fix(generic): respect APIS_DETAIL_VIEWS_ALLOWED setting

Skip adding permissions to DetailView if APIS_DETAIL_VIEWS_ALLOWED is
set by using a DetailViewObjectMixin that overrides GenericModelMixin's
get_permission_required method.

fixes #1400

apis_core/core/mixins.py

@@ -51,3 +51,15 @@ def get_permission_required(self):
         if getattr(settings, "APIS_LIST_VIEWS_ALLOWED", False):
             return []
         return super().get_permission_required()
+
+
+class DetailViewObjectMixin:
+    """
+    This mixin ensures that no permissions are required for the detail view
+    of the object IF APIS_DETAIL_VIEWS_ALLOWED is set.
+    """
+
+    def get_permission_required(self):
+        if getattr(settings, "APIS_DETAIL_VIEWS_ALLOWED", False):
+            return []
+        return super().get_permission_required()

apis_core/generic/views.py

@@ -23,7 +23,7 @@
 from django_tables2.tables import table_factory
 
 from apis_core.apis_metainfo.models import Uri
-from apis_core.core.mixins import ListViewObjectFilterMixin
+from apis_core.core.mixins import DetailViewObjectMixin, ListViewObjectFilterMixin
 from apis_core.utils.helpers import create_object_from_uri, get_importer_for_model
 
 from .filtersets import GenericFilterSet
@@ -211,7 +211,9 @@ def get_paginate_by(self, table_data) -> Optional[int]:
         return getattr(self.get_table_class(), "paginate_by", None)
 
 
-class Detail(GenericModelMixin, PermissionRequiredMixin, DetailView):
+class Detail(
+    DetailViewObjectMixin, GenericModelMixin, PermissionRequiredMixin, DetailView
+):
     """
     Detail view for a generic model.
     Access requires the `<model>_view` permission.