探究Python的Tornado框架对子域名和泛域名的支持

class Application(tornado.web.Application):
  def __init__(self):
    handlers = [
      (r"/", MainHandler),
      (r"/auth/login", AuthLoginHandler),
      (r"/auth/logout", AuthLogoutHandler),
      (r"/a/message/new", MessageNewHandler),
      (r"/a/message/updates", MessageUpdatesHandler),
    ]
    settings = dict(
      cookie_secret="43oETzKXQAGaYdkL5gEmGeJJFuYh7EQnp2XdTP1o/Vo=",
      login_url="/auth/login",
      template_path=os.path.join(os.path.dirname(__file__), "templates"),
      static_path=os.path.join(os.path.dirname(__file__), "static"),
      xsrf_cookies=True,
      autoescape="xhtml_escape",
    )
    tornado.web.Application.__init__(self, handlers, **settings)

  def add_handlers(self, host_pattern, host_handlers):
    """Appends the given handlers to our handler list.
 
    Note that host patterns are processed sequentially in the
    order they were added, and only the first matching pattern is
    used. This means that all handlers for a given host must be
    added in a single add_handlers call.
    """

 super(Application, self).__init__(handlers, **settings)
 
  # add handlers for sub domains
  for sub_handler in sub_handlers:
    # host pattern and handlers
    self.add_handlers(sub_handler[0], sub_handler[1])

sub_handlers.append(site.sub_handlers)
sub_handlers.append(blog.sub_handlers)
sub_handlers.append(admin.sub_handlers)
# wildcard subdomain handler for project should be the last one.
sub_handlers.append(project.sub_handlers)

sub_handlers = ["^sites.poweredsites.org$",
        [
         (r"/", _WebsiteIndexHandler),
         (r"/feeds", _WebsitesFeedsHandler),
         (r"/([a-z0-9]{32})", _WebsiteHandler),
         (r"/([^/]+)", WebsiteHandler),
         ]
        ]

sub_handlers = ["^[a-zA-Z_\-0-9]*\.poweredsites.org$",
        [(r"/", ProjectIndexHandler),
         (r"/top", ProjectTopHandler),
         (r"/opensource", ProjectOpensourceHandler),
         ]
        ]

class ProjectIndexHandler(ProjectBaseHandler):
  def get(self):
    subdomain = self.request.host.split(".")[0]