一 前戏

二 中间件介绍

Middleware is a framework of hooks into Django’s request/response processing. <br>It’s a light, low-level “plugin” system for globally altering Django’s input or output.

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',
]

三 自定义中间件

from django.utils.deprecation import MiddlewareMixinclass MD1(MiddlewareMixin):#自定义中间件，不是必须要有下面这两个方法，有request方法说明请求来了要处理，有response方法说明响应出去时需要处理，不是非要写这两个方法，如果你没写process_response方法，那么会一层一层的往上找，哪个中间件有process_response方法就将返回对象给哪个中间件def process_request(self, request):print("MD1里面的 process_request")def process_response(self, request, response):print("MD1里面的 process_response")return response

from django.utils.deprecation import MiddlewareMixinclass MD1(MiddlewareMixin):def process_request(self, request):print("MD1里面的 process_request")class MD2(MiddlewareMixin):def process_request(self, request):print("MD2里面的 process_request")pass

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','middlewares.MD1',  # 自定义中间件MD1，这个写的是你项目路径下的一个路径，例如，如果你放在项目下，文件夹名成为utils，那么这里应该写utils.middlewares.MD1'middlewares.MD2'  # 自定义中间件MD2
]

MD1里面的 process_request
MD2里面的 process_requestapp01 中的 index视图

MD2里面的 process_request
MD1里面的 process_requestapp01 中的 index视图

from django.utils.deprecation import MiddlewareMixinclass MD1(MiddlewareMixin):def process_request(self, request):print("MD1里面的 process_request")#不必须写return值def process_response(self, request, response):#request和response两个参数必须有，名字随便取print("MD1里面的 process_response")        #print(response.__dict__['_container'][0].decode('utf-8')) #查看响应体里面的内容的方法，或者直接使用response.content也可以看到响应体里面的内容，由于response是个变量，直接点击看源码是看不到的，你打印type(response)发现是HttpResponse对象，查看这个对象的源码就知道有什么方法可以用了。

　　　　 return response  #必须有返回值，写return response  ，这个response就像一个接力棒一样#return HttpResponse('瞎搞') ,如果你写了这个，那么你视图返回过来的内容就被它给替代了class MD2(MiddlewareMixin):def process_request(self, request):print("MD2里面的 process_request")passdef process_response(self, request, response): #request和response两个参数必须要有，名字随便取print("MD2里面的 process_response") return response  #必须返回response，不然你上层的中间件就没有拿到httpresponse对象，就会报错

MD2里面的 process_request
MD1里面的 process_request
app01 中的 index视图
MD1里面的 process_response
MD2里面的 process_response

from django.utils.deprecation import MiddlewareMixin
from django.shortcuts import HttpResponseclass Md1(MiddlewareMixin):def process_request(self,request):print("Md1请求")　　　　 #process_request方法里面不写返回值，默认也是返回None，如果你自己写了return None，也是一样的效果，不会中断你的请求，但是如果你return 的一个httpresponse对象，那么就会在这个方法中断你的请求，直接返回给用户，这就成了非正常的流程了        #并且，如果你在这里return了httpresponse对象，那么会从你这个中间件类中的process_response方法开始执行返回操作，所以这个类里面只要有process_response方法，肯定会执行def process_response(self,request,response):print("Md1返回")return responseclass Md2(MiddlewareMixin):def process_request(self,request):print("Md2请求")#return HttpResponse("Md2中断")def process_response(self,request,response):print("Md2返回")return response

Md1请求
Md2请求
view函数...
Md2返回
Md1返回

Md1请求
Md2请求
Md2返回
Md1返回

class M1(MiddlewareMixin):def process_request(self,request):#设置路径白名单，只要访问的是login登陆路径，就不做这个cookie认证if request.path not in [reverse('login'),]:print('我是M1中间件') #客户端IP地址# return HttpResponse('sorry,没有通过我的M1中间件')is_login = request.COOKIES.get('is_login', False)if is_login:passelse:# return render(request,'login.html')return redirect(reverse('login'))else:return None #别忘了return Nonedef process_response(self,request,response):print('M1响应部分')# print(response.__dict__['_container'][0].decode('utf-8'))return response# return HttpResponse('瞎搞')

from django.utils.deprecation import MiddlewareMixinclass MD1(MiddlewareMixin):def process_request(self, request):print("MD1里面的 process_request")def process_response(self, request, response):print("MD1里面的 process_response")return responsedef process_view(self, request, view_func, view_args, view_kwargs):print("-" * 80)print("MD1 中的process_view")print(view_func, view_func.__name__) #就是url映射到的那个视图函数，也就是说每个中间件的这个process_view已经提前拿到了要执行的那个视图函数        #ret = view_func(request) #提前执行视图函数，不用到了上图的试图函数的位置再执行，如果你视图函数有参数的话，可以这么写 view_func(request,view_args,view_kwargs) #return ret  #直接就在MD1中间件这里这个类的process_response给返回了，就不会去找到视图函数里面的这个函数去执行了。class MD2(MiddlewareMixin):def process_request(self, request):print("MD2里面的 process_request")passdef process_response(self, request, response):print("MD2里面的 process_response")return responsedef process_view(self, request, view_func, view_args, view_kwargs):print("-" * 80)print("MD2 中的process_view")print(view_func, view_func.__name__)

MD2里面的 process_request
MD1里面的 process_request
--------------------------------------------------------------------------------
MD2 中的process_view
<function index at 0x000001DE68317488> index
--------------------------------------------------------------------------------
MD1 中的process_view
<function index at 0x000001DE68317488> index
app01 中的 index视图
MD1里面的 process_response
MD2里面的 process_response

from django.utils.deprecation import MiddlewareMixinclass MD1(MiddlewareMixin):def process_request(self, request):print("MD1里面的 process_request")def process_response(self, request, response):print("MD1里面的 process_response")return responsedef process_view(self, request, view_func, view_args, view_kwargs):print("-" * 80)print("MD1 中的process_view")print(view_func, view_func.__name__)def process_exception(self, request, exception):print(exception)print("MD1 中的process_exception")class MD2(MiddlewareMixin):def process_request(self, request):print("MD2里面的 process_request")passdef process_response(self, request, response):print("MD2里面的 process_response")return responsedef process_view(self, request, view_func, view_args, view_kwargs):print("-" * 80)print("MD2 中的process_view")print(view_func, view_func.__name__)def process_exception(self, request, exception):print(exception)print("MD2 中的process_exception")

def index(request):print("app01 中的 index视图")raise ValueError("呵呵")return HttpResponse("O98K")

class MD1(MiddlewareMixin):def process_request(self, request):print("MD1里面的 process_request")def process_response(self, request, response):print("MD1里面的 process_response")return responsedef process_view(self, request, view_func, view_args, view_kwargs):print("-" * 80)print("MD1 中的process_view")print(view_func, view_func.__name__)def process_exception(self, request, exception):print(exception)print("MD1 中的process_exception")return HttpResponse(str(exception))  # 返回一个响应对象

MD2里面的 process_request
MD1里面的 process_request
--------------------------------------------------------------------------------
MD2 中的process_view
<function index at 0x0000022C09727488> index
--------------------------------------------------------------------------------
MD1 中的process_view
<function index at 0x0000022C09727488> index
app01 中的 index视图
呵呵
MD1 中的process_exception
MD1里面的 process_response
MD2里面的 process_response

class MD1(MiddlewareMixin):def process_request(self, request):print("MD1里面的 process_request")def process_response(self, request, response):print("MD1里面的 process_response")return responsedef process_view(self, request, view_func, view_args, view_kwargs):print("-" * 80)print("MD1 中的process_view")print(view_func, view_func.__name__)def process_exception(self, request, exception):print(exception)print("MD1 中的process_exception")return HttpResponse(str(exception))def process_template_response(self, request, response):print("MD1 中的process_template_response")return responseclass MD2(MiddlewareMixin):def process_request(self, request):print("MD2里面的 process_request")passdef process_response(self, request, response):print("MD2里面的 process_response")return responsedef process_view(self, request, view_func, view_args, view_kwargs):print("-" * 80)print("MD2 中的process_view")print(view_func, view_func.__name__)def process_exception(self, request, exception):print(exception)print("MD2 中的process_exception")def process_template_response(self, request, response):print("MD2 中的process_template_response")return response

def index(request):print("app01 中的 index视图")def render():print("in index/render")return HttpResponse("O98K")rep = HttpResponse("OK")rep.render = renderreturn rep

MD2里面的 process_request
MD1里面的 process_request
--------------------------------------------------------------------------------
MD2 中的process_view
<function index at 0x000001C111B97488> index
--------------------------------------------------------------------------------
MD1 中的process_view
<function index at 0x000001C111B97488> index
app01 中的 index视图
MD1 中的process_template_response
MD2 中的process_template_response
in index/render
MD1里面的 process_response
MD2里面的 process_response

四 中间件执行流程

五 中间件版登陆认证

from django.conf.urls import url
from app01 import viewsurlpatterns = [url(r'^index/$', views.index),url(r'^login/$', views.login, name='login'),
]

from django.shortcuts import render, HttpResponse, redirectdef index(request):return HttpResponse('this is index')def home(request):return HttpResponse('this is home')def login(request):if request.method == "POST":user = request.POST.get("user")pwd = request.POST.get("pwd")if user == "Q1mi" and pwd == "123456":# 设置sessionrequest.session["user"] = user# 获取跳到登陆页面之前的URLnext_url = request.GET.get("next")# 如果有，就跳转回登陆之前的URLif next_url:return redirect(next_url)# 否则默认跳转到index页面else:return redirect("/index/")return render(request, "login.html")

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta http-equiv="x-ua-compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>登录页面</title>
</head>
<body>
<form action="{% url 'login' %}"><p><label for="user">用户名：</label><input type="text" name="user" id="user"></p><p><label for="pwd">密 码：</label><input type="text" name="pwd" id="pwd"></p><input type="submit" value="登录">
</form>
</body>
</html>

class AuthMD(MiddlewareMixin):white_list = ['/login/', ]  # 白名单balck_list = ['/black/', ]  # 黑名单def process_request(self, request):from django.shortcuts import redirect, HttpResponsenext_url = request.path_infoprint(request.path_info, request.get_full_path())if next_url in self.white_list or request.session.get("user"):returnelif next_url in self.balck_list:return HttpResponse('This is an illegal URL')else:return redirect("/login/?next={}".format(next_url))

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','middlewares.AuthMD',
]

六 中间件案例

'django.contrib.sessions.middleware.SessionMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',

八 xxx

from django.conf.urls import url
from app01 import viewsurlpatterns = [url(r'^index/$', views.index),url(r'^login/$', views.login, name='login'),
]

from django.shortcuts import render, HttpResponse, redirectdef index(request):return HttpResponse('this is index')def home(request):return HttpResponse('this is home')def login(request):if request.method == "POST":user = request.POST.get("user")pwd = request.POST.get("pwd")if user == "Q1mi" and pwd == "123456":# 设置sessionrequest.session["user"] = user# 获取跳到登陆页面之前的URLnext_url = request.GET.get("next")# 如果有，就跳转回登陆之前的URLif next_url:return redirect(next_url)# 否则默认跳转到index页面else:return redirect("/index/")return render(request, "login.html")

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><meta http-equiv="x-ua-compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>登录页面</title>
</head>
<body>
<form action="{% url 'login' %}"><p><label for="user">用户名：</label><input type="text" name="user" id="user"></p><p><label for="pwd">密 码：</label><input type="text" name="pwd" id="pwd"></p><input type="submit" value="登录">
</form>
</body>
</html>

class AuthMD(MiddlewareMixin):white_list = ['/login/', ]  # 白名单balck_list = ['/black/', ]  # 黑名单def process_request(self, request):from django.shortcuts import redirect, HttpResponsenext_url = request.path_infoprint(request.path_info, request.get_full_path())if next_url in self.white_list or request.session.get("user"):returnelif next_url in self.balck_list:return HttpResponse('This is an illegal URL')else:return redirect("/login/?next={}".format(next_url))

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','middlewares.AuthMD',
]