Django REST framework序列化
Django REST framework序列化
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
models部分
from django.db import models 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.name
view部分
from django.views import View from rest_framework.response import Response from app01.serializer import * from rest_framework.views import APIView class PublishView(APIView): def get(self, request): # 序列化方式 # 方式1： # publish_list=list(Publish.objects.all().values("name","email")) # 方式2： # model_to_dict就是把一个model对象转换成字典 # from django.forms.models import model_to_dict # publish_list=Publish.objects.all() # temp=[] # for obj in publish_list: # temp.append(model_to_dict(obj)) # 方式3： # django的序列化组件，跟restful没关系，最简单的方式 # from django.core import serializers # ret=serializers.serialize("json",publish_list) # 方式4： # DjangoRESTframework序列组件，详见serializer部分 # 实例化一个序列化对象，传入要序列化的数据和many # many=True表示传入的是一个queryset，false是model对象 publish_list = Publish.objects.all() ps = PublishModelSerializers(publish_list, many=True) # 取序列化后的数据 return Response(ps.data)
# restframework中get取数据
# print("request.data", request.data)
# print("request.data type", type(request.data))
# print(request._request.GET)
# print(request.GET)
serializer部分
from rest_framework import serializers from app01.models import * # 类1： 为queryset,model对象做序列化 # 对哪些字段做序列化name = serializers.CharField() 这个字段序列化成什么类型 class PublishSerializers(serializers.Serializer): name = serializers.CharField() email = serializers.CharField()
# 类2： 上面的方式需要自己定义字段，faramework组件也有一个类似modelform的组件 class PublishModelSerializers(serializers.ModelSerializer): class Meta: model = Publish fields = "__all__"
# 类1中只设置了一些简单的字段，下面是一对多，多对多的字段时的方法 # class BookSerializers(serializers.Serializer): # title = serializers.CharField(max_length=32) # price = serializers.IntegerField() # pub_date = serializers.DateField() # publish=serializers.CharField(source="publish.name") # #authors=serializers.CharField(source="authors.all") # authors = serializers.SerializerMethodField() # def get_authors(self,obj): # temp=[] # for obj in obj.authors.all(): # temp.append(obj.name) # return temp ''' 序列化BookSerializers(book_list,many=True)过程： temp=[] for obj in book_list: temp.append({ "title":obj.title, "price":obj.price, "pub_date":obj.pub_date, "publish":str(obj.publish), # obj.publish.name #"authors":obj.authors.all, "authors": get_authors(obj) }) '''
ModelSerializer
上面的类2就用的ModelSerializer
class BookSerializers(serializers.ModelSerializer): class Meta: model=Book fields="__all__" depth=1
处理POST请求
def post(self, request): # 取数据,原生request支持的操作，如果contenttype其它的原生request不会帮你封装 # print("POST",request.POST) # print("body",request.body) # # print(request) # print(type(request)) # from django.core.handlers.wsgi import WSGIRequest # 新的request支持的操作 # print("request.data",request.data) # print("request.data type",type(request.data)) # post请求的数据 ps = PublishModelSerializers(data=request.data, many=False) if ps.is_valid(): print(ps.validated_data) ps.save() # create方法 return Response(ps.data) else: return Response(ps.errors)
重写save中的create方法
class BookModelSerializers(serializers.ModelSerializer): class Meta: model = Book fields = "__all__" # authors=serializers.CharField(source="authors.all") authors = serializers.SerializerMethodField() def get_authors(self,obj): temp=[] for obj in obj.authors.all(): temp.append(obj.name) return temp
# 假如你上面自定义了字段的显示，就需要重写create方法了 def create(self, validated_data):
authors = validated_data.pop('authors') book =Book.objects.create(**validated_data)
book.authors.add(*authors)
return book
单条数据的get、put、delete请求
class PublishDetailView(APIView): def get(self, request, pk): publish = Publish.objects.filter(pk=pk).first() ps = PublishModelSerializers(publish) return Response(ps.data) def put(self, request, pk):
# 先取出要更新的对象 publish = Publish.objects.filter(pk=pk).first() ps = PublishModelSerializers(publish, data=request.data) if ps.is_valid(): ps.save() return Response(ps.data) else: return Response(ps.errors) def delete(self, request, pk): Publish.objects.filter(pk=pk).delete() return Response()
超链接API：Hyperlinked
很多时候，我们就想一个字段的值是另一个字段的超链接，如下book表的publish字段就是publish表的超链接
class BookModelSerializers(serializers.ModelSerializer): class Meta: model = Book fields = "__all__" publish = serializers.HyperlinkedIdentityField( # 你要找的url的别名 view_name="detailpublish", # 含正则表达式如(\d+)的话，下两步是把什么字段的内容，赋值给哪个分组命名 lookup_field="publish_id", # 赋给什么分组命名 lookup_url_kwarg="pk" )
urls部分
urlpatterns = [ # View:view(request)=====APIView:dispatch() url(r'^publishes/$', views.PublishView.as_view(), name="publish"), url(r'^publishes/(?P<pk>\d+)/$', views.PublishDetailView.as_view(), name="detailpublish"), # View:view(request)=====APIView:dispatch() url(r'^books/$', views.BookView.as_view(), name="books"), url(r'^books/(\d+)/$', views.BookDetailView.as_view(), name="detailbook"), ]
小结
# 需要会的：
restframework(Django) ----针对数据：json (1)Django的原生request: 浏览器 ------------- 服务器 "GET url?a=1&b=2 http/1.1\r\user_agent:Google\r\ncontentType:urlencoded\r\n\r\n" "POST url http/1.1\r\user_agent:Google\r\ncontentType:urlencoded\r\n\r\na=1&b=2"
# post请求才有请求体，get没有请求体 request.body: a=1&b=2 request.POST: if contentType:urlencoded: # 才会给你封装 a=1&b=2----->{"a":1,"b":2}
(2)restframework 下的APIView： (3) class PublishSerializers(serializers.Serializer): name=serializers.CharField() email=serializers.CharField() PublishSerializers(queryset,many=true) PublishSerializers(model_obj) 总结： 1 reuqest类----源码 2 restframework 下的APIView--源码 url(r'^books/$', views.BookView.as_view(),name="books")# View下的view books/一旦被访问： view(request) ------APIView: dispatch() 3 def dispatch(): 构建request对象 self.request=Request(request) self.request._request self.request.GET # get self.request.data # POST PUT 分发----if get请求： if request.method.lower() in self.http_method_names: handler = getattr(self, request.method.lower(), self.http_method_not_allowed) else: handler = self.http_method_not_allowed response = handler(request, *args, **kwargs) # self.get(request, *args, **kwargs) return response 4 序列化类 # from django.core import serializers # ret=serializers.serialize("json",publish_list) restframework下的序列类 BookModelSerializers 将queryset或者model对象序列成一json数据 bs=BookModelSerializers(book_list,many=True,context={'request': request}) bs=BookModelSerializers(book,context={'request': request}) 还可以做校验数据，json-------》queryset/model-->记录 bs=BookModelSerializers(data=request.data) if bs.is_valid(): print(bs.validated_data) bs.save() # 重写create方法 5 操作数据： 以Book表为例 class BookView(APIView): # 查看所有书籍 def get(self,request): book_list=Book.objects.all() bs=BookModelSerializers(book_list,many=True,context={'request': request}) return Response(bs.data) # 添加一本书籍 def post(self,request): # post请求的数据 bs=BookModelSerializers(data=request.data) if bs.is_valid(): print(bs.validated_data) bs.save()# create方法 return Response(bs.data) else: return Response(bs.errors) class BookDetailView(APIView): # 查看一本书籍 def get(self,request,id): book=Book.objects.filter(pk=id).first() bs=BookModelSerializers(book,context={'request': request}) return Response(bs.data) # 更新一本书籍 def put(self,request,id): book=Book.objects.filter(pk=id).first() bs=BookModelSerializers(book,data=request.data) if bs.is_valid(): bs.save() return Response(bs.data) else: return Response(bs.errors) # 删除某一本书籍 def delete(self,request,id): Book.objects.filter(pk=id).delete() return Response() restframework 1 APIView 2 序列组件 3 视图、 4 组件（认证权限频率） 5 数据解析器 6 分页和Response
