在Meta中使用动态模型创建通用序列化程序

Question

当我在django-rest0-framework中创建一个基于ModelSerializer的Serializer时,我将不得不在Meta类中传递模型:

class ClientSerializer(ModelSerializer):
    class Meta:
        model = Client

我想创建一个通用的序列化程序,它基于URL动态地包含模型.

我的设置因此包括urls.py和viewset:

urls.py:

 url(r'^api/v1/general/(?P<model>\w+)', kernel_api_views.GeneralViewSet.as_view({'get':'list'}))

和views.py:

class GeneralViewSet(viewsets.ModelViewSet):

     def get_queryset(self):
            # Dynamically get the model class from myapp.models
            queryset = getattr(myapp.models, model).objects.all()
            return queryset

     def get_serializer_class(self):
         return getattr(myapp.serializers, self.kwargs['model']+'Serializer')

其中有:http://127.0.0.1:8000 /api/v1/general/Client将Client.objects.all()作为queryset,将ClientSerializer类作为序列化程序

问题:如何制作它以便我可以调用'GeneralSerializer'并动态分配模型？

Answer 1

您可以通过以下方式实现:

serializers.py

class GeneralSerializer(serializers.ModelSerializer):

    class Meta:
        model = None

views.py

class GeneralViewSet(viewsets.ModelViewSet):

     def get_queryset(self):
         model = self.kwargs.get('model')
         return model.objects.all()           

     def get_serializer_class(self):
         GeneralSerializer.Meta.model = self.kwargs.get('model')
         return GeneralSerializer  

在serializers.py,我们定义GeneralSerializer其model在Meta作为None.我们将model在调用时覆盖该值get_serializer_class().

然后在我们的views.py文件中,我们定义一个GeneralViewSetwith get_queryset()和 get_serializer_class()overridden.

在get_queryset(),我们获取modelfrom 的值kwargs并返回该查询集.

在 get_serializer_class(),我们将modelfor GeneralSerializer的值设置为从中获得的值kwargs然后返回GeneralSerializer.

Answer 2

到目前为止，我知道如果使用模型序列化器，则无法创建通用序列化器，但是可以使用基类并从该基类派生所有模型来获得相同的解决方案。实现一种方法以返回序列化器，然后使用该方法生成动态序列化器。在过去的两年中，我一直在使用这项技术，并且对我来说还算不错-

class BaseModel(models.Model):
    class Meta:
         abstract = True # define abstract so that it does not cause any problem with model hierarchy in database

    @classmethod
    def get_serializer(cls):
         class BaseSerializer(serializers.ModelSerializer):
               class Meta:
                    model = cls # this is the main trick here, this is how I tell the serializer about the model class

         return BaseSerializer #return the class object so we can use this serializer

现在从中导出模型-

class Derived1(BaseModel):
    pass

class Derived2(BaseModel):
    pass

如果要覆盖串行器，则只需在所需的序列器中进行即可。例如 -

class DerivedOverride(BaseModel):
    @classmethod
    def get_serializer(cls):
         super_serializer = BaseModel.get_serializer() # this important to not to break the serializing hierarchy
         class BaseSerializer(super_serializer):
               class Meta:
                    model = cls # this is the main trick here, this is how I tell the serializer about the model class

         return BaseSerializer

就是这样，现在每个类都有自己的动态序列化器，但我们只是在一个地方定义了它。

现在在视图集中使用序列化器-

class Derive1ViewSet(ModelViewSet):
    serializer_class = Derived1.get_serializer()

class Derive2ViewSet(ModelViewSet):
    serializer_class = Derived2.get_serializer()

然后从那里继续。