Django Rest Framework的贯穿模型问题

debugcn 发表于 Dev

贡萨洛·丹布拉

当我列出Recipe对象时会发生这种情况。试图尽可能做到这里，我没有得到任何错误，但我得到的响应是，如下：

# response of Recipe.objects.all()
[
    {
        "user": 1,
        "name": "sandwich",
        "ingredients": [
            {},
            {}
        ],
        "created": "2021-01-11T00:47:04.932071-03:00",
        "modified": "2021-01-11T00:47:04.932167-03:00"
    }
]

当模型是：

class Recipe(models.Model):
    user = models.ForeignKey('users.User', on_delete=models.CASCADE, null=False)
    name = models.CharField(blank=False, max_length=50)
    ingredients = models.ManyToManyField('recipes.Ingredient', through='recipes.IngredientComposition')
    # some other fields...

class Ingredient(BaseModel):
    name = models.CharField(blank=False, max_length=25, unique=True
                            error_messages={'unique': 'Ingredient already exists'})

class IngredientComposition(models.Model):    
    ingredient = models.ForeignKey('Ingredient', on_delete=models.CASCADE, null=False)
    recipe = models.ForeignKey('recipes.Recipe', on_delete=models.CASCADE, null=False)
    quantity = models.DecimalField(max_digits=21, decimal_places=3, null=False, default=1)

及其序列化器：

class RecipeSerializer(serializers.ModelSerializer):
    ingredients = IngredientCompositionSerializer(read_only=True, many=True)
    class Meta:
        model = Recipe
        fields = ['user', 'name', 'ingredients', 'created', 'modified']

class IngredientSerializer(serializers.ModelSerializer):
    class Meta:
        model = Ingredient
        fields = ['name', 'created', 'modified']

class IngredientCompositionSerializer(serializers.HyperlinkedModelSerializer):
    name = serializers.ReadOnlyField(source='ingredient.name')
    class Meta:
        model = IngredientComposition
        fields = ['name', 'quantity']

预期的响应是：

[
    {
        "user": 1,
        "name": "sandwich",
        "ingredients": [
            {"name": "bread", "quantity": 2.0},
            {"name": "cheese", "quantity": 3.0}
        ],
        "created": "2021-01-11T00:47:04.932071-03:00",
        "modified": "2021-01-11T00:47:04.932167-03:00"
    }
]

我想念什么？

阿什温地带

添加相关名称 recipe

class IngredientComposition(models.Model):    
    ingredient = models.ForeignKey('Ingredient', on_delete=models.CASCADE, null=False)
    recipe = models.ForeignKey('recipes.Recipe', on_delete=models.CASCADE, null=False, related_name='ingredients_list') # change here
    quantity = models.DecimalField(max_digits=21, decimal_places=3, null=False, default=1)

然后将该字段添加到 RecipeSerializer

class RecipeSerializer(serializers.ModelSerializer):
    ingredients_list = IngredientCompositionSerializer(read_only=True, many=True) # change here
    class Meta:
        model = Recipe
        fields = ['user', 'name', 'ingredients_list', 'created', 'modified'] # change here 'ingredients_list'

正如ingredients已经ManyToManyField在模型中那样Recipe，它会导致该问题。

PS：我认为您不需要ingredients = models.ManyToManyField('recipes.Ingredient', through='recipes.IngredientComposition')字段，但我不了解您的其余业务逻辑...

该解决方案应该不管。

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