Dead simple broker on top of sockjs-tornado

## client.html
<!DOCTYPE html>
<html>
<body>
  <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
  <script src="http://cdn.sockjs.org/sockjs-0.3.min.js"></script>
  <script>
    $(function() {
      var conn = new SockJS('http://localhost:8080/push');

      conn.onmessage = function(e) {
        console.log('Got', e.data);
      }
    });
</script>
</body>
</html>

## INSTALL.txt
1. pip install -r reqs.pip
2. server.py
3. open client.html in browser
4. redis-cli publish push '123456'
5. check browser console

## reqs.pip
Tornado>=2.2
sockjs-tornado
toredis

## server.py
# -*- coding: utf-8 -*-
import sys
import argparse

import tornado.ioloop
import tornado.web
import sockjs.tornado
import toredis


# Our sockjs connection class.
# sockjs-tornado will create new instance for every connected client.
class BrokerConnection(sockjs.tornado.SockJSConnection):
    clients = set()

    def on_open(self, info):
        logging.info('Incoming client from %s' % info.ip)
        self.clients.add(self)

    def on_message(self, message):
        logging.debug('Received something from client: %s', message)

    def on_close(self):
        self.clients.remove(self)

    @classmethod
    def pubsub(cls, data):
        msg_type, msg_chan, msg = data
        if msg_type == 'message':
            logging.debug('Pushing: %s' % msg)
            for c in cls.clients:
                c.send(msg)


if __name__ == "__main__":
    # Logging
    import logging
    logging.getLogger().setLevel(logging.DEBUG)

    # Parse options. TODO: Use decent option parsing library.
    parser = argparse.ArgumentParser()
    parser.add_argument('--endpoint',
                        default='/push', dest='endpoint',
                        help='SockJS URL endpoint')
    parser.add_argument('--port',
                        type=int, default=8080, dest='port',
                        help='SockJS server port')
    parser.add_argument('--key',
                        default='push', dest='key',
                        help='Redis key')
    parser.add_argument('--redis_server',
                        default='localhost', dest='redis_server',
                        help='Redis host')
    parser.add_argument('--redis_port',
                        default=6379, dest='redis_port',
                        help='Redis port')
    v = parser.parse_args()

    # Initialize tornado-redis and subscribe to key
    rclient = toredis.Client()
    rclient.connect(v.redis_server, v.redis_port)
    rclient.subscribe(v.key, BrokerConnection.pubsub)

    # Initialize sockjs-tornado and start IOLoop
    BrokerRouter = sockjs.tornado.SockJSRouter(BrokerConnection, v.endpoint)

    app = tornado.web.Application(BrokerRouter.urls)
    app.listen(v.port)

    logging.info('Listening on port %d for redis key %s', v.port, v.key)

    tornado.ioloop.IOLoop.instance().start()