Django之session验证的三种姿势

一.什么是session

session是保存在服务端的键值对，Django默认支持Session，并且默认是将Session数据存储在数据库中，即：django_session 表中。

二.FVB中使用装饰器进行session验证

认证装饰器：

# 登陆验证
def auth(func):
 '''判断是否登录装饰器'''
    def inner(request, *args, **kwargs):
        ck = request.session.get("username")
		'''如果没有登陆返回到login.html'''
        if not ck:
            return redirect("/login.html")
        return func(request, *args, **kwargs)
    return inner

 在需要认证的函数执行前加上装饰器认证即可，实际中应用如下：

def login(request):
    if request.method == "GET":
        return render(request, "login.html")
    else:
        username = request.POST.get("user")
        pwd = request.POST.get("pwd")
        pwd = md5(pwd)
        dic = {"flag":False}
        obj = User.objects.filter(username=username, pwd=pwd).first()
        if obj:
            request.session["username"] = username
            return redirect("/index.html")
        else:
            print(dic)
            return HttpResponse(json.dumps(dic))

@auth
def index(request):
    user = request.session.get("username")
    business = Business.objects.all().values("name")
    host_list = Host.objects.all().values("id","host","port","business__name")
    username = User.objects.all().values("username")
    return render(request, 'index.html', {'host_list':host_list,"business":business,"user":user,"username":username})
	
@auth
def addhost(request):
    business = Business.objects.all().values("name")
    if request.method == "POST":
        user = request.session.get("username")
        host = request.POST.get("host")
        port = request.POST.get("port")
        select_business = request.POST.get("business")
        business_id = Business.objects.filter(name=select_business).values("id")[0]
        host = Host.objects.create(host=host,
                                  port=port,
                                  business_id=business_id["id"])
        # host.business.add(*business)
        return render(request, "index.html")

    return render(request, "index.html", {"business":business})
	
@auth
def up_business(request):
    if request.method == "POST":
        user = request.session.get("username")
        host= request.POST.get("host")
        port= request.POST.get("port")
        business_name = request.POST.get("business")
        username = request.POST.get("username")
        print(host,port,business_name,username)
        return render(request,"保存成功")

 三.CBV中使用类继承的方式进行session认证

• cbv是 class based view(基于类)
• cbv基于dispatch进行反射,get获取,post提交
• 应用场景：登录认证(继承dispatch,在dispatch里做session验证)

CBV第一种方式继承

1.单继承

扫盲：(继承的时候,一定要清楚self是哪个类实例化出来的对象,下例,self为B实例化的对象,任何属性优先从自己里面找,找不到在去父类里找)

class A(object):
    def aaa(self):
        print('from A')
    def bbb(self):
        self.aaa()
 
class B(A):
    def aaa(self):
        print('from B')
 
c = B()
c.aaa()

应用：

from django.views import View
class BaseView(View):
    def dispatch(self, request, *args, **kwargs):  # 继承父类的dispatch,因为父类里有返回值,所以也要有return
        if request.session.get('username'):
            response = super(BaseView, self).dispatch(request, *args, **kwargs)
            return response
        else:
            return redirect('/login.html')
 
class IndexView(BaseView):
 
    def get(self, request, *args, **kwargs):
        return HttpResponse(request.session['username'])

 2.多继承(继承顺序从左到右)

class BaseView(object):
    def dispatch(self, request, *args, **kwargs):
        if request.session.get('username'):
            response = super(BaseView,self).dispatch(request, *args, **kwargs)
            return response
        else:
            return redirect('/login.html')
 
class IndexView(BaseView,View):#先去找BaseView,BaseView中未定义在去找View
 
    def get(self,request,*args,**kwargs):
        return HttpResponse(request.session['username'])

 CBV第二种方式装饰器

from django.utils.decorators import method_decorator
 
def auth(func): #定义装饰器
    def inner(request,*args,**kwargs):
        if request.session.get('username'):
            obj = func(request,*args,**kwargs)
            return obj
        else:
            return redirect('/login.html')
    return inner
 
@method_decorator(auth,name='get')  #放在类顶部就需要method_decorator这个装饰器
class IndexView(View):
 
    @method_decorator(auth) #放在dispatch上就相当于全局都需要经过认证
    def dispatch(self, request, *args, **kwargs):
        if request.session.get('username'):
            response = super(IndexView,self).dispatch(request, *args, **kwargs)
            return response
        else:
            return redirect('/login.html')
 
    @method_decorator(auth)
    def get(self,request,*args,**kwargs):
        return HttpResponse(request.session['username'])
 
    @method_decorator(csrf_exempt)  # 无效 csrf 放到post函数上的装饰器,是无效的,需要放到dispath上或者类上
    def post(self,request,*args,**kwargs):
        return HttpResponse(request.session['username'])

 四.中间件middleware

如下是django的生命周期

 如下为中间件的执行顺序

 - 中间件执行时机：请求到来，请求返回时
　　- 中间件是一个类：
　　def process_request(self,request):
　　　　print('m2.process_request')

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

　　　　- 应用：
　　　　- 请求日志
　　　　- 用户登录认证

Django根目录新建md文件夹，新建Middleware.py文件

from django.utils.deprecation import MiddlewareMixin

class M1(MiddlewareMixin):
    '''先执行request,然后到url路由,url之后返回到最上方,在执行view,如果出现错误就直接到response上,执行完,到真正到视图,如果有问题就
    执行exception,从下至上查找,如果找到exception就直接执行exception的return在走response返回用户
    每个中间件中,4个方法不需要都写.
    '''
    def process_request(self,request):

        if request.path_info == "/login.html":
            return None
        user_info = request.session.get("username")
        if not user_info:
            return redirect("/login.html")

 注:新的django版本可能不存在MiddlewareMixin,需要手动写一下这个类进行继承

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):

        if request.path_info == "/login.html":
            return None
        user_info = request.session.get("username")
        if not user_info:
            return redirect("/login.html")

 settings里配置：

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',
    'md.Middleware.M1',
]

WSGI_APPLICATION = 'BBS.wsgi.application'

SESSION_ENGINE = 'django.contrib.sessions.backends.db'  # 引擎（默认）

SESSION_COOKIE_NAME = "sessionid"  # Session的cookie保存在浏览器上时的key，即：sessionid＝随机字符串（默认）
SESSION_COOKIE_PATH = "/"  # Session的cookie保存的路径（默认）
SESSION_COOKIE_DOMAIN = None  # Session的cookie保存的域名（默认）
SESSION_COOKIE_SECURE = False  # 是否Https传输cookie（默认）
SESSION_COOKIE_HTTPONLY = True  # 是否Session的cookie只支持http传输（默认）
SESSION_COOKIE_AGE = 1209600  # Session的cookie失效日期（2周）（默认）
SESSION_EXPIRE_AT_BROWSER_CLOSE = False  # 是否关闭浏览器使得Session过期（默认）
SESSION_SAVE_EVERY_REQUEST = True  # 是否每次请求都保存Session，默认修改之后才保存（默认）