1.字段校验、局部钩子、全局钩子

from rest_framework.exceptions import ValidationError
from .models import Publish

class PublishSerializers(serializers.Serializer):
    #要序列化的字段
    id=serializers.IntegerField(required=False)#前端传入数据，可不填
    #allow_blank=True表示需要传入该字段，但是可以为空
    #allow_null=True表示可以不需要传入该字段，但是不可以为空

    name=serializers.CharField(allow_blank=True,required=False,max_length=10,min_length=2,error_messages={'max_length':
                               '太长','min_length':'太短'})
    addr=serializers.CharField(max_length=20,error_messages={'max_length':'too long'})

    phone=serializers.IntegerField(max_value=19999999999,min_value=10000000000,error_messages={'max_value':
                               '太长','min_value':'太短'})

    # 局部钩子：给某个字段做个校验
    '''  出版社名字不能包含东京，最大长度不能超过10，最短不能短于2
    地址长度不能超过20，没有最短现在，地址不能以上海开头
    手机号必须11位
    '''
    # validate_字段名
    def validate_name(self,name):
        print(name)
        if '东京' in name: raise ValidationError('出版社名字不能包含东京')
        else:return name
    def validate_addr(self,addr):

        print(addr,type(addr))
        if addr.startswith('上海'):
            raise ValidationError('地址不能以上海开头')
        else:return addr



    # 全局钩子   出版社名字和地址名字不能一样
    def validate(self, attrs):
        if attrs.get('name')==attrs.get('addr'):raise ValidationError('出版社名字和地址名字不能一样')
        else:return attrs



    def create(self, validated_data):#validated_data是校验后的数据
        publish=Publish.objects.create(**validated_data)
        return  publish
    def update(self, instance, validated_data):
        print('update',instance)#instance=Publish object (pk)#
        print('update',instance.pk)#传入的pk值
        print(type(instance))#<class 'app01.models.Publish'>
        print(validated_data)#{'name': 'a111a', 'addr': '1111', 'phone': 11111111111}
        for (key,values) in validated_data.items():
            print('key & values',key,values)
            setattr(instance,key,values)###重点看，只能用setatttr
            # instance[key]=values#b报错 'Publish' object does not support item assignment
            # instance.key = values

        instance.save()
        return instance

2.ModelSerializer

#serializer.py
from rest_framework import serializers
from rest_framework.serializers import ModelSerializer
from . import models


class BookSerializer(ModelSerializer):
    print('BookSerializier')

    class Meta:
        model = models.Book
        fields = ['name', 'price', 'publish_detail', 'author_list', 'publish', 'author']
        extra_kwargs = {
            'name': {'max_length': 10, 'min_length': 2, 'required': True},
            'publish': {'write_only': True},#只用来反序列化
            'author': {'write_only': True}
        }

    publish_detail = serializers.DictField(read_only=True)#只用来序列化
    author_list = serializers.ListField(read_only=True)


class PublishSerializer(ModelSerializer):

    print('PublishSerializer')

    class Meta:
        model = models.Publish
        fields = '__all__'


class AuthorSerializer(ModelSerializer):
    print('AuthorSerializer')
    class Meta:
        model = models.Author
        fields = ['name', 'phone', 'authordetail', 'book_list','age','email']#
        extra_kwargs = {
            'name': {'max_length': 10, 'min_length': 2, 'required': True},
        }

    book_list=serializers.ListField(read_only=True)
    authordetail = serializers.DictField(read_only=True)
    age=serializers.IntegerField(source='author_detail.age')
    email=serializers.CharField(source='author_detail.email')
    def create(self, validated_data):
        print(validated_data)
        detail_dict=validated_data.pop('author_detail')###这法子特别注意，方法极好
        author_obj_detail=models.AuthorDetail.objects.create(**detail_dict)
        validated_data['author_detail_id']=author_obj_detail.pk
        print(validated_data)
        author_obj=models.Author.objects.create(**validated_data)
        print(author_obj)
        return author_obj
    def update(self, instance, validated_data):
        print(instance)
        print(validated_data)
        return instance

#models.py
from django.db import models
# Create your models here.
class Book(models.Model):
    name = models.CharField(max_length=32)
    price = models.CharField(max_length=10)
    publish = models.ForeignKey(to='Publish', on_delete=models.SET_NULL, null=True)
    author = models.ManyToManyField(to='Author')

    @property
    def publish_detail(self):
        return {'id': self.publish.pk, 'name': self.publish.name, 'addr': self.publish.addr}

    # @property
    def author_list(self):
        l = []
        for author in self.author.all():
            print(author)
            l.append({'id': author.pk, 'name': author.name, 'phone': author.phone, 'age': author.author_detail.age})
        print(l)
        return l
class Publish(models.Model):
    name = models.CharField(max_length=32)
    addr = models.CharField(max_length=32)


class Author(models.Model):
    name = models.CharField(max_length=32)
    phone = models.CharField(max_length=11)
    author_detail = models.OneToOneField(to='AuthorDetail', on_delete=models.CASCADE)

    @property
    def authordetail(self):
        return {'email': self.author_detail.email, 'age': self.author_detail.age}

    # @property
    def book_list(self):
        l = []
        for book in self.book_set.all():
            l.append({'id': book.pk, 'price': book.price, 'publish': book.publish.name})
        return l


class AuthorDetail(models.Model):
    email = models.EmailField()
    age = models.SmallIntegerField()