def conflict(self, key, **kwargs):
"""
A helper method that simply raises a validation error.
"""
try:
msg = self.error_messages[key]
except KeyError:
class_name = self.__class__.__name__
msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key)
raise AssertionError(msg)
message_string = msg.format(**kwargs)
raise Conflict(message_string)
def to_internal_value(self, data):
"""
Ensure that the given type is one of the expected polymorphic types, then retrieve the
appropriate polymorphic serializer and use this to handle internal value.
"""
received_type = data.get('type')
expected_types = self.get_polymorphic_types()
if received_type not in expected_types:
raise Conflict(
'Incorrect relation type. Expected on of [{expected_types}], '
'received {received_type}.'.format(
expected_types=', '.join(expected_types), received_type=received_type))
serializer_class = self.get_polymorphic_serializer_for_type(received_type)
self.__class__ = serializer_class
return serializer_class(data, context=self.context).to_internal_value(data)
def delete(self, request, *args, **kwargs):
related_instance_or_manager = self.get_related_instance()
if isinstance(related_instance_or_manager, Manager):
related_model_class = related_instance_or_manager.model
serializer = self.get_serializer(data=request.data, model_class=related_model_class, many=True)
serializer.is_valid(raise_exception=True)
if frozenset(serializer.validated_data).isdisjoint(frozenset(related_instance_or_manager.all())):
return Response(status=204)
try:
related_instance_or_manager.remove(*serializer.validated_data)
except AttributeError:
raise Conflict(
'This object cannot be removed from this relationship without being added to another'
)
else:
raise MethodNotAllowed('DELETE')
result_serializer = self._instantiate_serializer(related_instance_or_manager)
return Response(result_serializer.data)