• django Rest Framework 视图和路由


    django Rest Framework 视图和路由

    DRF视图

    1. APIView

    • 我们django中写CBV的时候继承的是View,rest_framework继承的是APIView,那么他们两个有什么不同呢~~~

      urlpatterns = [
          url(r'^book$', BookView.as_view()),
          url(r'^book/(?P<id>d+)$', BookEditView.as_view()),
      ]
      
    1. 前端发来请求,根据正则匹配,然后调用APIView中的as_view()方法

      img

      APIView继承了View, 并且执行了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。

    2. View中的as_view()方法做了

      img

      看到self,要从最开始的类中开始看,然后再从父类中看,APIView中含有dispatch方法,所有要先看APIView中的

    3. 查看APIView中的dispatch方法

      img

      去initialize_request中看下把什么赋值给了request,并且赋值给了self.request, 也就是我们在视图中用的request.xxx到底是什么~~

    4. 查看initialize_request方法

      img

      这个方法返回的是Request这个类的实例对象~~我们注意我们看下这个Request类中的第一个参数request,是我们走我们django的时候的原来的request~

    5. 点击Request方法

      img

      Request类把原来的request赋值给了self._request, 也就是说以后_request是我们老的request,新的request是我们这个Request类~~

      即对request的功能进行的封装,扩展

    6. 继承APIView之后的数据在哪里来的

      img

      我们用了rest_framework框架以后,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~~~

    2. 第一次封装

    • 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")
      
    • 封装

      class GenericAPIView(APIView):
          queryset = None
          serializer_class = None
      
          def get_queryset(self):
              return self.queryset.all()
      
          def get_serializer(self, *args, **kwargs):
              return self.serializer_class(*args, **kwargs)
      
      
      class ListModelMixin(object):
          def list(self, request, *args, **kwargs):
              queryset = self.get_queryset()
              serializer = self.get_serializer(queryset, many=True)
              return Response(serializer.data)
      
      
      class CreateModelMixin(object):
          def create(self, request, *args, **kwargs):
              serializer = self.get_serializer(data=request.data)
              if serializer.is_valid():
                  serializer.save()
                  return Response(serializer.validated_data)
              else:
                  return Response(serializer.errors)
      
      
      class RetrieveModelMixin(object):
          def retrieve(self, request, id, *args, **kwargs):
              book_obj = self.get_queryset().filter(pk=id).first()
              book_ser = self.get_serializer(book_obj)
              return Response(book_ser.data)
      
      
      class UpdateModelMixin(object):
          def update(self, request, id, *args, **kwargs):
              book_obj = self.get_queryset().filter(pk=id).first()
              book_ser = self.get_serializer(book_obj, 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)
      
      
      class DestroyModelMixin(object):
          def destroy(self, request, id, *args, **kwargs):
              queryset = self.get_queryset()
              try:
                  queryset.get(pk=id).delete()
                  return Response("")
              except Exception as e:
                  return Response("信息有误")
      # 我们把公共的部分抽出来 这样不管写多少表的增删改查都变的很简单
      # 这样封装后我们的视图会变成这样
      
      class BookView(GenericAPIView, ListModelMixin, CreateModelMixin):
          queryset = Book.objects.all()
          serializer_class = BookSerializer
      
          def get(self, request, *args, **kwargs):
              return self.list(request, *args, **kwargs)
      
          def post(self, request, *args, **kwargs):
              return self.create(request, *args, **kwargs)
      
      
      class BookEditView(GenericAPIView, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin):
          queryset = Book.objects.all()
          serializer_class = BookSerializer
      
          def get(self, request, id, *args, **kwargs):
              return self.retrieve(request, id, *args, **kwargs)
      
          def patch(self, request, id, *args, **kwargs):
              return self.update(request, id, *args, **kwargs)
      
          def destroy(self, request, id, *args, **kwargs):
              return self.delete(request, id, *args, **kwargs)
      

      封装的GenericAPIView,包括封装每个方法的类,其实框架都帮我们封装好了

    3 第二次封装

    • 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, *args, **kwargs):
              return self.list(request, *args, **kwargs)
      
          def post(self, request, *args, **kwargs):
              return self.create(request, *args, **kwargs)
      
      
      class BookEditView(RetrieveUpdateDestroyAPIView):
          queryset = Book.objects.all()
          serializer_class = BookSerializer
      
          def get(self, request, id, *args, **kwargs):
              return self.retrieve(request, id, *args, **kwargs)
      
          def patch(self, request, id, *args, **kwargs):
              return self.update(request, id, *args, **kwargs)
      
          def delete(self, request, id, *args, **kwargs):
              return self.delete(request, id, *args, **kwargs)
      

      这次我们只是让继承变的简单了一点而已,好像并没有什么大的进步~~

      内置源码提供的方法

      img

      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

    4. 第三次封装

    • 路由url.py

      urlpatterns = [
          # url(r'^book$', BookView.as_view()),
          # url(r'^book/(?P<id>d+)$', BookEditView.as_view()),
          url(r'^book$', BookView.as_view({"get": "list", "post": "create"})),
          url(r'^book/(?P<pk>d+)$', BookView.as_view({"get": "retrieve", "patch": "update", "delete": "destroy"})),
      ]
      
    • view.py

      from rest_framework.viewsets import ViewSetMixin
      
      
      # class BookView(ViewSetMixin, ListCreateAPIView, RetrieveUpdateDestroyAPIView):
      #     queryset = Book.objects.all()
      #     serializer_class = BookSerializer
          
          
      # 如果我们再定义一个类
      class ModelViewSet(ViewSetMixin, ListCreateAPIView, RetrieveUpdateDestroyAPIView):
          pass
      
      
      class BookView(ModelViewSet):
          queryset = Book.objects.all()
          serializer_class = BookSerializer
      

      我们现在的视图就只要写两行就可以了~~~

      其实我们写的所有的视图框架都帮我们封装好了

      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~~

      奉献一张图来看下我们的继承顺序

      img

    DRF路由

    • 路由传参写的特别多~~框架也帮我们封装好了~

      from .views import BookView
      from rest_framework.routers import DefaultRouter
      
      router = DefaultRouter()
      router.register(r"book", BookView)
      
      urlpatterns = [
          # url(r'^book$', BookView.as_view()),
          # url(r'^book/(?P<id>d+)$', BookEditView.as_view()),
          # url(r'^book$', BookView.as_view({"get": "list", "post": "create"})),
          # url(r'^book/(?P<pk>d+)$', BookView.as_view({"get": "retrieve", "patch": "update", "delete": "destroy"})),
      
      ]
      urlpatterns += router.urls
      

      通过框架我们可以把路由视图变得很简单,但是需要自定制的时候还是需要自己用APIView写,

      路由组件
      	-- 导入 from rest_framework.routers import DefaultRouter
      	-- 实例化 
      		router = DefaultRouter()
      	-- 注册
      		router.register('路由',View)
      	-- 把自动生成的路由注册
      		urlpatterns += router.urls
      
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  • 原文地址:https://www.cnblogs.com/yuncong/p/10129000.html
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