DRF中ManyToManyField的自定义序列化器和ViewSet [重复]

Question

我在Entity 和EntityGroup 之间有M2M 关系，我想将相应的实体索引保存到EntityGroup，就像将实体数组保存到数据库一样。

由于我使用了一个自定义的模型，里面有额外的字段index，我需要将index序列化为对应的entity响应，我应该如何实现呢？

我是 django 和 django-rest-framework 的新手，经过几次谷歌搜索后似乎没有类似的 M2M 示例。这是我的想法，序列化程序只能序列化具有ForeignKey 关系的唯一一个模型的字段，视图集可以具有基于queryset 的自定义模型，它可以合并几个模型的关系。所以我需要实现一个更可扩展的视图集，里面有一个自定义的queryset？

这是我的代码：

models.py

class Entity(models.Model):
    uuid = models.CharField()
    name = models.CharField()

class EntityGroup(models.Model):
    name = models.CharField()
    entities = models.ManyToManyField(Entity,
        through='EntityGroupRelationship',
        through_fields=('group', 'entity'),
        related_name='groups'
    )

class EntityGroupRelationship(models.Model):
    entity = models.ForeignKey(Entity, on_delete=models.CASCADE)
    group = models.ForeignKey(EntityGroup, on_delete=models.CASCADE)
    index = models.PositiveIntegerField()

序列化器.py

class EntitySerializer(serializers.ModelSerializer):
    class Meta:
        model = Entity
        fields = '__all__'

class EntityGroupRelationshipSerializer(serializers.ModelSerializer):
    class Meta:
        model = EntityGroupRelationship
        fields = '__all__'

class EntityGroupSerializer(serializers.ModelSerializer):
    entities = EntitySerializer(many=True)

    class Meta:
        model = EntityGroup
        fields = '__all__'

views.py

class EntityGroupViewSet(BaseModelViewSet):
    queryset = EntityGroup.objects.all()
    serializer_class = EntityGroupSerializer

class EntityGroupRelationshipViewSet(BaseModelViewSet):
    queryset = EntityGroupRelationship.objects.all()
    serializer_class = EntityGroupRelationshipSerializer

当前响应

[
    {
        "id": 1,
        "entities": [{
            "id": 1,
            "name": "",
        }]
    },
    ...
]

预期响应

[
    {
        "id": 1,
        "entities": [
            {
                "index": 1,
                "info": {
                    "id": 1,
                    "name": "",
                }
            }
        ]
    },
    ...
]

Answer 1

您为此使用了不正确的序列化程序。使用EntityGroupRelationshipSerializer 而不是EntitySerializer。另外你需要通过正确的fields

class EntitySerializer(serializers.ModelSerializer):
    class Meta:
        model = Entity
        fields = '__all__'

class EntityGroupRelationshipSerializer(serializers.ModelSerializer):
    entity = EntitySerializer()
    class Meta:
        model = EntityGroupRelationship
        fields = ('index', 'entity')

class EntityGroupSerializer(serializers.ModelSerializer):
    entities = EntityGroupRelationshipSerializer(many=True) # here should be EntityGroupRelationshipSerializer

    class Meta:
        model = EntityGroup
        fields = '__all__'