创建一个序列化类
使用序列化有四种方式
- 使用json模块，完全手写
- 使用django自带的序列化模块 1，# from django.core import serializers 2，# data=serializers.serialize(“json”,book_list)
- 使用REST framework 带的序列化方法，但是自己写规则 BookSerializers(serializers.Serializer)
- 使用REST framework 带的序列化方法，不自定义，完全使用模块 BookSerializers(serializers.ModelSerializer)
开发我们的Web API的第一件事是为我们的Web API提供一种将代码片段实例序列化和反序列化为诸如json之类的表示形式的方式。我们可以通过声明与Django forms非常相似的序列化器（serializers）来实现。
models部分:
from django.db import models
# Create your models here.
class Book(models.Model):
title=models.CharField(max_length=32)
price=models.IntegerField()
pub_date=models.DateField()
publish=models.ForeignKey("Publish")
authors=models.ManyToManyField("Author")
def __str__(self):
return self.title
class Publish(models.Model):
name=models.CharField(max_length=32)
email=models.EmailField()
def __str__(self):
return self.name
class Author(models.Model):
name=models.CharField(max_length=32)
age=models.IntegerField()
def __str__(self):
return self.nameviews部分：
from rest_framework.views import APIView
from rest_framework.response import Response
from .models import *
from django.shortcuts import HttpResponse
from django.core import serializers
from rest_framework import serializers
# 方式三，自己定义序列化的规则
class BookSerializers(serializers.Serializer):
title=serializers.CharField(max_length=32)
price=serializers.IntegerField()
pub_date=serializers.DateField()
publish=serializers.CharField(source="publish.name") # 一对多，序列化时如果想要指定字段，需要使用参数source，跨表用.
#authors=serializers.CharField(source="authors.all")
authors=serializers.SerializerMethodField() # 多对多时，自定义字段字段
def get_authors(self,obj): # 名字固定写法 get_*
temp=[]
for author in obj.authors.all():
temp.append(author.name)
return temp
class Meta:
model=Book
fields=['title','price','pub_date','authors']
# 钩子函数
def validate_title(self, value):
if '草' in value:
raise ValidationError('不符合社会主义核心价值观')
return value
class BookViewSet(APIView):
def get(self,request,*args,**kwargs):
book_list=Book.objects.all()
# 序列化方式1 自己手写json:
# from django.forms.models import model_to_dict
# import json
# data=[]
# for obj in book_list:
# data.append(model_to_dict(obj))
# print(data)
# return HttpResponse("ok")
# 序列化方式2，使用django自带的序列化模块:
# from django.core import serializers
# data=serializers.serialize("json",book_list)
# return HttpResponse(data)
# 序列化方式3，使用REST framework 带的序列化方法，但是自己写规则:
bs=BookSerializers(book_list,many=True)
return Response(bs.data)
# 序列化方式4，使用REST framework 带的序列化方法，不自定义，完全使用模块，如下ModelSerializer
# ModelSerializer 继承自 Serializer
class BookSerializers(serializers.ModelSerializer): # 不自定义，完全使用模块
class Meta:
model=Book
fields="__all__"
depth=1 # 表的深度，即使用一对多，多对多时，跨表的深度
extra_kwargs = {
"tag": {
"error_messages": {
"does_not_exist": '"{pk_value}"对应的tag对象不存在。'
}
}
}在视图中使用序列化类
提交post（添加）请求
def post(self,request,*args,**kwargs):
bs=BookSerializers(data=request.data,many=False) # 实例化 ，many=false 是实例一个对象，many=true 是实例化querset
if bs.is_valid():
# print(bs.validated_data)
bs.save()
return Response(bs.data)
else:
return HttpResponse(bs.errors)单条数据的get（查询一条）和put（更新一条）请求
class BookDetailViewSet(APIView):
def get(self,request,pk):
book_obj=Book.objects.filter(pk=pk).first()
bs=BookSerializers(book_obj)
return Response(bs.data)
def put(self,request,pk):
book_obj=Book.objects.filter(pk=pk).first()
bs=BookSerializers(book_obj,data=request.data) # 有data参数，调用save是更新操作
if bs.is_valid():
bs.save()
return Response(bs.data)
else:
return HttpResponse(bs.errors)重写save中的create方法
重写create方法，当你要对某一个字段进行操作的时候，不能用父类的create方法，source不能被解析出来
class BookSerializers(serializers.ModelSerializer):
class Meta:
model=Book
fields="__all__"
# exclude = ['authors',]
# depth=1
def create(self, validated_data):
authors = validated_data.pop('authors')
obj = Book.objects.create(**validated_data)
obj.authors.add(*authors)
return obj自定义验证
from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import serializers
from .. import models
class PasswordValidator(object):
def __init__(self, base):
self.base = str(base)
def __call__(self, value):
if value != self.base:
message = 'This field must be %s.' % self.base
raise serializers.ValidationError(message)
def set_context(self, serializer_field):
# 执行验证之前调用,serializer_fields是当前字段对象
pass
class ModelUserSerializer(serializers.ModelSerializer):
user = serializers.CharField(max_length=32)
class Meta:
model = models.UserInfo
fields = "__all__"
# fields = ['user', 'pwd', 'ut']
depth = 2
extra_kwargs = {'user': {'min_length': 6},
'pwd': {'validators': [PasswordValidator(666), ]}}
# read_only_fields = ['user']超链接API：Hyperlinked
class BookSerializers(serializers.ModelSerializer):
publish= serializers.HyperlinkedIdentityField(
view_name='publish_detail', # 反向解析
lookup_field="publish_id", # 这里是取这个id值，当你循环到那个外键的那个id值的值的时候，作为参数传进去
lookup_url_kwarg="pk") # 把还是那个面的id作为参数传进去，就是在url路由里面的有名分组
class Meta:
model=Book
fields="__all__"
#depth=1urls部分：
urlpatterns = [
url(r'^books/$', views.BookViewSet.as_view(),name="book_list"), # 需要加name参数
url(r'^books/(?P<pk>\d+)$', views.BookDetailViewSet.as_view(),name="book_detail"),
url(r'^publishers/$', views.PublishViewSet.as_view(),name="publish_list"),
url(r'^publishers/(?P<pk>\d+)$', views.PublishDetailViewSet.as_view(),name="publish_detail"),
]