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在我使用的 Django 项目中mongoengine，它为 MongoDB 集合提供了 Django 样式模型。我还使用django-rest-framework-mongoenginewitch extends DRF 来支持Documents、EmbeddedDocuments和MongoDBDynamicDocuments的DynamicEmbeddedDocumentsMongoEngine 模型表示。

而 Django 和 DRF 允许在模型中使用抽象类。现在由 DRF-mongoengine 支持。但是我相信可以通过编写自定义序列化器来添加对抽象模型的支持。

到目前为止，我无法成功，如果您能帮助我实现这一目标，我将不胜感激。

class Entry(Document)
    meta = {
        'abstract': True,
        'allow_inheritance': True,
    }
    text = StringField()

class Post(Entry)
    meta = {
        'allow_inheritance': True,
    }

class comment(Entry)
    meta = {
        'allow_inheritance': True,
    }
    post = ReferenceField(Post) # No Problem serializing this
    # for the sake of Demonstration, related is a list of posts and comments
    related = ListField(ReferenceField(Entry)) # This is not supported by DRF-mongoengine

class PostSerializer(DocumentSerializer) # Works
    class Meta:
        model = Post
        fields = '__all__'

class PostsViewSet(ModelViewSet):
    serializer_class = PostSerializer
    queryset = Post.objects.all()

class CommentSerializer(DocumentSerializer) # Fails
    class Meta:
        model = Comment
        fields = '__all__'

class CommentsViewSet(ModelViewSet):
    serializer_class = CommentSerializer
    queryset = Comment.objects.all()

这是访问该 CommentViewSet 的错误消息的尾部：

 File "~/app/venv/lib/python3.9/site-packages/rest_framework_mongoengine/serializers.py", line 345, in get_fields
    field_class, field_kwargs = self.build_field(
  File "~/app/venv/lib/python3.9/site-packages/rest_framework_mongoengine/serializers.py", line 570, in build_field
    child_class, child_kwargs = self.build_field(child_name, info, model_class, nested_depth, embedded_depth)
  File "~/app/venv/lib/python3.9/site-packages/rest_framework_mongoengine/serializers.py", line 583, in build_field
    return self.build_reference_field(field_name, relation_info, nested_depth)
  File "~/app/venv/lib/python3.9/site-packages/rest_framework_mongoengine/serializers.py", line 674, in build_reference_field
    related_class = related_model.id.__class__
AttributeError: type object 'AbstractEntityModel' has no attribute 'id'

我目前要做的是为该字段编写一个自定义序列化程序CommentSerializer.related，我对此有疑问

class RelatedSerializer(DocumentSerializer) # should I use a different parent class?
    class Meta:
        model = Entry
        fields = '__all__'
    # What functions should I add here?
    # def create(self, data):
    #     do magic here     
    #     return instance
    # def update(self, instance, data):
    #     do magic here     
    #     return instance

class CommentSerializer(DocumentSerializer) # Fails
    class Meta:
        model = Comment
        fields = '__all__'
    related = RelatedSerializer()

这是访问该 CommentViewSet 的错误消息的尾部。

  File "~/app/venv/lib/python3.9/site-packages/rest_framework/serializers.py", line 349, in fields
    for key, value in self.get_fields().items():
  File "~/app/venv/lib/python3.9/site-packages/rest_framework_mongoengine/serializers.py", line 326, in get_fields
    self.field_info = get_field_info(model)
  File "~/app/venv/lib/python3.9/site-packages/rest_framework_mongoengine/utils.py", line 66, in get_field_info
    pk = model._fields[model._meta['id_field']]
KeyError: 'id_field'
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