662 Strange behaviour of CUDS remove (DataspaceSession) (#668)

Allow the CUDS objects to be initialized with extra triples, instead of having to add them after already having created the object.

This solves #668 because previously, the class of the `Wrapper` CUDS objects was not defined on the server until after having spawned the CUDS object, because it is created empty and then filled with triples. This caused it to go to the added buffer, ignoring the changes introduced in #638, which solved the issue for local sessions, for which the CUDS objects are not created first empty and then filled with triples.

osp/core/cuds.py

@@ -6,8 +6,8 @@
 
 import logging
 from uuid import uuid4, UUID
-from typing import Union, List, Iterator, Dict, Any, Optional, Tuple
-from rdflib import URIRef, RDF, Graph, Literal
+from typing import Union, List, Iterator, Dict, Any, Optional, Tuple, Iterable
+from rdflib import URIRef, BNode, RDF, Graph, Literal
 from osp.core.namespaces import cuba, from_iri
 from osp.core.ontology.relationship import OntologyRelationship
 from osp.core.ontology.attribute import OntologyAttribute
@@ -41,9 +41,11 @@ def __init__(self,
                  session: Session = None,
                  iri: URIRef = None,
                  uid: Union[UUID, URIRef] = None,
-                 # Create an empty CUDS and add the triples externally
-                 # afterwards.
-                 _from_triples: bool = False):
+                 # Specify extra triples for the CUDS object.
+                 extra_triples: Iterable[
+                     Tuple[Union[URIRef, BNode],
+                           Union[URIRef, BNode],
+                           Union[URIRef, BNode]]] = tuple()):
         """Initialize a CUDS object."""
         # Set uid. This is a "user-facing" method, so strict types
         # checks are performed.
@@ -71,7 +73,17 @@ def __init__(self,
             self._graph.add((
                 self.iri, RDF.type, oclass.iri
             ))
-        elif not _from_triples:
+        extra_oclass = False
+        for s, p, o in extra_triples:
+            if s != self.iri:
+                raise ValueError("Trying to add extra triples to a CUDS "
+                                 "object with a subject that does not match "
+                                 "the CUDS object's IRI.")
+            elif p == RDF.type:
+                extra_oclass = True
+            self._graph.add((s, p, o))
+        oclass_assigned = bool(oclass) or extra_oclass
+        if not oclass_assigned:
             raise TypeError(f"No oclass associated with {self}! "
                             f"Did you install the required ontology?")
 

osp/core/utils/wrapper_development.py

@@ -225,15 +225,17 @@ def create_from_triples(triples, neighbor_triples, session,
             for rel in rels:
                 cuds_object.remove(rel=rel)
         session.graph.remove((cuds_object.iri, None, None))
+        for triple in set(triples):
+            session.graph.add(triple)
     else:  # create new
         cuds_object = Cuds(attributes={},
                            oclass=None,
                            session=session,
                            uid=uid,
-                           _from_triples=True)
+                           extra_triples=set(triples))
 
     # add the triples
-    for triple in set(triples) | set(neighbor_triples):
+    for triple in set(neighbor_triples):
         session.graph.add(triple)
     if isinstance(session, WrapperSession):
         session._store_checks(cuds_object)

tests/test_api_city.py

@@ -673,11 +673,10 @@ def test_add_multi_session(self):
     def test_cuds_without_oclass(self):
         """Tries to create a cuds without oclass.
 
-        Should fail except if the argument _from_triples is set to True.
+        Should always fail.
         """
         self.assertRaises(TypeError,
                           Cuds, oclass=None, attributes={})
-        self.assertTrue(Cuds(oclass=None, attributes={}, _from_triples=True))
 
 
 if __name__ == '__main__':