web_server.py

import os
import sys
from datetime import datetime

import tornado.httpserver
import tornado.ioloop
import tornado.web
import tornado.websocket
import tornado.gen

from multiprocessing.connection import Client

AUDIO_SERVER_ADDRESS = ('localhost', 6000)
WEB_SERVER_ADDRESS = ('0.0.0.0', 8090)

# The highest (practical) volume for the microphone, which is used to normalize the signal
#  This depends on: microphone sensitivity, distance to crib, amount of smoothing
UPPER_LIMIT = 7000

# After the signal has been normalized to the range [0, 1], volumes higher than this will be
#  classified as noise.
# Vary based on: background noise, how loud the baby is, etc.
NOISE_THRESHOLD = 0.25

# seconds of quiet before transition mode from "noise" to "quiet"
MIN_QUIET_TIME = 30

# seconds of noise before transition mode from "quiet" to "noise"
MIN_NOISE_TIME = 5

class IndexHandler(tornado.web.RequestHandler):
    def get(self):
        self.render('index.html')

clients = []

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

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


def broadcast_mic_data():
    # get the latest data from the audio server
    parameters = {"upper_limit": UPPER_LIMIT,
                  "noise_threshold": NOISE_THRESHOLD,
                  "min_quiet_time": MIN_QUIET_TIME,
                  "min_noise_time": MIN_NOISE_TIME}

    try:
        conn = Client(AUDIO_SERVER_ADDRESS)
    except ConnectionRefusedError as e:
        print("No connection to audio server: {}".format(e))
        sys.exit(1)
        
    conn.send(parameters)
    results = conn.recv()
    conn.close()

    # send results to all clients
    now = datetime.now()
    results['date_current'] = '{dt:%A} {dt:%B} {dt.day}, {dt.year}'.format(dt=now)
    results['time_current'] = now.strftime("%H:%M:%S").lstrip('0')
    results['audio_plot'] = results['audio_plot'].tolist()
    for c in clients:
        c.write_message(results)


def main():
    settings = {
        "static_path": os.path.join(os.path.dirname(__file__), "static"),
    }
    app = tornado.web.Application(
        handlers=[
            (r"/", IndexHandler),
            (r"/ws", WebSocketHandler),
        ], **settings
    )
    http_server = tornado.httpserver.HTTPServer(app)
    http_server.listen(WEB_SERVER_ADDRESS[1], WEB_SERVER_ADDRESS[0])
    print('Listening on port: {}'.format(WEB_SERVER_ADDRESS[1]))
 
    main_loop = tornado.ioloop.IOLoop.instance()
    scheduler = tornado.ioloop.PeriodicCallback(broadcast_mic_data, 1000) #, io_loop=main_loop)
    scheduler.start()
    main_loop.start()
 
if __name__ == "__main__":
    main()