我收到一个 AttributeError: 'NoneType', webpy multiple sessions using beaker

Question

我正在为我的学校建立一个 webpy 平台，以便为他们的毕业典礼发帖等。我一直在编写这个 python 代码，但我不确定该怎么做。我尝试使用烧杯来管理多个会话，我将此代码基于StuFish's code，并且似乎不确定如何将我的代码与他的代码合成。我在渲染主页时遇到问题。
这是我们的代码：

    import web
    import datetime
    from beaker.middleware import SessionMiddleware
    from Models import RegisterModel, LoginModel, Posts

    web.config.debug = False

    urls = (
            '/', 'Home',
            '/adminhome', 'AdminHome',
            '/modhome', 'ModHome',
            '/register', 'Register', 
            '/postreg', 'PostRegistration',
            '/login', 'Login',
            '/check-login', "CheckLogin",
            '/logout', 'Logout',
            '/post-activity', 'PostActivity',
            '/profile', 'Profile',
            '/settings', 'Settings',
            '/update-user', 'UpdateSettings',
            '/admin', 'Admin'
            )

    t_globals = {
                 'datestr': web.datestr,
                 'str': str,
                 'datetime': datetime
                 }

    app = web.application(urls, globals())

    session = web.session.Session(app, web.session.DiskStore("sessions"),initializer={"user":None})
    session_data = session._initializer

    render = web.template.render("Views/Templates", base="MainLayout", globals={"session":session_data, "current_user": session_data["user"]})

    # beaker options are optional.... but it's good to see 
    # where they are called

    session_opts = {
        'session.cookie_expires': True,
        'session.timeout' : 600,
        'session.secure' : True,
    }

    # define webPy app

    # smash it all together and define name for cookie key (sid)
    def session_mw(app):
        return SessionMiddleware(app, config = session_opts, key = "sid")



    # function to check if we are logged in
    def logged(session):
        if 'Login' in session:
            if session['Login']==1:
                return True
            else:
                return False
        else:
            return False

    # create different renders based on log in privilege
    def create_render(privilege):
        session = web.ctx.environ['beaker.session']
        if logged(session) == True:
            if privilege == 0:
                print("OH BABY")
                render = web.template.render('/Views/Templates/user/', base='/Views/Templates/MainLayout', globals=t_globals)
            elif privilege == 1:
                print("LET ME LOVE YOU")
                render = web.template.render('/Views/Templates/user/', base='/Views/Templates/MainLayout', globals=t_globals)
            elif privilege == 2:
                print("DONT HURT ME")          
                render = web.template.render('/Views/Templates/admin/', base='/Views/Templates/MainLayout', globals=t_globals)
            else:
                print("NOOT NOOT")          
                render = web.template.render('/Views/Templates/viewer', base='/Views/Templates/MainLayout', globals=t_globals)

            render = web.template.render('/Views/Templates/', base='MainLayout', globals=t_globals)
            return render

    class Login:
        def GET(self):
            session = web.ctx.environ['beaker.session']
            if logged(session) == True:
                print("SOMEBODY ONCE TOLD ME THAT THE WORLD WAS GONNA ROLL ME BUT I AINT THE SHARPEST TOOL IN THE SHED")
                render = create_render(session['privilege'])
                return render.Home()
            else:
                render = create_render(0)
                print("BLAH BLAH BLAH BLAH")
                return render.Home()

    # I get user credentials from a database (called in model.get_users) 
        def POST(self):
            session = web.ctx.environ['beaker.session']
            data= web.input()
            name = data['user']
            password = data['password']
            ident = model.get_users(m, name)
            try:
                if password == ident.password.strip():
                    session['Login'] = 1
                    session['privilege'] = ident['privilege']
                    session['user'] = name
                    session.save()
                    render = create_render(session['privilege'])
                    print("HERE")
                    return render.Home()

                else:
                    session.login = 0
                    session.privilege = 0
                    session.user = 'none'
                    render = create_render(session['privilege'])
                    print("NO HERE YO")
                    return render.Login()
            except:
                session['Login'] = 0
                session['privilege'] = 0
                render = create_render(session['privilege'])
                print("BANANA")
                return render.Login()

    # Credits go to bbangert for the middleware code
    class Logout:
        def GET(self):
            session = web.ctx.environ['beaker.session']    
            try:
                render = create_render(0)
                session.invalidate()
                session.delete()
                print("TOPSY TURVY")
                return render.Login()
            except:
                session.invalidate()
                session.delete()
                render = create_render(0)
                print("MESSY RIGHT")
                return render.Login()

    class Home:
        def GET(self):
            session = web.ctx.environ['beaker.session']
            if logged(session) == False:
                raise web.seeother('/login')
            else:
                render = create_render(0)
                return render.Home()

    '''
            data = type('obj', (object,), {'username':'q', 'password':'q'})
            login = LoginModel.LoginModel()
            isValid = login.check_user(data)
            if isValid:
              session_data['user'] = isValid

            post_model = Posts.Posts()
            posts = post_model.get_all_posts()

            return render.Home(posts)
    '''

    class Register:
        def GET(self):
          return render.Register()

    class PostRegistration:
        def POST(self):
          print("DOING POST PROCESSING")
          data = web.input()
          reg_model = RegisterModel.RegisterModel()
          reg_model.insert_user(data)
          return data.username

    class CheckLogin:
        def POST(self):
          print("DOING CHECK LOGIN")
          data = web.input()
          login = LoginModel.LoginModel()
          isValid = login.check_user(data)
          if isValid:
            session_data["user"] = isValid
            return isValid
          return "error"

    class PostActivity:
        def POST(self):
          print("DOING POST ACTIVITY")
          data = web.input()
          data.username = session_data['user']['username']
          post_model = Posts.Posts()
          post_model.insert_post(data)    
          return "success"

    class Profile:
        def GET(self):
          return render.Profile()

    class Settings:
        def GET(self):
          return render.Settings()

    class UpdateSettings:
        def POST(self):
          data = web.input()
          data.username = session_data['user']['username']
          update = RegisterModel.RegisterModel()
          update.update_settings(data)
          return "success"

    class Admin:
      def GET(self):
        return render.Admin()

    class AdminHome:
      def GET(self):
        return AdminHome()

    class ModHome:
      def GET(self):
        return ModHome()

    if __name__ == "__main__":
        app.run(session_mw)

我知道我已经定义了多次渲染，但 this code 的情况相同，所以我不明白为什么会出现问题。

这是我们收到的错误消息：

    http://0.0.0.0:8080/
    BLAH BLAH BLAH BLAH
    Traceback (most recent call last):
      File "/usr/local/lib/python3.4/dist-packages/web/application.py", line 257, in process
        return self.handle()
      File "/usr/local/lib/python3.4/dist-packages/web/application.py", line 248, in handle
        return self._delegate(fn, self.fvars, args)
      File "/usr/local/lib/python3.4/dist-packages/web/application.py", line 488, in _delegate
        return handle_class(cls)
      File "/usr/local/lib/python3.4/dist-packages/web/application.py", line 466, in handle_class
        return tocall(*args)
      File "app.py", line 94, in GET
        return render.Home()
    AttributeError: 'NoneType' object has no attribute 'Home'

如果有人可以给我一个解决方案或帮助我解决这个错误，那将不胜感激

旁注：我与this guy 相关联，以防万一您认为代码相似

Answer 1

如果调用create_render(privilege)时logged(session)为假，create_render(privilege)将返回None。因此，当render = create_render(0) 在您出现错误之前运行两行时，您将render 设置为无。然后当render 为None 时尝试渲染页面Home，这将引发异常。

在create_render(privilege) 中，您应该考虑logged(session) 为假的情况。