Django视图函数函数之视图装饰器

FBV模式装饰器：

　　普通函数的装饰器（语法糖@）

　　views.py

 from django.shortcuts import render

 def wrapper(f):
     def inner(*args,**kwargs):
         print("before")
         ret=f(*args,**kwargs)
         print("after")
         return ret
     return inner

 @wrapper
 def index(request):
     return render(request,"index.html") 

CBV模式装饰器：

　　　　在CBV模式视图函数中必须先导入：from django.views import View

　　（1）重写父类dispatch分发方法，在分发执行每个请求响应函数前后加上相应功能为实现类比装饰器

　　　　views.py

 from django.shortcuts import render,HttpResponse
 from django.views import View
 from django.utils.decorators import method_decorator

 class Myview(View):

     def dispatch(self, request, *args, **kwargs):
         print("before")
         ret=super().dispatch(request, *args, **kwargs)
         print("after")
         return ret

     def get(self, request):
         return render(request, "login.html")

     def post(self, request):
         if request.method == "GET":
             return render(request, "login.html")
         elif request.method == "POST":
             if request.POST.get("username") == "yang" and request.POST.get("userpsd") == "":
                 return render(request, "login_success.html", {"name": request.POST.get("username")})
             else:
                 return HttpResponse("账号或密码有误！")

　　（2）在子类重写分发函数时加上装饰器（每个请求函数都会被装饰）

必须先导入：

from django.views import View

from django.utils.decorators import method_decorator

　　　　　　 views.py

 from django.shortcuts import render,HttpResponse
 from django.views import View
 from django.utils.decorators import method_decorator

 def wrapper(f):
     def inner(*args,**kwargs):
         print("before")
         ret=f(*args,**kwargs)
         print("after")
         return ret
     return inner

 class Myview(View):

     @method_decorator(wrapper)
     def dispatch(self, request, *args, **kwargs):
         ret=super().dispatch(request, *args, **kwargs)
         return ret

     def get(self, request):
         return render(request, "login.html")

     def post(self, request):
         if request.method == "GET":
             return render(request, "login.html")
         elif request.method == "POST":
             if request.POST.get("username") == "yang" and request.POST.get("userpsd") == "":
                 return render(request, "login_success.html", {"name": request.POST.get("username")})
             else:
                 return HttpResponse("账号或密码有误！")

　　（3）在子类重写的不同响应请求函数上加上装饰器

必须先导入：

from django.views import View

from django.utils.decorators import method_decorator

views.py

 from django.shortcuts import render,HttpResponse
 from django.views import View
 from django.utils.decorators import method_decorator

 def wrapper(f):
     def inner(*args,**kwargs):
         print("before")
         ret=f(*args,**kwargs)
         print("after")
         return ret
     return inner

 class Myview(View):
     # def dispatch(self, request, *args, **kwargs):
     #     ret=super().dispatch(request, *args, **kwargs)
     #     return ret

     def get(self, request):
         return render(request, "login.html")

     @method_decorator(wrapper)
     def post(self, request):
         if request.method == "GET":
             return render(request, "login.html")
         elif request.method == "POST":
             if request.POST.get("username") == "yang" and request.POST.get("userpsd") == "":
                 return render(request, "login_success.html", {"name": request.POST.get("username")})
             else:
                 return HttpResponse("账号或密码有误！")

　　（4）在子类定义时加上装饰器，必须指定而且唯一指定加在的函数

必须先导入：

from django.views import View

from django.utils.decorators import method_decorator

views.py

 from django.shortcuts import render,HttpResponse
 from django.views import View
 from django.utils.decorators import method_decorator

 def wrapper(f):
     def inner(*args,**kwargs):
         print("before")
         ret=f(*args,**kwargs)
         print("after")
         return ret
     return inner

 @method_decorator(wrapper,name="post")

 class Myview(View):
     # def dispatch(self, request, *args, **kwargs):
     #     ret=super().dispatch(request, *args, **kwargs)
     #     return ret

     def get(self, request):
         return render(request, "login.html")

     def post(self, request):
         if request.method == "GET":
             return render(request, "login.html")
         elif request.method == "POST":
             if request.POST.get("username") == "yang" and request.POST.get("userpsd") == "":
                 return render(request, "login_success.html", {"name": request.POST.get("username")})
             else:
                 return HttpResponse("账号或密码有误！")

　　

其它装饰器：

·         添加装饰器前必须导入from django.utils.decorators import method_decorator

·         添加装饰器的格式必须为@method_decorator()，括号里面为装饰器的函数名

·         给类添加是必须声明name

·         注意csrf-token装饰器的特殊性，在CBV模式下它只能加在dispatch上面(后面再说)

下面这是csrf_token的装饰器：

@csrf_protect，为当前函数强制设置防跨站请求伪造功能，即便settings中没有设置csrfToken全局中间件。

@csrf_exempt，取消当前函数防跨站请求伪造功能，即便settings中设置了全局中间件。

注意：from django.views.decorators.csrf import csrf_exempt,csrf_protect