app.py

from flask import Flask, request
from flask_socketio import SocketIO, emit, join_room

app = Flask(__name__)
app.secret_key = 'random secret key!'
socketio = SocketIO(app, cors_allowed_origins="*")


@socketio.on('join')
def join(message):
    username = message['username']
    room = message['room']
    join_room(room)
    print('RoomEvent: {} has joined the room {}\n'.format(username, room))
    emit('ready', {username: username}, to=room, skip_sid=request.sid)


@socketio.on('data')
def transfer_data(message):
    username = message['username']
    room = message['room']
    data = message['data']
    print('DataEvent: {} has sent the data:\n {}\n'.format(username, data))
    emit('data', data, to=room, skip_sid=request.sid)


@socketio.on_error_default
def default_error_handler(e):
    print("Error: {}".format(e))
    socketio.stop()


if __name__ == '__main__':
    socketio.run(app, host="0.0.0.0", port=5004)