NameError：名称“ MainPage”未定义python-2.7

Question

我正在尝试完成一个练习以使用python 2.7了解有关Google Appengine的更多信息

到目前为止，我的main.py文件中已有此代码，但是当我尝试通过本地主机访问它时，出现以下错误消息：NameError：未定义名称“ MainPage”

我找不到错误的出处，对此方面的任何帮助对我来说都是新事物，对此我将不胜感激。

import webapp2
import jinja2
from google.appengine.api import users
from google.appengine.ext import ndb

import os

from myuser import MyUser

JINJA_ENVIRONMENT = jinja2.Environment(
    loader=jinja2.FileSystemLoader(os.path.dirname(__file__)),
    extensions=['jinja2.ext.autoescape'],
    autoescape=True
)

class MainPage(webapp2.RequestHandler):
    def get(self):
        self.response.headers['Content-Type'] = 'text/html'

        url = ''
        url_string = ''
        welcome = 'Welcome back'
        myuser = None

        user = users.get_current_user()

        if user:
            url = users.create_logout_url(self.request.uri)
            url_string = 'logout'

            myuser_key = ndb.Key('MyUser', user.user_id())
            myuser = myuser_key.get()

            if myuser == None:
                welcome = 'Welcome to the application'
                myuser = MyUser(id=user.user_id())
                myuser.put()
        else:
            url = users.create_login_url(self.request.uri)
            url_string = 'login'

        template_values = {
            'url' : url,
            'url_string' : url_string,
            'user' : user,
            'welcome' : welcome,
            'myuser' : muyser
        }

        template = JINJA_ENVIRONMENT.get_templaet('main.html')
        self.response.write(template.render(template_values))

    app = webapp2.WSGIApplication([
        ('/', MainPage),
    ], debug=True)

    def post(self):
        self.response.header['Content-Type'] = 'text/html'

        user = users.get_current_user()
        myuser_key = ndb.Key('MyUser', user.user_id())

        myuser = myuser_key.get()

        myuser.name = self.request.get('users_name')
        myuser.age = int(self.request.get('users_age'))
        myuser.put()

       self.redirect('/')

Answer 1

一个更简单的示例，一个类变量不能引用该类本身

class Foo:
  x = Foo()

  def bar(self):
    pass

运行它

Traceback (most recent call last):
  File "python", line 1, in <module>
  File "python", line 2, in Foo
NameError: name 'Foo' is not defined

您在MainPage类中的get()和post()之间定义了app 。 上课后移开

class MainPage(webapp2.RequestHandler):
    def get(self):
        pass  # Fill this back in 

    def post(self):
        pass  # Fill this back in 


app = webapp2.WSGIApplication([
    ('/', MainPage),
], debug=True)

我可能还会建议您为HTTP路由使用一个单独的模块，并将此主脚本保持在最小限度，以仅设置该应用