
         try:
-            return json.loads(urllib.request.urlopen(uri).read())
+            return json.loads(urllib.request.urlopen(uri).read()), {}
         except Exception as e:
             logger.debug(e)
-        return {}
+        return {}, {}
 
     def mangle_data(self, data):
         return data
@@ -64,11 +65,12 @@ def get_data(self, drop_unknown_fields=True):
         remove all fields from the data dict that do not
         have an equivalent field in the model.
         """
-        data = self.request(self.import_uri)
+        data, defn = self.request(self.import_uri)
+        self.definition = defn
         data = self.mangle_data(data)
         if drop_unknown_fields:
             # we are dropping all fields that are not part of the model
-            modelfields = [field.name for field in self.model._meta.fields]
+            modelfields = [field.name for field in self.model._meta.fields] + ["sameas"]
             data = {key: data[key] for key in data if key in modelfields}
         if not data:
             raise ImproperlyConfigured(
@@ -85,5 +87,16 @@ def import_into_instance(self, instance, fields="__all__"):
                 setattr(instance, field, data[field])
         instance.save()
 
-    def create_instance(self):
-        return self.model.objects.create(**self.get_data(drop_unknown_fields=True))
+    def create_instance(self, follow_sameas=True):
+        data = self.get_data(drop_unknown_fields=True)
+        if follow_sameas:
+            sa = self.model.objects.filter(uri__uri__in=self.definition["sameas"])
+            if sa.count() == 1:
+                return sa.first()
+            elif sa.count() > 1:
+                raise IntegrityError(
+                    f"Multiple objects found for sameAs URIs {self.definition['sames']}. "
+                    f"This indicates a data integrity problem as these URIs should be unique."
+                )
+        obj = self.model.objects.create(**data)
+        return obj

apis_core/utils/rdf.py

@@ -68,6 +68,20 @@ def get_definition_and_attributes_from_uri(
             break
     model_attributes = dict()
     if matching_definition:
+        sameas = matching_definition.get(
+            "sameas",
+            """
+            PREFIX owl: <http://www.w3.org/2002/7/owl#>
+            SELECT ?sameas WHERE {
+                ?subject owl:sameAs ?sameas .
+            }
+        """,
+        )
+        model_attributes["sameas"] = []
+        result = graph.query(sameas)
+        for binding in result.bindings:
+            for value in binding.values():
+                model_attributes["sameas"].append(str(value))
         attributes = matching_definition.get("attributes", [])
         sparql_attributes = list(filter(lambda d: d.get("sparql"), attributes))
         for attribute in sparql_attributes: