DRF default_manager错误？

Question

我的基于DRF的API抛出了一个错误，我似乎无法解决，因为它不表明错误来自我的代码。

Traceback (most recent call last):
  File "/opt/venv/drf_app/lib/python3.5/site-packages/django/core/handlers/exception.py", line 39, in inner
    response = get_response(request)
  File "/opt/venv/drf_app/lib/python3.5/site-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "/opt/venv/drf_app/lib/python3.5/site-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/opt/venv/drf_app/lib/python3.5/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "/opt/venv/drf_app/lib/python3.5/site-packages/rest_framework/viewsets.py", line 83, in view
    return self.dispatch(request, *args, **kwargs)
  File "/opt/venv/drf_app/lib/python3.5/site-packages/rest_framework/views.py", line 477, in dispatch
    response = self.handle_exception(exc)
  File "/opt/venv/drf_app/lib/python3.5/site-packages/rest_framework/views.py", line 437, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/opt/venv/drf_app/lib/python3.5/site-packages/rest_framework/views.py", line 448, in raise_uncaught_exception
    raise exc
  File "/opt/venv/drf_app/lib/python3.5/site-packages/rest_framework/views.py", line 474, in dispatch
    response = handler(request, *args, **kwargs)
  File "/opt/venv/drf_app/lib/python3.5/site-packages/rest_framework/mixins.py", line 40, in list
    queryset = self.filter_queryset(self.get_queryset())
  File "/opt/venv/drf_app/lib/python3.5/site-packages/rest_framework/generics.py", line 151, in filter_queryset
    queryset = backend().filter_queryset(self.request, queryset, self)
  File "/opt/venv/drf_app/lib/python3.5/site-packages/django_filters/rest_framework/filterset.py", line 28, in __init__
    super(FilterSet, self).__init__(*args, **kwargs)
  File "/opt/venv/drf_app/lib/python3.5/site-packages/django_filters/filterset.py", line 284, in __init__
    queryset = self._meta.model._default_manager.all()
AttributeError: 'NoneType' object has no attribute '_default_manager'

是rest框架代码中的错误还是来自其他地方？

仅供参考，django管理端工作正常。

下面是正在使用的模型和序列化程序：

class ListCreateRetrieveUpdateViewSet(mixins.ListModelMixin, mixins.CreateModelMixin,
                                      mixins.RetrieveModelMixin, mixins.UpdateModelMixin,
                                      viewsets.GenericViewSet):
    """
    A viewset that provides `list`, `create`, `retrieve`, `update` actions.
    """
    pass


class BaseModel(models.Model):
    """
    An abstract base class model that provides self updating
    ``created`` and ``modified`` fields.
    """
    created_on = models.DateTimeField(auto_now_add=True, editable=False)
    created_by = models.ForeignKey(settings.AUTH_USER_MODEL,
                                   related_name="%(app_label)s_%(class)s_created_by", editable=False)
    modified_on = models.DateTimeField(auto_now=True, editable=False)
    modified_by = models.ForeignKey(settings.AUTH_USER_MODEL,
                                    related_name="%(app_label)s_%(class)s_modified_by", editable=False)
    is_deleted = models.BooleanField(default=False, verbose_name='Delete Entry')
    deleted_on = models.DateTimeField(null=True, blank=True, editable=False)
    deleted_by = models.ForeignKey(settings.AUTH_USER_MODEL, related_name="%(app_label)s_%(class)s_deleted_by",
                                   null=True, blank=True, editable=False)

    class Meta:
        abstract = True

class Country(BaseModel):
    """
    List of Countries
    """
    code = models.CharField(max_length=3, unique=True)
    title = models.CharField(max_length=100, unique=True)

    def __str__(self):
        return '{} - {}'.format(self.code, self.title)

class CountrySerializer(serializers.ModelSerializer):
    """Serialize model"""

    class Meta:
        model = Country

class CountryViewSet(viewsets.ReadOnlyModelViewSet):
    """
    list and create countries
    """
    end_point_name = 'CoreApp'
    queryset = Country.objects.all()
    serializer_class = CountrySerializer
    filter_fields = ('id',)

Answer 1

我今天遇到了一个类似的问题:似乎从DRF3.5开始，filters classes have completely moved to django-filter package。我修正了我的import语句，一切都很顺利。希望能对你有所帮助！

内置DjangoFilterBackend的功能现在完全包含在django-filter包中。

您应该更改导入和REST框架筛选器设置，如下所示：

rest_framework.filters.DjangoFilterBackend变成了django_filters.rest_framework.DjangoFilterBackend。rest_framework.filters.FilterSet变成了django_filters.rest_framework.FilterSet。

现有的导入将继续工作，但现在正在等待弃用。

在我的例子中，最后一句话是错误的，它不起作用。