如果我们想要使⽤序列化器对应的是Django的模型类，DRF为我们提供了ModelSerializer模型类序列化器来帮助我们快速创建⼀个Serializer类。

ModelSerializer与常规的Serializer相同，但提供了：
基于模型类⾃动⽣成⼀系列字段
基于模型类⾃动为Serializer⽣成validators，⽐如unique_together 包含默认的create()和update()的实现

一、定义了ModelSerializer类

1、__all__

from rest_framework import serializers
from app2.models import *

class NewsChannelSerializer(serializers.ModelSerialzer):
	class Meta:
		model=NewsChannel
		fields='__all__'

测试结果

>>> from app2.serializers1 import *
>>> serializer=NewsChannelSerializer()
>>> serializer
NewsChannelSerializer():
    id = IntegerField(label='ID', read_only=True)
    name = CharField(label='频道名称', max_length=30, validators=[<UniqueValidator(queryset=NewsChannel.objects.all())>])
    url = CharField(allow_blank=True, allow_null=True, label='频道页面链接', max_length=50, required=False)

2、指定字段

1、model：指明参照那个模型类

2、fields指定模型类中哪些字段需要自动生成序列化器字段

• 如果指定为__all__，那么模型类中所有的字段需要自动转化为序列化器字段
• 如果将特定的字段转化为序列化器字段,用元组表示
  fields=(‘id’,‘name’,‘leader’,‘interfaces_set’,‘token’)
• exclude指定模型类中哪些字段不需要设置为序列化器字段，其他的字段需要转化
  exclude=(‘create_time’,‘update_time’)

3、显示指明字段

from rest_framework import serializers
from app2.models import *

class NewsChannelSerializer(serializers.ModelSerializer):
    class Meta:
        model=NewsChannel
        fields=['id','name']

测试结果

>>> from app2.serializers1 import *
>>> from app2.models import *
>>> serializer=NewsChannelSerializer()
>>> serializer
NewsChannelSerializer():
    id = IntegerField(label='ID', read_only=True)
    name = CharField(label='频道名称', max_length=30, validators=[<UniqueValidator(queryset=NewsChannel.objects.all())>])

4、exclude

from rest_framework import serializers
from app2.models import *

class NewsChannelSerializer(serializers.ModelSerializer):
    class Meta:
        model=NewsChannel
        exclude=['id']

测试结果

>>> from app2.serializers1 import *
>>> serializer=NewsChannelSerializer()
>>> serializer
NewsChannelSerializer():
    name = CharField(label='频道名称', max_length=30, validators=[<UniqueValidator(queryset=NewsChannel.objects.all())>])
    url = CharField(allow_blank=True, allow_null=True, label='频道页面链接', max_length=50, required=False)

5、指明只读字段

可以通过read_only_fields指明只读字段，即仅⽤于序列化输出的字段

from rest_framework import serializers
from app2.models import *

class NewsChannelSerializer(serializers.ModelSerializer):
    class Meta:
        model=NewsChannel
        fields='__all__'
        read_only_fields=['id','url']

测试结果：

>>> from app2.serializers1 import *
>>> serializer=NewsChannelSerializer()
>>> serializer
NewsChannelSerializer():
    id = IntegerField(label='ID', read_only=True)
    name = CharField(label='频道名称', max_length=30, validators=[<UniqueValidator(queryset=NewsChannel.objects.all())>])
    url = CharField(allow_null=True, label='频道页面链接', read_only=True)

6、添加额外参数

我们可以使⽤extra_kwargs参数为ModelSerializer添加或修改原有的选项参数

from rest_framework import serializers
from app2.models import *

class NewsChannelSerializer(serializers.ModelSerializer):
    class Meta:
        model=NewsChannel
        fields='__all__'
        extra_kwargs={
            'url':{'max_length':60,'required':True}
        }

测试结果：

>>> from app2.serializers1 import *
>>> serializer=NewsChannelSerializer()
>>> serializer
NewsChannelSerializer():
    id = IntegerField(label='ID', read_only=True)
    name = CharField(label='频道名称', max_length=30, validators=[<UniqueValidator(queryset=NewsChannel.objects.all())>])
    url = CharField(allow_blank=True, allow_null=True, label='频道页面链接', max_length=60, required=True)