如何在 django-rest 中设置默认的内部序列化程序数据？

Question

我有两个简单的序列化器

class UserSerializer(Serializer);
    name = serializers.CharField(required=False, default='Mile')
    age =  serializers.IntegerField(required=False, default=25)

class AccountSerializer(Serializer):
    account_id = serializers.UUIDField(required=False, default=uuid4())
    user = UserSerializer()

如果未指定，我想在 AccountSerializer 中设置默认用户。 例如，

account = AccountSerializer(data={'account_id': uuid.UUID('e623429d-b1d1-4238-91b8-03e6f5ec58f1')})
account.is_valid()
account.data


  {
    'account_id': 'e623429d-b1d1-4238-91b8-03e6f5ec58f1',
    'user': {
        'name': 'Mike',                              # user must be default
        'age': 25
    }
}

我还想在“用户字段”中设置自己的值，并默认保留其他字段 例如，

account = AccountSerializer(data={'account_id': uuid.UUID('e623429d-b1d1-4238-91b8-03e6f5ec58f1'),
                                   'user': {'name': 'Julie'}})
    account.is_valid()
    account.data

{
        'account_id': 'e623429d-b1d1-4238-91b8-03e6f5ec58f1',
        'user': {
            'name': 'Julie',                              # user name must be 'Julie' but age by default
            'age': 25
        }
    }

我应该如何实现这个？请注意，我不会将模型保存到数据库中！我只需要检查传入的 json 并将字段设置为默认值（如果未设置）

Answer 1

您可以在序列化程序中直接设置default，最后调用serializer.validated_data。它会将数据保留在您的请求中，如果没有则自动填充默认值

class UserSerializer(serializers.Serializer);
    name = serializers.CharField(required=False, default='Mike') #you want default is Mike?
    age =  serializers.IntegerField(required=False, default=25)

class AccountSerializer(serializers.Serializer):
    account_id = serializers.UUIDField(required=False, default=uuid.UUID('e623429d-b1d1-4238-91b8-03e6f5ec58f1')) #this is your default uuid user
    user = UserSerializer(required=False, default={
    'name': 'Mike',
    'age': 25
})

如果您想要更多自定义来处理验证中的特殊逻辑。你可以试试覆盖validate

class UserSerializer(serializers.Serializer):
    name = serializers.CharField(required=False)
    age = serializers.IntegerField(required=False)

    def validate_name(self, value):
        if not value:
            return 'Mike' #default name, or anything logic you want
        return value

    def validate_age(self, value):
        if not value:
            return 25 #default age
        return value

class AccountSerializer(serializers.Serializer):
    account_id = serializers.UUIDField(required=False)
    user = UserSerializer()

    def validate_account_id(self, value):
        if not value:
            return uuid.UUID('e623429d-b1d1-4238-91b8-03e6f5ec58f1')
        return value

在此之后，您调用

serializer.is_valid(raise_exception=True)
print(serializer.validated_data)

serializer.validated_data 会有你想要的数据。

Answer 2

正如你所说，你没有模型

1.serializer.py '''

class UserSerializer(serializers.Serializer):
    name = serializers.CharField(required=False, default='Mile')
    age = serializers.IntegerField(required=False, default=25) #if key age is missing, value of age become 25

    def validate(self,data):
        #other wise you can set default value of age here,
        if data.get('name',None) is None: #this conditon will be true only when name = serializer.CharField(required=False)
            data['name']='Mike'
        if data.get('age',None)is None: #this conditon will be true only when age = serializer.IntergerField(required=False)
                data['age']=25  
        return data

''' 视图.py '''

serializer = UserSerializer(data={'name': 'cc', 'age': 14})
serializer.is_valid()
# True
serializer.validated_data
# {'id': 1, 'name': 'cc', 'age': 14} 

''' 或者如果您错过在 views.py 中指定年龄 '''

serializer = UserSerializer(data={'name': 'cc'})
serializer.is_valid()
# True
serializer.validated_data
# { 'name': 'cc', 'age': 25} 

'''