django rest框架嵌套对象

我正在尝试使用Django REST框架找到遇到此问题的优雅解决方案.我们有一个带有子对象和一对一关系的父模型.我们的要求是子对象是可选的,可以为null,也可以从先前存在的值修补为null.此外,如果删除父对象,则子对象也应该是.

这个简单的设置可以重现问题:

class ChildSerializer(serializers.ModelSerializer):
    class Meta:
        model = Child


class ParentSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Parent

    parent_value = serializers.CharField(required=False, max_length=1024)
    child = ChildSerializer(read_only=False, required=False, many=False)


class Parent(models.Model):
    class Meta:
        app_label = "testparent"

    parent_value = models.CharField(max_length=1024, null=True, blank=True)


class Child(models.Model):
    class Meta:
        app_label = "testparent"

    child_value = models.CharField(max_length=1024, null=True, blank=True)
    parent = models.ForeignKey(Parent, null=True, blank=True, related_name="child")


class ParentViewSet(viewsets.ModelViewSet):
    permission_classes = (AllowAny,)

    queryset = Parent.objects.all()
    serializer_class = ParentSerializer

这有效:

{
    "parent_value": "abc", 
    "child": { "child_value": "something" }
}

这会出错:

{
    "parent_value": "abc", 
    "child": null
}

请注意,子对象是可选的,默认情况下,REST框架使用null填充该字段.

我正在使用Django v.1.5.4和REST框架v.2.3.13

错误:

Traceback:
File "{site-packages}/django/core/handlers/base.py" in get_response
  115.                         response = callback(request, *callback_args, **callback_kwargs)
File "{site-packages}/rest_framework/viewsets.py" in view
  78.             return self.dispatch(request, *args, **kwargs)
File "{site-packages}/django/views/decorators/csrf.py" in wrapped_view
  77.         return view_func(*args, **kwargs)
File "{site-packages}/rest_framework/views.py" in dispatch
  400.             response = self.handle_exception(exc)
File "{site-packages}/rest_framework/views.py" in dispatch
  397.             response = handler(request, *args, **kwargs)
File "{site-packages}/rest_framework/mixins.py" in create
  54.             self.object = serializer.save(force_insert=True)
File "{site-packages}/rest_framework/serializers.py" in save
  596.             self.save_object(self.object, **kwargs)
File "{site-packages}/rest_framework/serializers.py" in save_object
  1023.                     setattr(obj, accessor_name, related)
File "{site-packages}/django/db/models/fields/related.py" in __set__
  474.         manager.add(*value)


Exception Value: add() argument after * must be a sequence, not NoneType

我们当前使用的解决方法是为父级提供OneToOne字段,然后使用post_delete信号处理程序删除子对象.这感觉非常hacky.我们一般在尝试操作嵌套对象时遇到了一些问题,并且想知道我们是否错了,或者在这种情况下我们遇到了django或其他框架中的错误.

谢谢!