DRF框架之 serializers 序列化组件

1. 什么是序列化,其实在python中我们就学了序列化工具json工具,就是吧信息存为类字典形式

2. DRF框架自带序列化的工具: serializers 

3. DRF框架 serializers 分为:第一种 Serializer   第二种 ModelSerializer

 

第一种用法之 Serializer

from django.db import models

# Create your models here.


class Book(models.Model):
    nid = models.AutoField(primary_key=True)
    name = models.CharField(max_length=32)
    price = models.DecimalField(max_digits=5, decimal_places=2)
    publish_date = models.DateField()
    publish = models.ForeignKey(to='Publish',to_field='nid',on_delete=models.CASCADE)
    authors=models.ManyToManyField(to='Author')
    def __str__(self):
        return self.name


    def test(self):    #注意: 这里是给后面序列化组件的source指定方法用的
        return str(self.price)+self.name


class Author(models.Model):
    nid = models.AutoField(primary_key=True)
    name = models.CharField(max_length=32)
    age = models.IntegerField()
    author_detail = models.OneToOneField(to='AuthorDatail',to_field='nid',unique=True,on_delete=models.CASCADE)


class AuthorDatail(models.Model):
    nid = models.AutoField(primary_key=True)
    telephone = models.BigIntegerField()
    birthday = models.DateField()
    addr = models.CharField(max_length=64)


class Publish(models.Model):
    nid = models.AutoField(primary_key=True)
    name = models.CharField(max_length=32)
    city = models.CharField(max_length=32)
    email = models.EmailField()

    def __str__(self):
        return self.name

from  rest_framework import serializers
from app.models import Book,Author

####################这里是serializers 实例化方法一的实现
#
class Bookserializer(serializers.Serializer):
    # 这里是通过rest_framwork 来实例化对象中的内容,返回给前端的数据信息
    id = serializers.CharField()
    # source指定数据库中的名字,前面可以自定义名字来使用,给前端显示的是自定义名字 bookname 是自己自定义的名字
    bookname = serializers.CharField(source='name')

    price = serializers.CharField()
    # source还可以通过对象继续点其他属性, 可以跨表点其他的想要的属性(这个只是拿到publish的单个字段)
    publish_name = serializers.CharField(source='publish.name')
    #注意source 还可以调用models中 Book 表内的方法
    maxprice = serializers.CharField(source='test')

#注意,source 可以名字自定义显示,可以跨表链接其他想要的属性,还可以调用book表中的自定义的方法
    # publish字段，返回出版社的所有信息，包括id，name，email。。。。
    #     #SerializerMethodField配合一个方法，方法的返回值会付给publish
    #SerializerMethodField 可以拿到跨表内的多个字段,你吧想要的都返还回去就行了(这里是拿到publish的多个字段信息)
    publish = serializers.SerializerMethodField()
    #这里这里的obj 是当前序列化的对象 这里的对象就是book!!!!
    def get_publish(self,obj):
        return {'id':obj.publish.pk, 'name': obj.publish.name,'city':obj.publish.city}

####################这里是serializers 实例化方法一的实现

 

第二种用法之ModelSerializer

 

###################这里是serializers实例化实现方法二 的实现,调用ModelSerializer
class Bookserializer(serializers.ModelSerializer):
    #这里一个meta类去调用Book这个表
    class Meta:
        model = models.Book
        #fields  是然他显示所有的内容,渲染出去
        fields = "__all__"         # '__all__' 是渲染全部出去
#         #fields = ['id', 'name']     # ['....'] 是渲染指定的
#         # exclude=['name']            #是除了name 之外的全部都渲染出去,不能和fields同时出现
#         #depth = 3                   #深度 ,官方建议最多写10,深度显示所有的表
#
    #这里是可以自定义,自定义显示publish的名字,
    publish_name = serializers.CharField(source='publish.name')
    publish = serializers.SerializerMethodField()
    #也可以拿到publish的多个字段信息
    def get_publish(self,obj):
        return {'id':obj.publish.pk, 'name':obj.publish.name}

###################这里是serializers实例化实现方法二 的实现,调用ModelSerializer
最后建议使用serializers.ModelSerializer 来实现序列化 ,因为在修改接口和添加接口 对save() 有很好的依赖关系

# 局部钩子函数，对单个字段校验
    #校验name字段不能以sb开头
    def validate_name(self,value):
        if value.startswith('sb'):
            #不能让你过
            raise ValidationError('书名不能以sb开头')
        else:
            return value

    #全局钩子函数，对全局字段进行校验
    # def validate(self,a):
    #     # print(a)
    #     name=a.get('name')
    #     price=a.get('price')
    #     if name != price:
    #         raise ValidationError('错了')
    #     else:
    #         return a

 

最后视图函数调用序列化的内容并返回给前端进行渲染处理

在View视图层操作:

 查询多本书的方法:
from rest_framework.views import APIView
from rest_framework.response import Response
from app.models import Book
from app.Myserialize import Bookserializer


class Books(APIView):  # 这个是获取多本书的接口

    def get(self, request, *args, **kwargs):  # 这里是通过对drf框架 使用cbv 的get请求
        response = {'status': 100, 'msg': '获取成功'}  # 设置发送出去response 信息
        book_list = Book.objects.all()
        book_ser = Bookserializer(book_list, many=True)  # 使用drf 实例化 自定义的Bookserializer 来实例化
        response['data'] = book_ser.data  # 把实例化book_ser 的data数据放入 response['data']中
        return Response(response)  # 在使用Response来返回出去

    def post(self, request):        #这个是添加书的接口
        response = {'status': 100, 'msg': '添加成功'}

        try:
            book_ser = Bookserializer(data=request.data)
            if book_ser.is_valid():         #这里就是晕倒的反序列的内部工具和钩子判断
                book_ser.save()
                response['data'] = book_ser.data    #判断通过吧数据返回出去
            else:
                response['msg'] = book_ser.errors
        except Exception as e:
            response['msg'] = str(e)
        return Response(response)

class BookView(APIView):        #获取单本图书的接口
    def get(self, request, pk,*args, **kwargs):
        response = {'status': 100, 'msg': '获取成功'}
        #取到pk为传入的pk的书，book对象
        book = models.Book.objects.all().filter(pk=pk).first()
        #要序列化单条，many=False
        book_ser=BookSerializer(instance=book,many=False)
        # book_ser=BookSerializer(book,many=False)
        response['data']=book_ser.data


        return Response(response)


    def put(self,request,pk):     #修改某本书
        response = {'status': 100, 'msg': '修改'}
        book=models.Book.objects.filter(pk=pk).first()
        #修改
        book_ser = BookSerializer(instance=book,data=request.data)
        if book_ser.is_valid():
            book_ser.save()
            response['data']=book_ser.data
        else:
            response['msg']=book_ser.errors
        return Response(response)

在路由层的配置:
urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^books/$', views.BooksView.as_view()),    #查看全部书的接口
    url(r'^books/(?P<pk>\d+)', views.BookView.as_view()),   #查看单个书的接口
]

#总结,个人建议使用第二种序列化的方法,这样对反序列化有很好的帮助

---

以下是全部的接口信息

from  app import  models
from  app.Myserializers import  BookSerializers

# Create your views here.
from rest_framework.views import  APIView
from rest_framework.response import Response



class Booksview(APIView):

    def get(self,request,*args,**kwargs):       #获取多本书
        response = {'status':100, 'msg':'查询成功'}
        book_list = models.Book.objects.all()
        book_ser = BookSerializers(book_list,many=True)
        response['data'] = book_ser.data
        return Response(response)

    def post(self,request):                     #添加书
        response = {'status':100, 'msg':'添加成功'}
        try:
            book_ser = BookSerializers(data=request.data)   #序列化工具拿到的数据是在request.data内的字典中获取
            if book_ser.is_valid(): #进行钩子判断与基础验证
                book_ser.save()
                response['data'] =book_ser.data
            else:
                response['msg']= book_ser.errors
        except Exception as e:
            response['msg'] =str(e)
        return  Response(response)

class Bookview(APIView):

    def get(self, request, pk, *args, **kwargs):        #获取单本书的接口
        response = {'status':100 , 'msg': '获取成功'}
        book = models.Book.objects.all().filter(pk=pk).first()
        book_ser = BookSerializers(instance=book,many=False)
        response['data'] = book_ser.data
        return  Response(response)

    def put(self, request,pk):          #修改但本书的接口
        response = {'status':100, 'msg':'修改成功'}
        book = models.Book.objects.filter(pk=pk).first()
        book_ser = BookSerializers(instance=book,data=request.data)
        if book_ser.is_valid():
            book_ser.save()
            response['data']= book_ser.data
        else:
            response['msg']= book_ser.errors
        return  Response(response)

    def delete(self,request,pk):        #删除的接口
        response = {'status':100, 'msg': '删除成功'}
        book = models.Book.objects.filter(pk=pk).delete()
        return Response(response)