如何在 Django Rest Framework 嵌套序列化程序中动态更改深度？

Question

我有一组嵌套的序列化程序，它们在各自的 Meta 类上设置了 depth。我想根据传入视图的参数以编程方式更改深度。

class ResourceSerializer(serializers.ModelSerializer):
    type         = serializers.PrimaryKeyRelatedField(queryset=EntityType.objects.all())
    tags         = serializers.PrimaryKeyRelatedField(queryset=Tag.objects.all(), many=True)

    class Meta:
        model  = Resource
        fields = ('id', 'type', 'uri', 'tags', 'created_date')
        depth = 1

不幸的是，似乎没有办法在运行时覆盖depth 属性。我目前的解决方案是继承“浅”序列化程序并覆盖它们的 Meta 类以调整深度。

class ResourceNestedSerializer(ResourceSerializer):
    class Meta(ResourceSerializer.Meta):
        depth = 2

在我看来：

    if nested:
        serializer = ContainerNestedSerializer(containers, many=True)
    else:
        serializer = ContainerSerializer(containers, many=True)
    return Response(serializer.data)

在调用serializer.data之前有什么方法可以调整depth？

Answer 1

这是我的代码，其中包含/排除字段，以及动态调整深度。根据你的口味调整它。 :)

class DynamicModelSerializer(serializers.ModelSerializer):
"""
A ModelSerializer that takes an additional `fields` argument that
controls which fields should be displayed, and takes in a "nested"
argument to return nested serializers
"""

def __init__(self, *args, **kwargs):
    fields = kwargs.pop("fields", None)
    exclude = kwargs.pop("exclude", None)
    nest = kwargs.pop("nest", None)

    if nest is not None:
        if nest == True:
            self.Meta.depth = 1

    super(DynamicModelSerializer, self).__init__(*args, **kwargs)

    if fields is not None:
        # Drop any fields that are not specified in the `fields` argument.
        allowed = set(fields)
        existing = set(self.fields.keys())
        for field_name in existing - allowed:
            self.fields.pop(field_name)

    if exclude is not None:
        for field_name in exclude:
            self.fields.pop(field_name)