gistfile1.py

class CometConnections(tornado.web.RequestHandler):
	connections = set({})

	@tornado.web.asynchronous
	def get(self):
		CometConnections.connections.add(self)

	def tell(self, js):
		if self in CometConnections.connections:
			CometConnections.connections.remove(self)
		self.write(js)
		self.finish()

	@staticmethod
	def tellall(js):
		copy = set(CometConnections.connections)
		for connection in copy:
			try:
				connection.tell(js)
			except IOError:
				if connection in CometConnections.connections:
					CometConnections.connections.remove(connection)

clientside = """
     <script type="text/javascript"      src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
     <script type="text/javascript">
     function waitForMsg() {
     // Simple long polling
     $.ajax({
      type: "GET", url: "/comet", async: true, cache: false, timeout: 50000,
      success: function(data) { eval(data); waitForMsg(); },
      error: function(XMLHttpRequest, textStatus, errorThrown) { if(textStatus != 'error') waitForMsg();      }
     });
     };
     waitForMsg();
     </script>""""

class MainHandler(tornado.web.RequestHandler):
	def get(self):
             self.write(clientside + whateverelsecode)

class IRCBot(threading.Thread):
    def run(self):
         while(1):
              # irc bot stuff
              CometConnections.tellall("$('iframe')[0].src = " + youtube_url)

application = tornado.web.Application([
	(r"/", MainHandler),
	(r"/comet", CometConnections),
])

if __name__ == "__main__":
	irc = IRCBot()
	irc.start()

	http_server = tornado.httpserver.HTTPServer(application)
	http_server.listen(8888)
	tn = tornado.ioloop.IOLoop.instance()
	try:
		tn.start()
	except KeyboardInterrupt:
		irc.running = False