类型错误：字段 'id' 需要一个数字，但得到 <django.contrib.auth.models.AnonymousUser object at 0x048C7E90>

Question

Cannot cast AnonymousUser to int.
Are you trying to use it in place of User?

当我向我的网址发出发布请求时，我不确定如何调整我的代码以停止生成此错误。我附上了我的序列化程序、视图和模型的代码。

class ActivitySessionSerializer(serializers.Serializer):
    activity_name = serializers.CharField(min_length=1, max_length=100)

    def create(self, validated_data):
        activity, created = Activity.objects.get_or_create(name=validated_data['activity_name'], 
        owner=self.context['request'].user)

        return ActivitySession.objects.create(activity=activity, start_time=datetime.datetime.now())



class StartSessionView(generics.CreateAPIView):
    serializer_class = serializers.ActivitySessionSerializer


    User = get_user_model()
    
    class ActivityType(models.Model):
        name = models.CharField(max_length=100)
        user = models.ForeignKey(User, on_delete=models.CASCADE)

    class Activity(models.Model):
        name = models.CharField(max_length=100)
        owner = models.ForeignKey(User, on_delete=models.CASCADE)
        activity_type = models.ForeignKey(ActivityType, on_delete=models.CASCADE, null=True, blank=True)

    class ActivitySession(models.Model):
        activity = models.ForeignKey(Activity, on_delete=models.CASCADE)
        start_time = models.DateTimeField()
        end_time = models.DateTimeField()


    urlpatterns = [
        path('starting_session/', views.StartSessionView.as_view()),
    ]

我相信我通过换行解决了它

Activity.objects.get_or_create(name=validated_data['activity_name'], 
        owner=self.context['request'].user)

到

Activity.objects.get_or_create(name=validated_data['activity_name'], 
        owner=self.context['request'].user.id)

我必须专门添加 id 字段而不是总用户对象

Answer 1

对于那些也来这里的人，一个可能的错误是（这就是我遇到的）：

您可以通过foreignkey 或reverse foreignkey 在其他地方调用匿名user 实例。

例如，在我的代码中：

1. 我在CustomView 中收到了匿名请求，如下所示：

class CustomView(RetrieveAPIView):
    serializer_class = CustomSerializer
    queryset =CustomModel.objects.all()

1. CustomView 的CustomModel 有一个反向外键-which_model，像这样：

from django.contrib.auth import get_user_model
User = get_user_model()

class CustomModel(BaseModel):
    name = models.CharField(verbose_name="Custom name", max_length=256)
 
class CustomRecord(BaseModel):
    which_user = models.ForeignKey(User, on_delete=models.CASCADE, verbose_name="related user")
    which_model = models.ForeignKey("CustomModel", on_delete=models.CASCADE, verbose_name="related model",related_name="user_record",)

1. 为了在匿名请求中获取CustomModel 实例的同时获取相关的CustomRecord 实例，我在CustomSerializer 中使用了SerializerMethodField，如下所示：

class CustomSerializer(ModelSerializer):
    related_user_record = SerializerMethodField(read_only=True, source="user_record")
    def get_related_user_record(self, obj):
        # This is where the problem is !!!!
        user_record = CustomRecord.objects.filter(
            which_model=obj.id, which_user=self.context["request"].user
        )
        if not user_record:
            return None
        else:
            return CustomRecordSerializer(user_record.get()).data

由于我在get_related_user_record函数中使用了self.context["request"].user，django尝试将用户实例的id转换为int； 但是，就像@Brad Solomon 所说，匿名用户的id 或pk 为None。，这就是错误的来源。老实说，当这个错误发生时，djano 并没有很好地报告错误源。

为了解决这个问题，我在使用用户实例之前添加了一个检查，以查看它是否是匿名用户，如下所示：

def get_related_user_record(self, obj):
    # check if it's an anonymous user
    if not self.context["request"].user.pk:
        return None
    # This is where the problem is !!!!
    user_record = CustomRecord.objects.filter(
        which_model=obj.id, which_user=self.context["request"].user
    )
    if not user_record:
        return None
    else:
        return CustomRecordSerializer(user_record.get()).data

Answer 2

AnonymousUser 有id=None 和pk=None，所以在这种情况下不能直接使用。相反，建议发送至create an instance of user that reflects an anonymous user。