notebook.py

import os
import time
import json

import tornado.httpserver
import tornado.ioloop
import tornado.options
import tornado.web

from tornado.options import define, options

import zmq
from zmq.eventloop import ioloop, zmqstream
# hijack ioloop
tornado.ioloop.IOLoop = ioloop.IOLoop

ctx = zmq.Context()
sub = ctx.socket(zmq.SUB)
sub.setsockopt(zmq.SUBSCRIBE, b'')
sub.bind('tcp://*:5555')

define("port", default=8888, help="run on the given port", type=int)

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.render('notebook.html')

class SUBHandler(tornado.web.RequestHandler):
    @tornado.web.asynchronous
    def get(self):
        self.loop = self.application.loop
        self.loop.add_handler(self.application.sub, self._really_get, zmq.POLLIN)
    
    def _really_get(self, sub, evt):
        
        # fetch all available messages, there will be at least one
        msgs = []
        while True:
            try:
                msgs.append(sub.recv_multipart(zmq.NOBLOCK))
            except zmq.ZMQError as e:
                if e.errno != zmq.EAGAIN:
                    raise e
                else:
                    break
        # unregister callback
        self.loop.remove_handler(sub)
        # write reply and finish
        self.write(json.dumps(msgs))
        self.finish()

class NotebookApplication(tornado.web.Application):
    def __init__(self, sub, loop):
        self.sub=sub
        self.loop = loop
        handlers = [
            (r"/", MainHandler),
            (r"/sub", SUBHandler)
        ]
        settings = dict(
            template_path=os.path.join(os.path.dirname(__file__), "templates"),
            static_path=os.path.join(os.path.dirname(__file__), "static"),
        )
        tornado.web.Application.__init__(self, handlers, **settings)


def main():
    tornado.options.parse_command_line()
    loop = tornado.ioloop.IOLoop.instance()
    application = NotebookApplication(sub, loop)
    http_server = tornado.httpserver.HTTPServer(application)
    http_server.listen(options.port)
    print loop
    loop.start()


if __name__ == "__main__":
    main()