视图家族

视图家族

视图类

APIView和GenericAPIView

GenericAPIView中比较重要的两个方法:

get_object
- 获取单查对象
get_serializer
- 获取单查对象的序列化

from rest_framework.generics import GenericAPIView

class CarGenericAPIView(GenericAPIView):
    # 
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializers.CarModelSerializer
    lookup_url_kwarg = 'pk'
    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中query_set默认为None,需要自己进行赋值

注: models.Car.objects 是Manager对象,管理QuerySet

Mixins视图工具类

必须配合GenericAPIView类使用,将单查, 群查, 单增, 整体/局部单改, 单删留个接口封装成retrieve, list, create, update, partial_update, destroy六个方法

原因: 六个方法的实现体,调用的方法就是GenericAPIView提供的

ListModelMixin

群查功能源码

class ListModelMixin:
    """
    List a queryset.
    """
    def list(self, request, *args, **kwargs):
        queryset = self.filter_queryset(self.get_queryset())

        page = self.paginate_queryset(queryset)
        if page is not None:
            serializer = self.get_serializer(page, many=True)
            return self.get_paginated_response(serializer.data)

        serializer = self.get_serializer(queryset, many=True)
        return Response(serializer.data)

RetrieveModelMixin

单查功能源码

class RetrieveModelMixin:
    """
    Retrieve a model instance.
    """
    def retrieve(self, request, *args, **kwargs):
        instance = self.get_object()
        serializer = self.get_serializer(instance)
        return Response(serializer.data)

CreateModelMixin

单增功能源码

class CreateModelMixin:
    """
    Create a model instance.
    """
    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        self.perform_create(serializer)
        headers = self.get_success_headers(serializer.data)
        return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)

    def perform_create(self, serializer):
        serializer.save()

    def get_success_headers(self, data):
        try:
            return {'Location': str(data[api_settings.URL_FIELD_NAME])}
        except (TypeError, KeyError):
            return {}

DestroyModelMixin

单删功能源码

class DestroyModelMixin:
    """
    Destroy a model instance.
    """
    def destroy(self, request, *args, **kwargs):
        instance = self.get_object()
        self.perform_destroy(instance)
        return Response(status=status.HTTP_204_NO_CONTENT)

    def perform_destroy(self, instance):
        instance.delete()

UpdateModelMixin

整体或局部单改功能源码

class UpdateModelMixin:
    """
    Update a model instance.
    """
    def update(self, request, *args, **kwargs):
        partial = kwargs.pop('partial', False)
        instance = self.get_object()
        serializer = self.get_serializer(instance, data=request.data, partial=partial)
        serializer.is_valid(raise_exception=True)
        self.perform_update(serializer)

        if getattr(instance, '_prefetched_objects_cache', None):
            # If 'prefetch_related' has been applied to a queryset, we need to
            # forcibly invalidate the prefetch cache on the instance.
            instance._prefetched_objects_cache = {}

        return Response(serializer.data)

    def perform_update(self, serializer):
        serializer.save()

    def partial_update(self, request, *args, **kwargs):
        kwargs['partial'] = True
        return self.update(request, *args, **kwargs)

视图工具类的使用

from rest_framework.mixins import RetrieveModelMixin, ListModelMixin, CreateModelMixin
class CarReadCreateGenericAPIView(ListModelMixin, RetrieveModelMixin, CreateModelMixin, GenericAPIView):
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializers.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)
        return self.list(request, *args, **kwargs)
    # """

    # 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)
        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)

Generic工具视图类

工具视图类就是将不同种类的mixins与GenericAPIView进行组合,一共有9个类(九种组合)

(单查群查不能在一起)

只需要我们配置三个类属性即可: queryset, serializer_class, lookup_url_kwarg

CreateAPIView

class CreateAPIView(mixins.CreateModelMixin,
                    GenericAPIView):
    def post(self, request, *args, **kwargs):
        return self.create(request, *args, **kwargs)

ListAPIView

class ListAPIView(mixins.ListModelMixin,
                  GenericAPIView):
    def get(self, request, *args, **kwargs):
        return self.list(request, *args, **kwargs)

RetrieveAPIView

class RetrieveAPIView(mixins.RetrieveModelMixin,
                      GenericAPIView):
    def get(self, request, *args, **kwargs):
        return self.retrieve(request, *args, **kwargs)

DestroyAPIView

class DestroyAPIView(mixins.DestroyModelMixin,
                     GenericAPIView):
    def delete(self, request, *args, **kwargs):
        return self.destroy(request, *args, **kwargs)

UpdateAPIView

class UpdateAPIView(mixins.UpdateModelMixin,
                    GenericAPIView):
    def put(self, request, *args, **kwargs):
        return self.update(request, *args, **kwargs)

    def patch(self, request, *args, **kwargs):
        return self.partial_update(request, *args, **kwargs)

ListCreateAPIView

class ListCreateAPIView(mixins.ListModelMixin,
                        mixins.CreateModelMixin,
                        GenericAPIView):
    def get(self, request, *args, **kwargs):
        return self.list(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):
        return self.create(request, *args, **kwargs)

RetrieveUpdateAPIView

class RetrieveUpdateAPIView(mixins.RetrieveModelMixin,
                            mixins.UpdateModelMixin,
                            GenericAPIView):
    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 patch(self, request, *args, **kwargs):
        return self.partial_update(request, *args, **kwargs)

RetrieveDestroyAPIView

class RetrieveDestroyAPIView(mixins.RetrieveModelMixin,
                             mixins.DestroyModelMixin,
                             GenericAPIView):
    def get(self, request, *args, **kwargs):
        return self.retrieve(request, *args, **kwargs)

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

RetrieveUpdateDestroyAPIView

class RetrieveUpdateDestroyAPIView(mixins.RetrieveModelMixin,
                                   mixins.UpdateModelMixin,
                                   mixins.DestroyModelMixin,
                                   GenericAPIView):
    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 patch(self, request, *args, **kwargs):
        return self.partial_update(request, *args, **kwargs)

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

视图集

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,额外多出了参数actions(解决如单查群查能放在同一个类中的问题)

ViewSet

该分支满足的接口与资源Model类关系不是特别密切:登录接口, 短信验证码接口
GenericViewSet

该分支严格满足资源接口,与数据库进行交互
ModelViewSet

能满足六大接口,只需要提供两个类属性
ReadOnlyModelViewSet

只满足单查群查接口

视图集产生的问题

没有群增,群整体改,群局部改,群删四个接口
删除操作视图集默认走的detroy方法是将资源从数据库中删除,通常是做一个字段is_delete字段修改表示删除
响应的结构只有数据,没有数据状态码和状态信息

解决:

class CarModelViewSet(ModelViewSet):
    queryset = models.Car.objects.filter(is_delete=False).all()
    serializer_class = serializers.CarModelSerializer
    # 分析：从实际开发角度分析不合理点
    # 1）没有群增，群整体改，群局部改，群删四个接口
    # 2）删除操作视图集默认走的destroy方法是将资源从数据库中删除，通常一个做字段is_delete字段修改表示删除
    # 3）响应的结果只有数据，没有数据状态码和状态信息

    # 解决1,
    # 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)
            book_query = models.Car.objects.filter(is_delete=False, pk__in=pks).all()
            if len(pks) != len(book_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 = self.get_serializer(instance=book_query, data=request_data, many=True)

        car_ser.is_valid(raise_exception=True)
        car_list = car_ser.save()
        return APIResponse(results=self.get_serializer(car_list, many=True).data)
    
    def many_partial_update(self, request, *args, **kwargs):
        return APIResponse(msg='这个地方是群局部改，你会写！')
    
    def many_destroy(self, request, *args, **kwargs):
        return APIResponse(msg='这个地方是群删，你会写！')
    # 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):
        request_data = request.data
        if isinstance(request_data, list):
            car_ser = self.get_serializer(data=request_data, many=True)
            car_ser.is_valid(raise_exception=True)
            car_obj = car_ser.save()
            return APIResponse(msg='群增成功', results=self.get_serializer(car_obj, many=True).data)

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


    # 解决2，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')


    # 解决3，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)

Day 75 视图类/视图工具类/工具视图类/视图集

视图家族

视图类

Mixins视图工具类

Generic工具视图类

视图集

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