Django Rest Framework如何将序列化返回的对象列表扁平化为字符串列表

你可以通过以下两种常用方式实现扁平化的ID数组返回，同时可搭配性能优化配置避免额外查询开销：

方案1：使用SerializerMethodField（最简洁直观） #

直接在用户序列化器中自定义字段取值逻辑，无需额外定义嵌套的关联序列化器：

from rest_framework import serializers
from .models import MyUser

class BulkQualificationSerializer(serializers.ModelSerializer):
    qualifications = serializers.SerializerMethodField()

    class Meta:
        model = MyUser
        fields = ["qualifications"]

    def get_qualifications(self, obj):
        # 直接遍历关联数据返回ID字符串列表
        return [str(qual.qualification.id) for qual in obj.qualifications.all()]

方案2：重写嵌套序列化器的to_representation方法 #

如果要保留独立的关联序列化器复用逻辑，可以修改子序列化器的返回格式：

from rest_framework import serializers
from .models import MyUser, MyUserQualification

class MyUserQualificationBulkSerializer(serializers.ModelSerializer):
    class Meta:
        model = MyUserQualification
        fields = []

    def to_representation(self, instance):
        # 直接返回ID字符串，替代默认的字典结构
        return str(instance.qualification.id)

class BulkQualificationSerializer(serializers.ModelSerializer):
    qualifications = MyUserQualificationBulkSerializer(
        many=True,
        read_only=True,
    )

    class Meta:
        model = MyUser
        fields = ["qualifications"]

可选性能优化 #

为了避免N+1查询问题，建议修改视图的查询集，提前预加载关联数据：

from django.db.models import Prefetch
from rest_framework import generics
from .models import MyUser, MyUserQualification
from .serializers import BulkQualificationSerializer

class MyUserDetail(generics.RetrieveAPIView):
    lookup_field = "email"
    queryset = MyUser.objects.prefetch_related(
        Prefetch("qualifications", queryset=MyUserQualification.objects.select_related("qualification"))
    ).all()
    serializer_class = BulkQualificationSerializer

注意：你的原有代码中存在模型类名拼写错误（myUserQualification应为MyUserQualification、myUser应为MyUser），调整时请同步修正。

内容的提问来源于stack exchange，提问作者zigzagzoom