## FBV /?CBV? FBV：function base view ``` url(r'^index$',user) ``` ~~~ def users(request): return HttpResponse(‘OK’) ~~~ CBV：class base view ~~~ url(r'^students/', views.StudentsView.as_view()) ~~~ ``` from django.views import View class StudentsView(View): def get(self,request,*args,**kwargs): return HttpResponse('GET') def post(self, request, *args, **kwargs): return HttpResponse('POST') def put(self, request, *args, **kwargs): return HttpResponse('PUT') def delete(self, request, *args, **kwargs): return HttpResponse('DELETE') 視圖 ``` **CBV實現原理** 　　基于反射實現根據請求方式不同，執行不同的方法。具體實現流程：url中的as\_view() —》 view方法 —》 dispatch方法（根據反射執行相應函數） CBV中可以使用的方法： ~~~ http_method_names = ['get', 'post', 'put', 'patch', 'delete', 'head', 'options', 'trace'] ~~~ ``` from django.views import View class RestApi(View): def dispatch(self,request,*args,**kwargs): func = getattr(self,request.method.lower()) ret = func(request,*args,**kwargs) return ret def get(self,request,*args,**kwargs): return HttpResponse('get') def post(self,request,*args,**kwargs): return HttpResponse('post') def put(self,request,*args,**kwargs): return HttpResponse('put') def delete(self,request,*args,**kwargs): return HttpResponse('delete') 手動實現dispatch方法 ``` ``` from django.views import View class RestApi(View): def dispatch(self,request,*args,**kwargs): ret = super(RestApi, self).dispatch(request,*args,**kwargs) return ret def get(self,request,*args,**kwargs): return HttpResponse('get') def post(self,request,*args,**kwargs): return HttpResponse('post') def put(self,request,*args,**kwargs): return HttpResponse('put') def delete(self,request,*args,**kwargs): return HttpResponse('delete') 手動繼承dispatch方法 ``` ## Django中間件 　　django 中的中間件（middleware），在django中，中間件其實就是一個類，在請求到來和結束后，django會根據自己的規則在合適的時機執行中間件中相應的方法。 我們從瀏覽器發出一個請求 Request，得到一個響應后的內容 HttpResponse ，這個請求傳遞到 Django的過程如下：  　　每一個請求都是先通過中間件中的 process\_request 函數，這個函數返回 None 或者 HttpResponse 對象，如果返回前者，繼續處理其它中間件，如果返回一個 HttpResponse，就處理中止，返回到網頁上。 中間件中可以定義4個方法,分別是: 1. process\_request(self,request) 發送請求 2. process\_view(self, request, callback, callback\_args, callback\_kwargs) 執行完 request 預處理函數并確定待執行的 view 之后，但在 view 函數實際執行之前。 3. process\_template\_response(self,request,response) 4. process\_exception(self, request, exception) 收集錯誤信息 5. process\_response(self, request, response) 必須返回 HttpResponse 對象. 這個 response 對象可以是傳入函數的那一個原始對象（通常已被修改），也可以是全新生成的。 執行順序也是按照以上順序執行的. 自定義中間件 ``` from django.utils.deprecation import MiddlewareMixin class test1(MiddlewareMixin): def process_request(self, request): print('wusir') class test2(MiddlewareMixin): def process_request(self, request): print('jack') ``` 注冊中間件 ``` MIDDLEWARE = [ 'django.middleware.security.SecurityMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.common.CommonMiddleware', 'django.middleware.csrf.CsrfViewMiddleware', 'django.contrib.auth.middleware.AuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware', 'django.middleware.clickjacking.XFrameOptionsMiddleware', 'wusir.m1.test1', 'wusir.m1.test2', ] ``` 終端輸出結果 ~~~ wusir jack tom [17/Dec/2018 17:08:04] "GET /app/aa HTTP/1.1" 200 2 ~~~ PS:與mange.py在同一目錄下的文件夾 wusir下的m1.py文件中的test1,test2類 **中間件可以做什么** * 　　權限 * 　　用戶登錄驗證 * 　　Django的csrf的實現 ``` 情況一： MIDDLEWARE = [ 'django.middleware.security.SecurityMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.common.CommonMiddleware', 'django.middleware.csrf.CsrfViewMiddleware', # 全站使用csrf認證 'django.contrib.auth.middleware.AuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware', 'django.middleware.clickjacking.XFrameOptionsMiddleware', ] from django.views.decorators.csrf import csrf_exempt @csrf_exempt # 該函數無需認證 def users(request): user_list = ['alex','oldboy'] return HttpResponse(json.dumps((user_list))) 情況二： MIDDLEWARE = [ 'django.middleware.security.SecurityMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.common.CommonMiddleware', #'django.middleware.csrf.CsrfViewMiddleware', # 全站不使用csrf認證 'django.contrib.auth.middleware.AuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware', 'django.middleware.clickjacking.XFrameOptionsMiddleware', ] from django.views.decorators.csrf import csrf_exempt @csrf_protect # 該函數需認證 def users(request): user_list = ['alex','oldboy'] return HttpResponse(json.dumps((user_list))) 為某個函數單獨增加或取消CSRF認證 ``` **CSRF在CBV中的使用補充** 　　裝飾器@csrf\_exempt，@csrf\_protect必須在dispatch方法中（單獨方法無效） ``` 方式一： from django.views.decorators.csrf import csrf_exempt,csrf_protect from django.utils.decorators import method_decorator class StudentsView(View): @method_decorator(csrf_exempt) def dispatch(self, request, *args, **kwargs): return super(StudentsView,self).dispatch(request, *args, **kwargs) def get(self,request,*args,**kwargs): print('get方法') return HttpResponse('GET') def post(self, request, *args, **kwargs): return HttpResponse('POST') def put(self, request, *args, **kwargs): return HttpResponse('PUT') def delete(self, request, *args, **kwargs): return HttpResponse('DELETE') 方式二： from django.views.decorators.csrf import csrf_exempt,csrf_protect from django.utils.decorators import method_decorator @method_decorator(csrf_exempt,name='dispatch') class StudentsView(View): def get(self,request,*args,**kwargs): print('get方法') return HttpResponse('GET') def post(self, request, *args, **kwargs): return HttpResponse('POST') def put(self, request, *args, **kwargs): return HttpResponse('PUT') def delete(self, request, *args, **kwargs): return HttpResponse('DELETE') ```