diff --git a/sylk/applications/webrtcgateway/models/janus.py b/sylk/applications/webrtcgateway/models/janus.py
index 0bafa4b..a70ed1b 100644
--- a/sylk/applications/webrtcgateway/models/janus.py
+++ b/sylk/applications/webrtcgateway/models/janus.py
@@ -1,870 +1,870 @@
 
 import os
 
 from application.python import subclasses
 from application.python.descriptor import classproperty
 from binascii import b2a_hex as hex_encode
 from typing import Union
 
 from ..configuration import JanusConfig
 from .jsonobjects import AbstractProperty, BooleanProperty, IntegerProperty, StringProperty, ArrayProperty, ObjectProperty
 from .jsonobjects import FixedValueProperty, LimitedChoiceProperty, AbstractObjectProperty, JSONObject, JSONArray
 from .sylkrtc import ICECandidates
 from .validators import URIValidator
 
 
 # Base models (these are abstract and should not be used directly)
 
 class JanusRequestBase(JSONObject):
     transaction = StringProperty()
     apisecret = FixedValueProperty(JanusConfig.api_secret or None)
 
     def __init__(self, **kw):
         if 'transaction' not in kw:
             kw['transaction'] = hex_encode(os.urandom(16))  # uuid4().hex is really slow
         super(JanusRequestBase, self).__init__(**kw)
 
 
 class JanusCoreMessageBase(JSONObject):    # base class for messages/ sent by the Janus core (responses and events)
     pass
 
 
 class JanusPluginMessageBase(JSONObject):  # base class for messages sent by the Janus plugins (responses and events)
     pass
 
 
 class PluginDataBase(JSONObject):
     pass
 
 
 class SIPPluginData(PluginDataBase):
     __plugin__ = 'sip'
 
     # noinspection PyMethodParameters,PyUnresolvedReferences
     @classproperty
     def __id__(cls):
         if cls is SIPErrorEvent:
             return cls.__plugin__, cls.sip.value, cls.error.name
         else:
             return cls.__plugin__, cls.sip.value, cls.result.object_type.event.value
 
 
 class VideoroomPluginData(PluginDataBase):
     __plugin__ = 'videoroom'
     __event__ = None  # for events, the name of the property that describes the event
 
     # noinspection PyMethodParameters,PyUnresolvedReferences
     @classproperty
     def __id__(cls):
         if cls.__event__ is not None:
             return cls.__plugin__, cls.videoroom.value, cls.__event__
         else:
             return cls.__plugin__, cls.videoroom.value
 
 
 class CoreResponse(JanusCoreMessageBase):
     transaction = StringProperty()
 
 
 class CoreEvent(JanusCoreMessageBase):
     session_id = IntegerProperty()
     sender = IntegerProperty()
 
 
 # Miscellaneous models
 
 class NumericId(JSONObject):
     id = IntegerProperty()
 
 
 class UserId(JSONObject):
     id = IntegerProperty()
     display = StringProperty(optional=True)
 
 
 class ErrorInfo(JSONObject):
     code = IntegerProperty()
     reason = StringProperty()
 
 
 class PluginDataContainer(JSONObject):
     plugin = StringProperty()
     data = AbstractObjectProperty()  # type: Union[SIPPluginData, VideoroomPluginData]
 
 
 class SIPDataContainer(JSONObject):
     sip = FixedValueProperty('event')
     result = AbstractObjectProperty()
 
 
 class SDPOffer(JSONObject):
     type = FixedValueProperty('offer')
     sdp = StringProperty()
 
 
 class SDPAnswer(JSONObject):
     type = FixedValueProperty('answer')
     sdp = StringProperty()
 
 
 class JSEP(JSONObject):
     type = LimitedChoiceProperty(['offer', 'answer'])
     sdp = StringProperty()
 
 
 class VideoroomPublisher(JSONObject):
     id = IntegerProperty()
     display = StringProperty(optional=True)
     audio_codec = StringProperty(optional=True)
     video_codec = StringProperty(optional=True)
     talking = BooleanProperty(optional=True)
 
 
 class VideoroomPublishers(JSONArray):
     item_type = VideoroomPublisher
 
 
 # Janus requests
 
 class InfoRequest(JanusRequestBase):
     janus = FixedValueProperty('info')
 
 
 class SessionCreateRequest(JanusRequestBase):
     janus = FixedValueProperty('create')
 
 
 class SessionDestroyRequest(JanusRequestBase):
     janus = FixedValueProperty('destroy')
     session_id = IntegerProperty()
 
 
 class SessionKeepaliveRequest(JanusRequestBase):
     janus = FixedValueProperty('keepalive')
     session_id = IntegerProperty()
 
 
 class PluginAttachRequest(JanusRequestBase):
     janus = FixedValueProperty('attach')
     session_id = IntegerProperty()
     plugin = StringProperty()
 
 
 class PluginDetachRequest(JanusRequestBase):
     janus = FixedValueProperty('detach')
     session_id = IntegerProperty()
     handle_id = IntegerProperty()
 
 
 class MessageRequest(JanusRequestBase):
     janus = FixedValueProperty('message')
     session_id = IntegerProperty()
     handle_id = IntegerProperty()
     body = AbstractObjectProperty()
     jsep = AbstractObjectProperty(optional=True)
 
 
 class TrickleRequest(JanusRequestBase):
     janus = FixedValueProperty('trickle')
     session_id = IntegerProperty()
     handle_id = IntegerProperty()
     candidates = ArrayProperty(ICECandidates)  # type: ICECandidates
 
     @property
     def __data__(self):
         data = super(TrickleRequest, self).__data__
         candidates = data.pop('candidates', [])
         if len(candidates) == 0:
             data['candidate'] = {'completed': True}
             # data['candidate'] = None
         elif len(candidates) == 1:
             data['candidate'] = candidates[0]
         else:
             data['candidates'] = candidates
         return data
 
 
 # SIP plugin messages (to be used as body for MessageRequest for the SIP plugin messages)
 
 class SIPRegister(JSONObject):
     request = FixedValueProperty('register')
     username = StringProperty()  # this is the account.uri which is already a valid URI
     ha1_secret = StringProperty()
     display_name = StringProperty(optional=True)
     user_agent = StringProperty(optional=True)
     proxy = StringProperty(optional=True)
     send_register = BooleanProperty(optional=True)
 
 
 class SIPUnregister(JSONObject):
     request = FixedValueProperty('unregister')
 
 
 class SIPCall(JSONObject):
     request = FixedValueProperty('call')
     uri = StringProperty(validator=URIValidator())  # this comes from the client request.uri which was validated as an AOR and we need a URI
     srtp = LimitedChoiceProperty(['sdes_optional', 'sdes_mandatory'], optional=True)
-    autoack = BooleanProperty(default=False)
+    autoack = BooleanProperty(optional=True, default=False)
 
 
 class SIPAccept(JSONObject):
     request = FixedValueProperty('accept')
 
 
 class SIPDecline(JSONObject):
     request = FixedValueProperty('decline')
     code = IntegerProperty()
 
 
 class SIPHangup(JSONObject):
     request = FixedValueProperty('hangup')
 
 
 # Videoroom plugin messages (to be used as body for MessageRequest for videoroom plugin messages)
 
 class VideoroomCreate(JSONObject):
     request = FixedValueProperty('create')
     room = IntegerProperty()
     pin = StringProperty(optional=True)
     description = StringProperty(optional=True)
     publishers = IntegerProperty(optional=True, default=10)
     videocodec = StringProperty(optional=True)  # don't need a validator, as the value comes from the configuration and it's validated there
     bitrate = IntegerProperty(optional=True)    # don't need a validator, as the value comes from the configuration and it's validated there
     record = BooleanProperty(optional=True, default=False)
     rec_dir = StringProperty(optional=True)
 
 
 class VideoroomDestroy(JSONObject):
     request = FixedValueProperty('destroy')
     room = IntegerProperty()
 
 
 class VideoroomJoin(JSONObject):
     request = FixedValueProperty('joinandconfigure')
     ptype = FixedValueProperty('publisher')
     room = IntegerProperty()
     display = StringProperty(optional=True)
     audio = BooleanProperty(optional=True, default=True)
     video = BooleanProperty(optional=True, default=True)
     bitrate = IntegerProperty(optional=True)
 
 
 class VideoroomLeave(JSONObject):
     request = FixedValueProperty('leave')
 
 
 class VideoroomUpdatePublisher(JSONObject):
     request = FixedValueProperty('configure')
     audio = BooleanProperty(optional=True)
     video = BooleanProperty(optional=True)
     bitrate = IntegerProperty(optional=True)
 
 
 class VideoroomFeedAttach(JSONObject):
     request = FixedValueProperty('join')
     ptype = FixedValueProperty('listener')
     room = IntegerProperty()
     feed = IntegerProperty()
 
 
 class VideoroomFeedDetach(JSONObject):
     request = FixedValueProperty('leave')
 
 
 class VideoroomFeedStart(JSONObject):
     request = FixedValueProperty('start')
 
 
 class VideoroomFeedPause(JSONObject):
     request = FixedValueProperty('pause')
 
 
 class VideoroomFeedUpdate(JSONObject):
     request = FixedValueProperty('configure')
     audio = BooleanProperty(optional=True)
     video = BooleanProperty(optional=True)
     substream = IntegerProperty(optional=True)       # for VP8 simulcast
     temporal = IntegerProperty(optional=True)        # for VP8 simulcast
     spatial_layer = IntegerProperty(optional=True)   # for VP9 SVC
     temporal_layer = IntegerProperty(optional=True)  # for VP9 SVC
 
 
 # Janus core messages
 
 class AckResponse(CoreResponse):
     janus = FixedValueProperty('ack')
     session_id = IntegerProperty()
 
 
 class ErrorResponse(CoreResponse):
     janus = FixedValueProperty('error')
     session_id = IntegerProperty(optional=True)  # not used
     error = ObjectProperty(ErrorInfo)            # type: ErrorInfo
 
 
 class SuccessResponse(CoreResponse):
     janus = FixedValueProperty('success')
     session_id = IntegerProperty(optional=True)      # not used
     data = ObjectProperty(NumericId, optional=True)  # type: NumericId
 
 
 class ServerInfoResponse(CoreResponse):
     janus = FixedValueProperty('server_info')
     name = StringProperty()
     version = IntegerProperty()
     version_string = StringProperty()
     data_channels = BooleanProperty()
 
 
 class DetachedEvent(CoreEvent):
     janus = FixedValueProperty('detached')
 
 
 class HangupEvent(CoreEvent):
     janus = FixedValueProperty('hangup')
     reason = StringProperty(optional=True)
 
 
 class MediaEvent(CoreEvent):
     janus = FixedValueProperty('media')
     type = LimitedChoiceProperty(['audio', 'video'])
     receiving = BooleanProperty()
     seconds = IntegerProperty(optional=True)
 
 
 class SlowlinkEvent(CoreEvent):
     janus = FixedValueProperty('slowlink')
     uplink = BooleanProperty()
     nacks = IntegerProperty()
 
 
 class WebrtcUpEvent(CoreEvent):
     janus = FixedValueProperty('webrtcup')
 
 
 # Janus plugin messages
 
 class PluginResponse(JanusPluginMessageBase):
     janus = FixedValueProperty('success')
     transaction = StringProperty()
     session_id = IntegerProperty()
     sender = IntegerProperty()
     plugindata = ObjectProperty(PluginDataContainer)  # type: PluginDataContainer
 
 
 class PluginEvent(JanusPluginMessageBase):
     janus = FixedValueProperty('event')
     transaction = StringProperty(optional=True)
     session_id = IntegerProperty()
     sender = IntegerProperty()
     plugindata = ObjectProperty(PluginDataContainer)  # type: PluginDataContainer
     jsep = ObjectProperty(JSEP, optional=True)        # type: JSEP
 
 
 # SIP plugin data messages
 
 # Results
 
 class SIPResultRegistering(JSONObject):
     event = FixedValueProperty('registering')
 
 
 class SIPResultRegistered(JSONObject):
     event = FixedValueProperty('registered')
     username = StringProperty()  # not used
     register_sent = BooleanProperty()
 
 
 class SIPResultRegistrationFailed(JSONObject):
     event = FixedValueProperty('registration_failed')
     code = IntegerProperty()
     reason = StringProperty()
 
 
 class SIPResultUnregistering(JSONObject):
     event = FixedValueProperty('unregistering')
 
 
 class SIPResultUnregistered(JSONObject):
     event = FixedValueProperty('unregistered')
     username = StringProperty()  # not used
 
 
 class SIPResultCalling(JSONObject):
     event = FixedValueProperty('calling')
 
 
 class SIPResultRinging(JSONObject):
     event = FixedValueProperty('ringing')
 
 
 class SIPResultProceeding(JSONObject):
     event = FixedValueProperty('proceeding')
     code = IntegerProperty()
 
 
 class SIPResultProgress(JSONObject):
     event = FixedValueProperty('progress')
     username = StringProperty()  # not used
 
 
 class SIPResultDeclining(JSONObject):
     event = FixedValueProperty('declining')
     code = IntegerProperty()
 
 
 class SIPResultAccepting(JSONObject):
     event = FixedValueProperty('accepting')
 
 
 class SIPResultAccepted(JSONObject):
     event = FixedValueProperty('accepted')
     username = StringProperty(optional=True)  # not used (only present for outgoing)
 
 
 class SIPResultHolding(JSONObject):
     event = FixedValueProperty('holding')
 
 
 class SIPResultResuming(JSONObject):
     event = FixedValueProperty('resuming')
 
 
 class SIPResultHangingUp(JSONObject):
     event = FixedValueProperty('hangingup')
 
 
 class SIPResultHangup(JSONObject):
     event = FixedValueProperty('hangup')
     code = IntegerProperty()
     reason = StringProperty()
 
 
 class SIPResultIncomingCall(JSONObject):
     event = FixedValueProperty('incomingcall')
     username = StringProperty()
     displayname = StringProperty(optional=True)
     srtp = LimitedChoiceProperty(['sdes_optional', 'sdes_mandatory'], optional=True)
 
 
 class SIPResultMissedCall(JSONObject):
     event = FixedValueProperty('missed_call')
     caller = StringProperty()
     displayname = StringProperty(optional=True)
 
 
 class SIPResultInfo(JSONObject):
     event = FixedValueProperty('info')
     sender = StringProperty()
     displayname = StringProperty(optional=True)
     type = StringProperty()
     content = StringProperty()
 
 
 class SIPResultInfoSent(JSONObject):
     event = FixedValueProperty('infosent')
 
 
 class SIPResultMessage(JSONObject):
     event = FixedValueProperty('message')
     sender = StringProperty()
     displayname = StringProperty(optional=True)
     content = StringProperty()
 
 
 class SIPResultMessageSent(JSONObject):
     event = FixedValueProperty('messagesent')
 
 
 class SIPResultDTMFSent(JSONObject):
     event = FixedValueProperty('dtmfsent')
 
 
 # Data messages
 
 class SIPErrorEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     error_code = IntegerProperty()
     error = StringProperty()
 
 
 class SIPRegisteringEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultRegistering)         # type: SIPResultRegistering
 
 
 class SIPRegisteredEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultRegistered)          # type: SIPResultRegistered
 
 
 class SIPRegistrationFailedEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultRegistrationFailed)  # type: SIPResultRegistrationFailed
 
 
 class SIPUnregisteringEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultUnregistering)       # type: SIPResultUnregistering
 
 
 class SIPUnregisteredEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultUnregistered)        # type: SIPResultRegistered
 
 
 class SIPCallingEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultCalling)             # type: SIPResultCalling
 
 
 class SIPRingingEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultRinging)             # type: SIPResultRinging
 
 
 class SIPProceedingEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultProceeding)          # type: SIPResultProceeding
 
 
 class SIPProgressEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultProgress)            # type: SIPResultProgress
 
 
 class SIPDecliningEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultDeclining)           # type: SIPResultDeclining
 
 
 class SIPAcceptingEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultAccepting)           # type: SIPResultAccepting
 
 
 class SIPAcceptedEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultAccepted)            # type: SIPResultAccepted
 
 
 class SIPHoldingEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultHolding)             # type: SIPResultHolding
 
 
 class SIPResumingEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultResuming)            # type: SIPResultResuming
 
 
 class SIPHangingUpEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultHangingUp)           # type: SIPResultHangingUp
 
 
 class SIPHangupEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultHangup)              # type: SIPResultHangup
 
 
 class SIPIncomingCallEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultIncomingCall)        # type: SIPResultIncomingCall
 
 
 class SIPMissedCallEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultMissedCall)          # type: SIPResultMissedCall
 
 
 class SIPInfoEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultInfo)                # type: SIPResultInfo
 
 
 class SIPInfoSentEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultInfoSent)            # type: SIPResultInfoSent
 
 
 class SIPMessageEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultMessage)             # type: SIPResultMessage
 
 
 class SIPMessageSentEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultMessageSent)         # type: SIPResultMessageSent
 
 
 class SIPDTMFSentEvent(SIPPluginData):
     sip = FixedValueProperty('event')
     result = ObjectProperty(SIPResultDTMFSent)            # type: SIPResultDTMFSent
 
 
 # Videoroom plugin data messages
 
 class VideoroomCreated(VideoroomPluginData):
     videoroom = FixedValueProperty('created')
     room = IntegerProperty()
     # permanent = BooleanProperty()  # this is not available in older janus versions. not used.
 
 
 class VideoroomEdited(VideoroomPluginData):
     videoroom = FixedValueProperty('edited')
     room = IntegerProperty()
     # permanent = BooleanProperty()  # this is not available in older janus versions. not used.
 
 
 class VideoroomDestroyed(VideoroomPluginData):  # this comes both in the response to 'destroy' and in an event to participants still in the room when destroyed (if any)
     videoroom = FixedValueProperty('destroyed')
     room = IntegerProperty()
     # permanent = BooleanProperty(optional=True)  # this is not available in older janus versions (only present in the response, but not in the event). not used.
 
 
 class VideoroomJoined(VideoroomPluginData):
     videoroom = FixedValueProperty('joined')
     room = IntegerProperty()
     description = StringProperty()
     id = IntegerProperty()
     publishers = ArrayProperty(VideoroomPublishers)  # type: VideoroomPublishers
     # private_id = IntegerProperty()  # this is not available in older janus versions. not used.
 
 
 class VideoroomAttached(VideoroomPluginData):
     videoroom = FixedValueProperty('attached')
     room = IntegerProperty()
     id = IntegerProperty()
     display = StringProperty(optional=True)
 
 
 class VideoroomSlowLink(VideoroomPluginData):
     videoroom = FixedValueProperty('slow_link')
     # current_bitrate = IntegerProperty()  # this is actually defined as 'current-bitrate' in JSON, so we cannot map it to an attribute name. also not used.
 
 
 class VideoroomErrorEvent(VideoroomPluginData):
     __event__ = 'error'
 
     videoroom = FixedValueProperty('event')
     error_code = IntegerProperty()
     error = StringProperty()
 
 
 class VideoroomStartedEvent(VideoroomPluginData):
     __event__ = 'started'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     started = FixedValueProperty('ok')
 
 
 class VideoroomPublishersEvent(VideoroomPluginData):
     __event__ = 'publishers'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     publishers = ArrayProperty(VideoroomPublishers)  # type: VideoroomPublishers
 
 
 class VideoroomConfiguredEvent(VideoroomPluginData):
     __event__ = 'configured'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     configured = FixedValueProperty('ok')
 
 
 class VideoroomLeftEvent(VideoroomPluginData):
     __event__ = 'left'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     left = FixedValueProperty('ok')
 
 
 class VideoroomLeavingEvent(VideoroomPluginData):
     __event__ = 'leaving'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     leaving = AbstractProperty()  # this is either a participant id or the string "ok"
     reason = StringProperty(optional=True)
 
 
 class VideoroomKickedEvent(VideoroomPluginData):
     __event__ = 'kicked'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     kicked = IntegerProperty()
 
 
 class VideoroomUnpublishedEvent(VideoroomPluginData):
     __event__ = 'unpublished'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     unpublished = AbstractProperty()  # this is either a participant id or the string "ok"
 
 
 class VideoroomPausedEvent(VideoroomPluginData):
     __event__ = 'paused'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     paused = FixedValueProperty('ok')
 
 
 class VideoroomSwitchedEvent(VideoroomPluginData):
     __event__ = 'switched'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     id = IntegerProperty()
     switched = FixedValueProperty('ok')
 
 
 class VideoroomJoiningEvent(VideoroomPluginData):  # only sent if room has notify_joining == True (default is False). Can be used to monitor non-publishers.
     __event__ = 'joining'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     joining = ObjectProperty(UserId)  # type: UserId
 
 
 class VideoroomDisplayEvent(VideoroomPluginData):  # participant display name change
     __event__ = 'display'
 
     videoroom = FixedValueProperty('event')
     id = IntegerProperty()
     display = StringProperty()
 
 
 class VideoroomSubstreamEvent(VideoroomPluginData):  # simulcast substream change
     __event__ = 'substream'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     substream = IntegerProperty()
 
 
 class VideoroomTemporalEvent(VideoroomPluginData):  # simulcast temporal layer change
     __event__ = 'temporal'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     temporal = IntegerProperty()
 
 
 class VideoroomSpatialLayerEvent(VideoroomPluginData):  # SVC spatial layer change
     __event__ = 'spatial_layer'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     spatial_layer = IntegerProperty()
 
 
 class VideoroomTemporalLayerEvent(VideoroomPluginData):  # SVC temporal layer change
     __event__ = 'temporal_layer'
 
     videoroom = FixedValueProperty('event')
     room = IntegerProperty()
     temporal_layer = IntegerProperty()
 
 
 # Janus message to model mapping
 
 class ProtocolError(Exception):
     pass
 
 
 class PluginDataHandler(object):
     pass
 
 
 class SIPDataHandler(PluginDataHandler):
     __plugin__ = 'sip'
 
     __classmap__ = {cls.__id__: cls for cls in subclasses(SIPPluginData) if cls.__plugin__ in cls.__properties__}
 
     @classmethod
     def decode(cls, data):
         try:
             sip = data[cls.__plugin__]
             if 'error' in data:
                 data_key = cls.__plugin__, sip, 'error'
             elif 'result' in data:
                 data_key = cls.__plugin__, sip, data['result']['event']
             else:
                 data_key = cls.__plugin__, sip
         except KeyError:
             raise ProtocolError('could not get {!s} plugin data type from {!r}'.format(cls.__plugin__, data))
         try:
             data_class = cls.__classmap__[data_key]
         except KeyError:
             raise ProtocolError('unknown {!s} plugin data: {!r}'.format(cls.__plugin__, data))
         return data_class(**data)
 
 
 class VideoroomDataHandler(PluginDataHandler):
     __plugin__ = 'videoroom'
 
     __classmap__ = {cls.__id__: cls for cls in subclasses(VideoroomPluginData) if cls.__plugin__ in cls.__properties__}
     __eventset__ = frozenset(cls.__event__ for cls in subclasses(VideoroomPluginData) if cls.__event__)
 
     @classmethod
     def decode(cls, data):
         try:
             data_type = data[cls.__plugin__]
         except KeyError:
             raise ProtocolError('could not get {!s} plugin data type from {!r}'.format(cls.__plugin__, data))
         if data_type == 'event':
             common_keys = list(cls.__eventset__.intersection(data))
             if len(common_keys) != 1:
                 raise ProtocolError('unknown {!s} plugin event: {!r}'.format(cls.__plugin__, data))
             event_type = common_keys[0]
             data_key = cls.__plugin__, data_type, event_type
         else:
             data_key = cls.__plugin__, data_type
         try:
             data_class = cls.__classmap__[data_key]
         except KeyError:
             raise ProtocolError('unknown {!s} plugin data: {!r}'.format(cls.__plugin__, data))
         return data_class(**data)
 
 
 class JanusMessage(object):
     __core_classmap__ = {cls.janus.value: cls for cls in subclasses(JanusCoreMessageBase) if 'janus' in cls.__properties__}
     __plugin_classmap__ = {cls.janus.value: cls for cls in subclasses(JanusPluginMessageBase) if 'janus' in cls.__properties__}
     __plugin_handlers__ = {handler.__plugin__: handler for handler in subclasses(PluginDataHandler)}
 
     @classmethod
     def from_payload(cls, payload):
         try:
             message_type = payload['janus']
         except KeyError:
             raise ProtocolError('could not get Janus message type')
         if 'plugindata' in payload:
             try:
                 message_class = cls.__plugin_classmap__[message_type]
             except KeyError:
                 raise ProtocolError('unknown Janus message: {!s}'.format(message_type))
             data_container = payload['plugindata']
             try:
                 plugin_name = data_container['plugin'].rpartition('.')[2]
                 plugin_data = data_container['data']
             except KeyError:
                 raise ProtocolError('invalid plugin data: {!r}'.format(data_container))
             try:
                 data_handler = cls.__plugin_handlers__[plugin_name]
             except KeyError:
                 raise ProtocolError('could not find a data handler for {!r}'.format(plugin_data))
             data_container['data'] = data_handler.decode(plugin_data)
         else:
             try:
                 message_class = cls.__core_classmap__[message_type]
             except KeyError:
                 raise ProtocolError('unknown Janus message: {!s}'.format(message_type))
         return message_class(**payload)