Django Rest框架限制get_queryset结果不包括所有字段

Question

view.py

class charity_totals(generics.ListAPIView):
    serializer_class= CharityTotalSerializer
    queryset=Transaction.objects.all()
    def get_queryset(self):
        queryset = super().get_queryset()
        user_id = self.request.GET.get('userID')
        if user_id is None:
            return queryset
        queryset = queryset.filter(userID=user_id)
        return queryset.values('charityID').annotate(total_donation=Sum('transactionAmount'))

serializer.py

class CharityTotalSerializer(ModelSerializer):
    charity_name= serializer.ReadOnlyField(source='charityID.charityName')
    total_donation= serializer.DecimalField(max_digits=64,decimal_places=2)
    class Meta:
        model = Transaction
        fields = ['charity_name','total_donation']

型号

class Transaction(models.Model):
    transactionAmount = models.DecimalField(max_digits=6, decimal_places=2)
    userID = models.ForeignKey(User,on_delete=models.CASCADE)
    charityID = models.ForeignKey(Charity,on_delete=models.CASCADE, related_name='charity_set')
    processed = models.BooleanField(auto_created=True, default=False)
    transactionDate = models.DateField(auto_now_add=True)

关闭诸如 http://localhost:8000/requests/charitytotal/?userID=1 这样的请求，我的 json 响应仅限于 [{"total_donation":"3.00"},{"total_donation":"17.00"}] 并且不包括慈善机构名称在序列化程序中指定。据我了解，.values 应该返回charityID 和指定的total_donation 的字典，它们应该能够与我的序列化程序交互。任何见解将不胜感激

Answer 1

这是因为当您在 request.GET 中获取 userID 的值时，您正在从 get_queryset 方法返回 Values 查询集。此外，我认为以这种方式返回对您很重要，这样您就可以按总捐赠的值进行分组和求和。所以，我认为你可以这样处理：

首先，更改get_queryset方法，返回标注的慈善机构名称：

from django.db.models import F, Sum
...

def get_queryset(self):
    queryset = super().get_queryset()
    user_id = self.request.GET.get('userID')
    if user_id is not None:
        queryset = queryset.filter(userID=user_id)
    return queryset.values('charityID').annotate(total_donation=Sum('transactionAmount')).annotate(charity_name=F('charityID__charityName'))

然后像这样更新序列化器：

class CharityTotalSerializer(ModelSerializer):
    charity_name= serializer.ReadOnlyField()  # no need to define source
    total_donation= serializer.DecimalField(max_digits=64,decimal_places=2)
    class Meta:
        model = Transaction
        fields = ['charity_name','total_donation']

另外，最好有charityName 唯一（在模型中使用unique=True），这样它就不会产生令人困惑的结果。

Answer 2

你必须把它放到 Serializer 中，它才能正常工作。

charity_name = serializer.SerializerMethodField()

def get_charity_name(self, instance):
    return instance.charityID.name