server.py

import json
import queue

import tornado.httpserver
import tornado.ioloop
import tornado.web
import tornado.websocket
from tornado.options import define, options

import serialporttask

define("port", default=8080, help="port to listen on", type=int)

clients = []

serialport = None

input_queue = queue.Queue()
output_queue = queue.Queue()


class IndexHandler(tornado.web.RequestHandler):
 def get(self):
 self.render("./public/index.html")


class WebSocketHandler(tornado.websocket.WebSocketHandler):
 def open(self):
 print("connection opened")
 clients.append(self)

 def on_message(self, message):
 data = json.loads(message)
 msg = serialport.command(data)
 if msg:
 self.write_message(msg)
 else:
 input_queue.put(data['args']['data'])

 def on_close(self):
 print("connection closed")
 clients.remove(self)


# check the queue for pending messages to all connected clients
def checkQueue():
 if not output_queue.empty():
 message = output_queue.get()
 for c in clients:
 c.write_message(message)


if __name__ == "__main__":
 # start the serial port task in background (as a deamon)
 serialport = serialporttask.SerialPortThread(input_queue, output_queue)
 serialport.daemon = True
 serialport.start()

 tornado.options.parse_command_line()

 app = tornado.web.Application(
 handlers=[
 (r"/", IndexHandler),
 (r"/static/(.*)", tornado.web.StaticFileHandler, {"path": "./public/"}),
 (r"/ws", WebSocketHandler)
 ]
 )

 httpServer = tornado.httpserver.HTTPServer(app)
 httpServer.listen(options.port)
 print("Listening on port:", options.port)

 mainLoop = tornado.ioloop.IOLoop.instance()
 # adjust the scheduler_interval according to the frames sent by the serial port
 scheduler_interval = 100
 scheduler = tornado.ioloop.PeriodicCallback(checkQueue, scheduler_interval)
 scheduler.start()
 mainLoop.start()