如何使用嵌套对象序列化Django模型(Django REST Framework)

Question

如果我有两个序列化程序,其中一个是嵌套的,我该如何设置restore_object方法？例如,如果我定义了以下序列化程序,如何为嵌套序列化程序定义还原对象字段？从文档中可以看出如何处理这种情况并不明显.

class UserSerializer(serializers.Serializer):
    first_name = serializers.CharField(required=True, max_length=30)
    last_name = serializers.CharField(required=True, max_length=30)
    username = serializers.CharField(required=True, max_length=30)
    email = serializers.EmailField(required=True)
    password = serializers.CharField(required=True)

    def restore_object(self, attrs, instance=None):
        if instance:
            instance.first_name = attrs.get('first_name', instance.first_name)
            instance.last_name = attrs.get('last_name', instance.last_name)
            instance.email = attrs.get('email', instance.email)
            instance.password = attrs.get('password', instance.password)

class UserProfileSerializer(serializers.Serializer):
    user = UserSerializer()
    bio = serializers.CharField()
    def restore_object(self, attrs, instance=None):
        if instance:
            instance.bio = attrs.get('bio', instance.bio)
            instance.user = ?????

Answer 1

重要的旁注: 看起来您使用的是旧用户/配置文件方法.由于Django 1.5没有默认用户和您的自定义配置文件模型的分离.您必须创建自己的用户模型并使用它而不是默认用户模型: 自定义用户配置文件@Django Docs

序列化

我想为您提供一种序列化和恢复模型的不同方法.可以使用以下代码序列化所有模型对象:

from django.core import serializers
serialized_data = serializers.serialize("json", myInstance)

或序列化多个对象:

serialized_data = serializers.serialize("json", User.objects.all())

然后将外键和m2m关系存储在id数组中.

如果只想序列化一部分字段:

serialized_data = serializers.serialize("json", myUserInstance, fields=('first_name ','last_name ','email ','password '))

要保存用户配置文件,您只需编写:

serialized_data = serializers.serialize("json", myUserProfileInstance)

用户标识保存在序列化数据中,如下所示:

{
    "pk": 1,
    "model": "profile.UserProfile",
    "fields": {
        "bio": "self-taught couch potato",
        "user": 1
    }
}

如果您也想要序列化中的相关用户字段,则需要修改用户模型:

class UserManager(models.Manager):
    def get_by_natural_key(self, first_name, last_name):
        return self.get(first_name=first_name, last_name=last_name)

class User(models.Model):
    objects = UserManager()

    first_name = models.CharField(max_length=100)
    last_name = models.CharField(max_length=100)
    ...

    def natural_key(self):
        return (self.first_name, self.last_name)

    class Meta:
        unique_together = (('first_name', 'last_name'),)

使用自然键进行序列化时,需要添加use_natural_keys参数:

serialized_data = serializers.serialize("json", myUserProfileInstance, use_natural_keys=True)

这导致以下输出:

{
    "pk": 2,
    "model": "profile.UserProfile",
    "fields": {
        "bio": "time-traveling smartass",
        "user": ["Dr.", "Who"]
    }
}

反序列化

反序列化和保存就像以下一样简单:

for deserialized_object in serializers.deserialize("json", serialized_data):
    deserialized_object.save()

可以在Django文档中找到更多信息:序列化Django对象