websocket.py

import threading
import tornado
import tornado.httpserver
import tornado.websocket

wss = []

class WSHandler(tornado.websocket.WebSocketHandler):

    def check_origin(self, origin):
        return True

    def open(self):
        print ('New connection established.')
        if self not in wss:
            wss.append(self)

    def on_message(self, message):
        print ('Received message: %s' % message)
        write_data(message)

    def on_close(self):
        print ('Connection closed.')
        if self in wss:
            wss.remove(self)
            
class Application(tornado.web.Application):
        def __init__(self):
            settings = dict(
                debug = True,
            )
            super(Application, self).__init__([ (".*", WSHandler), ], **settings)
application = Application()

def write_data(message):
    for ws in wss:
        print ("Sending: %s" % message)
        ws.write_message(message);
            
class ServerThread(threading.Thread):

    def run(self):
        print ("Starting server.")
        http_server = tornado.httpserver.HTTPServer(application)
        http_server.listen(4044)
        main_loop = tornado.ioloop.IOLoop.instance()
        main_loop.start()

    def send_data(self, message):
        write_data(message);

server_thread = ServerThread()
server_thread.start()