'collections.OrderedDict' 对象没有属性 'uuid' - Django REST Framework

问题描述

我正在使用 django-mptt 为我的 Section 模型创建一个树状结构。不幸的是，当我使用 drf-writable-nested 对其进行序列化时，出现错误。此错误仅在将 url 字段添加到序列化程序时发生。

此外，当我从自定义查找字段中删除 uuid 时，错误仅替换为 pk。

我发现了这个：https://stackoverflow.com/a/55173445/9137820，但我没有直接访问任何数据，所以我不确定这可能是什么问题。

代码：

# models.py

class Section(MPTTModel,TimeStampedModel):
    uuid = models.UUIDField(default=uuid_lib.uuid4,editable=False)
    name = models.CharField(max_length=255,unique=True)
    objects = TreeManager()
    parent = TreeForeignKey('self',related_name='section_children',on_delete=models.CASCADE,null=True,blank=True)

# serializers.py

class SectionSerializer(UniqueFieldsMixin,WritablenestedModelSerializer):
    children = serializers.ListField(source='get_children',child=RecursiveField())

    class Meta:
        model = Section
        fields = ['url','uuid','name','children']

        extra_kwargs = {
            'url': {'lookup_field': 'uuid'},}

# views.py

class SectionDetail(generics.RetrieveUpdateDestroyAPIView,viewsets.GenericViewSet):
    queryset = Section.objects.all()
    serializer_class = SectionSerializer
    lookup_field = 'uuid'

追溯：

Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/django/core/handlers/exception.py",line 47,in inner
    response = get_response(request)
  File "/usr/local/lib/python3.9/site-packages/django/core/handlers/base.py",line 181,in _get_response
    response = wrapped_callback(request,*callback_args,**callback_kwargs)
  File "/usr/local/lib/python3.9/site-packages/django/views/decorators/csrf.py",line 54,in wrapped_view
    return view_func(*args,**kwargs)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/viewsets.py",line 125,in view
    return self.dispatch(request,*args,**kwargs)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/views.py",line 509,in dispatch
    response = self.handle_exception(exc)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/views.py",line 469,in handle_exception
    self.raise_uncaught_exception(exc)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/views.py",line 480,in raise_uncaught_exception
    raise exc
  File "/usr/local/lib/python3.9/site-packages/rest_framework/views.py",line 506,in dispatch
    response = handler(request,**kwargs)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/mixins.py",line 75,in update
    return Response(serializer.data)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/serializers.py",line 548,in data
    ret = super().data
  File "/usr/local/lib/python3.9/site-packages/rest_framework/serializers.py",line 246,in data
    self._data = self.to_representation(self.instance)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/serializers.py",line 515,in to_representation
    ret[field.field_name] = field.to_representation(attribute)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/fields.py",line 1661,in to_representation
    return [self.child.to_representation(item) if item is not None else None for item in data]
  File "/usr/local/lib/python3.9/site-packages/rest_framework/fields.py",in <listcomp>
    return [self.child.to_representation(item) if item is not None else None for item in data]
  File "/usr/local/lib/python3.9/site-packages/rest_framework/serializers.py",in to_representation
    ret[field.field_name] = field.to_representation(attribute)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/relations.py",line 399,in to_representation
    url = self.get_url(value,self.view_name,request,format)
  File "/usr/local/lib/python3.9/site-packages/rest_framework/relations.py",line 335,in get_url
    lookup_value = getattr(obj,self.lookup_field)

Exception Type: AttributeError at /api/v1/sections/3b15cbda-f61e-4a00-89fb-817beed10b14/
Exception Value: 'collections.OrderedDict' object has no attribute 'uuid'

解决方法

我做了一些挖掘，这就是我能找到的。 Dictionaries 和 OrderedDicts 不会将键和值保存为类属性。因此您无法使用 getattr() 检索它们。您需要从 dict.keys() 请求方法或属性，例如 dict.values() 或 OrderedDict。您不能使用密钥名称。

看这个例子：

from collections import OrderedDict

g = OrderedDict()

g['test'] = 1

g = getattr(g,'values')

print(list(g())[0])

这很好用，但如果你改变了

g = getattr(g,'values')

到

g = getattr(g,'test')

它产生与您遇到的相同的错误