Django REST框架：使用嵌套对象值（而不是主键）创建和更新对象 [英] Django REST Framework: create and update an object with a nested object value (instead of Primary Key)

问题描述

我有两个模型一个国家和一个办公室模型。办公室模型有一个ForeignKey到国家模型：

  class国家（TranslatableModel）：
 iso = models.CharField （
 max_length = 2，verbose_name = _（'iso code'），
 help_text =ISO 3166 ALPHA-2代码）
 translations = TranslatedFields（
 name = models。 CharField（max_length = 100，verbose_name = _（'name'）），
）
 
 
 
 class Office（models.Model）：
 country = models.ForeignKey（
 Country，related_name ='country'，verbose_name = _（'country'））
  

现在我想编写一个django-rest-framework-serializer来简单地发送 {country：us} 来获取ForeingKey到国家

如何实现？

解决方案

只有

只需将发送表示给客户端（只读，而不是处理从他们的反序列化演示）

  class OfficeSerializer（serializers.ModelSerializer）：
 country = serializers.Field（source ='country.iso '）＃这个序列化程序的字段
＃是只读
  

正如你所见，将从您的办公室实例中读取 country.iso ，解析为 'us'例如，如果输出的 {'，则将其放入一个名为'country'国家'：'我们'}

可写嵌套字段

现在完成这个，我们写一个自定义的 OfficeSerializer.create（）：

  def create（self，validated_data）：
＃这个输入格式是{country：iso} 
 
＃而不是使用国家/地区的ID / PK，我们查找使用iso字段
 country_iso = validated_data.pop（'country'）
c ountry = Country.objects.get（iso = country_iso）
 
＃创建新的Office对象，并将国家/地区对象附加到
 office = Office.objects.create（country = country， ** validated_data）
 
＃注意事项我已将** validated_data放在Office对象生成器
＃中，以防万一您想将更多的字段发送到Office模型
 
＃最后一个serializer.create（）预计返回对象实例
 return office 
  

对于 OfficeSerializer.update（），类似于：

  def update（self，instance，validated_data）：
＃instance是你的Office对象
＃你应该在这里更新Office字段
＃instance.field_x = validated_data ['field_x'] 
 
＃再次获取Country对象
 
 country_iso = validated_data.pop（'country'）
 country = Country.objects.get（iso = country_iso）
 
＃更新Office对象
 instance.country = country 
 instance.save（）
 
返回实例
  

I have two models one Country and one Office model. The office model has a ForeignKey to the Country model:

class Country(TranslatableModel):
    iso = models.CharField(
        max_length=2, verbose_name=_('iso code'),
        help_text="ISO 3166 ALPHA-2 code")
    translations = TranslatedFields(
        name=models.CharField(max_length=100, verbose_name=_('name')),
    )



class Office(models.Model):
    country = models.ForeignKey(
        Country, related_name='country', verbose_name=_('country'))

Now I want to write a django-rest-framework-serializer to send simply {"country": "us"} to get a ForeingKey to the Country Model.

How can I achieve this?

解决方案

Read-only

To simply send that representation to the client (read-only, not dealing with creating objects from their deserialized representation)

class OfficeSerializer(serializers.ModelSerializer):
    country = serializers.Field(source='country.iso') # this field of the serializer
                                                      # is read-only

As you can see, it'll read will read country.iso from your office instance, which resolves to 'us' e.g., then gets put into a serializer key called 'country', given you an output of {'country': 'us'}

Writable nested field

Now to complete this, let's write a custom OfficeSerializer.create():

def create(self, validated_data):
    # This expects an input format of {"country": "iso"}

    # Instead of using the ID/PK of country, we look it up using iso field
    country_iso = validated_data.pop('country')
    country = Country.objects.get(iso=country_iso)

    # Create the new Office object, and attach the country object to it
    office = Office.objects.create(country=country, **validated_data)

    # Notice I've left **validated_data in the Office object builder,
    # just in case you want to send in more fields to the Office model

    # Finally a serializer.create() is expected to return the object instance
    return office

As for a OfficeSerializer.update() it's similar:

def update(self, instance, validated_data):
    # instance is your Office object
    # You should update the Office fields here
    # instance.field_x = validated_data['field_x']

    # Let's grab the Country object again

    country_iso = validated_data.pop('country')
    country = Country.objects.get(iso=country_iso)

    # Update the Office object
    instance.country = country
    instance.save()

    return instance

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