audio_monitor.py

#!/usr/bin/env python

import sys

from flask import Flask, render_template
from flask.json import jsonify
from flask_socketio import SocketIO

from devices import DeviceMonitor, AudioLevelMonitor

import gi
import gi.repository

gi.require_version('Gst', '1.0')
from gi.repository import Gst, GLib, GObject    # noqa

GObject.threads_init()
Gst.init(sys.argv)


app = Flask(__name__)
app.config['SECRET_KEY'] = 'secret!'
socketio = SocketIO(app)

device_monitor = DeviceMonitor()


@app.route('/')
def index():
    return render_template('index.html')


@app.route('/devices')
def devices():
    return jsonify(device_monitor.get_devices())


def yield_to_socketio(*args, **kwargs):
    socketio.sleep(0.01)
    return True


def glib_loop(*args, **kwargs):
    loop = GLib.MainLoop.new(None, False)
    GLib.idle_add(yield_to_socketio)
    return loop.run()


if __name__ == '__main__':
    import signal
    signal.signal(signal.SIGINT, signal.SIG_DFL)

    audio_monitors = []
    audio_monitors_map = {}

    glib_task = socketio.start_background_task(target=glib_loop)

    def on_device_added(monitor, device):
        audio_monitor = AudioLevelMonitor(device=device)
        audio_monitors.append(audio_monitor)
        audio_monitors_map[device.internal_name] = audio_monitor
        audio_monitor.connect('level', on_level)

        socketio.emit('device-added', {
            'display_name':  device.display_name,
            'internal_name': device.internal_name,
        }, broadcast=True)

    def on_device_removed(monitor, device):
        socketio.emit('device-removed', {
            'display_name':  device.display_name,
            'internal_name': device.internal_name,
        }, broadcast=True)

        audio_monitor = audio_monitors_map.get(device.internal_name, None)
        if audio_monitor:
            del audio_monitors_map[device.internal_name]
            audio_monitor.stop()
            audio_monitor.disconnect_by_func(on_level)

    def on_level(audio_monitor, payload):
        socketio.emit('level', payload)

    for device in device_monitor.get_devices():
        audio_monitor = AudioLevelMonitor(device=device)
        audio_monitors.append(audio_monitor)
        audio_monitor.connect('level', on_level)

    device_monitor.connect('device-added',   on_device_added)
    device_monitor.connect('device-removed', on_device_removed)
    device_monitor.start()

    socketio.run(app)