django Rest Framework 視圖和路由

時間 2019-12-13

標籤 django rest framework 視圖路由欄目 Python 简体版

原文原文鏈接

django Rest Framework 視圖和路由

DRF視圖

1. APIView

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

前端發來請求，根據正則匹配，而後調用APIView中的as_view()方法python

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。django
View中的as_view()方法作了api

看到self，要從最開始的類中開始看，而後再從父類中看，APIView中含有dispatch方法，全部要先看APIView中的框架
查看APIView中的dispatch方法iview

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~~函數
查看initialize_request方法post

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~url
點擊Request方法spa

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~~

即對request的功能進行的封裝，擴展
繼承APIView以後的數據在哪裏來的

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~~~

2. 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")

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)

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

3 第二次封裝

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~~

內置源碼提供的方法

actions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~

4. 第三次封裝

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


# 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~~~

其實咱們寫的全部的視圖~框架都幫咱們封裝好了~

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~~

奉獻一張圖來看下咱們的繼承順序

DRF路由

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

經過框架咱們能夠把路由視圖變得很簡單，可是須要自定製的時候仍是須要本身用APIView寫，

路由組件
  -- 導入 from rest_framework.routers import DefaultRouter
  -- 實例化 
      router = DefaultRouter()
  -- 註冊
      router.register('路由'，View)
  -- 把自動生成的路由註冊
      urlpatterns += router.urls

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