DRF如何仅显示序列化嵌套对象的非空值

Question

我创建了序列化嵌套 be 使用序列化器作为文档

models.py

class Category(models.Model):
    name = models.CharField("Name", "name", max_length=255)
    iconname = models.CharField("Icon Name", "iconname", max_length=255)
    budgetamount = models.DecimalField(
        max_digits=19, decimal_places=2, default=0)
    iconcolor = models.CharField(
        "Icon Color", "iconcolor", default='4294951175', max_length=255)

    def __str__(self):
        return self.name


class DailyExpense(models.Model):
    payee_item_desc = models.CharField(
        "Payee Item Description", "payee_item_desc", max_length=255)
    category = models.ForeignKey(
        Category, related_name='dailyexpense_category', on_delete=models.CASCADE, blank=True, null=True)
    amount = models.DecimalField(max_digits=19, decimal_places=2)
    remarks = models.CharField(
        "Remarks", "remarks", max_length=255, blank=True, null=True)
    tran_date = models.DateTimeField()
    isnotclear = models.BooleanField(default=False)

    def __str__(self):
        return self.payee_item_desc

serializers.py

class DailyExpenseSerializer(serializers.ModelSerializer):
    class Meta:
        model = DailyExpense
        fields = "__all__"


class CategoryWithDailyExpenseSerializer(serializers.ModelSerializer):
    dailyexpense_category = DailyExpenseSerializer(
        source='filtered_dailyexpense_category', many=True, read_only=True)

    class Meta:
        model = Category
        fields = ('id', 'name', 'iconname',
                  'budgetamount', 'iconcolor', 'dailyexpense_category')

views.py

class CategoryWithDailyExpenseViewSet(viewsets.ModelViewSet):
    def get_queryset(self):
        fromDate = parse_datetime(self.request.query_params.get(
            'fromDate') + ' ' + '00:00:00').strftime('%Y-%m-%d %H:%M:%S')
        toDate = parse_datetime(self.request.query_params.get(
            'toDate') + ' ' + '00:00:00').strftime('%Y-%m-%d %H:%M:%S')
        queryset = Category.objects.prefetch_related(
            Prefetch('dailyexpense_category', queryset=DailyExpense.objects.filter(
                tran_date__range=[fromDate, toDate]).order_by('tran_date'), to_attr='filtered_dailyexpense_category')
        )
        return queryset

    # queryset = Category.objects.all().order_by('name')
    serializer_class = CategoryWithDailyExpenseSerializer
    filter_class = CategoryFilter

我得到的结果如下

[
{
    "id": 1,
    "name": "Auto",
    "iconname": "taxi_alert_outlined",
    "budgetamount": "0.00",
    "iconcolor": "4294951175",
    "dailyexpense_category": []
},
{
    "id": 2,
    "name": "Foods:Breakfast",
    "iconname": "emoji_food_beverage",
    "budgetamount": "0.00",
    "iconcolor": "4294951175",
    "dailyexpense_category": [
        {
            "id": 24574,
            "payee_item_desc": "เซเว่น",
            "amount": "-100.00",
            "remarks": "เฟิส",
            "tran_date": "2022-04-01T00:00:00Z",
            "isnotclear": false,
            "category": 2
        }
    ]
}

]

但我只想显示非空白嵌套对象，如下所示

[
{
    "id": 2,
    "name": "Foods:Breakfast",
    "iconname": "emoji_food_beverage",
    "budgetamount": "0.00",
    "iconcolor": "4294951175",
    "dailyexpense_category": [
        {
            "id": 24574,
            "payee_item_desc": "เซเว่น",
            "amount": "-100.00",
            "remarks": "เฟิส",
            "tran_date": "2022-04-01T00:00:00Z",
            "isnotclear": false,
            "category": 2
        }
    ]
}

]

我尝试创建自定义字段，例如对嵌套对象求和或对嵌套对象计数但我想要一些更容易过滤的东西，而不是空白反对。

Answer 1

我认为您需要添加如下过滤器。

queryset = Category.objects.prefetch_related(
    Prefetch('dailyexpense_category', 
    queryset=DailyExpense.objects.filter(tran_date__range=[fromDate, toDate]).order_by('tran_date'))
).annotate(num_daily=Count('dailyexpense_category', filter = Q('dailyexpense_category__tran_date__range' =[fromDate, toDate]))).filter(num_daily__gt=0)

希望对您有所帮助。

DRF如何仅显示序列化嵌套对象的非空值

DRF How to display only not blank value of serializing nested object

django

django-views

django-rest-framework