json - Django RestFramework 分组依据

Question

我的问题与 django-rest-framework 有关，是关于如何对元素进行分组的。

这是我的serializers.py

from collaborativeAPP.models import *
from rest_framework import serializers

class VocabSerializer(serializers.ModelSerializer):
    term_word = serializers.CharField(source='term.word',read_only=True)
    kwdGroup = serializers.StringRelatedField()
    class Meta:
        model = Vocab
        fields = ('id','term_word', 'meaning','kwdGroup')

class TermSerializer(serializers.ModelSerializer):
    word = serializers.CharField(read_only=True)
    class Meta:
        model = Term
        fields = ('url', 'word')

下面的 JSON 是实际结果:

{"results":[
            {
                "id": 5,
                "term_word": "word1",
                "meaning": "Text1"
                "kwdGroup": "A"
            },
            {
                "id": 6,
                "term_word": "word2",
                "meaning": "Text2"
                "kwdGroup": "A"
            },
            {
                "id": 7,
                "term_word": "word3",
                "meaning": "Text3"
                "kwdGroup": "A"
            }
        ]}

如您所见，kwdGroup 是我要分组的重复元素。

我想按kwdGroup分组:

{"A":[
       {
        "id": 5,
        "term_word": "word1",
        "meaning": "Text1"
        },
        {
        "id": 6,
        "term_word": "word2",
        "meaning": "Text2"
        },
        {
        "id": 7,
        "term_word": "word3",
        "meaning": "Text3"
        }
    ]
}

我正在 http://www.django-rest-framework.org/ 上寻找答案在 API 指南上，但我很难找到一种方法来引导它。你有同样的问题吗？你对我该怎么做有什么建议吗？您有使用 django-rest-framework 处理元素分组的示例吗？

提前致谢。

Answer 1

假设 kwdGroup 字段是与名为 KeyWordGroup 的模型的关系字段。

默认的 ListSerializer 使用 to_representation 方法来呈现序列化对象的列表 rest_framework :

class ListSerializer(BaseSerializer):
     ...

    def to_representation(self, data):
        """
          List of object instances -> List of dicts of primitive datatypes.
        """
        # Dealing with nested relationships, data can be a Manager,
        # so, first get a queryset from the Manager if needed
        iterable = data.all() if isinstance(data, models.Manager) else data

        return [
            self.child.to_representation(item) for item in iterable
        ]

我们可以修改 ListSerializer 来对结果进行分组，例如:

class VocabListSerializer(serializers.ListSerializer):

    def to_representation(self, data):
        iterable = data.all() if isinstance(data, models.Manager) else data
        return {
            kwdGroup: super().to_representation(Vocab.objects.filter(kwdGroup=kwdGroup))
            for kwdGroup in KeyWordGroup.objects.all()
        }

然后我们可以将修改后的 VocabListSerializer 与 VocabSerializer 一起使用。

class VocabSerializer(serializers.Serializer):
...
    class Meta:
        list_serializer_class = VocabListSerializer