有的时候序列化出来的字段并不是我们想要的， 比如说返回的用户 id，而我们想要返回的是用户名， 这个时候可以用到 django rest framework 的自定义字段功能。

先看一下原始数据

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[
    {
        "id": 1,
        "name": "1",
        "desc": "sdg",
        "user": 1
    },
    {
        "id": 5,
        "name": "1",
        "desc": "sdg",
        "user": 2
    }
]

这里 user 显示的是 id, 并不是我们想要的 username

增加一个字段, 显示 username

models:

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from django.db import models


# Create your models here.
class Game(models.Model):
    name = models.CharField(verbose_name='游戏名字', max_length=10)
    desc = models.CharField(verbose_name='描述', max_length=20)
    user = models.ForeignKey(to='auth.User', on_delete=models.CASCADE)

serializers:

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from rest_framework import serializers
from .models import Game
from django.contrib.auth.models import User


class GameSerializer(serializers.ModelSerializer):

    # 这里使用StringRelatedField来获取系统自带用户的username(依赖于models里面定义个__str__方法), 详情见下图
    user_val = serializers.StringRelatedField(source='user', read_only=True, )

    class Meta:
        model = Game
        fields = '__all__'
        # exclude = ('user',)
        
        # 如果不需要user字段, 下面可以去掉, 上面exclude = ('user',)
        extra_kwargs = {
            "user": {"read_only": True}
        }

image.png

views:

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class GameList(generics.ListCreateAPIView):
    queryset = Game.objects.all()
    serializer_class = GameSerializer

    # 这里重写了perform_create, 保存数据的时候, user使用当前登录的用户.
    def perform_create(self, serializer):
        serializer.save(user=self.request.user)

返回结果:

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[
    {
        "id": 1,
        "user_val": "iuxt",
        "name": "1",
        "desc": "sdg",
        "user": 1
    },
    {
        "id": 5,
        "user_val": "test",
        "name": "1",
        "desc": "sdg",
        "user": 2
    }
]

返回用户的多个字段

首先需要自定义一个序列化器

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from rest_framework import serializers
from .models import Game
from django.contrib.auth.models import User


# 自定义一个序列化, 使用django 自带的user 模型类
class CustomUserSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ['username', 'email'] # 指定序列化的字段


class GameSerializer(serializers.ModelSerializer):
    class Meta:
        model = Game
        fields = '__all__'
        # exclude = ('user',)

        extra_kwargs = {
            "user": {"read_only": True}
        }

    def to_representation(self, instance):
        representation = super(GameSerializer, self).to_representation(instance)
        # 这里修改user字段, 使用自定义序列化器.
        # 获取多个属性
        representation['user'] = CustomUserSerializer(instance.user, context=self.context).data
        
        # 或者获取其中的某一个值
        # representation['user'] = CustomUserSerializer(instance.user, context=self.context).data.get('username')
        return representation

这个时候返回结果:

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[
    {
        "id": 1,
        "name": "1",
        "desc": "sdg",
        "user": {
            "username": "iuxt",
            "email": "iuxt@qq.com"
        }
    },
    {
        "id": 5,
        "name": "1",
        "desc": "sdg",
        "user": {
            "username": "test",
            "email": "test@qq.com"
        }
    }