django——rest_framework 视图与逻辑の使用详细分析

django rest_framework 视图与逻辑の使用详细分析

视图类

`django.views.generic.base.View`

实现了简单的路由分发，不同的method实现不同的方法

`rest_framewrok.views.APIView`

基于 django的View，又实现了用户认证，权限，限流，版本，解析器

`rest_framework.generic.GenericAPIView`

基于 rest_framewrok的APIView，又实现了分页过滤，分页，上下文处理，基础的数据集获取，单条数据获取

这些都是基于django的View实现的视图功能，使用的时候，还是要自己写method对应的方法（get, post, delete.....）

功能类

rest_framework.mixins.py文件，实现了不同请求的逻辑处理

`CreateModelMixin`

创建

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 {}

`ListModelMixin`

列表查询

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)

`DestroyModelMixin`

删除

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()

`RetrieveModelMixin`

详情页

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)

`UpdateModelMixin`

更新

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)

视图和功能的整合之自动匹配路由与方法

现在有了逻辑处理，有了视图路由分发，但是视图功能最多的GenericAPIView，对应的路由分发，逻辑还是通过url请求方法反射对应的方法，无法和mixins中的增删改查对应上。
所以，还有一个类，总和了GenericAPIView视图和mixins的各种方法：

`rest_framework.generics.ListCreateAPIView`

汇总了GenericAPIView视图，和ListModelMixin列表和CreateModelMixin创建

class ListCreateAPIView(mixins.ListModelMixin,
                        mixins.CreateModelMixin,
                        GenericAPIView):
    """
    Concrete view for listing a queryset or creating a model instance.
    """
    def get(self, request, *args, **kwargs):
        return self.list(request, *args, **kwargs)

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

如果不让创建的话，就是用ListAPIView

class ListAPIView(mixins.ListModelMixin,
                  GenericAPIView):
    """
    Concrete view for listing a queryset.
    """
    def get(self, request, *args, **kwargs):
        return self.list(request, *args, **kwargs)

`rest_framework.generics.RetrieveUpdateDestroyAPIView`

GenericAPIView视图，RetrieveModelMixin数据详情，UpdateModelMixin数据更新，DestroyModelMixin数据删除
class RetrieveUpdateDestroyAPIView(mixins.RetrieveModelMixin,
                                   mixins.UpdateModelMixin,
                                   mixins.DestroyModelMixin,
                                   GenericAPIView):
    """
    Concrete view for retrieving, updating or deleting a model instance.
    """
    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)

有些功能不需要的，就取消对应功能的类，

DestroyAPIView只有删除
UpdateAPIView只能更新
RetrieveAPIView只有详情功能（不能删除和更新）
RetrieveUpdateAPIView只有详情和更新功能（不能删除）
RetrieveDestroyAPIView只有详情和删除功能（不能修改）

视图和功能的整合之自定义匹配路由与方法

`rest_framework.viewsets.GenericViewSet`

GenericViewSet视图，ViewSetMixin，路由反射通过自定义实现

class GenericViewSet(ViewSetMixin, generics.GenericAPIView):
    """
    The GenericViewSet class does not provide any actions by default,
    but does include the base set of generic view behavior, such as
    the `get_object` and `get_queryset` methods.
    """
    pass

看一下ViewSetMixin，as_view方法里面有一段是这样的

      @classonlymethod
      def as_view(cls, actions=None, **initkwargs):
            # .........
            for method, action in actions.items():
                handler = getattr(self, action)
                setattr(self, method, handler)

# 就是，as_view里面传入字典格式，就可以自定义了
view = MyViewSet.as_view({'get': 'list', 'post': 'create'})

继承关系图

`ListCreateAPIView`

ListCreateAPIView

`RetrieveUpdateDestroyAPIView`

RetrieveUpdateDestroyAPIView

`GenericViewSet`

GenericViewSet