diff --git a/sylk/applications/conference/room.py b/sylk/applications/conference/room.py index c4e3f94..7bbc8e7 100644 --- a/sylk/applications/conference/room.py +++ b/sylk/applications/conference/room.py @@ -1,652 +1,652 @@ # Copyright (C) 2010-2011 AG Projects. See LICENSE for details. # import random from datetime import datetime from glob import glob from itertools import cycle from time import mktime from application import log from application.notification import IObserver, NotificationCenter from application.python.util import Null, Singleton from eventlet import coros, proc from sipsimple.application import SIPApplication from sipsimple.audio import WavePlayer, WavePlayerError from sipsimple.conference import AudioConference from sipsimple.configuration.settings import SIPSimpleSettings from sipsimple.core import FromHeader, ToHeader, RouteHeader, SIPURI, Message, SIPCoreInvalidStateError from sipsimple.lookup import DNSLookup, DNSLookupError from sipsimple.payloads.conference import Conference, ConferenceDescription, ConferenceState, Endpoint, EndpointStatus, HostInfo, JoiningInfo, Media, User, Users, WebPage from sipsimple.payloads.iscomposing import IsComposingMessage, State, LastActive, Refresh, ContentType from sipsimple.streams.applications.chat import CPIMIdentity, CPIMMessage, CPIMParserError from sipsimple.streams.msrp import ChatStreamError from sipsimple.threading import run_in_twisted_thread from sipsimple.threading.green import run_in_green_thread from sipsimple.util import Timestamp from twisted.internet import reactor from zope.interface import implements from sylk.applications.conference import database from sylk.applications.conference.configuration import ConferenceConfig from sylk.configuration.datatypes import ResourcePath def format_identity(identity, cpim_format=False): uri = identity.uri if identity.display_name: return '%s ' % (identity.display_name, uri.user, uri.host) elif cpim_format: return '' % (uri.user, uri.host) else: return 'sip:%s@%s' % (uri.user, uri.host) def format_stream_types(streams): if not streams: return '' if len(streams) == 1: txt = 'with %s' % streams[0].type else: txt = 'with %s' % ','.join(stream.type for stream in streams[:-1]) txt += ' and %s' % streams[-1:][0].type return txt def format_conference_stream_type(stream): if stream.type == 'chat': return 'message' return stream.type def format_identity_with_stream_types(identity, streams): return '%s %s' % (format_identity(identity), format_stream_types(streams)) def format_session_duration(session): if session.start_time: duration = session.end_time - session.start_time seconds = duration.seconds if duration.microseconds < 500000 else duration.seconds+1 minutes, seconds = seconds / 60, seconds % 60 hours, minutes = minutes / 60, minutes % 60 hours += duration.days*24 if not minutes and not hours: duration_text = '%d seconds' % seconds elif not hours: duration_text = '%02d:%02d' % (minutes, seconds) else: duration_text = '%02d:%02d:%02d' % (hours, minutes, seconds) else: duration_text = '0s' return duration_text def chunks(text, size): for i in xrange(0, len(text), size): yield text[i:i+size] class SIPMessage(object): def __init__(self, sender, recipient, content_type, body): self.sender = sender self.recipient = recipient self.content_type = content_type self.body = body self.timestamp = None class Room(object): """ Object representing a conference room, it will handle the message dispatching among all the participants. """ __metaclass__ = Singleton implements(IObserver) def __init__(self, uri): self.uri = uri self.identity = CPIMIdentity.parse('<%s>' % self.uri) self.sessions = [] self.sessions_with_proposals = [] self.subscriptions = [] self.state = 'stopped' self.incoming_message_queue = coros.queue() self.message_dispatcher = None self.audio_conference = None self.moh_player = None self.conference_info_payload = None @classmethod def get_room(cls, uri): room_uri = '%s@%s' % (uri.user, uri.host) room = cls(room_uri) return room @property def empty(self): return len(self.sessions) == 0 @property def started(self): return self.state == 'started' def start(self): if self.state != 'stopped': return self.message_dispatcher = proc.spawn(self._message_dispatcher) self.audio_conference = AudioConference() self.audio_conference.hold() self.moh_player = MoHPlayer(self.audio_conference) self.moh_player.initialize() self.state = 'started' def stop(self): if self.state != 'started': return self.state = 'stopped' self.message_dispatcher.kill(proc.ProcExit) self.moh_player = None self.audio_conference = None def _message_dispatcher(self): """Read from self.incoming_message_queue and dispatch the messages to other participants""" while True: session, message_type, data = self.incoming_message_queue.wait() if message_type == 'message': if data.timestamp is not None and isinstance(data.timestamp, Timestamp): timestamp = datetime.fromtimestamp(mktime(data.timestamp.timetuple())) else: timestamp = datetime.now() if data.sender.uri != session.remote_identity.uri: return recipient = data.recipients[0] database.async_save_message(format_identity(session.remote_identity, True), self.uri, data.body, data.content_type, unicode(data.sender), unicode(recipient), timestamp) if recipient.uri == self.identity.uri: self.dispatch_message(session, data) else: self.dispatch_private_message(session, data) elif message_type == 'sip_message': database.async_save_message(format_identity(session.remote_identity, True), self.uri, data.body, data.content_type, unicode(data.sender), data.recipient, data.timestamp) self.dispatch_message(session, data) elif message_type == 'composing_indication': if data.sender.uri != session.remote_identity.uri: return recipient = data.recipients[0] if recipient.uri == self.identity.uri: self.dispatch_iscomposing(session, data) else: self.dispatch_private_iscomposing(session, data) def dispatch_message(self, session, message): for s in (s for s in self.sessions if s is not session): try: identity = CPIMIdentity.parse(format_identity(session.remote_identity, True)) chat_stream = (stream for stream in s.streams if stream.type == 'chat').next() chat_stream.send_message(message.body, message.content_type, local_identity=identity, recipients=[self.identity], timestamp=message.timestamp) except ChatStreamError, e: log.error('Error dispatching message to %s: %s' % (s.remote_identity.uri, e)) except StopIteration: # This session doesn't have a chat stream, send him a SIP MESSAGE if ConferenceConfig.enable_sip_message: self.send_sip_message(session.remote_identity.uri, s.remote_identity.uri, message.content_type, message.body) def dispatch_private_message(self, session, message): # Private messages are delivered to all sessions matching the recipient but also to the sender, # for replication in clients recipient = message.recipients[0] for s in (s for s in self.sessions if s is not session and s.remote_identity.uri in (recipient.uri, session.remote_identity.uri)): try: identity = CPIMIdentity.parse(format_identity(session.remote_identity, True)) chat_stream = (stream for stream in s.streams if stream.type == 'chat').next() chat_stream.send_message(message.body, message.content_type, local_identity=identity, recipients=[recipient], timestamp=message.timestamp) except ChatStreamError, e: log.error('Error dispatching private message to %s: %s' % (s.remote_identity.uri, e)) def dispatch_iscomposing(self, session, data): for s in (s for s in self.sessions if s is not session): try: identity = CPIMIdentity.parse(format_identity(session.remote_identity, True)) chat_stream = (stream for stream in s.streams if stream.type == 'chat').next() - chat_stream.send_composing_indication(data.state, data.refresh, data.last_active, local_identity=identity, recipients=[self.identity]) + chat_stream.send_composing_indication(data.state, data.refresh, local_identity=identity, recipients=[self.identity]) except ChatStreamError, e: log.error('Error dispatching composing indication to %s: %s' % (s.remote_identity.uri, e)) except StopIteration: # This session doesn't have a chat stream, send him a SIP MESSAGE if ConferenceConfig.enable_sip_message: body = IsComposingMessage(state=State(data.state), refresh=Refresh(data.refresh), last_active=LastActive(data.last_active or datetime.now()), content_type=ContentType('text')).toxml() self.send_sip_message(session.remote_identity.uri, s.remote_identity.uri, IsComposingMessage.content_type, body) def dispatch_private_iscomposing(self, session, data): recipient_uri = data.recipients[0].uri for s in (s for s in self.sessions if s is not session and s.remote_identity.uri == recipient_uri): try: identity = CPIMIdentity.parse(format_identity(session.remote_identity, True)) chat_stream = (stream for stream in s.streams if stream.type == 'chat').next() - chat_stream.send_composing_indication(data.state, data.refresh, data.last_active, local_identity=identity) + chat_stream.send_composing_indication(data.state, data.refresh, local_identity=identity) except ChatStreamError, e: log.error('Error dispatching private composing indication to %s: %s' % (s.remote_identity.uri, e)) def dispatch_server_message(self, body, content_type='text/plain', exclude=None): for session in (session for session in self.sessions if session is not exclude): try: chat_stream = (stream for stream in session.streams if stream.type == 'chat').next() chat_stream.send_message(body, content_type, local_identity=self.identity, recipients=[self.identity]) except StopIteration: # This session doesn't have a chat stream, send him a SIP MESSAGE if ConferenceConfig.enable_sip_message: self.send_sip_message(self.identity.uri, session.remote_identity.uri, content_type, body) self_identity = format_identity(self.identity, cpim_format=True) database.async_save_message(self_identity, self.uri, body, content_type, self_identity, self_identity, datetime.now()) def dispatch_conference_info(self): data = self.build_conference_info_payload() for subscription in (subscription for subscription in self.subscriptions if subscription.state == 'active'): try: subscription.push_content(Conference.content_type, data) except SIPCoreInvalidStateError: pass @run_in_green_thread def send_sip_message(self, from_uri, to_uri, content_type, body): lookup = DNSLookup() settings = SIPSimpleSettings() try: routes = lookup.lookup_sip_proxy(to_uri, settings.sip.transport_list).wait() except DNSLookupError: log.warning('DNS lookup error while looking for %s proxy' % to_uri) else: route = routes.pop(0) from_header = FromHeader(self.identity.uri) to_header = ToHeader(SIPURI.new(to_uri)) route_header = RouteHeader(route.get_uri()) sender = CPIMIdentity(from_uri) for chunk in chunks(body, 1000): msg = CPIMMessage(chunk, content_type, sender=sender, recipients=[self.identity]) message_request = Message(from_header, to_header, route_header, 'message/cpim', str(msg)) message_request.send() def render_text_welcome(self, session): txt = 'Welcome to the conference.' user_count = len(set(str(s.remote_identity.uri) for s in self.sessions) - set([str(session.remote_identity.uri)])) if user_count == 0: txt += ' You are the first participant in the room.' else: if user_count == 1: txt += ' There is one more participant in the room.' else: txt += ' There are %s more participants in the room.' % user_count return txt def _play_file_in_player(self, player, file, delay): player.filename = str(file) player.pause_time = delay try: player.play().wait() except WavePlayerError, e: log.warning("Error playing file %s: %s" % (file, e)) @run_in_green_thread def play_audio_welcome(self, session, play_welcome=True): audio_stream = (stream for stream in session.streams if stream.type == 'audio').next() player = WavePlayer(audio_stream.mixer, '', pause_time=1, initial_play=False, volume=50) audio_stream.bridge.add(player) if play_welcome: file = ResourcePath('sounds/co_welcome_conference.wav').normalized self._play_file_in_player(player, file, 1) user_count = len(set(str(s.remote_identity.uri) for s in self.sessions if any(stream for stream in s.streams if stream.type == 'audio')) - set([str(session.remote_identity.uri)])) if user_count == 0: file = ResourcePath('sounds/co_only_one.wav').normalized self._play_file_in_player(player, file, 0.5) elif user_count == 1: file = ResourcePath('sounds/co_there_is.wav').normalized self._play_file_in_player(player, file, 0.5) elif user_count < 100: file = ResourcePath('sounds/co_there_are.wav').normalized self._play_file_in_player(player, file, 0.2) if user_count <= 24: file = ResourcePath('sounds/bi_%d.wav' % user_count).normalized self._play_file_in_player(player, file, 0.1) else: file = ResourcePath('sounds/bi_%d0.wav' % (user_count / 10)).normalized self._play_file_in_player(player, file, 0.1) file = ResourcePath('sounds/bi_%d.wav' % (user_count % 10)).normalized self._play_file_in_player(player, file, 0.1) file = ResourcePath('sounds/co_more_participants.wav').normalized self._play_file_in_player(player, file, 0) audio_stream.bridge.remove(player) self.audio_conference.add(audio_stream) self.audio_conference.unhold() if len(self.audio_conference.streams) == 1: # Play MoH self.moh_player.play() else: self.moh_player.pause() def add_session(self, session): notification_center = NotificationCenter() notification_center.add_observer(self, sender=session) self.sessions.append(session) try: chat_stream = (stream for stream in session.streams if stream.type == 'chat').next() except StopIteration: pass else: notification_center.add_observer(self, sender=chat_stream) remote_identity = CPIMIdentity.parse(format_identity(session.remote_identity, cpim_format=True)) # getting last messages may take time, so new messages can arrive before messages the last message from history for msg in database.get_last_messages(self.uri, ConferenceConfig.replay_history): recipient = CPIMIdentity.parse(msg.cpim_recipient) sender = CPIMIdentity.parse(msg.cpim_sender) if recipient.uri in (self.identity.uri, remote_identity.uri) or sender.uri == remote_identity.uri: chat_stream.send_message(msg.cpim_body, msg.cpim_content_type, local_identity=sender, recipients=[recipient], timestamp=msg.cpim_timestamp) try: audio_stream = (stream for stream in session.streams if stream.type == 'audio').next() except StopIteration: pass else: notification_center.add_observer(self, sender=audio_stream) log.msg('Audio stream using %s/%sHz (%s), end-points: %s:%d <-> %s:%d' % (audio_stream.codec, audio_stream.sample_rate, 'encrypted' if audio_stream.srtp_active else 'unencrypted', audio_stream.local_rtp_address, audio_stream.local_rtp_port, audio_stream.remote_rtp_address, audio_stream.remote_rtp_port)) self.play_audio_welcome(session) self.dispatch_conference_info() if len(self.sessions) == 1: log.msg('%s started conference %s %s' % (format_identity(session.remote_identity), self.uri, format_stream_types(session.streams))) else: log.msg('%s joined conference %s %s' % (format_identity(session.remote_identity), self.uri, format_stream_types(session.streams))) if str(session.remote_identity.uri) not in set(str(s.remote_identity.uri) for s in self.sessions if s is not session): self.dispatch_server_message('%s has joined the room %s' % (format_identity(session.remote_identity), format_stream_types(session.streams)), exclude=session) def remove_session(self, session): notification_center = NotificationCenter() try: chat_stream = (stream for stream in session.streams or [] if stream.type == 'chat').next() except StopIteration: pass else: notification_center.remove_observer(self, sender=chat_stream) try: audio_stream = (stream for stream in session.streams or [] if stream.type == 'audio').next() except StopIteration: pass else: notification_center.remove_observer(self, sender=audio_stream) try: self.audio_conference.remove(audio_stream) except ValueError: # User may hangup before getting bridged into the conference pass if len(self.audio_conference.streams) == 0: self.moh_player.pause() self.audio_conference.hold() elif len(self.audio_conference.streams) == 1: self.moh_player.play() notification_center.remove_observer(self, sender=session) self.sessions.remove(session) self.dispatch_conference_info() log.msg('%s left conference %s after %s' % (format_identity(session.remote_identity), self.uri, format_session_duration(session))) if not self.sessions: log.msg('Last participant left conference %s' % self.uri) if str(session.remote_identity.uri) not in set(str(s.remote_identity.uri) for s in self.sessions if s is not session): self.dispatch_server_message('%s has left the room after %s' % (format_identity(session.remote_identity), format_session_duration(session))) def handle_incoming_sip_message(self, message_request, data): content_type = data.headers.get('Content-Type', Null)[0] from_header = data.headers.get('From', Null) if content_type is Null or from_header is Null: message_request.answer(400) return try: # Take the first session which doesn't have a chat stream. This is needed because the # seession picked up here will later be ignored. It doesn't matter if we ignore a session # without a chat stream, because that means we will send SIP MESSAGE, and it will fork, so # everyone will get it. session = (session for session in self.sessions if str(session.remote_identity.uri) == str(from_header.uri) and any(stream for stream in session.streams if stream.type != 'chat')).next() except StopIteration: # MESSAGE from a user which is not in this room message_request.answer(503) return if content_type == 'message/cpim': try: message = CPIMMessage.parse(data.body) except CPIMParserError: message_request.answer(500) return else: body = message.body content_type = message.content_type sender = message.sender or format_identity(from_header, cpim_format=True) if message.timestamp is not None and isinstance(message.timestamp, Timestamp): timestamp = datetime.fromtimestamp(mktime(message.timestamp.timetuple())) else: timestamp = datetime.now() else: body = data.body sender = format_identity(from_header, cpim_format=True) timestamp = datetime.now() message_request.answer(200) if content_type == IsComposingMessage.content_type: return log.msg('New incoming MESSAGE from %s' % session.remote_identity.uri) self_identity = format_identity(self.identity, cpim_format=True) message = SIPMessage(sender=sender, recipient=self_identity, content_type=content_type, body=body) message.timestamp = timestamp self.incoming_message_queue.send((session, 'sip_message', message)) def build_conference_info_payload(self): if self.conference_info_payload is None: settings = SIPSimpleSettings() conference_description = ConferenceDescription(display_text='Ad-hoc conference', free_text='Hosted by %s' % settings.user_agent) host_info = HostInfo(web_page=WebPage('http://sylkserver.com')) self.conference_info_payload = Conference(self.identity.uri, conference_description=conference_description, host_info=host_info, users=Users()) user_count = len(set(str(s.remote_identity.uri) for s in self.sessions)) self.conference_info_payload.conference_state = ConferenceState(user_count=user_count, active=True) users = Users() for session in self.sessions: try: user = (user for user in users if user.entity == str(session.remote_identity.uri)).next() except StopIteration: user = User(str(session.remote_identity.uri), display_text=session.remote_identity.display_name) users.append(user) joining_info = JoiningInfo(when=session.start_time) holdable_streams = [stream for stream in session.streams if stream.hold_supported] session_on_hold = holdable_streams and all(stream.on_hold_by_remote for stream in holdable_streams) hold_status = EndpointStatus('on-hold' if session_on_hold else 'connected') endpoint = Endpoint(str(session._invitation.remote_contact_header.uri), display_text=session.remote_identity.display_name, joining_info=joining_info, status=hold_status) for stream in session.streams: endpoint.append(Media(id(stream), media_type=format_conference_stream_type(stream))) user.append(endpoint) self.conference_info_payload.users = users return self.conference_info_payload.toxml() def handle_incoming_subscription(self, subscribe_request, data): content = self.build_conference_info_payload() notification_center = NotificationCenter() notification_center.add_observer(self, sender=subscribe_request) subscribe_request.accept(Conference.content_type, content) self.subscriptions.append(subscribe_request) def accept_proposal(self, session, streams): if session in self.sessions_with_proposals: session.accept_proposal(streams) self.sessions_with_proposals.remove(session) @run_in_twisted_thread def handle_notification(self, notification): handler = getattr(self, '_NH_%s' % notification.name, Null) handler(notification) def _NH_AudioStreamDidTimeout(self, notification): stream = notification.sender session = stream._session log.msg('Audio stream for session %s timed out' % format_identity(session.remote_identity)) if session.streams == [stream]: session.end() def _NH_ChatStreamGotMessage(self, notification): data = notification.data.message session = notification.sender.session self.incoming_message_queue.send((session, 'message', data)) def _NH_ChatStreamGotComposingIndication(self, notification): data = notification.data session = notification.sender.session self.incoming_message_queue.send((session, 'composing_indication', data)) def _NH_SIPIncomingSubscriptionDidEnd(self, notification): subscription = notification.sender notification_center = NotificationCenter() notification_center.remove_observer(self, sender=subscription) self.subscriptions.remove(subscription) def _NH_SIPSessionDidChangeHoldState(self, notification): session = notification.sender if notification.data.originator == 'remote': if notification.data.on_hold: log.msg('%s has put the audio session on hold' % format_identity(session.remote_identity)) else: log.msg('%s has taken the audio session out of hold' % format_identity(session.remote_identity)) self.dispatch_conference_info() def _NH_SIPSessionGotProposal(self, notification): session = notification.sender audio_streams = [stream for stream in notification.data.streams if stream.type=='audio'] chat_streams = [stream for stream in notification.data.streams if stream.type=='chat'] if not audio_streams and not chat_streams: session.reject_proposal() return streams = [streams[0] for streams in (audio_streams, chat_streams) if streams] self.sessions_with_proposals.append(session) reactor.callLater(4, self.accept_proposal, session, streams) def _NH_SIPSessionGotRejectProposal(self, notification): session = notification.sender self.sessions_with_proposals.remove(session) def _NH_SIPSessionDidRenegotiateStreams(self, notification): notification_center = NotificationCenter() session = notification.sender streams = notification.data.streams if notification.data.action == 'add': try: chat_stream = (stream for stream in streams if stream.type == 'chat').next() except StopIteration: pass else: notification_center.add_observer(self, sender=chat_stream) remote_identity = CPIMIdentity.parse(format_identity(session.remote_identity, cpim_format=True)) # getting last messages may take time, so new messages can arrive before messages the last message from history for msg in database.get_last_messages(self.uri, ConferenceConfig.replay_history): recipient = CPIMIdentity.parse(msg.cpim_recipient) sender = CPIMIdentity.parse(msg.cpim_sender) if recipient.uri in (self.identity.uri, remote_identity.uri) or sender.uri == remote_identity.uri: chat_stream.send_message(msg.cpim_body, msg.cpim_content_type, local_identity=sender, recipients=[recipient], timestamp=msg.cpim_timestamp) log.msg('%s has added chat to %s' % (format_identity(session.remote_identity), self.uri)) self.dispatch_server_message('%s has added chat' % format_identity(session.remote_identity), exclude=session) try: audio_stream = (stream for stream in streams if stream.type == 'audio').next() except StopIteration: pass else: notification_center.add_observer(self, sender=audio_stream) log.msg('Audio stream using %s/%sHz (%s), end-points: %s:%d <-> %s:%d' % (audio_stream.codec, audio_stream.sample_rate, 'encrypted' if audio_stream.srtp_active else 'unencrypted', audio_stream.local_rtp_address, audio_stream.local_rtp_port, audio_stream.remote_rtp_address, audio_stream.remote_rtp_port)) log.msg('%s has added audio to %s' % (format_identity(session.remote_identity), self.uri)) self.dispatch_server_message('%s has added audio' % format_identity(session.remote_identity), exclude=session) self.play_audio_welcome(session, False) elif notification.data.action == 'remove': try: chat_stream = (stream for stream in streams if stream.type == 'chat').next() except StopIteration: pass else: notification_center.remove_observer(self, sender=chat_stream) log.msg('%s has removed chat from %s' % (format_identity(session.remote_identity), self.uri)) self.dispatch_server_message('%s has removed chat' % format_identity(session.remote_identity), exclude=session) try: audio_stream = (stream for stream in streams if stream.type == 'audio').next() except StopIteration: pass else: notification_center.remove_observer(self, sender=audio_stream) try: self.audio_conference.remove(audio_stream) except ValueError: # User may hangup before getting bridged into the conference pass if len(self.audio_conference.streams) == 0: self.moh_player.pause() self.audio_conference.hold() elif len(self.audio_conference.streams) == 1: self.moh_player.play() log.msg('%s has removed audio from %s' % (format_identity(session.remote_identity), self.uri)) self.dispatch_server_message('%s has removed audio' % format_identity(session.remote_identity), exclude=session) if not session.streams: log.msg('%s has removed all streams from %s, session will be terminated' % (format_identity(session.remote_identity), self.uri)) session.end() self.dispatch_conference_info() class MoHPlayer(object): implements(IObserver) def __init__(self, conference): self.conference = conference self.disabled = False self.files = None self.paused = False self._player = None def initialize(self): files = glob('%s/*.wav' % ResourcePath('sounds/moh').normalized) if not files: log.error('No files found, MoH is disabled') self.disabled = True return random.shuffle(files) self.files = cycle(files) self._player = WavePlayer(SIPApplication.voice_audio_mixer, '', pause_time=1, initial_play=False, volume=20) self.conference.bridge.add(self._player) notification_center = NotificationCenter() notification_center.add_observer(self, sender=self._player) def stop(self): if self.disabled: return notification_center = NotificationCenter() notification_center.remove_observer(self, sender=self._player) self.conference.bridge.remove(self, self._player) self._player.stop() self._player = None def play(self): if not self.disabled: self.paused = False self._play_next_file() log.msg('Started playing music on hold') def pause(self): if not self.disabled: self.paused = True self._player.stop() log.msg('Stopped playing music on hold') def _play_next_file(self): file = self.files.next() self._player.filename = str(file) self._player.play() @run_in_twisted_thread def handle_notification(self, notification): handler = getattr(self, '_NH_%s' % notification.name, Null) handler(notification) def _NH_WavePlayerDidFail(self, notification): if not self.paused: self._play_next_file() def _NH_WavePlayerDidEnd(self, notification): if not self.paused: self._play_next_file()