class UserID(models.Model):
  login_id=models.CharField(max_length=32)
  login_pwd=models.CharField(max_length=32,blank=False)
  nickname=models.CharField(max_length=50)

def checklogin(request):
  """ 用户登录简易判断 """
  try:
    login_id=request.POST.get('user','')
    userpwd=request.POST.get('password','')
    existuser=models.UserID.objects.get(login_id=login_id,login_pwd=userpwd)
    #假设存在此用户，就要给session 赋值
    request.session['myuser']=existuser
  except:
    .....

def check_session(func):
  ''' check user session '''
  def wrapper(request,*args, **kv):
    userinfo=request.session.get('myuser',None)
    if not userinfo:
      return HttpResponseRedirect('/login') #没有登录，则跳转到登录页面
    return func(request,*args, **kv)
  return wrapper

@check_session
def get_all_infomation(request):
  context={}
  context.update(csrf(request))
  ......
  return render_to_response('customer/all_information.html',context)

def logout(request):
  try:
    del request.session['myuser']
  except KeyError:
    pass
  return HttpResponseRedirect('/')