drf从入门到飞升仙界 04

序列化类常用字段和字段参数

常用字段类

#1 BooleanField
    BooleanField()
#2 NullBooleanField
    NullBooleanField()
#3 CharField
    CharField(max_length=None, min_length=None, allow_blank=False, trim_whitespace=True)
#4 EmailField
    EmailField(max_length=None, min_length=None, allow_blank=False)
#5 RegexField
    RegexField(regex, max_length=None, min_length=None, allow_blank=False)
#6 SlugField
    SlugField(max_length=50, min_length=None, allow_blank=False) 正则字段，验证正则模式 [a-zA-Z0-9-]+
#7 URLField
    URLField(max_length=200, min_length=None, allow_blank=False)
#8 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"
#9 IPAddressField
    IPAddressField(protocol=’both’, unpack_ipv4=False, **options)
#10 IntegerField
    IntegerField(max_value=None, min_value=None)
#11 FloatField
    FloatField(max_value=None, min_value=None)
#12 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
#13 DateTimeField    
    DateTimeField(format=api_settings.DATETIME_FORMAT, input_formats=None)
#14 DateField
    DateField(format=api_settings.DATE_FORMAT, input_formats=None)
#15 TimeField
    TimeField(format=api_settings.TIME_FORMAT, input_formats=None)
#16 DurationField
    DurationField()
#17 ChoiceField
    ChoiceField(choices) choices与Django的用法相同
#18 MultipleChoiceField
    MultipleChoiceField(choices)
#19 FileField
    FileField(max_length=None, allow_empty_file=False, use_url=UPLOADED_FILES_USE_URL)
#20 ImageField
    ImageField(max_length=None, allow_empty_file=False, use_url=UPLOADED_FILES_USE_URL)

# 重要的，后续讲到
    - ListField
             ListField(child=, min_length=None, max_length=None)
    - DictField
             DictField(child=)

# 需要掌握记住的：
     - CharField  IntegerField  DecimalField  DateTimeField BooleanField ListField DictField

常用字段参数

- 选项参数：

# CharField及其子类的(EmailField) ---》反序列化的校验,字段自己的规则
    max_length    最大长度
    min_lenght    最小长度
    allow_blank    是否允许为空
    trim_whitespace    是否截断空白字符

# IntegerField
    max_value    最小值
    min_value    最大值

# 所有字段类都有的
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
----看一眼忘掉-----
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：
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

# 反序列化校验执行流程
    -1.先执行字段自己的校验规则
         最大长度，最小长度，是否为空，是否必填，最小数字...
    -2.validators=[方法，]
         单独给这个字段加校验规则： 
             
name=serializers.CharField(validators=[方法,])
    -3.局部钩子校验规则
    -4.全局钩子校验规则

序列化高级用法source(了解即可)

# 1.创建模型类，关联表关系
from django.db import models

class Book(models.Model):
    name = models.CharField(max_length=32)
    price = models.CharField(max_length=32)

    publish = models.ForeignKey(to='Publish',on_delete=models.CASCADE)
    authors = models.ManyToManyField(to='Author')

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)
# 2.迁移表数据

# 3.序列化定制字段名字source
from rest_framework import serializers

class BookSerializer(serializers.Serializer):
    # 字段参数，通用的一些限制
    # 所有字段都可以通过source指定定制字段
    name_real = serializers.CharField(max_length=8,source='name')
    price_real = serializers.CharField(source='price')
    # 一对一，自己字段直接写
    # 一对多，关联字段直接点
    publish = serializers.CharField(source='publish.name')
    # 多对多，搞不了，source不能用
    authors = serializers.CharField(source='author.all')
    

序列化高级用法之定制字段的两种方式

# 方法一：SerializerMethodField定制

from rest_framework import serializers

class BookSerializer(serializers.Serializer):
    name = serializers.CharField(max_length=8)
    price = serializers.CharField()

    # 定制返回格式：方式1
    publish_detail = serializers.SerializerMethodField()

    def get_publish_detail(self,obj):
        return {'name':obj.publish.name,'addr': obj.publish.addr}

    # 定制返回格式：方式2
    author_list = serializers.SerializerMethodField()

    def get_author_list(self, obj):
        l = []
        for author in obj.authors.all():
            l.append({'name': author.name, 'phone': author.phone})
        return l

# 高级序列化之SerializerMethodField
"""
{
    "name": "西游记",
    "price": "77",
    "publish":{"name":"北京出版社","addr":"北京"}，
    authors:[{name:lqz,phone:1111},{name:罗贯中,phone:1111}]
}

"""

# 方法二：在表模型中定制

# 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=32)

    publish = models.ForeignKey(to='Publish',on_delete=models.CASCADE)
    authors = models.ManyToManyField(to='Author')

    def publish_detail(self):
        return {'name': self.publish.name,'addr': self.publish.addr}

    def author_list(self):
        l = []
        for author in self.authors.all():
            l.append({'name': author.name,'phone':author.phone})
        return l

# serializers.py    : 序列化类

from rest_framework import serializers

class BookSerializer(serializers.Serializer):
    name = serializers.CharField(max_length=8)
    price = serializers.CharField()

    publish_detail = serializers.DictField()
    author_list = serializers.ListField()

多表关联反序列化保存

新增接口

# 视图类 views.py
from rest_framework import serializers
from .models import Book,Author,Publish

class BookView(APIView):
    # def get(self,request):
    #     books = Book.objects.all()
    #     ser = BookSerializer(instance=books, many=True)
    #     return Response(ser.data)
    def post(self,request):
        ser = BookSerializer(data=request.data)
        if ser.is_valid():
            ser.save()
            return Response({'code':100,'msg':'新增成功'})
        else:
            return Response({'code':101,'msg':ser.errors})

# 序列化类 serializers.py
class BookSerializer(serializers.Serializer):
# name和price  可用来序列化，也可用来反序列化，又读又写，不用加read_only,write_only
    name = serializers.CharField(max_length=8)
    price = serializers.CharField()
    # 只用来序列化   只读 read_only
    publish_detail = serializers.DictField(read_only=True)
    author_list = serializers.ListField(read_only=True)
    # 只用来反序列化 只写 write_only
    publish = serializers.CharField(write_only=True)
    authors = serializers.ListField(write_only=True)
    # 新增    要重写create方法
    def create(self,validated_data):
        # validated_data是校验过后的数据，
        # 新增一本图书
        book = Book.objects.create(name=validated_data.get('name'),price=validated_data.get('price'),
                                   publish_id = validated_data.get('publish'))
        # price = validated_data.get('price'),
        # publish_id = validated_data.get('publish')
        # 把作者与书关联
        book.authors.add(*validated_data.get('authors'))
        return book

修改更新接口

# 视图类 views.py
from rest_framework.views import APIView
from .models import Book
from .serializers import BookSerializer
from rest_framework.response import Response
from rest_framework.exceptions import ValidationError

class BookDetailView(APIView):
    def put(self,request,pk):
        book = Book.objects.filter(pk=pk).first()
        ser = BookSerializer(data=request.data,instance=book)
        if ser.is_valid():
            ser.save()
            return Response({'code':100,'msg':'修改成功'})
        else:
            return Response({'code': 101, 'msg':ser.errors})

# 序列化类  serializers.py
from rest_framework import serializers
from .models import Book,Author,Publish
class BookSerializer(serializers.Serializer):
    name = serializers.CharField(max_length=8)
    price = serializers.CharField()
    # 只用来序列化   只读 read_only
    publish_detail = serializers.DictField(read_only=True)
    author_list = serializers.ListField(read_only=True)
    # 只用来反序列化 只写 write_only
    publish = serializers.CharField(write_only=True)
    authors = serializers.ListField(write_only=True)

    # 修改要重写update
    def update(self,instance,validated_data):
        instance.name = validated_data.get('name')
        instance.price = validated_data.get('price')
        instance.publish_id = validated_data.get('publish')
        # 先清空，在添加
        authors = validated_data.get('authors')
        instance.authors.clear()
        instance.authors.add(*authors)
        instance.save()
        return instance

反序列化字段校验其他

# 步骤:
    -1 字段自己的：举例：name = serializers.CharField(max_length=8, error_messages={'max_length': '太长了'})
    -2 validators=[方法，]   忽略掉
    -3 局部钩子
    -4 全局钩子

ModelSerializer使用

# ModelSerializer 继承自Serializer
   -跟表模型强关联
   -大部分请求，不用写create和update了

# ModelSerializer的使用
class BookSerializer(serializers.ModelSerializer):
    # 和表有关联
    class Meta:
        model = Book  # 跟book表建立了关系     序列化类和表模型类
        # 序列化所有Book中的字段  id name price publish authors
        # fields = '__all__'
        # 序列化所有Book中的name和price字段字段
        fields = ['name', 'price', 'publish_detail', 'author_list', 'publish', 'authors']  

        # 定制name反序列化时，最长不能超过8  ，给字段类加属性
        # 方式一
        extra_kwargs = {'name': {'max_length': 8},
                        'publish_detail': {'read_only': True},
                        'author_list': {'read_only': True},
                        'publish': {'write_only': True},
                        'authors': {'write_only': True},
                        }

         # 如果Meta写了__all__ ,就相当于，复制了表模型中的所有字段，放在了这里，做了个映射
        # name = serializers.CharField(max_length=32)
        # price = serializers.CharField(max_length=32)

       # 定制name反序列化时，最长不能超过8   给字段类加属性---方式二，重写name字段
       # name = serializers.CharField(max_length=8)

       # 同理，所有的read_only和wirte_only都可以通过重写或使用extra_kwargs传入

       # 最后，把这个序列化类写成跟之前一模一样项目
       # publish_detail = serializers.SerializerMethodField(read_only=True)
       # def get_publish_detail(self, obj):
       #     return {'name': obj.publish.name, 'addr': obj.publish.addr}
       # author_list = serializers.SerializerMethodField(read_only=True)
       # def get_author_list(self, obj):
       #     l = []
       #     for author in obj.authors.all():
       #         l.append({'name': author.name, 'phone': author.phone})
       #     return l

       # 局部钩子和全局钩子跟之前完全一样
       def validate_name(self, name):
           if name.startswith('sb'):
               raise ValidationError('不能sb')

           else:
               return name