Django-Rest-Framework的視圖和路由

時間  2019-11-08
標籤 django rest framework 視圖 路由 欄目 Python 简体版
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Django-Rest-Framework的視圖和路由

 restful framework 

Django-Rest-Framework的視圖

APIView

django中寫CBV的時候繼承的是View，rest_framework繼承的是APIView，那麼他們兩個有什麼不一樣呢django

urlpatterns = [
    url(r'^book$', BookView.as_view()),
    url(r'^book/(?P<id>\d+)$', BookEditView.as_view()),
]

能夠看到，無論是View仍是APIView最開始調用的都是as_view()方法，那走進源碼看看restful

咱們能看到，APIView繼承了View, 而且執行了View中的as_view()方法，最後把view返回了，用csrf_exempt()方法包裹後去掉了csrf的認證。

那咱們看看View中的as_view()方法作了什麼
咱們看到了~在View中的as_view方法返回了view函數，而view函數執行了self.dispatch()方法~~可是這裏的dispatch方法應該是咱們APIView中的
咱們去initialize_request中看下把什麼賦值給了request，而且賦值給了self.request, 也就是咱們在視圖中用的request.xxx究竟是什麼
咱們看到，這個方法返回的是Request這個類的實例對象
咱們注意咱們看下這個Request類中的第一個參數request，是咱們走咱們django的時候的原來的request~
咱們看到了，這個Request類把原來的request賦值給了self._request, 也就是說之後_request是咱們老的request，新的request是咱們這個Request類

那咱們繼承APIView以後請求來的數據都在哪呢~~
咱們用了rest_framework框架之後，咱們的request是從新封裝的Request類~

request.query_params 存放的是咱們get請求的參數

request.data 存放的是咱們全部的數據，包括post請求的以及put，patch請求

相比原來的django的request，咱們如今的request更加精簡，清晰了~~~

如今咱們知道了APIView和View的一些區別~~固然還有~~後面還會說~~

咱們寫的視圖可能對多個表進行增刪改查，就致使咱們的視圖特別多重複的代碼~~

那麼咱們嘗試着來進行封裝一下~~

第一次封裝

APIView視圖

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("刪除的書籍不存在")

第一次封裝

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("信息有誤")
# 咱們把公共的部分抽出來 這樣無論寫多少表的增刪改查都變的很簡單
# 這樣封裝後咱們的視圖會變成這樣

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)

咱們封裝的GenericAPIView，包括封裝每一個方法的類，其實框架都幫咱們封裝好了~~框架

咱們能夠直接繼承這些類來實現上面的視圖但是還有沒有更簡單的方法呢~咱們再次封裝一下~~ide

第二次封裝

# 上面咱們寫的繼承類太長了~~咱們再改改

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)

此次咱們只是讓繼承變的簡單了一點而已，好像並無什麼大的進步
咱們可不能夠把這兩個視圖合併成一個視圖呢~~~框架給咱們提供了一個路由傳參的方法函數

咱們看下ViewSetMixinpost

action這個默認參數其實就是咱們路由能夠進行傳參了

下面這個循環~能夠看出~咱們要傳的參數是一個字段~key應該是咱們的請求方式，value應該對應咱們處理的方法~

這樣咱們每一個視圖就不用在寫函數了~由於已經和內部實現的函數相對應了~

第三次封裝

路由 urls.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"})),
]

第三次封裝

from rest_framework.viewsets import ViewSetMixin

# class BookView(ViewSetMixin, ListCreateAPIView, RetrieveUpdateDestroyAPIView):
#     queryset = Book.objects.all()
#     serializer_class = BookSerializer


# 若是咱們再定義一個類
class ModelViewSet(ViewSetMixin, ListCreateAPIView, RetrieveUpdateDestroyAPIView):
    pass


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

咱們如今的視圖就只要寫兩行就能夠了url

其實咱們寫的全部的視圖~框架都幫咱們封裝好了spa

注意一點~用框架封裝的視圖~咱們url上的那個關鍵字參數要用pk~系統默認的rest

奉獻一張圖來看下咱們的繼承順序code

Django-Rest-Framework的路由

咱們上面的路由傳參寫的特別多~~框架也幫咱們封裝好了~

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

咱們能夠看到經過框架咱們能夠把路由視圖都變的很是簡單~~

可是須要自定製的時候仍是須要咱們本身用APIView寫，當不須要那麼多路由的時候，也不要用這種路由註冊~~

總之一切按照業務須要去用~~~

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