python-day76--django-中间件

什么是中间件？中间件应用场景？和装饰器区别？

中间件
    对于所有批量的请求用中间件合适，而对于某些请求个数少用装饰器合适
    - 中间件是什么？
        - 是一个类
        - 方法名必须是process_request/process_response，否则无效
    - 返回值注意：
        # 无返回值：继续执行后续中间件和视图函数
        # 有返回值：执行自己的process_response和上面的response
    - 做过什么：
        - 用户登录验证 - csrf
        - session
        - 权限管理***
        

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asd.a.py

from django.conf import settings
from django.shortcuts import redirect
class MiddlewareMixin(object):
    def __init__(self, get_response=None):
        self.get_response = get_response
        super(MiddlewareMixin, self).__init__()

    def __call__(self, request):
        response = None
        if hasattr(self, 'process_request'):
            response = self.process_request(request)
        if not response:
            response = self.get_response(request)
        if hasattr(self, 'process_response'):
            response = self.process_response(request, response)
        return response

class M1(MiddlewareMixin):

    def process_request(self,request):
        # 无返回值：继续执行后续中间件和视图函数
        # 有返回值：执行自己的process_response和上面的response
        # request.xxxx= 888
        # request.path_info # /login/
        if request.path_info == "/login/":
        # if request.path == "/login/":
            print(request.path)
            return None
        user_info = request.session.get(settings.SESS)
        if not user_info:
            return redirect('/login/')

    def process_response(self,request,response):
        print('m1.process_response')
        return response

class M2(MiddlewareMixin):

    def process_request(self,request):
        print('m2.process_request')

    def process_response(self,request,response):
        print('m2.process_response')
        return response
  

--------------------------------------------------
settings.py

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',
    'asd.a.M1',
    'asd.a.M2',

]
注意：必须在最后面加自定义的中间件