自定义django中间件

自定义中间件

第一步：在根目录创建路径Middle/m1.py(注意如果是python2的话Middle下要有__init__.py文件，不然会报找不到模块错误)

m1.py的内容：

 # -*- coding: utf-8 -*-
 from django.utils.deprecation import MiddlewareMixin
 from django.shortcuts import HttpResponse

 class Row1(MiddlewareMixin):
     def process_request(self,request):
         print ('第一步')

     def process_view(self, request, view_func, view_func_args, view_func_kwargs):
         print('中间第一步')

     def process_response(self,request,response):
         print ('倒数第一步')
         return  response

 class Row2(MiddlewareMixin):
     def process_request(self,request):
         print ('第2步')

     def process_view(self, request, view_func, view_func_args, view_func_kwargs):
         print('中间第2步')

     def process_response(self,request,response):
         print ('倒数第2步')
         return  response

 class Row3(MiddlewareMixin):
     def process_request(self,request):
         print ('第3步')

     def process_view(self, request, view_func, view_func_args, view_func_kwargs):
         print('中间第3步')

     def process_response(self,request,response):
         print ('倒数第3步')
         return  response

     def process_exception(self, request, exception):
         if isinstance(exception,ValueError):
             return HttpResponse('出现异常》。。')

     def process_template_response(self,request,response):
         # 如果Views中的函数返回的对象中，具有render方法
         print('-----------------------')
         return response

项目setting.py中间件的内容：

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',
    'Middle.m1.Row1',
    'Middle.m1.Row2',
    'Middle.m1.Row3',
]

实际输出结果：

第一步
第2步
倒数第2步
倒数第一步

中间件的作用流程

实际的请求流程图：