Django Rest框架可写嵌套序列化程序 [英] Django Rest Framework writable nested serializers

问题描述

我正在写一个食谱组织者作为课程的示例项目。除了使用一些非常基本的功能之外，我对DRF的经验也不是很高。这是目标：

创建一个新的配方与相关的成分。在创建配方对象的同时创建成分对象。

models.py：

  class Ingredient（models.Model）：
 name = models.CharField（max_length = 100）
 
 def __str __（self） 
 return self.name 
 
 
 class食谱（models.Model）：
 name = models.CharField（max_length = 100）
 description = models。 TextField（blank = True，null = True，help_text =这是您的食谱的快速描述）
 directions = models.TextField（help_text =如何制作食谱）
 ingredients = models .ManyToManyField（Ingredient）
 
 def __str __（self）：
 return self.name 
  

serializers.py

  class IngredientSerializer serializer.ModelSerializer）：
 
 class Meta：
 model = Ingredient 
 
 
 class RecipeSerializer（serializers.ModelSerializer）：
 ingredientsie nts = IngredientSerializer（many = True）
 
 class Meta：
 model =配方
 
 def create（self，validated_data）：
 ingredients_data = validated_data。 pop（'ingredients'）
 recipe = Recipe.objects.create（** validated_data）
在ingredients_data中的ingredients_data：
 Ingredient.objects.create（** ingredients_data）
返回食谱
  

这成功地在数据库中创建了食谱对象和成分对象，但不将食谱配料清单。我假设这是因为当我运行 ingredients_data = validated_data.pop（'ingredients'）时， validated_data 删除原料，所以当我使用 validated_data 创建新的食谱时，没有相关的成分。

然而我似乎没有找出一种方法来保持与食谱相关的成分。

解决方案

我想到，ManyToMany关系可以'直到所有未处理的对象都被创建为止。 （有关许多文档，请参阅Django文档页面对于许多关系）

以下是工作代码：

序列化器。

$ b

 $ code class RecipeSerializer（serializers.ModelSerializer）：
 ingredients = IngredientSerializer（many = True） 
 
 class Meta：
 model = Recipe 
 
 def create（self，validated_data）：
 ingredients_data = validated_data.pop（'ingredients'）
 recipe = Recipe.objects.create（** validated_data）
 
在ingredients_data中的成分：
 ingredients，created = Ingredient.objects.get_or_create（name = ingredients ['name']） 
 recipe.ingredients.add（成分）
返回食谱
  

I'm writing a recipe organizer as a sample project for a class. I'm not very experienced with DRF other than using some very basic functionality. Here's the objective:

Create a new Recipe with associated Ingredients. Create the Ingredient objects at the same time as creating the Recipe object.

models.py:

class Ingredient(models.Model):
name = models.CharField(max_length=100)

def __str__(self):
    return self.name


class Recipe(models.Model):
    name = models.CharField(max_length=100)
    description = models.TextField(blank=True, null=True, help_text="This is a quick description of your recipe")
    directions = models.TextField(help_text="How to make the recipe")
    ingredients = models.ManyToManyField(Ingredient)

    def __str__(self):
        return self.name

serializers.py

class IngredientSerializer(serializers.ModelSerializer):

    class Meta:
        model = Ingredient


class RecipeSerializer(serializers.ModelSerializer):
    ingredients = IngredientSerializer(many=True)

    class Meta:
        model = Recipe

    def create(self, validated_data):
        ingredients_data = validated_data.pop('ingredients')
        recipe = Recipe.objects.create(**validated_data)
        for ingredient_data in ingredients_data:
            Ingredient.objects.create(**ingredient_data)
        return recipe

This successfully creates the Recipe object AND the Ingredients objects in the database, but doesn't associate the list of Ingredients with the Recipe. I assume this is because when I run ingredients_data = validated_data.pop('ingredients'), the validated_data dictionary gets its Ingredients removed, so when I create a new Recipe using validated_data, there aren't associated ingredients.

However I can't seem to figure out a way to keep ingredients associated with the recipe.

解决方案

I figured out that ManyToMany relationships can't be established until all of the uncreated objects have been created. (See the Django Docs page on many-to-many relationships.)

Here's the working code:

serializers.py

class RecipeSerializer(serializers.ModelSerializer):
    ingredients = IngredientSerializer(many=True)

    class Meta:
        model = Recipe

    def create(self, validated_data):
        ingredients_data = validated_data.pop('ingredients')
        recipe = Recipe.objects.create(**validated_data)

        for ingredient in ingredients_data:
            ingredient, created = Ingredient.objects.get_or_create(name=ingredient['name'])
            recipe.ingredients.add(ingredient)
        return recipe

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