restful-framwork续集1

时间 2019-11-05

标签 restful framwork 续集繁體版

原文原文链接

1.DRF的视图

1.1APIView与View的区别

咱们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一样呢~~~

urlpatterns = [
    url(r'^book$', BookView.as_view()),
    url(r'^book/(?P<id>\d+)$', BookEditView.as_view()),
]
咱们能够看到，无论是View仍是APIView最开始调用的都是as_view()方法~~那咱们走进源码看看~~

咱们能看到，APIView继承了View, 而且执行了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。

那咱们看看View中的as_view()方法作了什么~

咱们看到了~在View中的as_view方法返回了view函数，而view函数执行了self.dispatch()方法~~可是这里的dispatch方法应该是咱们APIView中的~~

咱们去initialize_request中看下把什么赋值给了request，而且赋值给了self.request, 也就是咱们在视图中用的request.xxx究竟是什么~~

咱们看到，这个方法返回的是Request这个类的实例对象~~咱们注意咱们看下这个Request类中的第一个参数request，是咱们走咱们django的时候的原来的request~

咱们看到了，这个Request类把原来的request赋值给了self._request, 也就是说之后_request是咱们老的request，新的request是咱们这个Request类~~

那咱们继承APIView以后请求来的数据都在哪呢~~

咱们用了rest_framework框架之后，咱们的request是从新封装的Request类~

request.query_params 存放的是咱们get请求的参数

request.data 存放的是咱们全部的数据，包括post请求的以及put，patch请求~~~

相比原来的django的request，咱们如今的request更加精简，清晰了~~~

如今咱们知道了APIView和View的一些区别~~固然还有~~后面咱们还会说~~

咱们写的视图可能对多个表进行增删改查，就致使咱们的视图特别多重复的代码~~

那么咱们尝试着来进行封装一下~~

1.2第一次封装

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")

# 第一次封装

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")
# 咱们把公共的部分抽出来 这样无论写多少表的增删改查都变的很简单
# 这样封装后咱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)

咱们封装的GenericAPIView，包括封装每一个方法的类，其实框架都帮咱们封装好了~~

咱们能够直接继承这些类~~来实现上面的视图~~但是还有没有更简单的方法呢~咱们再次封装一下~~

1.3二次封装

# 上面咱们写的继承类太长了~~咱们再改改

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)

此次咱们只是让继承变的简单了一点而已，好像并无什么大的进步~~

咱们可不能够把这两个视图合并成一个视图呢~~~框架给咱们提供了一个路由传参的方法~~

咱们看下ViewSetMixin

actions这个默认参数其实就是咱们路由能够进行传参了~~~

下面这个循环~能够看出~咱们要传的参数是一个字段~key应该是咱们的请求方式，value应该对应咱们处理的方法~

这样咱们每一个视图就不用在写函数了~由于已经和内部实现的函数相对应了~

1.4三次封装

#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"})),
]

from rest_framework.viewsets import ViewSetMixin

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

# 若是咱们再定义一个类
class ModelViewSet(ViewSetMixin, ListCreateAPIView, RetrieveUpdateDestroyAPIView):
    pass

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

咱们如今的视图就只要写两行就能够了~~~

其实咱们写的全部的视图~框架都帮咱们封装好了~

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

奉献一张图来看下咱们的继承顺序~~~

2.DRF的路由

from django.contrib import admin
from django.urls import path,include
from app.views import BookView
from rest_framework.routers import DefaultRouter

router = DefaultRouter()

router.register(r"book", BookView)
urlpatterns = [
    path('admin/', admin.site.urls),
    # path(r'book/', BookView.as_view({"get": "list", "post": "create"})),
    # path('book/<int:pk>/', BookView.as_view({"get": "list",  "put": "update", "delete": "destroy"})),

]
urlpatterns += router.urls

咱们能够看到~~经过框架咱们能够把路由视图都变的很是简单~~

可是须要自定制的时候仍是须要咱们本身用APIView写~~当不须要那么多路由的时候~也不要用这种路由注册~~

3.案例展现

#views.py

from app.models import Book, Publisher
from rest_framework.viewsets import ModelViewSet

from app.serializers import BookSerializer
class BookView(ModelViewSet):
    queryset = Book.objects.all()
    serializer_class = BookSerializer

#urls.py

from django.contrib import admin
from django.urls import path,include
from app.views import BookView
from rest_framework.routers import DefaultRouter

router = DefaultRouter()

router.register(r"book", BookView)
urlpatterns = [
    path('admin/', admin.site.urls),
    # path(r'book/', BookView.as_view({"get": "list", "post": "create"})),
    # path('book/<int:pk>/', BookView.as_view({"get": "list",  "put": "update", "delete": "destroy"})),

]
urlpatterns += router.urls

#自定制的urls.py
默认的urls配置，暴露了过多的方法，有的时候，咱们不想暴露put或delete，就须要自定制url
from django.contrib import admin
from django.urls import path,include
from app.views import BookView
from rest_framework.routers import DefaultRouter

router = DefaultRouter()

urlpatterns = [
    path('admin/', admin.site.urls),
    path(r'book/', BookView.as_view({"get": "list", "post": "create"})),
        #注意get对应retrive,只获取一条数据
        #不但愿有delete,就去掉delete便可。
    path('book/<int:pk>/', BookView.as_view({"get": "retrieve",  "put": "update", "delete": "destroy"})),

]