python - Django REST框架: create and update an object with a nested object value (instead of Primary Key)

Question

我有两种型号，一种是国家/地区型号，一种是办公室型号。办公室模型有一个到国家/地区模型的ForeignKey:

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'))

现在我想编写一个 django-rest-framework-serializer 来简单地发送 {"country": "us"} 以获得国家/地区模型的 ForeingKey。

我怎样才能实现这个目标？

Answer 1

只读

简单地发送该表示到客户端(只读，不处理从反序列化表示创建对象)

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

如您所见，它将从您的 office 实例读取 country.iso，解析为 'us'，例如，然后放入名为 'country' 的序列化器键中，输出为 {'country': 'us'}

可写嵌套字段

现在为了完成此任务，让我们编写一个自定义 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

至于 OfficeSerializer.update() ，它是类似的:

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