old_contents: #!/usr/bin/env python
  #
  # Copyright 2009 Facebook
  #
  # Licensed under the Apache License, Version 2.0 (the "License"); you may
  # not use this file except in compliance with the License. You may obtain
  # a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  # License for the specific language governing permissions and limitations
  # under the License.
  
  import tornado.auth
  import tornado.escape
  import tornado.httpserver
  import tornado.ioloop
  import tornado.options
  import tornado.web
  
  from tornado.options import define, options
  
  define("port", default=8888, help="run on the given port", type=int)
  
  
  class Application(tornado.web.Application):
      def __init__(self):
          handlers = [
              (r"/", MainHandler),
              (r"/auth/login", AuthHandler),
          ]
          settings = dict(
              cookie_secret="32oETzKXQAGaYdkL5gEmGeJJFuYh7EQnp2XdTP1o/Vo=",
              login_url="/auth/login",
          )
          tornado.web.Application.__init__(self, handlers, **settings)
  
  
  class BaseHandler(tornado.web.RequestHandler):
      def get_current_user(self):
          user_json = self.get_secure_cookie("user")
          if not user_json: return None
          return tornado.escape.json_decode(user_json)
  
  
  class MainHandler(BaseHandler):
      @tornado.web.authenticated
      def get(self):
          name = tornado.escape.xhtml_escape(self.current_user["name"])
          self.write("Hello, " + name)
  
  
  class AuthHandler(BaseHandler, tornado.auth.GoogleMixin):
      @tornado.web.asynchronous
      def get(self):
          if self.get_argument("openid.mode", None):
              self.get_authenticated_user(self.async_callback(self._on_auth))
              return
          self.authenticate_redirect()
      
      def _on_auth(self, user):
          if not user:
              raise tornado.web.HTTPError(500, "Google auth failed")
          self.set_secure_cookie("user", tornado.escape.json_encode(user))
          self.redirect("/")
  
  
  def main():
      tornado.options.parse_command_line()
      http_server = tornado.httpserver.HTTPServer(Application())
      http_server.listen(options.port)
      tornado.ioloop.IOLoop.instance().start()
  
  
  if __name__ == "__main__":
      main()
  
new_contents: #!/usr/bin/env python
  #
  # Copyright 2009 Facebook
  #
  # Licensed under the Apache License, Version 2.0 (the "License"); you may
  # not use this file except in compliance with the License. You may obtain
  # a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  # License for the specific language governing permissions and limitations
  # under the License.
  
  import tornado.auth
  import tornado.escape
  import tornado.httpserver
  import tornado.ioloop
  import tornado.options
  import tornado.web
  
  from tornado.options import define, options
  
  define("port", default=8888, help="run on the given port", type=int)
  
  
  class Application(tornado.web.Application):
      def __init__(self):
          handlers = [
              (r"/", MainHandler),
              (r"/auth/login", AuthHandler),
              (r"/auth/logout", LogoutHandler),
          ]
          settings = dict(
              cookie_secret="32oETzKXQAGaYdkL5gEmGeJJFuYh7EQnp2XdTP1o/Vo=",
              login_url="/auth/login",
          )
          tornado.web.Application.__init__(self, handlers, **settings)
  
  
  class BaseHandler(tornado.web.RequestHandler):
      def get_current_user(self):
          user_json = self.get_secure_cookie("user")
          if not user_json: return None
          return tornado.escape.json_decode(user_json)
  
  
  class MainHandler(BaseHandler):
      @tornado.web.authenticated
      def get(self):
          name = tornado.escape.xhtml_escape(self.current_user["name"])
          self.write("Hello, " + name)
          self.write("<br><br><a href=\"/auth/logout\">Log out</a>")
  
  
  class AuthHandler(BaseHandler, tornado.auth.GoogleMixin):
      @tornado.web.asynchronous
      def get(self):
          if self.get_argument("openid.mode", None):
              self.get_authenticated_user(self.async_callback(self._on_auth))
              return
          self.authenticate_redirect()
      
      def _on_auth(self, user):
          if not user:
              raise tornado.web.HTTPError(500, "Google auth failed")
          self.set_secure_cookie("user", tornado.escape.json_encode(user))
          self.redirect("/")
  
  class LogoutHandler(BaseHandler):
      def get(self):
          self.clear_cookie("user")
          self.redirect("/")
  
  def main():
      tornado.options.parse_command_line()
      http_server = tornado.httpserver.HTTPServer(Application())
      http_server.listen(options.port)
      tornado.ioloop.IOLoop.instance().start()
  
  
  if __name__ == "__main__":
      main()
  
subject: Add logout link to authdemo for testing purposes.