drf serializer 的序列化

文章目录

drf serializer 的序列化
- 1、序列化类常用字段类及字段参数
- - 1.1、常用字段类
  - 1.2、常用字段参数
- 2、序列化类高级用法之source
- 3、序列化类高级用法之定制序列化字段的两种方式
- - 3.1、方式一演示：
  - 2.2、方式二演示
- 3、反序列化
- 5、模型类序列化器（ModelSerializer））使用
- 6、反序列化之数据校验
- 7、断言 assert
- 作业
- - 1、写出book表（带关联关系）5 个接口
  - - 1.1、Serializer 方法
    - 1.2、ModelSerialize方法
  - 2、出版社，作者，作者详情 5个接口写完（ModelSerializer好些一些）

1、序列化类常用字段类及字段参数

1.1、常用字段类

# BooleanField   BooleanField()
# NullBooleanField  NullBooleanField()
# CharField CharField(max_length=None, min_length=None, allow_blank=False, trim_whitespace=True)
# EmailField    EmailField(max_length=None, min_length=None, allow_blank=False)
# RegexField    RegexField(regex, max_length=None, min_length=None, allow_blank=False)
# SlugField SlugField(maxlength=50, min_length=None, allow_blank=False) 正则字段，验证正则模式 [a-zA-Z0-9-]+
# URLField  URLField(max_length=200, min_length=None, allow_blank=False)
# UUIDField UUIDField(format=’hex_verbose’) format: 1) 'hex_verbose' 如"5ce0e9a5-5ffa-654b-cee0-1238041fb31a" 2） 'hex' 如 "5ce0e9a55ffa654bcee01238041fb31a" 3）'int' - 如: "123456789012312313134124512351145145114" 4）'urn' 如: "urn:uuid:5ce0e9a5-5ffa-654b-cee0-1238041fb31a"
# IPAddressField    IPAddressField(protocol=’both’, unpack_ipv4=False, **options)
# IntegerField  IntegerField(max_value=None, min_value=None)
# FloatField    FloatField(max_value=None, min_value=None)
# DecimalField  DecimalField(max_digits, decimal_places, coerce_to_string=None, max_value=None, min_value=None) max_digits: 最多位数 decimal_palces: 小数点位置
# DateTimeField DateTimeField(format=api_settings.DATETIME_FORMAT, input_formats=None)
# DateField DateField(format=api_settings.DATE_FORMAT, input_formats=None)
# TimeField TimeField(format=api_settings.TIME_FORMAT, input_formats=None)
# DurationField DurationField()
# ChoiceField   ChoiceField(choices) choices与Django的用法相同
# MultipleChoiceField   MultipleChoiceField(choices)
# FileField FileField(max_length=None, allow_empty_file=False, use_url=UPLOADED_FILES_USE_URL)
# ImageField    ImageField(max_length=None, allow_empty_file=False, use_url=UPLOADED_FILES_USE_URL)

常用字段
CharField
BooleanField
IntegerField
DecimalField

ListField： {name:'lqz',age:19,hobby:['篮球','足球']}
DictField：{name:'lqz',age:19,wife:{'name':'刘亦菲','age':33}}

1.2、常用字段参数

给CharField 字段用的参数

参数名称	作用
`max_length`	最大长度
`min_lenght`	最小长度
`allow_blank`	是否允许为空
`trim_whitespace`	是否允许为空

给IntegerField字段用的参数

参数名称	作用
`max_value`	最小值
`min_value`	最小值

**通用参数 **

参数名称	作用
`required`	表明该字段在反序列化时必须输入，默认True
`default`	反序列化时使用的默认值
`allow_null`	表明该字段是否允许传入None，默认False
`validators`	该字段使用的验证器【不需要了解】
`error_messages`	包含错误编号与错误信息的字典
`label`	用于HTML展示API页面时，显示的字段名称
`help_text`	用于HTML展示API页面时，显示的字段帮助提示信息

重点

参数名称	作用
`read_only`	表明该字段仅用于序列化输出，默认False
`write_only`	表明该字段仅用于反序列化输入，默认False

2、序列化类高级用法之source

修改序列化字段名字
使用source，字段参数，可以指定序列化表中得哪个字段

book_name = serializers.CharField(max_length=8, min_length=3,source='name')

source指定的可以是字段，也可以是方法，用于重命名
source可以做跨表查询

演示

class BookSerializer(serializers.Serializer):name_detail = serializers.CharField(max_length=8, min_length=3,source='name')# 或publish_name = serializers.CharField(max_length=8, min_length=3,source='publish.name')# 或xx = serializers.CharField(max_length=8, min_length=3,source='xx') #source的xx表示表模型中得方法

3、序列化类高级用法之定制序列化字段的两种方式

前端显示形式

{"name": "西游记","price": 33,"publish": {name:xx,city:xxx,email:sss}
}

方式一：
在【序列化类】中写SerializerMethodField

publish = serializers.SerializerMethodField()def get_publish(self, obj):# obj 是当前序列化的对象return {'name': obj.publish.name, 'city': obj.publish.city, 'email': obj.publish.email}

方式二：
在【表模型】中写方法（又多一些）

def publish_detail(self):return {'name': self.publish.name, 'city': self.publish.city, 'email': self.publish.email}在序列化中取publish_detail=serializers.DictField

在模型类中写逻辑代码，称之为ddd，领域驱动模型

3.1、方式一演示：

class BookSerializer(serializers.Serializer):name = serializers.CharField(max_length=8, min_length=3)price = serializers.IntegerField(min_value=10, max_value=99)publish_date = serializers.DateField()# publish要序列化成 {name:北京出版社，city：北京，email:2@qq.com}# 方式一：SerializerMethodField必须配合一个方法(get_字段名,需要接受一个参数)，方法返回什么，这个字段就是什么publish = serializers.SerializerMethodField()def get_publish(self, obj):# obj 是当前序列化的对象return {'name': obj.publish.name, 'city': obj.publish.city, 'email': obj.publish.email}# 练习，用方式一，显示所有作者对象  []authors = serializers.SerializerMethodField()def get_authors(self, obj):res_list = []for author in obj.authors.all():res_list.append({'id': author.id, 'name': author.name, 'age': author.age})return res_list

2.2、方式二演示

# 表模型中
class Book(models.Model):name = models.CharField(max_length=32)price = models.DecimalField(max_digits=5, decimal_places=2)publish_date = models.DateField(null=True)publish = models.ForeignKey(to='Publish', on_delete=models.CASCADE)authors = models.ManyToManyField(to='Author')# 写了个方法，可以包装成数据属性，也可以不包def publish_detail(self):return {'name': self.publish.name, 'city': self.publish.city, 'email': self.publish.email}def author_list(self):res_list = []for author in self.authors.all():res_list.append({'id': author.id, 'name': author.name, 'age': author.age})return res_list

序列化类中

class BookSerializer(serializers.Serializer):name = serializers.CharField(max_length=8, min_length=3)price = serializers.IntegerField(min_value=10, max_value=99)publish_date = serializers.DateField()# 方式二：在表模型中写方法publish_detail = serializers.DictField(read_only=True)# 练习，使用方式二实现，显示所有作者author_list = serializers.ListField(read_only=True)

3、反序列化

序列化和反序列化字段不一样【】

publish = serializers.CharField(write_only=True)
authors = serializers.ListField(write_only=True)

重写create
使用继承Serializer的序列化类保存需要重写create方法

def create(self, validated_data): # validated_data 校验过后的数据  {"name":"三国1演义","price":19,"publish_date": "2022-09-27","publish":1,"authors":[1,2]}book = Book.objects.create(name=validated_data.get('name'),price=validated_data.get('price'),publish_date=validated_data.get('publish_date'),publish_id=validated_data.get('publish'),)authors = validated_data.get('authors')book.authors.add(*authors)return book

5、模型类序列化器（ModelSerializer））使用

比继承Serializers序列化方法更方便

class BookModelSerializer(serializers.ModelSerializer): #ModelSerializer继承Serializer# 不需要写字段了，字段从表模型映射过来class Meta:model = Book  # 要序列化的表模型# fields='__all__' # 所有字段都序列化fields = ['name', 'price', 'publish_date', 'publish', 'authors', 'publish_detail','author_list']  # 列表中有什么，就是序列化哪个字段# 给authors和publish加write_only属性# name加max_len属性extra_kwargs = {'name': {'max_length': 8},'publish': {'write_only': True},'authors': {'write_only': True},}

6、反序列化之数据校验

跟 form数据校验方法很像

# 字段自己的校验规则-如果继承的是Serializer，写法如下name=serializers.CharField(max_length=8,min_length=3,error_messages={'min_length': "太短了"})-如果继承的是ModelSerializer，写法如下extra_kwargs = {'name': {'max_length': 8, 'min_length': 3, 'error_messages': {'min_length': "太短了"}},}# 局部钩子-如果继承的是Serializer，写法一样-如果继承的是ModelSerializer，写法一样def validate_name(self, name):if name.startswith('sb'):# 校验不通过，抛异常raise ValidationError('不能以sb卡头')else:return name# 全局钩子-如果继承的是Serializer，写法一样-如果继承的是ModelSerializer，写法一样def validate(self, attrs):if attrs.get('name') == attrs.get('publish_date'):raise ValidationError('名字不能等于日期')else:return attrs

局部钩子
继承的是Serializer 与继承ModelSerializer写法一样

def validate_name(self, name):if name.startswith('sb'):# 校验不通过，抛异常raise ValidationError('不能以sb卡头')else:return name

全局钩子
继承的Serializer与继承ModelSerializer 写法一样

def validate(self, attrs):if attrs.get('name') == attrs.get('publish_date'):raise ValidationError('名字不能等于日期')else:return attrs

7、断言 assert

在框架源码中，大量使用断言

断言，作用的判断，断定一个变量必须是xx，如果不是就报错
assert :

普通写法

name = 'lqz1'
if not name == 'ming':raise Exception('name不等于ming')
print('程序执行完了')

断言写法

name = 'lqz1'
assert name == 'lqz', 'name不等于lqz'
print('程序执行完了')

作业

写出book表（带关联关系）5 个接口

Serializer
ModelSerializer（简单，不用重写create和update）
name最大8，最小3，名字中不能带sb
price最小9，最大199，不能为66

1、写出book表（带关联关系）5 个接口

1.1、Serializer 方法

serializer.py

from rest_framework import serializers
from app01.models import Book,Author,Author_Detail,Publishfrom rest_framework.exceptions import ValidationErrorclass BookSerializer(serializers.Serializer):name = serializers.CharField(max_length=8,min_length=3)price = serializers.IntegerField(max_value=199,min_value=9)publish_date = serializers.DateField()publish_out = serializers.SerializerMethodField(read_only=True,)def get_publish_out(self, obj):return {'name': obj.publish.name, 'city': obj.publish.city, 'email': obj.publish.email}author_out = serializers.SerializerMethodField(read_only=True)def get_author_out(self, obj):author_list = []for author_obj in obj.author.all():author_list.append({'name': author_obj.name, 'age': author_obj.age})return author_listpublish = serializers.IntegerField(write_only=True)author = serializers.ListField(write_only=True)def validate_price(self,price):if price == 66:raise ValidationError('不饿能为66')else:return pricedef validate_name(self,name):if name.count('sb')>=1:raise ValidationError('名字中有铭感词汇')else:return namedef create(self, validated_data):book=Book.objects.create(name=validated_data.get('name'),price=validated_data.get('price'),publish_date=validated_data.get('publish_date'),publish_id=validated_data.get('publish'),)author_list = validated_data.get('author')book.author.add(*author_list)return bookdef update(self, instance, validated_data):instance.name = validated_data.get('name')instance.price = validated_data.get('price')instance.publish_date = validated_data.get('publish_date')instance.publish_id = validated_data.get('publish')instance.author.set(validated_data.get('author'))instance.save()return instance

view.py

from app01.models import Bookfrom rest_framework.views import APIView
from rest_framework.response import Response
from app01.serializer import BookSerializerclass BookView(APIView):def get(self, request):book = Book.objects.all()ser = BookSerializer(instance=book, many=True)return Response(ser.data)def post(self, request):ser = BookSerializer(data=request.data)if ser.is_valid():ser.save()return Response(ser.data)else:return Response(ser.errors)class Book_View(APIView):def get(self,request,pk):book_obj = Book.objects.filter(pk=pk).first()ser = BookSerializer(instance=book_obj)return Response(ser.data)def put(self, request, pk):book_obj = Book.objects.filter(pk=pk).first()ser = BookSerializer(instance=book_obj, data=request.data)if ser.is_valid():ser.save()return Response(ser.data)else:return Response(ser.errors)def delete(self, request, pk):book_obj = Book.objects.filter(pk=pk).delete()return Response()

1.2、ModelSerialize方法

serializer.py

from rest_framework import serializers
from app01.models import Book,Author,Author_Detail,Publishfrom rest_framework.exceptions import ValidationErrorclass BookModelSerializer(serializers.ModelSerializer):class Meta:model = Bookfields = ['name', 'price', 'publish_date', 'publish', 'author', 'publish_int', 'author_li']extra_kwargs = {'name':{'max_length':8,'min_length':3,'error_messages':{'max_length':'名字太长了','min_length':'名字太短了'}},'price':{'max_value':199,'min_value':9,'error_messages':{'max_value':'最大值为199','min_value':'最小值为9',}},'publish':{'write_only':True},'author':{'write_only':True},}def validate_price(self, price):if price == 66:raise ValidationError('不饿能为66')else:return pricedef validate_name(self, name):if name.count('sb')>=1:raise ValidationError('名字中有铭感词汇')else:return name

views.py

from app01.models import Bookfrom rest_framework.views import APIView
from rest_framework.response import Response
from app01.serializer import BookModelSerializerclass BookView(APIView):def get(self, request):book = Book.objects.all()ser = BookModelSerializer(instance=book, many=True)return Response(ser.data)def post(self, request):ser = BookModelSerializer(data=request.data)if ser.is_valid():ser.save()return Response(ser.data)else:return Response(ser.errors)class Book_View(APIView):def get(self,request,pk):book_obj = Book.objects.filter(pk=pk).first()ser = BookModelSerializer(instance=book_obj)return Response(ser.data)def put(self, request, pk):book_obj = Book.objects.filter(pk=pk).first()ser = BookModelSerializer(instance=book_obj, data=request.data)if ser.is_valid():ser.save()return Response(ser.data)else:return Response(ser.errors)def delete(self, request, pk):book_obj = Book.objects.filter(pk=pk).delete()return Response()

2、出版社，作者，作者详情 5个接口写完（ModelSerializer好些一些）

class Publish_Mser(serializers.ModelSerializer):class Meta:model = Publishfields = ['name','city','email',]class Author_Mser(serializers.ModelSerializer):class Meta:model = Authorfields = ['name','age']class Author_Detail_MSer(serializers.ModelSerializer):class Meta:model = Author_Detailfields = ['phone','addr']