第十四章： 会话、用户和注册

存取Cookie

def show_color(request):
  if "favorite_color" in request.COOKIES:
    return HttpResponse(request.COOKIES['favorite_color'])      

写cookie 需要使用HttpResponse对象的set_cookie()方法

response=HttpResponse(request.GET["favorite_color"])
response.set_cookie("favorite_color",request.GET["favorite_color"])
return response

response.set_cookie()传递参数控制cookie的行为

• max_age cookie需要延续的时间
• expires cookie失效的实际日期

打开session

通过一个中间件实现

• 编辑MIDDLEWARE_CLASSES配置
  'django.contrib.sessions.middleware.SessionMiddleware'
• 确认INSTALL_APPS 中有'django.contrib.sessions'(如果你是刚打开这个应用，别忘了运行 manage.py syncdb )

视图中使用session

#set a session
request.session["fav_color"]="blue"
#get a session
fav_color=request.session["fav_color"]
#clear a session
del request.session["fav_color"]
#ckeck if the session has a given key
if "fav_color" in request.session:

防止用户对此评论

def post_comment(request):
  if request.session.get('has_commented',False):
      return HttpResponse("You have aleardy commented")
  ....
  request.session['has_commented']=True
return HttpResponse("Thanks for your comment!")

设置测试Cookie

Dajngo提供一个简单的方法来测试用户的浏览器是否接收cookie。
request.session.test_cookie_worked()
request.session.set_test_cookie()

def login(request):

    # If we submitted the form...
    if request.method == 'POST':

        # Check that the test cookie worked (we set it below):
        if request.session.test_cookie_worked():

            # The test cookie worked, so delete it.
            request.session.delete_test_cookie()

            # In practice, we'd need some logic to check username/password
            # here, but since this is an example...
            return HttpResponse("You're logged in.")

        # The test cookie failed, so display an error message. If this
        # were a real site, we'd want to display a friendlier message.
        else:
            return HttpResponse("Please enable cookies and try again.")

    # If we didn't post, send the test cookie along with the login form.
    request.session.set_test_cookie()
    return render_to_response('foo/login_form.html')

用户与Ａuthentication

• 验证（用户名密码）