Django系列之Serializer的source参数使用、自定义序列化方法

数据准备

models.py

from django.contrib.auth.models import AbstractUser
from django.db import models


class Publish(models.Model):
    name = models.CharField(max_length=32)
    city = models.CharField(max_length=8)
    email = models.CharField(max_length=32)
    
    def __str__(self):
        return self.name


class AuthorDetail(models.Model):
    birthday = models.DateField()
    telephone = models.BigIntegerField()
    addr = models.CharField(max_length=64)


class Author(models.Model):
    name = models.CharField(max_length=32)
    age = models.IntegerField()
    gender = models.IntegerField(choices=(('1', '男'), ('0', '女')))
    ad = models.OneToOneField(AuthorDetail, on_delete=models.CASCADE, null=True)

    def __str__(self):
        return self.name


class Book(models.Model):
    title = models.CharField(max_length=32)
    price = models.DecimalField(max_digits=5, decimal_places=2)
    pub_date = models.DateField()
    publish = models.ForeignKey(Publish, on_delete=models.CASCADE, null=True)
    authors = models.ManyToManyField(Author, db_table="book2author")

    def __str__(self):
        return self.title
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serializers字段的source参数

使用默认的序列化器时，视图函数访问 具有choices参数 的字段或 一对一 或 一对多 或 多对多 字段时，返回的数据只有 id 值，就像下面这种方式，性别是0或1，居住地址是居住详情表中的id值：

[
    {
        "id": 1,
        "name": "阿明",
        "age": 16,
        "gender": 1,
        "ad": 1
    },
    {
        "id": 3,
        "name": "阿美",
        "age": 21,
        "gender": 0,
        "ad": 3
    }
]
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对上面这些场景使用source参数：

1. get_xxx_display 用于显示 choices 参数对应的文本信息。
   serializers.py

   class AuthorSerializer(serializers.ModelSerializer):
   gender_txt = serializers.CharField(source='get_gender_display')		# 使用get_xxx_display
   
   class Meta:
       model = Author
       fields = "__all__"
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   返回的结果：

   [
       {
           "id": 1,
           "gender_txt": "男",
           "name": "阿明",
           "age": 16,
           "gender": "1",
           "ad": 1
       },
       {
           "id": 2,
           "gender_txt": "男",
           "name": "阿伟",
           "age": 25,
           "gender": "1",
           "ad": 2
       },
       {
           "id": 3,
           "gender_txt": "男",
           "name": "阿华",
           "age": 21,
           "gender": "1",
           "ad": 3
       },
       {
           "id": 4,
           "gender_txt": "女",
           "name": "阿美",
           "age": 16,
           "gender": "0",
           "ad": 4
       }
   ]
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   注意：为什么添加了 source=get_xxx_display 还是没有显示出对应文本信息？把 choices=(('1', '男'), ('0', '女')) 的 0 和 1 改成字符串形式再试试。

   当然，也可以在视图函数中，使用 obj.get_xxx.display() 来获取choices文本值。

   >>> Author.objects.get(id=1).gender
   '1'
   >>> Author.objects.get(id=1).get_gender_display()
   '男'
   >>>
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2. 显示 一对一 或 一对多 或 多对多 字段对应的文本信息。
   serializers.py

   class AuthorSerializer(serializers.ModelSerializer):
       gender_txt = serializers.CharField(source='get_gender_display')
       address_txt = serializers.CharField(source='ad.addr')	# 支持连表查询
   
       class Meta:
           model = Author
           fields = "__all__"
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   返回的结果：

   [
       {
           "id": 1,
           "gender_txt": "男",
           "address_txt": "beijing",
           "name": "阿明",
           "age": 16,
           "gender": "1",
           "ad": 1
       },
       {
           "id": 2,
           "gender_txt": "男",
           "address_txt": "shanghai",
           "name": "阿伟",
           "age": 25,
           "gender": "1",
           "ad": 2
       },
       {
           "id": 3,
           "gender_txt": "男",
           "address_txt": "shanghai",
           "name": "阿华",
           "age": 21,
           "gender": "1",
           "ad": 3
       },
       {
           "id": 4,
           "gender_txt": "女",
           "address_txt": "guangzhou",
           "name": "阿美",
           "age": 16,
           "gender": "0",
           "ad": 4
       }
   ]
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3. 自定义序列化输出方法

   class AuthorSerializer(serializers.ModelSerializer):
       gender_txt = serializers.CharField(source='get_gender_display')
       address_zidingyi = serializers.SerializerMethodField()		# 自定义序列化方法, 会寻找并执行'get_xxx'的方法。
   
       def get_address_zidingyi(self, obj):
           return obj.ad.addr
   
       class Meta:
           model = Author
           fields = "__all__"
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   返回的结果：

   [
       {
           "id": 1,
           "gender_txt": "男",
           "address_zidingyi": "beijing",
           "name": "阿明",
           "age": 16,
           "gender": "1",
           "ad": 1
       },
       {
           "id": 2,
           "gender_txt": "男",
           "address_zidingyi": "shanghai",
           "name": "阿伟",
           "age": 25,
           "gender": "1",
           "ad": 2
       },
       {
           "id": 3,
           "gender_txt": "男",
           "address_zidingyi": "shanghai",
           "name": "阿华",
           "age": 21,
           "gender": "1",
           "ad": 3
       },
       {
           "id": 4,
           "gender_txt": "女",
           "address_zidingyi": "guangzhou",
           "name": "阿美",
           "age": 16,
           "gender": "0",
           "ad": 4
       }
   ]
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