视图家族

视图家族简介

from rest_framework import views, mixins, generics, viewsets
  • views:视图类 APIView,GenericAPIView(generics中)
  • mixins:视图工具类 CreateModelMixin,ListModelMixin,RetrieveModelMixin,UpdateModelMixin,DestroyModelMixin
  • generics:工具视图类 有九个类
  • viewsets:视图集 两个视图集基类,两个视图集子类,一个工具类

视图类APIView

  • 继承View,拥有View的所有
  • 重写了as_view方法,局部禁用csrf认证
  • 重写dispatch
  • 增加一系列类属性,局部 渲染和解析配置

视图类GenericAPIView

GenericAPIView 继承APIView,拥有APIView的所有方法、属性

# 工具视图类
from rest_framework.generics import GenericAPIView

class CarGenericAPIView(GenericAPIView):
    # 不能直接写到objects结束,因为objects结束时,不是QuerySet对象,而是Manager对象,但 .all() 和 .filter() 后一定是QuerySet对象
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializer.CarModelSerializer
    lookup_url_kwarg = 'pk'

    # 群查
    """
    def get(self, request, *args, **kwargs):
        car_query = self.get_queryset()
        car_ser = self.get_serializer(car_query, many=True)
        return APIResponse(results=car_ser.data)
    """

    # 单查
    def get(self, request, *args, **kwargs):
        car_obj = self.get_object()
        car_ser = self.get_serializer(car_obj)
        return APIResponse(results=car_ser.data)

GenericAPIView总结:

  • 继承APIView,拥有APIView的所有
  • get_queryset方法,配置queryset类属性,提供视图类相关的Models
  • get_queryset方法的基础上,有了get_object方法,配置lookup_url_kwarg属性,提供视图类相关的具体的models
  • get_serializer方法,配置serializer_class类属性,提供视图类相关的序列化对象

GenericAPIView就是在APIView的基础上额外提供了三个方法、三个类属性,如果不配合视图工具类,体现不出优势

其目的:视图中的增删改查逻辑相似,但操作的资源不一致,操作资源就是操作 资源对象们、资源对象以及资源相关的序列化类,将这三者形成配置,那操作逻辑就一致,就可以进行封装。

视图工具类mixins

# mixins视图工具类
from rest_framework.mixins import RetrieveModelMixin, ListModelMixin, CreateModelMixin
class CarReadCreateGenericAPIView(RetrieveModelMixin, ListModelMixin, CreateModelMixin, GenericAPIView):
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializer.CarModelSerializer
    lookup_url_kwarg = 'pk'

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

    # 单查
    def get(self, request, *args, **kwargs):
        response = self.retrieve(request, *args, **kwargs)
        return APIResponse(results=response.data)


    # 单增
    def post(self, request, *args, **kwargs):
        return self.create(request, *args, **kwargs)
  • mixins视图工具类:有五个类、六个方法
  • 需要配合GenericAPIView类使用,将单查、群查、单增、整体单改、局部单改、单删六个接口封装成retrievelistcreateupdatepartial_updatedestroy 六个方法
  • 调用的方法就是GenericAPIView提供的,配合GenericAPIView 类使用

工具视图类generics

# 单独完成单查接口
from rest_framework.generics import RetrieveAPIView
class CarRetrieveAPIView(RetrieveAPIView):
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializer.CarModelSerializer
    lookup_url_kwarg = 'pk'


# 单独完成群查接口
from rest_framework.generics import ListAPIView
class CarListAPIView(ListAPIView):
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializer.CarModelSerializer


# 完成单查接口、整体单改接口、局部单改接口、单删接口
from rest_framework.generics import RetrieveUpdateDestroyAPIView
class CarRetrieveUpdateDestroyAPIView(RetrieveUpdateDestroyAPIView):
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializer.CarModelSerializer

generics工具视图类 有九种组合

  • 帮我们将不同种类的mixinsGenericAPIView进行组合
  • 不同的组合帮我们实现好对应的 getpostputpatchdelete 方法
  • 只要我们自己配置三个类属性即可:querysetserializer_classlookup_url_kwarg

视图集viewsets

这里的ViewSetMixin重写了as_view方法

# 视图集
from rest_framework.viewsets import ViewSetMixin, ViewSet, GenericViewSet, ModelViewSet

class CarReadOnlyAPIView(RetrieveModelMixin, ListModelMixin, GenericViewSet):
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializer.CarModelSerializer
    
    
# urls.py 
url(r'^v7/cars/$', views.CarReadOnlyAPIView.as_view({'get': 'list'})),
url(r'^v7/cars/(?P<pk>\d+)/$', views.CarReadOnlyAPIView.as_view({'get': 'retrieve'})),

视图集实现六大接口

# 实现了六大接口,单查、群查、单增、整体单改、局部单改、单删
class CarModelViewSet(ModelViewSet):
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializer.CarModelSerializer

# urls.py
url(r'^v8/cars/$', views.CarModelViewSet.as_view({
        'get': 'list',
        'post': 'create'
})),

url(r'^v8/cars/(?P<pk>\d+)/$', views.CarModelViewSet.as_view({
        'get': 'retrieve',
        'put': 'update',
        'patch': 'partial_update',
        'delete': 'destroy'
}))

这样设计的不合理点:

  • 没有群增、整体群改、局部群改、群删 四个接口
  • 删除操作视图集默认 走的是 destroy方法, 是将资源从数据库中删除,而不是将一个字段is_delete字段修改
  • 响应的结果只有数据,没有数据状态码和状态信息

解决视图集的不合理

# 实现了六大接口,单查、群查、单增、整体单改、局部单改、单删
class CarModelViewSet(ModelViewSet):
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializer.CarModelSerializer

    # 群整体改,群局部改,全删三个接口可以独立成三个方法
    def many_update(self, request, *args, **kwargs):
        request_data = request.data
        try:
            pks = []
            for dic in request_data:
                pk = dic.pop('pk')
                pks.append(pk)
            car_query = models.Car.objects.filter(is_delete=False, pk__in=pks).all()
            if len(pks) != len(car_query):
                raise Exception('pk对应的数据不存在')

        except Exception as e:
            return Response({'detail': '%s' % e}, status=400)
        car_ser = serializer.CarModelSerializer(instance=car_query, data=request_data, many=True)
        car_ser.is_valid(raise_exception=True)
        car_list = car_ser.save()
        return APIResponse(results=serializer.CarModelSerializer(instance=car_list, many=True).data)

    def many_partial_update(self, request, *args, **kwargs):
        request_data = request.data
        try:
            pks = []
            for dic in request_data:
                pk = dic.pop('pk')
                pks.append(pk)
            car_query = models.Car.objects.filter(is_delete=False, pk__in=pks).all()
            if len(pks) != len(car_query):
                raise Exception('pk对应的数据不存在')

        except Exception as e:
            return Response({'detail': '%s' % e}, status=400)
        car_ser = serializer.CarModelSerializer(instance=car_query, data=request_data, partial=True, many=True)
        car_ser.is_valid(raise_exception=True)
        car_list = car_ser.save()
        return APIResponse(results=serializer.CarModelSerializer(instance=car_list, many=True).data)

    def many_destroy(self, request, *args, **kwargs):
        pks = request.data
        try:
            rows = models.Car.objects.filter(is_delete=False, pk__in=pks).update(is_delete=True)
        except:
            return APIResponse(1, '数据有误')

        if rows:
            return APIResponse(0, '删除成功')
        return APIResponse(1, '删除失败')

    # 群增与单增必须公用一个接口,都要走create方法 - 重写create方法,用逻辑进行拆分
    def create(self, request, *args, **kwargs):
        if isinstance(request.data, list):
            car_ser = serializer.CarModelSerializer(data=request.data, many=True)
            car_ser.is_valid(raise_exception=True)
            car_obj = car_ser.save()
            return APIResponse(results=serializer.CarModelSerializer(car_obj, many=True).data)

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

    # destroy方法是完成is_delete字段值修改 - 重写destroy方法,自定义实现体
    def destroy(self, request, *args, **kwargs):
        car_obj = self.get_object()
        car_obj.is_delete = True
        car_obj.save()
        return APIResponse(msg='删除成功')

    # 让群查有状态码和状态信息 - 重写list方法
    def list(self, request, *args, **kwargs):
        response = super().list(request, *args, **kwargs)
        return APIResponse(results=response.data)
    
    # 重写retrieve方法
    def retrieve(self, request, *args, **kwargs):
        response = super().retrieve(request, *args, **kwargs)
        return APIResponse(results=response.data)

# urls.py
url(r'^v8/cars/$', views.CarModelViewSet.as_view({
        'get': 'list',
        'post': 'create',
        'put': 'many_update',
        'patch': 'many_partial_update',
        'delete': 'many_destroy'
})),
url(r'^v8/cars/(?P<pk>\d+)/$', views.CarModelViewSet.as_view({
        'get': 'retrieve',
        'put': 'update',
        'patch': 'partial_update',
        'delete': 'destroy'
}))

视图集总结:

  • 核心:视图集都继承了ViewSetMixin类,该类重写了as_view方法,相比APIView的as_view方法,额外多出了一个参数actionsas_view({'get': 'list'}) 传入的 {'get': 'list'} 就被actions参数接收,原理是将get请求映射到视图类的list 函数进行处理
  • 在源码中 GenericViewSetViewSet两个视图集基类
    • GenericViewSet(ViewSetMixin, GenericAPIView),该分支严格满足资源接口
    • ViewSet(ViewSetMixin, views.APIView), 该分支吗,满足的接口与资源Model类关系 不是特别密切:如登录接口、短信验证码接口
  • ReadOnlyModelViewSetModelViewSet两个视图集子类,就是做一堆mixins与GenericViewSet的组合,自己在urls.py文件中配置as_view设置映射关系。

补充路由层写法

# urls.py
from rest_framework.routers import SimpleRouter
router = SimpleRouter()
router.register('v8/cars', views.CarModelViewSet, basename='car')

url(r'', include(router.urls))
posted @ 2019-12-30 22:55  SetCreed  阅读(185)  评论(0编辑  收藏