Add nested ordering filter

Add nested ordering filter to instead original one
in rest framework.
Modified the comment of class RelatedNestedOrderingFilter.
Add the underscore comment on ordering doc.
Change the DEFAULT_FILTER_BACKENDS in settings_local.py.
Skip nested ordering check here and check in is_valid_field.
Add test cases on new codes.

JIRA: PDC-1746

pdc/apps/common/renderers.py

@@ -66,6 +66,7 @@
 
 URL_SPEC_RE = re.compile(r'\$(?P<type>URL|LINK):(?P<details>[^$]+)\$')
 ORDERING_STRING = "\n * `ordering` is used to override the ordering of the results, the value could be: "
+ORDERING_STRING_NESTED = "The nested ordering is supported by using double underscore \_\_ ."
 
 
 class ReadOnlyBrowsableAPIRenderer(BrowsableAPIRenderer):
@@ -144,7 +145,7 @@ def format_docstring(self, view, method, docstring):
             if 'list' == method:
                 ordering_field = get_ordering_field(view, method)
                 if ordering_field:
-                    ordering_string = ORDERING_STRING + " %s ." % ordering_field
+                    ordering_string = ORDERING_STRING + " %s . " % ordering_field + ORDERING_STRING_NESTED
                     macros['FILTERS'] += ordering_string
             if '%(SERIALIZER)s' in docstring:
                 macros['SERIALIZER'] = get_serializer(view, include_read_only=True)

pdc/apps/common/viewsets.py

@@ -205,7 +205,8 @@ def _check_ordering_keys(self, request):
         serializer_fields = self._get_fields_from_serializer_class()
         valid_fields = list(set(model_fields).intersection(set(serializer_fields)))
         valid_fields += self.queryset.query.aggregates.keys()
-        tmp_list = [param.strip().lstrip('-') for param in ordering_keys.split(',')]
+        # If there is a netsted ordering with '__', check if it is valid in the RelatedNestedOrderingFilter
+        tmp_list = [param.strip().lstrip('-') for param in ordering_keys.split(',') if '__' not in param]
         invalid_fields = set(tmp_list) - set(valid_fields)
         if invalid_fields:
             raise FieldError('Unknown query key: %s not in fields: %s' %

pdc/apps/component/tests.py

@@ -1866,6 +1866,25 @@ def test_delete_group(self):
         response = self.client.get(url, format='json')
         self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)
 
+    def test_list_relationship_by_nested(self):
+
+        def f(ordering_value):
+            response = self.client.get(reverse("rcrelationship-list"), {'ordering': ordering_value}, format='json')
+            self.assertEqual(response.status_code, status.HTTP_200_OK)
+            self.assertEqual(response.data.get('count'), 2)
+            data = response.data.get('results')
+            if ordering_value == "to_component__name":
+                self.assertTrue(self, data[0].get('to_component')["name"] <= data[1].get('to_component')["name"])
+            elif ordering_value == "-to_component__name":
+                self.assertTrue(self, data[0].get('to_component')["name"] >= data[1].get('to_component')["name"])
+            elif ordering_value == "to_component__release":
+                self.assertTrue(self, data[0].get('to_component')["release"] <= data[1].get('to_component')["release"])
+            else:
+                self.assertTrue(self, data[0].get('to_component')["release"] >= data[1].get('to_component')["release"])
+
+        for v in ["to_component__name", "-to_component__name", "to_component__release", "-to_component__release"]:
+            f(v)
+
 
 class ComponentRelationshipTypeRESTTestCase(TestCaseWithChangeSetMixin, APITestCase):
     """

pdc/apps/utils/utils.py

@@ -11,6 +11,8 @@
 from django.contrib.contenttypes.models import ContentType
 from django.db.models.signals import pre_save
 from django.forms.models import model_to_dict
+from rest_framework.filters import OrderingFilter
+from django.core.exceptions import FieldError
 
 
 def connect_app_models_pre_save_signal(app, models=None):
@@ -59,3 +61,43 @@ def read_permission_for_all():
 
 def get_model_name_from_obj_or_cls(obj_or_cls):
     return ContentType.objects.get_for_model(obj_or_cls).model
+
+
+class RelatedNestedOrderingFilter(OrderingFilter):
+    """
+    Extends OrderingFilter to support ordering by fields in related models
+    using Django orm '__'.
+
+    This class is copied and changed from the patch of the github issue.
+    https://github.com/encode/django-rest-framework/issues/1005
+
+    This is based on rest_framework 3.2.5 because pdc-server is using
+    this version.
+
+    The patch has not been merged in the latest version yet. If pdc-server
+    upgrades the rest_framework to the version which includes this patch in
+    the future, this class should obsolete.
+    """
+    def is_valid_field(self, model, field):
+        """
+        Return true if the field exists within the model or there is a '__' here.
+        """
+        components = field.split('__', 1)
+        try:
+            field, parent_model, direct, m2m = \
+                model._meta.get_field_by_name(components[0])
+
+            # Check if foreign key value exists
+            if field.rel and len(components) == 2:
+                return self.is_valid_field(field.rel.to, components[1])
+            return True
+        except Exception as e:
+            # There is no such field
+            raise FieldError("Unknown query key: %s" % e)
+
+    def remove_invalid_fields(self, queryset, ordering_files, view):
+        """
+        Rewrite the remove_invalid_fields methods and add the nested ordering
+        """
+        return [term for term in ordering_files
+                if self.is_valid_field(queryset.model, term.lstrip('-'))]

pdc/settings.py

@@ -93,7 +93,7 @@
     'DEFAULT_METADATA_CLASS': 'contrib.bulk_operations.metadata.BulkMetadata',
 
     'DEFAULT_FILTER_BACKENDS': ('rest_framework.filters.DjangoFilterBackend',
-                                'rest_framework.filters.OrderingFilter'),
+                                'pdc.apps.utils.utils.RelatedNestedOrderingFilter'),
 
     'DEFAULT_RENDERER_CLASSES': (
         'rest_framework.renderers.JSONRenderer',

pdc/settings_local.py.dist

@@ -38,7 +38,7 @@
 #     #    ],
 #
 #         'DEFAULT_FILTER_BACKENDS': ('rest_framework.filters.DjangoFilterBackend',
-#                                     'rest_framework.filters.OrderingFilter',),
+#                                     'pdc.apps.utils.utils.RelatedNestedOrderingFilter'),
 #
 #         'DEFAULT_METADATA_CLASS': 'contrib.bulk_operations.metadata.BulkMetadata',
 #