python - Django Rest Framework 动态分组对象

Question

我的问题与 Django RestFramework 以及如何动态分组对象有关。我找到的最相似的答案来自 Rex Salisbury here但不适用于 n 个组:

模型.py

class Product(models.Model):
    name = models.CharField(max_length=20)

class Ingredient(models.Model):
    name = models.CharField(max_length=20)

class Mix(models.Model):
    product = models.ForeignKey(Product, on_delete=models.CASCADE)
    ingredient = models.ForeignKey(Ingredient, on_delete=models.CASCADE)
    percentage = models.FloatField()

    class Meta:
        unique_together = ('product', 'ingredient')

serializer.py

class MixSerializer(serializer.ModelSerializer):
    class Meta:
        model = Mix
        fields = ('product', 'liquid', 'percentage')

views.py

class MixView(viewsets.ModelViewSet):
    queryset = Mix.objects.all()
    serializer_class = MixSerializer

这是我目前从 API 获得的结构示例:

[ 
    {
        "product": "White Russian",
        "ingredient": "Vodka",
        "percentage": 0.54
    },
    {
        "product": "White Russian",
        "ingredient": "Coffee Liquer",
        "percentage": 0.27
    },
    {
        "product": "White Russian",
        "ingredient": "Single Cream",
        "percentage": 0.19
    }
]   

我一直在尝试以尽量减少产品名称重复的方式对这些进行分组，就像这样，

{
    "product": "White Russian",
    "ingredients": {
        "Vodka": 0.54,
        "Coffee Liquer": 0.27,
        "Single Cream": 0.19
    }
}

遵循 Nested Relationship 的文档但我不再相信这是正确的做法。我很乐意从对象过滤器获取这些数据，但无法与序列化程序/ View 一起实现。

Answer 1

首先请注意，根据您的示例，您是按产品分组的，因此您不是在寻找 MixView，而是在寻找 ProductView。

你可以做什么:

# Serializers
class MixSerializer(serializer.ModelSerializer):
    ingredient_name = serializers.CharField(source='ingredient.name')
    class Meta:
        model = Mix
        fields = ('ingredient_name', 'percentage')

class ProductSerializer(serializer.ModelSerializer):
    ingridients = MixSerializer(many=True, read_only=True)
    class Meta:
        model = Product
        fields = ('name', 'ingridients')

# Views
class ProductView(viewsets.ModelViewSet):
    queryset = Product.objects.all()
    serializer_class = ProductSerializer

应该给你这样的东西:

{
    "name": "White Russian",
    "ingredients": [
        {"ingredient_name": "Vodka", "percentage" : 0.54},
        {"ingredient_name": "Coffee Liquer", "percentage" : 0.27},
        {"ingredient_name": "Single Cream", "percentage" : 0.19}
    ]
}

附言要使其成为非只读的，您还需要在 ProductSerializer 下实现 create 和 update 方法