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Day21-Cookie

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11/29
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1. Cookie，有时也用其复数形式 Cookies，指某些网站为了辨别用户身份、进行 session 跟踪而储存在用户本地终端上的数据（通常经过加密）。例如在某个网站上保存了用户名和密码，3个月内免登陆。如果你换台电脑或者浏览器的话，则需要重新登录。就此说明cookie是保存在客户端浏览器上的一个文件。

2.实例---基于cookie实现用户信息验证

当用户名和密码都正确的时候，才跳转到index页面。否则就停留在login.html页面。

2.1 在setting中注释掉下面一句，防止报错

2.2 在urls.py中写路由对应关系

2.3 views.py写后端

dic = user_info.get(u) #如果获取到了，表明用户是存在的。 

from django.shortcuts import render,HttpResponse,redirect

from django.urls import reverse

# Create your views here.

user_info={

    'dachengzi':{'pwd':"123123"},

    'kanbazi':{'pwd':"kkkkkkk"},

}

def login(request):

    if request.method=='GET':

        return render(request,'login.html')

    if request.method == 'POST':

        u=request.POST.get('username')

        p=request.POST.get('pwd')

        dic=user_info.get(u)

        if not dic:

            return render(request,'login.html')

        if dic['pwd']==p:

            res=redirect('/index/')

            res.set_cookie('username111',u)

            return res

        else:

            return render(request,'login.html')

def index(request):

    #获取当前已经登录的用户名字

    v=request.COOKIES.get('username111')

    if not v:

        return redirect(request,'/login/')

    return render(request,'index.html',{'current_user':v})

2.4 写前端 index.html 

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<body>

    <h1>欢迎登录：{{current_user}}</h1>

</body>

</html>

2.4 写前端 login.html 

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<body>

    <form action="/login/" method="POST">

        <input type="text" name="username" placeholder="用户名"/>

        <input type="password" name="pwd" placeholder="密码"/>

        <input type="submit"/>

    </form>

</body>

</html>

2.5 效果

没有登录之前，是无法访问index页面的。

只有先从login页面登录了以后，才能跳转到index页面。

3. 在Django里面给cookie提供了一些额外的功能。 

request.COOKIES-------表示用户发来数据的时候，它里面带的所携带的所有cookie信息。。。从请求中获取cookie
def cookie(request):

    #用户发来请求时，它里面所携带的所有的cookie信息

    request.COOKIES

    request.COOKIES['username111']

    request.COOKIES.get('username111')

设置cookie 键-值对 

response.set_cookie('key','value')
def cookie(request):

    #用户发来请求时，它里面所携带的所有的cookie信息

    request.COOKIES

    request.COOKIES['username111']

    request.COOKIES.get('username111')

    response=render(request,'index.html') #通过render，redirect把内容返回给浏览器

    response=redirect('/index/')

    #设置cookie,关闭浏览器后就失效

    response.set_cookie('key','value')  #还可以设置新的cookie 键-值对，也一并返回给浏览器

    return response #里面不仅包含了内容，还包含了cookie的键-值对。

 

4. 默认情况下，关闭浏览器后，cookie就失效了，需要重新登录了。通过下面几种方法可以设置失效时间。

设置用户名和密码的失效时间-方法1，max_age=None 


   
--------res.set_cookie('username111',u,max_age=10)  设置失效时间为10秒

   


效果：10秒之后，用户名和密码就失效了，从index自动倒退回到login界面，需要重新登录了。

5. 设置用户名和密码的失效时间-方法2,expires=None

   
import datetime 
current_date=datetime.datetime.utcnow() 
current_daate=current_date+datetime.timedelta(seconds=5) 
response.set_cookie('username111', "value", expires=current_date)

   


6. 其它属性
   设置cookie的生效路: ---path='/',意思是在所有的url中都生效。path='/index' 指只在index页面有效。
   生效的域名: domain=None
   https传输: secure=False
　　httponly:  只支持http传输，在JS前端是无法获取的，没有安全不安全一说。示例如下：

设置2个cookie，其中1个有httponly=True属性，对比看效果



在页面上访问的时候，看到了2个cookie

   

    但是在前端却获取不到
   

   

    
   

   

    7. 增加2个月内免登陆的功能，自己完成。把2个月换算成秒，添加到max_age=XXX里面就可以了。
   

   

    注销的本质就是把cookie清除掉。
   

   

    
     8. 完善实例，基于cookie实现定制显示数据条数
    
   

   

    8.1----cookie在服务器端能读能写，在客户端也是能读能写的。
   

   

    
   

   

    8.2----------jQuery有个插件叫jQuery-cookie，通过这个插件可以直接去浏览器上去操作cookie了。
   

   

    从官网下载插件http://plugins.jquery.com/cookie/
   

   

    
   

   

    
   

   

    8.3 用实例来验证，浏览器端确实可以获取到per_page_count这个值。
   

   

    
   

   

    user_list.html
   

   

    
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

    <style>

        .pagination .page{

            display:inline-block;

            padding:5px;

            background-color:cyan;

            margin:5px;

        }

        .pagination .page.active{

            background-color:brown;

            color:white;

        }

    </style>

</head>

<body>

    <ul>

        {% for item in li %}

            {% include 'li.html' %}

        {%endfor%}

    </ul>

    <div>

        请选择每页显示条数

        <select id="ps" onchange="changePageSize(this)">

            <option value="10">10</option>

            <option value="30">30</option>

            <option value="50">50</option>

            <option value="100">100</option>

        </select>

    </div>

    <div class="pagination">

        {{page_str}}

    </div>

    <script src="/static/jquery-1.12.4.js"></script>

    <script src="/static/jquery.cookie.js"></script>

    <script>

        function changePageSize(ths){

            var v=$(ths).val();

            console.log(v);

            $.cookie('per_page_count',v);

        }

    </script>

</body>

</html>


   

   

    在Console中也可以看到这个效果。
   

   

    
   

   

    8.4 服务器端从客户端传过来的cookie中获取到这个值。并且在实例化的时候，把它传递给类。
   

   

    
   

   

    views.py
   

   

    
from django.shortcuts import render,HttpResponse,redirect

from utils import pagination

from django.urls import reverse

# Create your views here.

LIST=[]

for i in range(1000):

    LIST.append(i)

def user_list(request):

    current_page=request.GET.get('p')

    current_page = int(current_page)

    val=request.COOKIES.get('per_page_count')

    print(val)

    val=int(val)

    page_obj=pagination.Page(current_page,len(LIST),val)

    data=LIST[page_obj.start:page_obj.end]

    page_str=page_obj.page_str("/user_list/")

    return render(request,'user_list.html',{'data':data,'page_str':page_str})

user_info = {

    'dachengzi': {'pwd': "123123"},

    'kanbazi': {'pwd': "kkkkkkk"},

}

def login(request):

    if request.method == 'GET':

        return render(request, 'login.html')

    if request.method == 'POST':

        u = request.POST.get('username')

        p = request.POST.get('pwd')

        dic = user_info.get(u)

        if not dic:

            return render(request, 'login.html')

        if dic['pwd'] == p:

            res = redirect('/index/')

            res.set_cookie('username111', u)

            return res

        else:

            return render(request, 'login.html')

def index(request):

    # 获取当前已经登录的用户名字

    v = request.COOKIES.get('username111')

    if not v:

        return redirect(request, '/login/')

    return render(request, 'index.html', {'current_user': v})


   

   

    8.5 完善功能。用户选中每页显示多少条，浏览器上就显示多少条。
   

   

    
   

   

    代码修改如下：
   

   

    
   

   

    8.6 完善功能，指定生效的url路径
   

   

    var v=$.cookie('per_page_count',{'path':"/user_list/"}); 指定路径
   

   

    
   

   

    9. 至此，程序粘贴如下：
   

   

    urls.py
   

   

    
from django.conf.urls import url

from django.contrib import admin

from app_ch import views

urlpatterns = [

    url(r'^admin/', admin.site.urls),

    url(r'^user_list/$', views.user_list),

    url(r'^login', views.login),

    url(r'^index', views.index),

]


   

   

    views.py
   

   

    
from django.shortcuts import render,HttpResponse,redirect

from utils import pagination

from django.urls import reverse

# Create your views here.

LIST=[]

for i in range(1000):

    LIST.append(i)

def user_list(request):

    current_page=request.GET.get('p')

    current_page = int(current_page)

    val=request.COOKIES.get('per_page_count')

    print(val)

    val=int(val)

    page_obj=pagination.Page(current_page,len(LIST),val)

    data=LIST[page_obj.start:page_obj.end]

    page_str=page_obj.page_str("/user_list/")

    return render(request,'user_list.html',{'data':data,'page_str':page_str})

user_info = {

    'dachengzi': {'pwd': "123123"},

    'kanbazi': {'pwd': "kkkkkkk"},

}

def login(request):

    if request.method == 'GET':

        return render(request, 'login.html')

    if request.method == 'POST':

        u = request.POST.get('username')

        p = request.POST.get('pwd')

        dic = user_info.get(u)

        if not dic:

            return render(request, 'login.html')

        if dic['pwd'] == p:

            res = redirect('/index/')

            res.set_cookie('username111', u)

            return res

        else:

            return render(request, 'login.html')

def index(request):

    # 获取当前已经登录的用户名字

    v = request.COOKIES.get('username111')

    if not v:

        return redirect(request, '/login/')

    return render(request, 'index.html', {'current_user': v})


   

   

    pagination.py
   

   

    
from django.utils.safestring import mark_safe

class Page:

    def __init__(self,current_page,data_count,per_page_count=10,pager_num=7):

        self.current_page=current_page

        self.data_count=data_count

        self.per_page_count=per_page_count

        self.pager_num=pager_num

    @property

    def start(self):

        return (self.current_page - 1) * self.per_page_count

    @property

    def end(self):

        return self.current_page*self.per_page_count

    @property

    def total_count(self):

        v, y = divmod(self.data_count,self.per_page_count)

        if y:

            v = v+ 1

        return v

    def page_str(self,base_url):

        page_list = []

        if self.total_count < self.pager_num:

            start_index = 1

            end_index = self.total_count + 1

        else:

            if self.current_page <= (self.pager_num + 1) / 2:

                start_index = 1

                end_index = self.pager_num + 1

            else:

                start_index = self.current_page - (self.pager_num - 1) / 2

                end_index = self.current_page + (self.pager_num + 1) / 2

                if (self.current_page + (self.pager_num - 1) / 2) > self.total_count:

                    end_index = self.total_count + 1

                    start_index = self.total_count - self.pager_num + 1

        if self.current_page == 1:

            prev = '<a class="page" href="javascript:void(0)">上一页</a>'

        else:

            prev = '<a class="page" href="%s?p=%s">上一页</a>' % (base_url,self.current_page - 1)

        page_list.append(prev)

        for i in range(int(start_index), int(end_index)):

            if i == self.current_page:

                temp = '<a class="page active" href="%s?p=%s">%s</a>' % (base_url,i, i)

            else:

                temp = '<a class="page" href="%s?p=%s">%s</a>' % (base_url,i, i)

            page_list.append(temp)

        if self.current_page == self.total_count:

            nex = '<a class="page" href="javascript:void(0);">下一页</a>'

        else:

            nex = '<a class="page" href=%s?p=%s>下一页</a>' % (base_url,self.current_page + 1)

        page_list.append(nex)

        jump = '''

            <input type='text'/><a onclick='jumpTo(this,"%s?p=");'>Go</a>

            <script>

                function jumpTo(ths,base){

                    var val=ths.previousSibling.value;

                    location.href=base+val;

                }

            </script>

        '''%(base_url)

        page_list.append(jump)

        page_str = mark_safe("".join(page_list))

        return page_str


   

   

    user_list.html
   

   

    
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

    <style>

        .pagination .page{

            display:inline-block;

            padding:5px;

            background-color:cyan;

            margin:5px;

        }

        .pagination .page.active{

            background-color:brown;

            color:white;

        }

    </style>

</head>

<body>

    <ul>

        {% for i in data%}

            <li>{{i}}</li>

        {% endfor %}

    </ul>

    <div>

        选择每页显示的条数：

        <select id="ps" onchange="changePageSize(this)">

            <option value="10">10</option>

            <option value="30">30</option>

            <option value="50">50</option>

        </select>

    </div>

    <div class="pagination">

        {{page_str}}

    </div>

    <script src="/static/jquery-1.12.4.js"></script>

    <script src="/static/jquery.cookie.js"></script>

    <script>

        $(function(){

            var v=$.cookie('per_page_count',{'path':"/user_list/"});

            $('#ps').val(v);

        });

        function changePageSize(ths){

            var v=$(ths).val();

            $.cookie('per_page_count',v,{'path':"/user_list/"});

            location.reload();

        }

    </script>

</body>

</html>


   

   

    login.html
   

   

    
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<body>

    <form action="/login/" method="POST">

        <input type="text" name="username" placeholder="用户名"/>

        <input type="password" name="pwd" placeholder="密码"/>

        <input type="submit"/>

    </form>

</body>

</html>


   

   

    index.html
   

   

    
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<body>

    <h1>欢迎登录：{{current_user}}</h1>

</body>

</html>


   

   

    10. 带签名的cookie
   

   

    -------明文：
   

   

    获取cookie： request.COOKIES.get('......')
   

   

    设置cookie： response.set_cookie(.....)
   

   

    --------密文：
   

   

    加密解密如下，注意盐要对应，否则解密会不成功。
   

   

    obj=HttpResponse('s')  #返回给客户端的数据
    

    obj.set_signed_cookie('username',"kangbazi",salt='XXX') 通过XXX这个字符串，对cookie的内容进行加密。
    

    request.get_signed_cookie('username',salt="XXX") 服务器端获取得时候，需要解密。
   

   

   
11. 用装饰器实现用户验证
假设这里不仅有index页面需要验证，然后还有一个order页面也需要验证。我们尝试用装饰器来实现。


新建1个order页面，用FBV装饰器来实现。



用另外一种方法CBV实现



现在还没有登录，尝试用get访问的时候，效果如下：



在dispatch方法执行完了以后，才执行下面的方法。


   

    
from django.shortcuts import render,HttpResponse,redirect

from utils import pagination

from django.urls import reverse

# Create your views here.

LIST=[]

for i in range(1000):

    LIST.append(i)

def user_list(request):

    current_page=request.GET.get('p')

    current_page = int(current_page)

    val=request.COOKIES.get('per_page_count')

    print(val)

    val=int(val)

    page_obj=pagination.Page(current_page,len(LIST),val)

    data=LIST[page_obj.start:page_obj.end]

    page_str=page_obj.page_str("/user_list/")

    return render(request,'user_list.html',{'data':data,'page_str':page_str})

user_info = {

    'dachengzi': {'pwd': "123123"},

    'kanbazi': {'pwd': "kkkkkkk"},

}

def login(request):

    if request.method == 'GET':

        return render(request, 'login.html')

    if request.method == 'POST':

        u = request.POST.get('username')

        p = request.POST.get('pwd')

        dic = user_info.get(u)

        if not dic:

            return render(request, 'login.html')

        if dic['pwd'] == p:

            res = redirect('/index/')

            res.set_cookie('username111', u)

            return res

        else:

            return render(request, 'login.html')

def auth(func):

    def inner(request,*args,**kwargs):

        v = request.COOKIES.get('username111')

        if not v:

            return redirect(request, '/login/')

        return func(request,*args,**kwargs)

    return inner

@auth

def index(request):

    # 获取当前已经登录的用户名字

    v = request.COOKIES.get('username111')

    return render(request, 'index.html', {'current_user': v})

from django import views

from django.utils.decorators import method_decorator

class Order(views.View):

    @method_decorator(auth)

    def dispatch(self,request,*args,**kwargs):

        return super(Order,self).dispatch(request,*args,**kwargs)

    def get(self,request):

        v = request.COOKIES.get('username111')

        return render(request, 'index.html', {'current_user': v})

    def post(self,request):

        v = request.COOKIES.get('username111')

        return render(request, 'index.html', {'current_user': v})

def order(request):

    # 获取当前已经登录的用户名字

    v = request.COOKIES.get('username111')

    return render(request, 'index.html', {'current_user': v})


   

   

   
可以更优化，把装饰器写到类的上面。


FBV和CBV两种方法实现装饰器的比较



至此程序如下：

urls.py

   

    
from django.conf.urls import url

from django.contrib import admin

from app_ch import views

urlpatterns = [

    url(r'^admin/', admin.site.urls),

    url(r'^user_list/$', views.user_list),

    url(r'^login', views.login),

    url(r'^index', views.index),

    url(r'^order', views.Order.as_view()),

]


   

   
views.py

   

    
from django.shortcuts import render,HttpResponse,redirect

from utils import pagination

from django.urls import reverse

# Create your views here.

LIST=[]

for i in range(1000):

    LIST.append(i)

def user_list(request):

    current_page=request.GET.get('p')

    current_page = int(current_page)

    val=request.COOKIES.get('per_page_count')

    print(val)

    val=int(val)

    page_obj=pagination.Page(current_page,len(LIST),val)

    data=LIST[page_obj.start:page_obj.end]

    page_str=page_obj.page_str("/user_list/")

    return render(request,'user_list.html',{'data':data,'page_str':page_str})

user_info = {

    'dachengzi': {'pwd': "123123"},

    'kanbazi': {'pwd': "kkkkkkk"},

}

def login(request):

    if request.method == 'GET':

        return render(request, 'login.html')

    if request.method == 'POST':

        u = request.POST.get('username')

        p = request.POST.get('pwd')

        dic = user_info.get(u)

        if not dic:

            return render(request, 'login.html')

        if dic['pwd'] == p:

            res = redirect('/index/')

            res.set_cookie('username111', u)

            return res

        else:

            return render(request, 'login.html')

def auth(func):

    def inner(request,*args,**kwargs):

        v = request.COOKIES.get('username111')

        if not v:

            return redirect(request, '/login/')

        return func(request,*args,**kwargs)

    return inner

@auth

def index(request):

    # 获取当前已经登录的用户名字

    v = request.COOKIES.get('username111')

    return render(request, 'index.html', {'current_user': v})

from django import views

from django.utils.decorators import method_decorator

@method_decorator(auth,name='dispatch')

class Order(views.View):

    def get(self,request):

        v = request.COOKIES.get('username111')

        return render(request, 'index.html', {'current_user': v})

    def post(self,request):

        v = request.COOKIES.get('username111')

        return render(request, 'index.html', {'current_user': v})

def order(request):

    # 获取当前已经登录的用户名字

    v = request.COOKIES.get('username111')

    return render(request, 'index.html', {'current_user': v})


   

   

   

    utils-->pagination.py
   

   

    
from django.utils.safestring import mark_safe

class Page:

    def __init__(self,current_page,data_count,per_page_count=10,pager_num=7):

        self.current_page=current_page

        self.data_count=data_count

        self.per_page_count=per_page_count

        self.pager_num=pager_num

    @property

    def start(self):

        return (self.current_page - 1) * self.per_page_count

    @property

    def end(self):

        return self.current_page*self.per_page_count

    @property

    def total_count(self):

        v, y = divmod(self.data_count,self.per_page_count)

        if y:

            v = v+ 1

        return v

    def page_str(self,base_url):

        page_list = []

        if self.total_count < self.pager_num:

            start_index = 1

            end_index = self.total_count + 1

        else:

            if self.current_page <= (self.pager_num + 1) / 2:

                start_index = 1

                end_index = self.pager_num + 1

            else:

                start_index = self.current_page - (self.pager_num - 1) / 2

                end_index = self.current_page + (self.pager_num + 1) / 2

                if (self.current_page + (self.pager_num - 1) / 2) > self.total_count:

                    end_index = self.total_count + 1

                    start_index = self.total_count - self.pager_num + 1

        if self.current_page == 1:

            prev = '<a class="page" href="javascript:void(0)">上一页</a>'

        else:

            prev = '<a class="page" href="%s?p=%s">上一页</a>' % (base_url,self.current_page - 1)

        page_list.append(prev)

        for i in range(int(start_index), int(end_index)):

            if i == self.current_page:

                temp = '<a class="page active" href="%s?p=%s">%s</a>' % (base_url,i, i)

            else:

                temp = '<a class="page" href="%s?p=%s">%s</a>' % (base_url,i, i)

            page_list.append(temp)

        if self.current_page == self.total_count:

            nex = '<a class="page" href="javascript:void(0);">下一页</a>'

        else:

            nex = '<a class="page" href=%s?p=%s>下一页</a>' % (base_url,self.current_page + 1)

        page_list.append(nex)

        jump = '''

            <input type='text'/><a onclick='jumpTo(this,"%s?p=");'>Go</a>

            <script>

                function jumpTo(ths,base){

                    var val=ths.previousSibling.value;

                    location.href=base+val;

                }

            </script>

        '''%(base_url)

        page_list.append(jump)

        page_str = mark_safe("".join(page_list))

        return page_str


   

   

    login.html
   

   

    
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<body>

    <form action="/login/" method="POST">

        <input type="text" name="username" placeholder="用户名"/>

        <input type="password" name="pwd" placeholder="密码"/>

        <input type="submit"/>

    </form>

</body>

</html>


   

   

    index.html
   

   

    
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<body>

    <h1>欢迎登录：{{current_user}}</h1>

</body>

</html>


   

   

   



  
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