试图运行webpy示例：app未定义

Question

我正在尝试使用webpy实现基于某些elses代码的验证码。我开始的代码在这里：https://kzar.co.uk/blog/2009/07/14/web.py-captcha/

那里的示例代码不完整，我需要弄清楚如何处理这个app变量。这是我的代码：

import web
from captcha import getCaptcha

render = web.template.render('templates/')

urls = (
        '/([a-zA-Z]+/[a-zA-Z]+)', 'index',
        '/', 'index',
        '/captcha.gif', 'captcha'
        )

if web.config.get("_session") is None:
    session = web.session.Session(app, web.session.DiskStore('sessions'), initializer={'captcha': ''})
    web.config._session = session
else:
    session = web.config._session

vcaptcha = form.Validator('Please enter the code', lambda x:x == session.captcha)

enquiry_form = form.Form(
        form.Textbox("captcha", vcaptcha, description="Validation Code", pre="<img src='/captcha.gif' valign=center><br>", class_="standard", style="width:70px;"),
        )

class index:
    def GET(self, argu = "Anonymous/Person"):
        args = argu.split('/')
        firstname = args[0]
        if (len(args) >= 2):
            lastname = args[1]
            return render.index(firstname, lastname)
        return render.index(firstname, "Snow")

class captcha:
    def GET(self):
        web.header("Content-Type", "image/gif")
        captcha = getCaptcha
        session.captcha = captcha[0]
        return captcha[1].read()

if __name__ == "__main__":
    app = web.application(urls, globals())
    app.run()

运行时出现此错误：

$ python code.py
Traceback (most recent call last):
  File "code.py", line 13, in <module>
    session = web.session.Session(app, web.session.DiskStore('sessions'), initializer={'captcha': ''})
NameError: name 'app' is not defined

我一直在查看webpy文档和API参考，我无法弄清楚如何正确初始化这个'app'变量。

Answer 1

当你打电话给app时，你正在使用尚未定义的session = web.session.Session(app, ...你有没有看过关于sessions的文档？在使用它之前，请看它们如何在示例中定义app。

Answer 2

在URL之后，应该有这个：

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