django-13-类是图

一、使用基于类的视图重写API

from django.http import  Http404

from rest_framework import status
from rest_framework.decorators import api_view, APIView
from rest_framework.response import Response

from crm.models import Student
from crm.serializers import StudentSerializer


class StudentList(APIView):
    """
    学生列表，创建视图
    """
    def get(self, request, format=None):
        objs = Student.objects.all()
        serializer = StudentSerializer(objs, many=True)
        return Response(serializer.data)

    def post(self, request, format=None):
        serializer = StudentSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data, status=status.HTTP_201_CREATED)
        else:
            return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)


class StudentDetail(APIView):
    """
    查看，更新或者删除一个项目
    """
    def get_object(self, pk):
        try:
            return Student.objects.get(pk=pk)
        except Student.DoesNotExist:
            raise Http404

    def get(self, request, pk, format=None):
        obj = self.get_object(pk)
        serializer = StudentSerializer(obj)
        return Response(serializer.data, status=status.HTTP_201_CREATED)

    def put(self, request, pk, format=None):
        obj = self.get_object(pk)
        serializer = StudentSerializer(obj, data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

    def delete(self, request, pk, format=None):
        obj = self.get_object(pk)
        obj.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

重构路由

urlpatterns = [
    path('students/', views.StudentList.as_view()),
    path('students/<int:pk>', views.StudentDetail.as_view()),
]

二、使用mixins

使用基于类的视图的一大优点是，它允许我们轻松地组合且可重用的行为。

在实际开发过程中，对任何模型的创建/检索/更新/删除操作非常相似。REST framework在mixin类中实现了这些公共行为。

让我们看看如何使用mixin类来组合视图。views.py模块代码如下：

from rest_framework import status, mixins, generics
from rest_framework.decorators import APIView
from rest_framework.response import Response

from crm.models import Student
from crm.serializers import StudentSerializer


class StudentList(mixins.ListModelMixin,
                  mixins.CreateModelMixin,
                  generics.GenericAPIView):
    """
    返回所有的项目或者创建一个新项目
    """
    queryset = Student.objects.all()
    serializer_class = StudentSerializer

    def get(self, request, *args, **kwargs):
        return self.list(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):

        return self.create(request, *args, **kwargs)

上面的代码使用GenericAPIView构建视图，并添加ListModelMixin和CreateModelMixin。

基类提供了核心功能，mixin类提供了.list()和.create()操作。然后显式地将get和post方法绑定到适当的操作。

class StudentDetail(mixins.RetrieveModelMixin,
                    mixins.UpdateModelMixin,
                    mixins.DestroyModelMixin,
                    generics.GenericAPIView):
    """
    查看，更新或者删除一个项目
    """
    queryset = Student.objects.all()
    serializer_class = StudentSerializer

    def get(self, request, *args, **kwargs):
        return self.retrieve(request, *args, **kwargs)

    def put(self, request, *args, **kwargs):
        
        return self.update(request, *args, **kwargs)

    def delete(self, request, *args, **kwargs):
        return self.destroy(request, *args, **kwargs)

同理，我们再次使用GenericAPIView类来提供核心功能，并在mixins中添加.retrieve()、.update()和.destroy()操作。

三、使用通用类视图

使用mixin类，我们已经重写了视图，代码比以前少了一些，但是我们可以更进一步。上面的代码显然是可以公用的，而REST框架提供了一组已经混合在一起的通用视图，我们可以使用这些视图进一步精简我们的views.py模块。

class StudentList(generics.ListCreateAPIView):
    """
    返回所有的项目或者创建一个新项目
    """
    queryset = Student.objects.all()
    serializer_class = StudentSerializer

  
class StudentDetail(generics.RetrieveUpdateDestroyAPIView):
    """
    查看，更新或者删除一个项目
    """
    queryset = Student.objects.all()
    serializer_class = ProjectSerializer