gevent-websocket.py

#!/usr/bin/env python
"""
Websocket Gevent Webserver
"""

__copyright__ = """
Copyright (C) by Wilco Baan Hofman <wilco@baanhofman.nl> 2013

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""

from gevent import monkey
monkey.patch_all()
from videoconference.wsgi import application
import simplejson as json

from gevent import pywsgi
from geventwebsocket.handler import WebSocketHandler

from websockets.websockethandler import Handler
from websockets.sockets import WebSockets
from scheduler.models import MCU, Reservation


from django.contrib.sessions.backends.db import SessionStore
from django.contrib.auth.models import User
from importlib import import_module
from django.http import parse_cookie
from django.contrib.sessions.models import Session
from django.utils import timezone
from copy import copy

import socket

from geventwebsocket.python_fixes import makefile
import uwsgi


class WSGIMiddlewareHandler(WebSocketHandler):
    def __init__(self, environ, start_response, application):
        self.environ = environ
        self.socket = socket.fromfd(uwsgi.connection_fd(), socket.AF_INET, socket.SOCK_STREAM)
        self.rfile = makefile(self.socket)
        self.application = application
        self.start_response = start_response
        self.request_version = environ['SERVER_PROTOCOL']

    def log_request(self):
        pass


def ws_middleware(wrapped_app):
    def application(environ, start_response):
        handler = WSGIMiddlewareHandler(environ, start_response, wrapped_app)
        upgrade = environ.get('HTTP_UPGRADE', '').lower()
        if upgrade == 'websocket':
            connection = environ.get('HTTP_CONNECTION', '').lower()
            if 'upgrade' in connection:
                return handler._handle_websocket()
        return wrapped_app(environ, start_response)
    return application



global_sockets = WebSockets()

def websocket_app(environ, start_response):
    if not 'wsgi.websocket' in environ:
        print "Not a websocket"
        return
    ws = environ["wsgi.websocket"]
    print ws

    # Important to call, otherwise we may get stale user sessions
    SessionStore.clear_expired() 

    # Get the session object and implicitly check if the session is valid
    cookie = parse_cookie(environ['HTTP_COOKIE'])
    if not 'sessionid' in cookie:
        print "No session cookie"
        return

    s = SessionStore(session_key=cookie['sessionid'])
    if not '_auth_user_id' in s:
        print "Invalid session"
        return

    user = User.objects.get(pk=s['_auth_user_id'])
    if not user:
        print "Invalid user"
        return

    path = environ['PATH_INFO'].split('/')
    if len(path) < 3 or path[1] != 'websocket' or path[2] != 'conference' or not path[3].isdigit():
        print "Invalid path"
        return

    conference_id = int(path[3])

    conference = Reservation.objects.get(pk=conference_id)
    if conference.user != user:
        print "User not owner of this conference"
        return

    #if conference.end_time < timezone.now() or conference.begin_time > timezone.now():
    #    print "Conference not currently in progress"
    #    return

    # FIXME Hardcoded
    backend_info = {
        'mcu': '127.0.0.1',
        'room': 'room101',
    }

    socket_info = copy(global_sockets)
    socket_info.subscribe(ws, conference)

    interface = Handler(backend_info=backend_info, conference=conference, sockets=socket_info)

    while True:
        try:
            data = ws.receive()
            if data is None:
                socket_info.close(socket_info.local)
                return

            try:
                message = json.loads(data)
            except Exception as e:
                print repr(e), data
                return


            handlers = {
                    'LIST_MOSAIC':           'list_mosaic',
                    'LIST_PARTICIPANTS':     'list_participants',
                    'MOVE_PARTICIPANT':      'move_participant',
                    'REMOVE_PARTICIPANT':    'remove_participant',
                    'OFFER_SDP':             'offer_sdp',
                    'SDP_OK':                'sdp_ok',
            }

            if not 'message_type' in message:
                print "Message has no message type"
                return
            if not message['message_type'] in handlers:
                print "No handler for message type", message['message_type']
                return

            print message['message_type'], "received"

            # Find and call the method in the MCUInterface class instance
            func = getattr(interface, handlers[message['message_type']])
            func(message['data'])

        except:
            socket_info.close(socket_info.local)
            ws.close()
            raise

if __name__ == "__main__":
    server = pywsgi.WSGIServer(("", 8000), websocket_app, handler_class=WebSocketHandler)
    server.serve_forever()
else:
    application = ws_middleware(websocket_app)