Make URL point to .py file in App Engine

I'm just now digging into GAE and I see two ways to make a particular URL pull up the right page.

The first way is using handlers:

handlers:
  - url: /.*
    script: helloworld.py

The other way is using the following:

application = webapp.WSGIApplication(
                                 [('/', MainPage),
                                  ('/sign', Guestbook)],
                                 debug=开发者_开发问答True)

Which is better or which is right? I don't fully understand what the second example is doing exactly.

You need to use both. The section in app.yaml tells App Engine where to look for your WSGI application. application = webapp.WSGIApplication(...) sets up your WSGI application using the webapp framework.

update:

app.yaml:

handlers:
  - url: /city.*
    script: cityhandler.py

cityhandler.py

application = webapp.WSGIApplication([('/city', ShowCityPage)],
                                     debug=True)