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Django Rest Framework 3非模型对象的序列化器?

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我正在从2.4升级到DRF3.1.1 . 我使用自定义序列化程序来创建不是模型的对象的实例 .

在2.4中,这样做很容易,因为在序列化器中,我会在 restore_object() 中创建对象 . 在视图中,我调用 serializer.is_valid() 然后使用 serializer.object 从序列化器中弹出对象的实例 . 然后我可以做任何我想做的事 .

随着3.x的更改,将实例从对象中取出更难,因为创建和更新方法应该进行保存,并且“serializer.object”不再可用 .

作为一个例子,我曾经为我的"UserRegistration"对象提供此功能 . 这不是一个模型,因为它是一个便利对象,服务器解析并将数据存储在许多其他对象/ db表中 .

class UserRegistration(object):
    def __init__(self, full_name, stage_name, password="", email="", locale="en_US"):
        self.full_name = full_name
        self.password = password
        self.locale = locale
        self.email = email
        self.stage_name = stage_name

这是相关的DRF-2.4序列化器:

class UserRegistrationSerializer(serializers.Serializer):
    full_name = serializers.CharField(max_length=128, required=False)
    stage_name = serializers.CharField(max_length=128)
    password = serializers.CharField(max_length=128, required=False)
    locale = serializers.CharField(max_length=10, required=False)
    # use CharField instead of EmailField for email. We do our own validation later to make for a better error msg.
    email = serializers.CharField(max_length=254, required=False)

    def restore_object(self, attrs, instance=None):
        if instance is not None:
            instance.full_name = attrs.get('full_name', instance.full_name)
            instance.password = attrs.get('password', instance.password)
            instance.locale = attrs.get('locale', instance.locale)
            instance.email = attrs.get('email', instance.email)
            instance.stage_name = attrs.get('stage_name', instance.stage_name)
            return instance
        return UserRegistration(**attrs)

然后在我看来,我这样做:

class UserRegistration(APIView):
    throttle_classes = ()
    serializer_class = UserRegistrationSerializer

    def post(self, request, format=None):
        event_type = "user_registration"
        serializer = UserRegistrationSerializer(data=request.DATA, context={'request': request})
        try:
            if serializer.is_valid():
            user_registration = serializer.object
            # save user_registration pieces in various places...

但是,在DRF3中,我 serializer.object 已经消失了 . 文档说使用 serializer.validated_data 做"validation",但这只是一个哈希而不是真正的对象 . 有没有办法获得对象?

整个事情似乎与DB对象结合在一起,在这种特殊情况下,这正是我想要避免的 .

我刚刚错过了一些新的DRF3概念吗?

2 回答

  • 12

    感谢@levi回答的开头,但不幸的是,这不是全部,所以我认为这是一个更完整的答案 .

    我原来问:

    我刚刚错过了一些新的DRF3概念吗?

    原来......是的 . 我曾是 . 文档讨论了新的 Single-step object creation ,这使我认为序列化和模型已经变得更加紧密耦合 . 这种想法是不正确的,因为如果您编写自己的自定义序列化程序,则由您在新的 serializer.update()serializer.create() 方法中执行实际对象保存( or not ) .

    我还问过:

    在2.4中,这样做很容易,因为在序列化程序中,我会在restore_object()中创建对象 . 在视图中,我调用serializer.is_valid()然后使用serializer.object将该对象的实例弹出序列化程序 . 然后我可以做任何我想做的事 . 随着3.x的更改,将实例从对象中取出更难,因为创建和更新方法应该进行保存,并且“serializer.object”不再可用 .

    虽然没有 serializer.object 可以用来在调用 serializer.is_valid() 之后拉出创建的对象,但是 serializer.save() 方法返回对象本身,在我的情况下这很好 .

    事实证明,代码变化根本不是很大 . 这是我对DRF-3非常满意的新代码:

    class UserRegistration(object):
        def __init__(self, full_name, stage_name, password="", email="", locale="en_US", notification_pref="ask"):
            self.full_name = full_name
            self.password = password
            self.locale = locale
            self.email = email
            self.stage_name = stage_name
    
    
    class UserRegistrationSerializer(serializers.Serializer):
        full_name = serializers.CharField(max_length=128, required=False)
        stage_name = serializers.CharField(max_length=128)
        password = serializers.CharField(max_length=128, required=False)
        locale = serializers.CharField(max_length=10, required=False)
        # use CharField instead of EmailField for email. We do our own validation later to make for a better error msg.
        email = serializers.CharField(max_length=254, required=False)
    
        def update(self, instance, validated_data):
            instance.full_name = validated_data.get('full_name', instance.full_name)
            instance.password = validated_data.get('password', instance.password)
            instance.locale = validated_data.get('locale', instance.locale)
            instance.email = validated_data.get('email', instance.email)
            instance.stage_name = validated_data.get('stage_name', instance.stage_name)
            return instance
    
        def create(self, validated_data):
            return UserRegistration(**validated_data)
    

    请注意,没有将对象保存到Serializer中的任何DB . 我只是创建或更新对象然后返回它 .

    现在视图看起来像这样:

    class UserRegistration(APIView):
        throttle_classes = ()
        serializer_class = UserRegistrationSerializer
    
        def post(self, request, format=None):
            event_type = "user_registration"
            serializer = UserRegistrationSerializer(data=request.DATA, context={'request': request})
            try:
                if serializer.is_valid():
                    user_registration = serializer.save()
                    # save user_registration pieces in various places...
    

    我在原帖中也说过:

    整个事情似乎更多地与DB对象结合,在这种特殊情况下,这正是我想要避免的 .

    此声明也是不正确的,因为创建和更新方法不必将任何内容保存到任何数据库 .

    这里需要注意的是代码是有用的,但显然我只是围绕一些DRF2.x-> 3.x更改,所以我可以用非DRF方式做这件事 . 如果是这样,有人知道请随时告诉我如何做得更好 . :)

  • 1

    是的,你可以使用DRF 3来获取对象 . 你的 update 方法应该有这个签名 update(self, instance, validated_data)

    您的序列化程序应如下所示:

    class UserRegistrationSerializer(serializers.Serializer):
        full_name = serializers.CharField(max_length=128, required=False)
        stage_name = serializers.CharField(max_length=128)
        password = serializers.CharField(max_length=128, required=False)
        locale = serializers.CharField(max_length=10, required=False)
        # use CharField instead of EmailField for email. We do our own validation later to make for a better error msg.
        email = serializers.CharField(max_length=254, required=False)
    
        def update(self, instance, validated_data):
              // here instance is the object .
    

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