Django Rest Framework：动态返回字段子集

Question

我想向fields基于Django Rest Framework的API 添加查询参数，该参数使用户只能为每个资源选择字段的子集。

例
序列化器：

class IdentitySerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = models.Identity
        fields = ('id', 'url', 'type', 'data')

常规查询将返回所有字段。

GET /identities/

[
  {
    "id": 1,
    "url": "http://localhost:8000/api/identities/1/",
    "type": 5,
    "data": "John Doe"
  },
  ...
]

具有fields参数的查询应仅返回字段的子集：

GET /identities/?fields=id,data

[
  {
    "id": 1,
    "data": "John Doe"
  },
  ...
]

具有无效字段的查询应忽略无效字段或引发客户端错误。

目标
这是否可能开箱即用？如果没有，最简单的实现方法是什么？周围是否有第三方包装？

Answer 1

你可以覆盖序列化__init__方法，并fields根据查询参数动态设置属性。你可以在request整个上下文中访问对象，并将其传递给序列化程序。

这是此问题的Django Rest Framework文档示例的复制和粘贴：

from rest_framework import serializers

class DynamicFieldsModelSerializer(serializers.ModelSerializer):
    """
    A ModelSerializer that takes an additional `fields` argument that
    controls which fields should be displayed.
    """

    def __init__(self, *args, **kwargs):
        # Instantiate the superclass normally
        super(DynamicFieldsModelSerializer, self).__init__(*args, **kwargs)

        fields = self.context['request'].query_params.get('fields')
        if fields:
            fields = fields.split(',')
            # 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)


class UserSerializer(DynamicFieldsModelSerializer, serializers.HyperlinkedModelSerializer):

    class Meta:
        model = User
        fields = ('url', 'username', 'email')