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django Rest Framework 视图和路由

DRF视图

1. APIView

我们django中写CBV的时候继承的是View，rest_framework继承的是APIView，那么他们两个有什么不同呢~~~
```
urlpatterns = [
    url(r'^book$', BookView.as_view()),
    url(r'^book/(?P<id>d+)$', BookEditView.as_view()),
]
```

前端发来请求，根据正则匹配，然后调用APIView中的as_view()方法

APIView继承了View, 并且执行了View中的as_view()方法，最后把view返回了，用csrf_exempt()方法包裹后去掉了csrf的认证。
View中的as_view()方法做了

看到self，要从最开始的类中开始看，然后再从父类中看，APIView中含有dispatch方法，所有要先看APIView中的
查看APIView中的dispatch方法

去initialize_request中看下把什么赋值给了request，并且赋值给了self.request, 也就是我们在视图中用的request.xxx到底是什么~~
查看initialize_request方法

这个方法返回的是Request这个类的实例对象~~我们注意我们看下这个Request类中的第一个参数request，是我们走我们django的时候的原来的request~
点击Request方法

Request类把原来的request赋值给了self._request, 也就是说以后_request是我们老的request，新的request是我们这个Request类~~

即对request的功能进行的封装，扩展
继承APIView之后的数据在哪里来的

我们用了rest_framework框架以后，我们的request是重新封装的Request类~

request.query_params 存放的是我们get请求的参数

request.data 存放的是我们所有的数据，包括post请求的以及put，patch请求~~~

2. 第一次封装

APIView视图

class BookView(APIView):

    def get(self, request):
        query_set = Book.objects.all()
        book_ser = BookSerializer(query_set, many=True)
        return Response(book_ser.data)

    def post(self, request):
        query_set = request.data
        book_ser = BookSerializer(data=query_set)
        if book_ser.is_valid():
            book_ser.save()
            return Response(book_ser.validated_data)
        else:
            return Response(book_ser.errors)


class BookEditView(APIView):

    def get(self, request, id):
        query_set = Book.objects.filter(id=id).first()
        book_ser = BookSerializer(query_set)
        return Response(book_ser.data)

    def patch(self, request, id):
        query_set = Book.objects.filter(id=id).first()
        book_ser = BookSerializer(query_set, data=request.data, partial=True)
        if book_ser.is_valid():
            book_ser.save()
            return Response(book_ser.validated_data)
        else:
            return Response(book_ser.errors)

    def delete(self, request, id):
        query_set = Book.objects.filter(id=id).first()
        if query_set:
            query_set.delete()
            return Response("")
        else:
            return Response("删除的书籍不存在")

封装

class GenericAPIView(APIView):
    queryset = None
    serializer_class = None

    def get_queryset(self):
        return self.queryset.all()

    def get_serializer(self, *args, **kwargs):
        return self.serializer_class(*args, **kwargs)


class ListModelMixin(object):
    def list(self, request, *args, **kwargs):
        queryset = self.get_queryset()
        serializer = self.get_serializer(queryset, many=True)
        return Response(serializer.data)


class CreateModelMixin(object):
    def create(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.validated_data)
        else:
            return Response(serializer.errors)


class RetrieveModelMixin(object):
    def retrieve(self, request, id, *args, **kwargs):
        book_obj = self.get_queryset().filter(pk=id).first()
        book_ser = self.get_serializer(book_obj)
        return Response(book_ser.data)


class UpdateModelMixin(object):
    def update(self, request, id, *args, **kwargs):
        book_obj = self.get_queryset().filter(pk=id).first()
        book_ser = self.get_serializer(book_obj, data=request.data, partial=True)
        if book_ser.is_valid():
            book_ser.save()
            return Response(book_ser.validated_data)
        else:
            return Response(book_ser.errors)


class DestroyModelMixin(object):
    def destroy(self, request, id, *args, **kwargs):
        queryset = self.get_queryset()
        try:
            queryset.get(pk=id).delete()
            return Response("")
        except Exception as e:
            return Response("信息有误")
# 我们把公共的部分抽出来 这样不管写多少表的增删改查都变的很简单
# 这样封装后我们的视图会变成这样

class BookView(GenericAPIView, ListModelMixin, CreateModelMixin):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

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

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


class BookEditView(GenericAPIView, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

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

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

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

封装的GenericAPIView，包括封装每个方法的类，其实框架都帮我们封装好了

3 第二次封装

class ListCreateAPIView(GenericAPIView, ListModelMixin, CreateModelMixin):
    pass


class RetrieveUpdateDestroyAPIView(GenericAPIView, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin):
    pass


class BookView(ListCreateAPIView):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

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

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


class BookEditView(RetrieveUpdateDestroyAPIView):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

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

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

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

这次我们只是让继承变的简单了一点而已，好像并没有什么大的进步~~

内置源码提供的方法

actions这个默认参数其实就是我们路由可以进行传参了~~~

下面这个循环_可以看出我们要传的参数是一个字段_{key应该是我们的请求方式，value应该对应我们处理的方法}

这样我们每个视图就不用在写函数了_{因为已经和内部实现的函数相对应了}

4. 第三次封装

路由url.py

urlpatterns = [
    # url(r'^book$', BookView.as_view()),
    # url(r'^book/(?P<id>d+)$', BookEditView.as_view()),
    url(r'^book$', BookView.as_view({"get": "list", "post": "create"})),
    url(r'^book/(?P<pk>d+)$', BookView.as_view({"get": "retrieve", "patch": "update", "delete": "destroy"})),
]

view.py

from rest_framework.viewsets import ViewSetMixin


# class BookView(ViewSetMixin, ListCreateAPIView, RetrieveUpdateDestroyAPIView):
#     queryset = Book.objects.all()
#     serializer_class = BookSerializer
    
    
# 如果我们再定义一个类
class ModelViewSet(ViewSetMixin, ListCreateAPIView, RetrieveUpdateDestroyAPIView):
    pass


class BookView(ModelViewSet):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

我们现在的视图就只要写两行就可以了~~~

其实我们写的所有的视图_{框架都帮我们封装好了}

注意一点:用框架封装的视图~我们url上的那个关键字参数要用pk 系统默认的~~

奉献一张图来看下我们的继承顺序

DRF路由

路由传参写的特别多~~框架也帮我们封装好了~

from .views import BookView
from rest_framework.routers import DefaultRouter

router = DefaultRouter()
router.register(r"book", BookView)

urlpatterns = [
    # url(r'^book$', BookView.as_view()),
    # url(r'^book/(?P<id>d+)$', BookEditView.as_view()),
    # url(r'^book$', BookView.as_view({"get": "list", "post": "create"})),
    # url(r'^book/(?P<pk>d+)$', BookView.as_view({"get": "retrieve", "patch": "update", "delete": "destroy"})),

]
urlpatterns += router.urls

通过框架我们可以把路由视图变得很简单，但是需要自定制的时候还是需要自己用APIView写，

路由组件
	-- 导入 from rest_framework.routers import DefaultRouter
	-- 实例化 
		router = DefaultRouter()
	-- 注册
		router.register('路由'，View)
	-- 把自动生成的路由注册
		urlpatterns += router.urls

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原文地址：https://www.cnblogs.com/yuncong/p/10129000.html