Group queries for SlugRelatedField many serializers

rest_framework/relations.py

@@ -4,7 +4,7 @@
 from urllib import parse
 
 from django.core.exceptions import ImproperlyConfigured, ObjectDoesNotExist
-from django.db.models import Manager
+from django.db.models import F, Manager
 from django.db.models.query import QuerySet
 from django.urls import NoReverseMatch, Resolver404, get_script_prefix, resolve
 from django.utils.encoding import smart_str, uri_to_iri
@@ -458,15 +458,26 @@ def __init__(self, slug_field=None, **kwargs):
  self.slug_field = slug_field
  super().__init__(**kwargs)
 
- def to_internal_value(self, data):
+ def to_many_internal_value(self, data):
  queryset = self.get_queryset()
  try:
- return queryset.get(**{self.slug_field: data})
- except ObjectDoesNotExist:
- self.fail('does_not_exist', slug_name=self.slug_field, value=smart_str(data))
+ result = (
+ queryset
+ .filter(**{self.slug_field + "__in": data})
+ .annotate(_slug_field_value=F(self.slug_field))
+ .all()
+ )
+ slugs = [item._slug_field_value for item in result]
+ for item in data:
+ if item not in slugs:
+ self.fail('does_not_exist', slug_name=self.slug_field, value=smart_str(item))
+ return result
  except (TypeError, ValueError):
  self.fail('invalid')
 
+ def to_internal_value(self, data):
+ return self.to_many_internal_value([data])[0]
+
  def to_representation(self, obj):
  slug = self.slug_field
  if "__" in slug:

tests/test_relations_slug.py

@@ -174,6 +174,12 @@ def test_reverse_foreign_key_create(self):
  ]
  assert serializer.data == expected
 
+ def test_reverse_foreign_key_create_grouped_queries(self):
+ data = {'id': 3, 'name': 'target-3', 'sources': ['source-1', 'source-3']}
+ serializer = ForeignKeyTargetSerializer(data=data)
+ with self.assertNumQueries(1):
+ assert serializer.is_valid()
+
  def test_foreign_key_update_with_invalid_null(self):
  data = {'id': 1, 'name': 'source-1', 'target': None}
  instance = ForeignKeySource.objects.get(pk=1)

tests/utils.py

@@ -35,7 +35,7 @@ def all(self):
  return list(self.items)
 
  def filter(self, **lookup):
- return MockQueryset(
+ return MockQueryset([
  item
  for item in self.items
  if all([
@@ -44,7 +44,13 @@ def filter(self, **lookup):
  else attrgetter(key.replace('__', '.'))(item) == value
  for key, value in lookup.items()
  ])
- )
+ ])
+
+ def annotate(self, **kwargs):
+ for key, value in kwargs.items():
+ for item in self.items:
+ setattr(item, key, attrgetter(value.name.replace('__', '.'))(item))
+ return self
 
 
 class BadType: