Django：序列化多个链接模型的列表 [英] Django: Serializing a list of multiple, chained models

问题描述

给出两个具有相同父基类的不同模型。有没有办法使用Django Rest Framework序列化程序或serpy序列化包含两个子模型实例的链表？

Given two different models, with the same parent base class. Is there any way, using either Django Rest Framework Serializers or serpy, to serialize a chained list containing instances of both the child models?

给出一些示例模型：

class BaseModel(models.Model):
   created_at = models.DateField()

   class Meta:
       abstract = True


class ChildModel1(BaseModel):
    field_one = models.TextField()


class ChildModel2(BaseModel):
    field_two = models.TextField()

和一个示例视图：

def get(self, request):

    q1 = ChildModel1.objects.all()
    q2 = ChildModel2.objects.all()

    chained_list = sorted(
        chain(q1, q2),
        key=attrgetter('created_at'))

    serializer = BaseModelSerializer(chained_list, many=True)

模型取自这个问题。

在我目前的尝试下，我得到一个相当明显的错误，内容如下：

With my current attempts I get a quite obvious error saying something like:

AttributeError: 'ChildModel1' object has no attribute 'field_two'

我知道将两个模型与

我测试过的一些序列化器示例：

Some examples of serializers I have tested:

第一个示例：

class BaseModelSerializer(serializers.ModelSerializer):

   class Meta:
       model = BaseModel

第二个示例：

class BaseModelSerializer(serpy.Serializer):
   created_at = serpy.StrField()

   field_one = serpy.StrField(required=False)
   field_two = serpy.StrField(required=False)

解决方案

您可以定义序列化程序，该序列化程序将根据模型将两个或多个序列化程序组合在一起：

You can define serializer that will combine two or more serializers together based on model:

class Model1Serializer(serializers.Serializer):
    ...

class Model2Serializer(serializers.Serializer):
    ...

class SummarySerializer(serializers.Serializer):
    """ Serializer that renders each instance with its own specific serializer """

    @classmethod
    def get_serializer(cls, model):
        if model == Model1:
            return Model1Serializer
        elif model == Model2:
            return Model2Serializer

    def to_representation(self, instance):
        serializer = self.get_serializer(instance.__class__)
        return serializer(instance, context=self.context).data

这将适用于所有型号，不仅适用于一类儿童。

This will work for any models, not only for childs of one class.

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