通过session，我们能够在多次浏览器请求中保持数据，接下来的部分就是用session来处理用户登录了。 当然，不能仅凭用户的一面之词，我们就相信，所以我们须要认证。

当然了，Django 也提供了工具来处理这种常见任务（就像其它常见任务一样）。 Django 用户认证系统处理用户帐号，组，权限以及基于cookie的用户会话。这个系统一般被称为 auth/auth (认证与授权)系统。 这个系统的名称同一时候也表明了用户常见的两步处理。 我们须要:

1.     验证 (认证) 用户是否是他所宣称的用户(一般通过查询数据库验证其username和password)

2.     验证用户是否拥有运行某种操作的 授权 (一般会通过检查一个权限表来确认)

依据这些需求，Django 认证/授权 系统会包括下面的部分：

§ 用户 :在站点注冊的人

§ 权限 :用于标识用户能否够运行某种操作的二进制(yes/no)标志

§ 组 :一种能够将标记和权限应用于多个用户的经常用法

§ Messages : 向用户显示队列式的系统消息的经常用法

假设你已经用了admin工具(详见第6章)，就会看见这些工具的大部分。假设你在admin工具中编辑过用户或组，那么实际上你已经编辑过授权系统的数据库表了。

在我们运行manage.py syncdb的时候,在命令行工具中,就已经依据向导创建了第一个用户,以下我们先来看看怎样使用Django的认证与授权系统做登陆和注销的功能。

首先我们先改动一下urls.py

from django.conf.urls import patterns, include, url
from django.contrib.auth.views import login, logout

# Uncomment the next two lines to enable the admin:
# from django.contrib import admin
# admin.autodiscover()

urlpatterns = patterns('',
    # Examples:
    # url(r'^$', 'Bidding.views.home', name='home'),
    # url(r'^Bidding/', include('Bidding.foo.urls')),

    # Uncomment the admin/doc line below to enable admin documentation:
    # url(r'^admin/doc/', include('django.contrib.admindocs.urls')),

    # Uncomment the next line to enable the admin:
    # url(r'^admin/', include(admin.site.urls)),
    url(r'^hello/$', 'Bidding.views.hello'),
    url(r'^time/$', 'Bidding.views.current_datetime'),
    url(r'^time/plus/(d{1,2})/$', 'Bidding.views.hours_ahead'),
    url(r'^hello_base/$', 'Bidding.views.hello_base'),
    url(r'^request_test/$', 'Bidding.views.request_test'),
    url(r'^UsersSearch/$', 'Bidding.Users.views.search_form'),
    url(r'^search/$', 'Bidding.Users.views.search'),
    url(r'^ClassRoom/add/$', 'person.views.ClassroonAdd'),
    url(r'^ClassRoom/list/$', 'person.views.ClassroonList'),
    url(r'^ClassRoom/modify/(d+)/$', 'person.views.ClassroonModify'),
    url(r'^ClassRoom/delete/(d+)/$', 'person.views.ClassroonDelete'),
    url(r'^testPIC/$', 'Bidding.views.my_image'),
    url(r'^testPDF/$', 'Bidding.views.hello_pdf'),
    url(r'^testCookie/show/$', 'Bidding.views.show_cookie'),
    url(r'^testCookie/set/(w+)/$', 'Bidding.views.set_cookie'),
    url(r'^testCookie/del/$', 'Bidding.views.del_cookie'),
    url(r'^testSession/show/$', 'Bidding.views.show_session'),
    url(r'^testSession/set/(w+)/$', 'Bidding.views.set_session'),
    url(r'^testSession/del/$', 'Bidding.views.del_session'),
#url(r'^accounts/login/$',  login),
    url(r'^accounts/login/$',  login, {'template_name': 'login.html'}),
    url(r'^accounts/logout/$', logout),
                       
)

注意：login和logout函数是不须要我们写视图的，由于在urls.py的顶部我增加了：

fromdjango.contrib.auth.views import login, logout

也就是说这两个函数时Django默认的视图，以下的问题就出来了，假设视图的默认的，我们无从编辑，那么视图相应的模板呢？这个不用着急，在Djiango中，login相应的模板存放在：registragiton/login.html  (能够通过视图的额外參数 template_name 改动这个模板名称)。 这个表单必须包括 username 和 password 域。例如以下演示样例：一个简单的 template 看起来是这种。

假设用户登录成功，缺省会重定向到 /accounts/profile 。你能够提供一个保存登录后重定向URL的next隐藏域来重载它的行为。也能够把值以GET參数的形式发送给视图函数，它会以变量next的形式保存在上下文中，这样你就能够把它用在隐藏域上了。
logout视图有一些不同。 默认情况下它渲染 registration/logged_out.html 模板（这个视图一般包括你已经成功退出的信息）。视图中还能够包括一个參数 next_page 用于退出后重定向。



这时输入你之前创建的usernamepassword，就能够登录了。为了以后的学习，我们先建立一个页面为登陆后的默认页：

新建welcom.html

加入视图views.py
def welcom(request):
       return render_to_response('welcom.html', locals())

配置urls.py
from django.conf.urls import patterns, include, url
from django.contrib.auth.views import login, logout

# Uncomment the next two lines to enable the admin:
# from django.contrib import admin
# admin.autodiscover()

urlpatterns = patterns('',
    # Examples:
    # url(r'^$', 'Bidding.views.home', name='home'),
    # url(r'^Bidding/', include('Bidding.foo.urls')),

    # Uncomment the admin/doc line below to enable admin documentation:
    # url(r'^admin/doc/', include('django.contrib.admindocs.urls')),

    # Uncomment the next line to enable the admin:
    # url(r'^admin/', include(admin.site.urls)),
    url(r'^hello/$', 'Bidding.views.hello'),
    url(r'^time/$', 'Bidding.views.current_datetime'),
    url(r'^time/plus/(d{1,2})/$', 'Bidding.views.hours_ahead'),
    url(r'^hello_base/$', 'Bidding.views.hello_base'),
    url(r'^request_test/$', 'Bidding.views.request_test'),
    url(r'^UsersSearch/$', 'Bidding.Users.views.search_form'),
    url(r'^search/$', 'Bidding.Users.views.search'),
    url(r'^ClassRoom/add/$', 'person.views.ClassroonAdd'),
    url(r'^ClassRoom/list/$', 'person.views.ClassroonList'),
    url(r'^ClassRoom/modify/(d+)/$', 'person.views.ClassroonModify'),
    url(r'^ClassRoom/delete/(d+)/$', 'person.views.ClassroonDelete'),
    url(r'^testPIC/$', 'Bidding.views.my_image'),
    url(r'^testPDF/$', 'Bidding.views.hello_pdf'),
    url(r'^testCookie/show/$', 'Bidding.views.show_cookie'),
    url(r'^testCookie/set/(w+)/$', 'Bidding.views.set_cookie'),
    url(r'^testCookie/del/$', 'Bidding.views.del_cookie'),
    url(r'^testSession/show/$', 'Bidding.views.show_session'),
    url(r'^testSession/set/(w+)/$', 'Bidding.views.set_session'),
    url(r'^testSession/del/$', 'Bidding.views.del_session'),
    url(r'^accounts/login/$',  login, {'template_name': 'login.html'}),
    url(r'^accounts/logout/$', logout),
    url(r'^welcom/$', 'Bidding.views.welcom'),                
)

建立这个页面，是为了登陆以后跳转到这里，而不是系统默认的/accounts/profile，因此我们要改动一下login.html的模板，在next隐藏域打上我们新建的这个页面的路径，例如以下：
在执行一下试试看，效果达到了吧！

正如我们上面所操心的，事实上welcom/页面假设没有登陆事实上也是能够訪问的，不用着急Django为我们提供了很简便的办法，我们仅仅须要在相应的视图上面加上一句@login_required 就能够了：
@login_required
def welcom(request):
       return render_to_response('welcom.html', locals())

这就意味着本页面必须通过验证的用户才干够訪问，注意一定要在头部加上
from django.contrib.auth.decorators import login_required 
才干够哦！
我们在直接訪问welcom/试验一下吧：


系统会自己主动定位到登陆页面，等我们登陆以后才会真正运行视图中的函数。
事实上另一种情况，就是尽管登陆了，可是一些关键的页面也不能让某些用户訪问，这里就用到权限的管理了。以下我们就来重点讨论一下管理 Users, Permissions 和 Groups的过程：
首先我们先模仿


的样例制作一个用户标的基础数据库操作



首先配置urls.py:

from django.conf.urls import patterns, include, url
from django.contrib.auth.views import login, logout

# Uncomment the next two lines to enable the admin:
# from django.contrib import admin
# admin.autodiscover()

urlpatterns = patterns('',
    # Examples:
    # url(r'^$', 'Bidding.views.home', name='home'),
    # url(r'^Bidding/', include('Bidding.foo.urls')),

    # Uncomment the admin/doc line below to enable admin documentation:
    # url(r'^admin/doc/', include('django.contrib.admindocs.urls')),

    # Uncomment the next line to enable the admin:
    # url(r'^admin/', include(admin.site.urls)),
    url(r'^hello/$', 'Bidding.views.hello'),
    url(r'^time/$', 'Bidding.views.current_datetime'),
    url(r'^time/plus/(d{1,2})/$', 'Bidding.views.hours_ahead'),
    url(r'^hello_base/$', 'Bidding.views.hello_base'),
    url(r'^request_test/$', 'Bidding.views.request_test'),
    url(r'^UsersSearch/$', 'Bidding.Users.views.search_form'),
    url(r'^search/$', 'Bidding.Users.views.search'),
    url(r'^ClassRoom/add/$', 'person.views.ClassroonAdd'),
    url(r'^ClassRoom/list/$', 'person.views.ClassroonList'),
    url(r'^ClassRoom/modify/(d+)/$', 'person.views.ClassroonModify'),
    url(r'^ClassRoom/delete/(d+)/$', 'person.views.ClassroonDelete'),
    url(r'^testPIC/$', 'Bidding.views.my_image'),
    url(r'^testPDF/$', 'Bidding.views.hello_pdf'),
    url(r'^testCookie/show/$', 'Bidding.views.show_cookie'),
    url(r'^testCookie/set/(w+)/$', 'Bidding.views.set_cookie'),
    url(r'^testCookie/del/$', 'Bidding.views.del_cookie'),
    url(r'^testSession/show/$', 'Bidding.views.show_session'),
    url(r'^testSession/set/(w+)/$', 'Bidding.views.set_session'),
    url(r'^testSession/del/$', 'Bidding.views.del_session'),
    url(r'^accounts/login/$',  login, {'template_name': 'login.html'}),
    url(r'^accounts/logout/$', logout,{'next_page':'/accounts/login'}),
    url(r'^welcom/$', 'Bidding.views.welcom'),
    url(r'^User/add/$', 'Bidding.Users.views.CreateUser'),
    url(r'^User/list/$', 'Bidding.Users.views.UserList'),
    url(r'^User/modify/(d+)/$', 'Bidding.Users.views.UserModify'),
    url(r'^User/delete/(d+)/$', 'Bidding.Users.views.UserDelete'),
)


加入视图,改动后的bidding/users/view.py是这种:

# -*- coding: utf-8 -*-
from django.http import HttpResponse
from django.shortcuts import render_to_response
from django.template import RequestContext
from django.contrib.auth.models import User

def search_form(request):
    return render_to_response('Users/search_form.html')

def search1(request):
    if 'q' in request.GET:
        message = '您搜索的keyword是: %r' % request.GET['q']
    else:
        message = '请输入您要检索的内容'
    return HttpResponse(message)

def search(request):
    if 'q' in request.GET and request.GET['q']:
        q = request.GET['q']
        return render_to_response('Users/search_results.html',
            {'query': q})
    else:
        return render_to_response('Users/search_form.html', {'error': True})
    

def CreateUser(request):
    if request.POST.has_key('username')  and request.POST.has_key('password') and request.POST.has_key('email') :
        username = request.POST['username']
        password = request.POST['password']
        email = request.POST['email']
        user = User.objects.create_user(username=username,
                                        email=email,
                                        password=password)
        user.save()
        return render_to_response('Users/User_Add_results.html',
            {'username': username},context_instance=RequestContext(request))
    else:
        return render_to_response('Users/User_Add.html', {'error': True},context_instance=RequestContext(request))

def UserList(request):
        UserList=User.objects.all()
        return render_to_response('Users/User_List.html',
            {'UserList': UserList})


def UserDelete(request,id1):
    
    GetHost=request.get_host()
    try:  
        GetHTTP_REFERER = request.META['HTTP_REFERER']  
    except KeyError:  
        GetHTTP_REFERER = 'unknown'
        
    if GetHTTP_REFERER!='unknown' and GetHTTP_REFERER.find(GetHost)>0:
        user=User.objects.get(id=id1)
        old_name = user.username
        user.delete()
        return render_to_response('Users/User_Delete_results.html',{'name':old_name})
    else:
        return render_to_response('Users/Error.html')


def UserModify(request,id1):

    GetHost=request.get_host()
    try:  
        GetHTTP_REFERER = request.META['HTTP_REFERER']  
    except KeyError:  
        GetHTTP_REFERER = 'unknown'
        
    if GetHTTP_REFERER!='unknown' and GetHTTP_REFERER.find(GetHost)>0:
        user=User.objects.get(id=id1)
        old_username = user.username
        old_email = user.email
        old_password = user.password
        if request.POST.has_key('username')  and request.POST.has_key('email') and request.POST.has_key('password') :
            new_username = request.POST['username']
            new_email = request.POST['email']
            new_password = request.POST['password']
            user.username=new_username
            user.email=new_email
            user.set_password(new_password)
            #Django 在 ``django.contrib.auth`` 提供了2个函数: ``authenticate()``和 ``login()`` 。
            #假设通过给定的username与password做认证，请使用 ``authenticate()`` 函数。
            #user = authenticate(username=username,password=old_password)
            #自己改动密码时首先验证旧密码是否正确
            #user.password=new_password  #这样不行的
            user.save()
            return render_to_response('Users/User_Modify_results.html',
                {'old_username': old_username,'old_email':old_email,'old_password':old_password,'new_username': new_username,'new_email':new_email,'new_password':new_password},context_instance=RequestContext(request))
        else:
            return render_to_response('Users/User_Modify.html', {'error': True,'id':id1,'username':old_username,'email':old_email,'password':old_password},context_instance=RequestContext(request))
    else:
        return render_to_response('Users/Error.html')


注意在改动和读取password的时候:


 由于数据库中存储的django加密以后的password,我们在读取的时候是一串加密后的字符串,这里不可以显示的表现出来,假设改动password用简单的user.password=new_password,也是不行的,必须使用user.set_password(new_password)来改动密。#假设用户自己改动password时首先验证旧password是否正确，可以通过给定的username和password做认证，请使用``authenticate()``
函数，代码例如以下：记得要导入django.contrib.auth哦


以下是一些模板，我把它们放在了Bidding/templates/Users中了

User_Add.html：


User_Add_results.html：

User_Delete_results.html


User_List.html：

User_Modify.html
User_Modify_results.html
<html>
<head>
    <title>查询用户结果页</title>
</head>
<body>
    <table border="1" cellpadding="5"><tr>
      <td align="center"> </td>
      <td align="center">改动前</td>
      <td align="center">改动后</td>
      </tr>
      <tr>
        <td align="right">用户名：</td>
        <td align="right">{{old_username}}</td>
        <td align="right">{{new_username}}</td>
      </tr>
      <tr>
        <td align="right">邮箱：</td>
        <td align="right">{{old_email}}</td>
        <td align="right">{{new_email}}</td>
      </tr>
	   <tr>
        <td align="right">密码：</td>
        <td align="right">{{old_password}}</td>
        <td align="right">{{new_password}}</td>
      </tr>
      <tr>
        <td colspan="3" align="center">改动成功！</td>
      </tr>
      <tr>
        <td colspan="3" align="center"><a href="../../list/">点击返回</a></td>
      </tr>
    </table>
</body>
</html>

这样我们就做好了一个管理用户信息的页面了,用我们新加入的用户也能够登录之前的那个登录页面了。以下就是怎样对这些用户设置详细的权限。