零、视图家族

Django REST framework 为了方便视图类的操作，构建了包括以下几种视图类和工具集：

  • views：API视图

  • generics：工具视图

  • mixins：视图工具集

  • viewsets：视图集

一、GenericAPIView：视图家族的基类

generics.py 中的 GenericAPIView 作为视图家族中重要的基类，在后面的接口代码的实现中起到重要作用。

用 Pycharm 可以看到 GenericAPIView 的方法和继承关系：
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GenericAPIView 继承自 APIView，使用兼容 APIView，也就是说依旧可以使用 get，post等方法。

但是，这里 GenericAPIView 封装了更多有趣的方法。

  • get_queryset(): 从类属性 queryset 中获得 model 的 queryset 数据
  • get_object(): 通过有名分组 pk 确定唯一操作对象
    自定义主键的有名分组 ：lookup_field = ‘id’
  • get_serializer()：从类属性 serializer_class 中获得serializer 的序列化类

二、Mixins：视图工具集

mixins.py：视图工具集，用来辅助 GenericAPIView
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包含有五个工具类文件，六个工具类方法：

  • CreateModeMixin：
    • 单增：create
  • ListModelMixin：
    • 群查：list
  • RetrieveModelMixin：
    • 单查：retrieve
  • UpdateModelMixin：
    • 单整体改：update
    • 单局部改：partial_update
  • DestroyModelMixin：
    • 单删：destroy，一般不使用该方法，或重写方法利用字段is_delete 来实现删除操作。

1.群查

查看源码

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class ListModelMixin:
    """
    List a queryset.
    """
    def list(self, request, *args, **kwargs):
        # get_queryset 通过子类继承 GenericAPIView 得到
        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)
        class ListModelMixin:
    """
    List a queryset.
    """
    def list(self, request, *args, **kwargs):
        # get_queryset 通过子类继承 GenericAPIView 得到
        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)
代码实现

继承工具类可以简化请求函数的实现体，但是必须继承 GenericAPIView，因为需要 GenericAPIView 提供类属性和方法。

工具类方法返回值是 Response 对象，可以用 response.data 拿到，扔给之前封装的APIResponse 类实现格式。

views.py

class BookListGenericAPIView(ListModelMixin, GenericAPIView):
    queryset = models.Book.objects.filter(is_delete=False)
    serializer_class = serializers.BookModelSerializer

    def get(self, request, *args, **kwargs):
        # 调用 ListModelMixin 的 list方法
        response = self.list(request, *args, **kwargs)
        # 添加自己封装的 APIResponse
        class BookListGenericAPIView(ListModelMixin, GenericAPIView):
    queryset = models.Book.objects.filter(is_delete=False)
    serializer_class = serializers.BookModelSerializer

    def get(self, request, *args, **kwargs):
        # 调用 ListModelMixin 的 list方法
        response = self.list(request, *args, **kwargs)
        # 添加自己封装的 APIResponse
        return APIResponse(results=response.data)

urls.py

from django.conf.urls import url

from api import views

urlpatterns = [
    url(r'^v3/books/$', views.BookListGenericAPIView.as_view()),
    url(from django.conf.urls import url

from api import views

urlpatterns = [
    url(r'^v3/books/$', views.BookListGenericAPIView.as_view()),
    url(r'^v3/books/(?P.*)/$', views.BookListGenericAPIView.as_view()),
]

测试接口

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2.单查

查看源码

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class RetrieveModelMixin:
    """
    Retrieve a model instance.
    """
    def retrieve(self, request, *args, **kwargs):
        instance = self.get_object()
        serializer = self.get_serializer(instance)
        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)
代码实现
class BookListGenericAPIView(ListModelMixin, RetrieveModelMixin, GenericAPIView):
    queryset = models.Book.objects.filter(is_delete=False)
    serializer_class = serializers.BookModelSerializer

    def get(self, request, *args, **kwargs):
        if 'pk' in kwargs:
            response = self.retrieve(request, *args, **kwargs)
        else:
            response = self.list(request, *args, **kwargs)
        class BookListGenericAPIView(ListModelMixin, RetrieveModelMixin, GenericAPIView):
    queryset = models.Book.objects.filter(is_delete=False)
    serializer_class = serializers.BookModelSerializer

    def get(self, request, *args, **kwargs):
        if 'pk' in kwargs:
            response = self.retrieve(request, *args, **kwargs)
        else:
            response = self.list(request, *args, **kwargs)
        return APIResponse(results=response.data)
测试接口

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3.单增

查看源码

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查看 CreateModelMixin 源码

class CreateModelMixin:
    """
    Create a model instance.
    """
    def create(self, request, *args, **kwargs):
        # 序列化
        serializer = self.get_serializer(data=request.data)
        # 验证
        serializer.is_valid(raise_exception=True)
        # 表单数据重建，函数名有语义，而直接调用逻辑是无意义的
        self.perform_create(serializer)
        # 设置 header
        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):
            class CreateModelMixin:
    """
    Create a model instance.
    """
    def create(self, request, *args, **kwargs):
        # 序列化
        serializer = self.get_serializer(data=request.data)
        # 验证
        serializer.is_valid(raise_exception=True)
        # 表单数据重建，函数名有语义，而直接调用逻辑是无意义的
        self.perform_create(serializer)
        # 设置 header
        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 {}
代码实现

可以看到这个类就是把之前单增的方法封装在一起方便调用

class BookListGenericAPIView(ListModelMixin, CreateModelMixin, GenericAPIView):
    queryset = models.Book.objects.filter(is_delete=False)
    serializer_class = serializers.BookModelSerializer

    def post(self, request, *args, **kwargs):
        response = self.create(request, *args, **kwargs)
        class BookListGenericAPIView(ListModelMixin, CreateModelMixin, GenericAPIView):
    queryset = models.Book.objects.filter(is_delete=False)
    serializer_class = serializers.BookModelSerializer

    def post(self, request, *args, **kwargs):
        response = self.create(request, *args, **kwargs)
        return APIResponse(results=response.data)
测试接口

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4.单改

查看源码
class UpdateModelMixin:
    """
    Update a model instance.
    """
    # 实现单整体改
    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()
	
    # 单局部改，调用 update 设置 partial = True
    def partial_update(self, request, *args, **kwargs):
        kwargs['partial'] = True
        class UpdateModelMixin:
    """
    Update a model instance.
    """
    # 实现单整体改
    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()
	
    # 单局部改，调用 update 设置 partial = True
    def partial_update(self, request, *args, **kwargs):
        kwargs['partial'] = True
        return self.update(request, *args, **kwargs)
代码实现
class BookListGenericAPIView(ListModelMixin, UpdateModelMixin, GenericAPIView):
    queryset = models.Book.objects.filter(is_delete=False)
    serializer_class = serializers.BookModelSerializer

    def put(self, request, *args, **kwargs):
        response = self.update(request, *args, **kwargs)
        return APIResponse(results=response.data)

    def patch(self, request, *args, **kwargs):
        response = self.partial_update(request, *args, **kwargs)
        class BookListGenericAPIView(ListModelMixin, UpdateModelMixin, GenericAPIView):
    queryset = models.Book.objects.filter(is_delete=False)
    serializer_class = serializers.BookModelSerializer

    def put(self, request, *args, **kwargs):
        response = self.update(request, *args, **kwargs)
        return APIResponse(results=response.data)

    def patch(self, request, *args, **kwargs):
        response = self.partial_update(request, *args, **kwargs)
        return APIResponse(results=response.data)
测试接口

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修改成功mark