feat(apis_relations): add obj and subj class filter to triple filters

Closes: #668

apis_core/apis_relations/filtersets.py

@@ -1,5 +1,8 @@
 from apis_core.generic.filtersets import GenericFilterSet, GenericFilterSetForm
-from django_filters import CharFilter
+from django_filters import CharFilter, ModelMultipleChoiceFilter
+from django.contrib.contenttypes.models import ContentType
+from apis_core.apis_relations.models import Property
+from django.db.models import Q
 
 PROPERTY_EXCLUDES = ["self_contenttype", "name", "property_class_uri", "rootobject_ptr"]
 
@@ -20,9 +23,30 @@ class Meta:
 class TripleFilterSet(GenericFilterSet):
     subj = CharFilter(method="subj_icontains")
     obj = CharFilter(method="obj_icontains")
+    subj_class = ModelMultipleChoiceFilter(
+        label="Subj class",
+        queryset=ContentType.objects.filter(
+            pk__in=Property.objects.all().values("subj_class")
+        ),
+        method="class_in",
+    )
+    obj_class = ModelMultipleChoiceFilter(
+        label="Obj class",
+        queryset=ContentType.objects.filter(
+            pk__in=Property.objects.all().values("obj_class")
+        ),
+        method="class_in",
+    )
 
     def subj_icontains(self, queryset, name, value):
         return queryset.filter(subj__name__icontains=value)
 
     def obj_icontains(self, queryset, name, value):
         return queryset.filter(obj__name__icontains=value)
+
+    def class_in(self, queryset, name, value):
+        # value is the list of contenttypes
+        if value and name:
+            name, _ = name.split("_")
+            return queryset.filter(Q(**{f"{name}__self_contenttype__in": value}))
+        return queryset