DRF的视图
APIView
Django中写CBV的时候继承的是View，rest_framework继承的是APIView，
urlpatterns = [
url(r'^book$', BookView.as_view()),
# url(r'^book/(?P<id>d+)', BookEditView.as_view()),
url(r'^book$', BookModelView.as_view({"get": "list", "post": "create"})),
# url(r'^book/(?P<pk>d+)', BookModelView.as_view({"get": "retrieve", "put": "update", "delete": "destroy"})),
]
View和APIView调用的都as_view()方法，我们知道APIView继承了View，并且重写了as_view()方法，并执行了View中的as_view()方法，最后把view返回了，用csrf_exempt()方法包裹后去掉了csrf的认证。看下图：
APIView还执行了dispatch方法，新的request是Request类的实例化对象，看下图：
我们看看initialize_request中的代码实现了什么功能：
点击Request可以看到Request类把原来的request赋值给了self._request，也就是说以后_request是我们旧的request，看下图：
继承APIVIew之后的请求来的数据，看下图：
当用了rest_framework框架后，我们的request是重新封装的Request类
request.query_params存放的是我们get请求的参数
request.data存放的是我们所有的数据，包括post请求的以及put，patch请求
相比原来的Django的request，我们现在的request更加精简，清晰了
由于我们写的视图可能对多个表进行增删改查，就导致我们的视图特别多重复的代码
所以我们需要封装一下。
第一次封装
因为代码中除了序列化器不同以及获取的queryset对象不同，其他的都类似。所有我们它相同的代码封装出来，提高代码的复用性。
APIView视图
class BookView(APIView):
def get(self, request):
query_set = Book.objects.all()
book_ser = BookSerializer(query_set, many=True)
return Response(book_ser.data)
def post(self, request):
query_set = request.data
book_ser = BookSerializer(data=query_set)
if book_ser.is_valid():
book_ser.save()
return Response(book_ser.validated_data)
else:
return Response(book_ser.errors)
class BookEditView(APIView):
def get(self, request, id):
query_set = Book.objects.filter(id=id).first()
book_ser = BookSerializer(query_set)
return Response(book_ser.data)
def patch(self, request, id):
query_set = Book.objects.filter(id=id).first()
book_ser = BookSerializer(query_set, data=request.data, partial=True)
if book_ser.is_valid():
book_ser.save()
return Response(book_ser.validated_data)
else:
return Response(book_ser.errors)
def delete(self, request, id):
query_set = Book.objects.filter(id=id).first()
if query_set:
query_set.delete()
return Response("")
else:
return Response("删除的书籍不存在")
第一次封装
from django.shortcuts import render
from rest_framework.views import APIView
from djangoDemo.models import Book
from .serializers import BookSerializer
from rest_framework.response import Response
# queryset不同
# 序列化器不同
# def get():
# def post():
class GenericAPIView(APIView):
queryset = None
serializer_class = None
def get_queryset(self):
# 放到缓存中再拿出来时就需要我们用all()来获取，这是Django机制导致的
return self.queryset.all()
def get_serializer(self, *args, **kwargs):
return self.serializer_class(*args, **kwargs)
class ListModelMixin(object):
def list(self, request):
# 调用外部的get方法
# 执行父类的方法
queryset = self.get_queryset()
# 实例化序列化器
ser_obj = self.get_serializer(queryset, many=True)
return Response(ser_obj.data)
class CreateModelMixin(object):
def create(self, request):
ser_obj = self.get_serializer(data=request.data)
if ser_obj.is_valid():
ser_obj.save()
# 校验过的数据存放在validated_data中
return Response(ser_obj.validated_data)
return Response(ser_obj.errors)
class RetrieveModelMixin(object):
def retrieve(self, request, id):
book_obj = self.get_queryset().filter(id=id).first()
ser_obj = BookSerializer(book_obj)
return Response(ser_obj.data)
class UpdateModelMixin(object):
def update(self, request, id):
book_obj = self.get_queryset().filter(id=id).first()
ser_obj = BookSerializer(instance=book_obj, data=request.data, partial=True)
if ser_obj.is_valid():
ser_obj.save()
# 去反序列化以后的数据中去找到并返回
return Response(ser_obj.validated_data)
return Response(ser_obj.errors)
class DestroyModelMixin(object):
def destroy(self, request, id):
book_obj = self.get_queryset().filter(id=id).first()
if not book_obj:
return Response('删除的数据不存在')
book_obj.delete()
return Response('')
class BookView(GenericAPIView, ListModelMixin, CreateModelMixin):
queryset = Book.objects.all()
serializer_class = BookSerializer
def get(self, request):
# 封装ListModelMixin类以后的执行过程
return self.list(request)
# 只封装GenericAPIView类的执行过程
# # 调用外部的get方法
# # 执行父类的方法
# queryset = self.get_queryset()
# # 实例化序列化器
# ser_obj = self.get_serializer(queryset, many=True)
# return Response(ser_obj.data)
# 没封装之前
# book_queryset = Book.objects.all()
# 用序列化器进行序列化
# ser_obj = BookSerializer(book_queryset, many=True)
# 通过点data来获取数据
# return Response(ser_obj.data)
# 没封装前的post执行过程
# def post(self, request):
# # 获取从前端传递过来的值
# book_obj = request.data
# # data=book_obj就是反序列化时的对象数据
# ser_obj = BookSerializer(data=book_obj)
# if ser_obj.is_valid():
# ser_obj.save()
# # 反序列化以后的数据放在validated_data中
# return Response(ser_obj.validated_data)
# # 如果校验不成功则返回错误信息
# return Response(ser_obj.errors)
# 继承CreateModelMixin类后的post执行过程
def post(self, request):
return self.create(request)
class BookEditView(GenericAPIView, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin):
queryset = Book.objects.all()
serializer_class = BookSerializer
def get(self, request, id):
# book_obj = Book.objects.filter(id=id).first()
# ser_obj = BookSerializer(book_obj)
# return Response(ser_obj.data)
return self.retrieve(request, id)
def put(self, request, id):
# book_obj = Book.objects.filter(id=id).first()
# ser_obj = BookSerializer(instance=book_obj, data=request.data, partial=True)
# if ser_obj.is_valid():
# ser_obj.save()
# # 去反序列化以后的数据中去找到并返回
# return Response(ser_obj.validated_data)
# return Response(ser_obj.errors)
return self.update(request, id)
def delete(self, request, id):
# book_obj = Book.objects.filter(id=id).first()
# if not book_obj:
# return Response('删除的数据不存在')
# book_obj.delete()
# return Response('')
return self.destroy(request, id)
第二次封装
# 我们把继承的类封装了一下
class ListCreateAPIView(GenericAPIView, ListModelMixin, CreateModelMixin):
pass
class RetrieveUpdateDestroyAPIView(GenericAPIView, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin):
pass
class BookView(ListCreateAPIView):
queryset = Book.objects.all()
serializer_class = BookSerializer
def get(self, request):
# 封装ListModelMixin类以后的执行过程
return self.list(request)
# 继承CreateModelMixin类后的post执行过程
def post(self, request):
return self.create(request)
class BookEditView(RetrieveUpdateDestroyAPIView):
queryset = Book.objects.all()
serializer_class = BookSerializer
def get(self, request, id):
return self.retrieve(request, id)
def put(self, request, id):
return self.update(request, id)
def delete(self, request, id):
return self.destroy(request, id)
第三次封装
我们可不可以把这两个视图合并成一个视图呢~~~框架给我们提供了一个路由传参的方法~~
actions这个默认参数其实就是我们路由可以进行传参了~~~
下面这个循环~可以看出~我们要传的参数是一个字段~key应该是我们的请求方式，value应该对应我们处理的方法~
这样我们每个视图就不用在写函数了~因为已经和内部实现的函数相对应了~
路由urls.py
from django.conf.urls import url, include
from .views import BookView, BookEditView, BookModelView
# 帮助我们生成带参数的路由
from rest_framework.routers import DefaultRouter
# 实例化DefaultRouter对象
router = DefaultRouter()
# 注册我们的路由以及视图
router.register(r'^book', BookModelView)
urlpatterns = [
url(r'^book$', BookView.as_view()),
# url(r'^book/(?P<id>d+)', BookEditView.as_view()),
url(r'^book$', BookModelView.as_view({"get": "list", "post": "create"})),
# url(r'^book/(?P<pk>d+)', BookModelView.as_view({"get": "retrieve", "put": "update", "delete": "destroy"})),
]
urlpatterns += router.urls
第三次封装
ViewSetMixin 重写了as_view()方法
from django.shortcuts import render
from rest_framework.views import APIView
from rest_framework.response import Response
from djangoDemo.models import Book
from .serializers import BookSerializer
from rest_framework.viewsets import ViewSetMixin
from rest_framework import views # APIView
from rest_framework import viewsets
from rest_framework import generics
from rest_framework import mixins
# 自定义了一个类，
class ModelViewSet(ViewSetMixin, ListModelMixin, CreateModelMixin, UpdateModelMixin, DestroyModelMixin):
pass
# 然后继承它
class BookModelView(ModelViewSet):
queryset = Book.objects.all()
serializer_class = BookSerializer
由于第三次封装所以路由发生了改变：
from django.conf.urls import url, include
from .views import BookView, BookEditView, BookModelView
urlpatterns = [
url(r'^book/$', BookModelView.as_view({"get": "list", "post": "create"})),
url(r'^book/(?P<pk>d+)/',
BookModelView.as_view({"get": "list", "post": "create", "put": "update", "delete": "destroy"})),
]
注意一点~~用框架封装的视图~我们url上的那个关键字参数要用pk~~系统默认的~~
看看我们的继承顺序
DRF的路由
路由
from django.conf.urls import url, include
from .views import BookView, BookEditView, BookModelView
# 帮我们生成带参数的路由（我们原本是不能传递参数的在路由中）
from rest_framework.routers import DefaultRouter
# 实例化DefaultRouter对象
router = DefaultRouter()
# 注册我们的路由以及视图
router.register(r'book', BookModelView)
urlpatterns = [
# url(r'^book/$', BookView.as_view()),
# url(r'^book/(?P<pk>d+)/', BookEditView.as_view()),
# url(r'^book/$', BookModelView.as_view({"get": "list", "post": "create"})),
# url(r'^book/(?P<pk>d+)/',
# BookModelView.as_view({"get": "list", "post": "create", "put": "update", "delete": "destroy"})),
]
urlpatterns += router.urls
需要自定制的时候还是需要我们自己用APIView写~~当不需要那么多路由的时候~也不要用这种路由注册~~