DRF：在具有“ManyToMany”字段和“through”表的模型中创建新对象

Question

我有以下 Django 模型：

class Product(models.Model):
    name = models.CharField(max_length=250, unique=True)
    quantity = models.IntegerField(default=0)

class Order(models.Model):
    products = models.ManyToManyField(
        Product,
        through='PositionInOrder'
    )
    discount = models.CharField(max_length=50, blank=True)
    total_sum = models.DecimalField(max_digits=11, decimal_places=2, default=0)

class PositionInOrder(models.Model):
    sale = models.ForeignKey(Order)
    product = models.ForeignKey(Product)
    quantity = models.PositiveIntegerField()
    price = models.PositiveIntegerField()

以及以下序列化程序：

class ProductSerializer(serializers.ModelSerializer):

    class Meta:
        model = Product
        fields = '__all__'

class PositionInOrderSerializer(serializers.HyperlinkedModelSerializer):
    sale = serializers.ReadOnlyField()
    product = serializers.ReadOnlyField()

    class Meta:
        model = PositionInOrder
        fields = "__all__"

class OrderSerializer(serializers.ModelSerializer):
    products = PositionInOrderSerializer(many=True)

    def create(self, validated_data):
        products = validated_data.pop('products')
        order = Order.objects.create(**validated_data)
        return order

    class Meta:
        model = Order
        fields = '__all__'

我想创建新订单。发送包含此 json 的 post 查询：

{
    "products": [{"id": 2606, "name": "Some name", "quantity": 140, "price": 250}],
    "discount": "15",
    "total_sum": 500
}

在 OrderSerialization 类的 create() 方法中，我得到 products=: [OrderedDict([('quantity', 140), ('price', 250)])] 并且没有关于 product_id 和产品名称。我怎样才能得到它们？

Answer 1

尝试在PositionInOrderSerializer 中显式定义id 和name 字段：

class PositionInOrderSerializer(serializers.HyperlinkedModelSerializer):
    sale = serializers.ReadOnlyField()
    id = serializers.IntegerField(source='product.id')
    name = serializers.IntegerField(source='product.name')

    class Meta:
        model = PositionInOrder
        fields = "__all__"