Exemplo n.º 1
0
class WampMQTTServerProtocol(Protocol):

    log = make_logger()

    def __init__(self, reactor):
        self._mqtt = MQTTServerTwistedProtocol(self, reactor)
        self._request_to_packetid = {}
        self._waiting_for_connect = None
        self._inflight_subscriptions = {}
        self._subrequest_to_mqtt_subrequest = {}
        self._subrequest_callbacks = {}
        self._topic_lookup = {}
        self._wamp_session = None

    def on_message(self, inc_msg):

        try:
            self._on_message(inc_msg)
        except:
            self.log.failure()

    @inlineCallbacks
    def _on_message(self, inc_msg):
        self.log.debug('WampMQTTServerProtocol._on_message(inc_msg={inc_msg})', inc_msg=inc_msg)

        if isinstance(inc_msg, message.Challenge):
            assert inc_msg.method == u"ticket"

            msg = message.Authenticate(signature=self._pw_challenge)
            del self._pw_challenge

            self._wamp_session.onMessage(msg)

        elif isinstance(inc_msg, message.Welcome):
            self._waiting_for_connect.callback((0, False))

        elif isinstance(inc_msg, message.Abort):
            self._waiting_for_connect.callback((1, False))

        elif isinstance(inc_msg, message.Subscribed):
            # Successful subscription!
            mqtt_id = self._subrequest_to_mqtt_subrequest[inc_msg.request]
            self._inflight_subscriptions[mqtt_id][inc_msg.request]["response"] = 0
            self._topic_lookup[inc_msg.subscription] = self._inflight_subscriptions[mqtt_id][inc_msg.request]["topic"]

            if -1 not in [x["response"] for x in self._inflight_subscriptions[mqtt_id].values()]:
                self._subrequest_callbacks[mqtt_id].callback(None)

        elif (isinstance(inc_msg, message.Error) and
              inc_msg.request_type == message.Subscribe.MESSAGE_TYPE):
            # Failed subscription :(
            mqtt_id = self._subrequest_to_mqtt_subrequest[inc_msg.request]
            self._inflight_subscriptions[mqtt_id][inc_msg.request]["response"] = 128

            if -1 not in [x["response"] for x in self._inflight_subscriptions[mqtt_id].values()]:
                self._subrequest_callbacks[mqtt_id].callback(None)

        elif isinstance(inc_msg, message.Event):

            topic = inc_msg.topic or self._topic_lookup[inc_msg.subscription]

            try:
                payload_format, mapped_topic, payload = yield self.factory.transform_wamp(topic, inc_msg)
            except:
                self.log.failure()
            else:
                self._mqtt.send_publish(mapped_topic, 0, payload, retained=inc_msg.retained or False)

        elif isinstance(inc_msg, message.Goodbye):
            if self._mqtt.transport:
                self._mqtt.transport.loseConnection()
                self._mqtt.transport = None

        else:
            self.log.warn('cannot process unimplemented message: {inc_msg}', inc_msg=inc_msg)

    def connectionMade(self, ignore_handshake=False):
        if ignore_handshake or not ISSLTransport.providedBy(self.transport):
            self._when_ready()

    def connectionLost(self, reason):
        if self._wamp_session:
            msg = message.Goodbye()
            self._wamp_session.onMessage(msg)
            del self._wamp_session

    def handshakeCompleted(self):
        self._when_ready()

    def _when_ready(self):
        if self._wamp_session:
            return

        self._mqtt.transport = self.transport

        self._wamp_session = RouterSession(self.factory._router_session_factory._routerFactory)
        self._wamp_transport = WampTransport(self.factory, self.on_message, self.transport)
        self._wamp_session.onOpen(self._wamp_transport)
        self._wamp_session._transport_config = self.factory._options

    def process_connect(self, packet):
        """
        Process the initial Connect message from the MQTT client.

        This should return a pair `(accept_conn, session_present)`, where
        `accept_conn` is a return code:

        0: connection accepted
        1-5: connection refused (see MQTT spec 3.2.2.3)
        """

        # Connect(client_id='paho/4E23D8C09DD9C6CF2C',
        #         flags=ConnectFlags(username=False,
        #                            password=False,
        #                            will=False,
        #                            will_retain=False,
        #                            will_qos=0,
        #                            clean_session=True,
        #                            reserved=False),
        #         keep_alive=60,
        #         will_topic=None,
        #         will_message=None,
        #         username=None,
        #         password=None)
        self.log.info('WampMQTTServerProtocol.process_connect(packet={packet})', packet=packet)

        # we don't support session resumption: https://github.com/crossbario/crossbar/issues/892
        if not packet.flags.clean_session:
            self.log.warn('denying MQTT connect from {peer}, as the clients wants to resume a session (which we do not support)', peer=peer2str(self.transport.getPeer()))
            return succeed((1, False))

        # we won't support QoS 2: https://github.com/crossbario/crossbar/issues/1046
        if packet.flags.will and packet.flags.will_qos not in [0, 1]:
            self.log.warn('denying MQTT connect from {peer}, as the clients wants to provide a "last will" event with QoS {will_qos} (and we only support QoS 0/1 here)', peer=peer2str(self.transport.getPeer()), will_qos=packet.flags.will_qos)
            return succeed((1, False))

        # this will be resolved when the MQTT connect handshake is completed
        self._waiting_for_connect = Deferred()

        roles = {
            u"subscriber": role.RoleSubscriberFeatures(
                payload_transparency=True,
                pattern_based_subscription=True),
            u"publisher": role.RolePublisherFeatures(
                payload_transparency=True,
                x_acknowledged_event_delivery=True)
        }

        realm = self.factory._options.get(u'realm', None)

        authmethods = []
        authextra = {
            u'mqtt': {
                u'client_id': packet.client_id,
                u'will': bool(packet.flags.will),
                u'will_topic': packet.will_topic
            }
        }

        if ISSLTransport.providedBy(self.transport):
            authmethods.append(u"tls")

        if packet.username and packet.password:
            authmethods.append(u"ticket")
            msg = message.Hello(
                realm=realm,
                roles=roles,
                authmethods=authmethods,
                authid=packet.username,
                authextra=authextra)
            self._pw_challenge = packet.password

        else:
            authmethods.append(u"anonymous")
            msg = message.Hello(
                realm=realm,
                roles=roles,
                authmethods=authmethods,
                authid=packet.client_id,
                authextra=authextra)

        self._wamp_session.onMessage(msg)

        if packet.flags.will:

            # it's unclear from the MQTT spec whether a) the publication of the last will
            # is to happen in-band during "connect", and if it fails, deny the connection,
            # or b) the last will publication happens _after_ "connect", and the connection
            # succeeds regardless whether the last will publication succeeds or not.
            #
            # we opt for b) here!
            #
            @inlineCallbacks
            @self._waiting_for_connect.addCallback
            def process_will(res):

                self.log.info()

                payload_format, mapped_topic, options = yield self.factory.transform_mqtt(packet.will_topic, packet.will_message)

                request = util.id()

                msg = message.Call(
                    request=request,
                    procedure=u"wamp.session.add_testament",
                    args=[
                        mapped_topic,
                        options.get('args', None),
                        options.get('kwargs', None),
                        {
                            # specifiy "retain" for when the testament (last will)
                            # will be auto-published by the broker later
                            u'retain': bool(packet.flags.will_retain)
                        }
                    ])

                self._wamp_session.onMessage(msg)

                returnValue(res)

        return self._waiting_for_connect

    @inlineCallbacks
    def _publish(self, event, acknowledge=None):
        """
        Given a MQTT event, create a WAMP Publish message and
        forward that on the forwarding WAMP session.
        """
        try:
            payload_format, mapped_topic, options = yield self.factory.transform_mqtt(event.topic_name, event.payload)
        except:
            self.log.failure()
            return

        request = util.id()

        msg = message.Publish(
            request=request,
            topic=mapped_topic,
            exclude_me=False,
            acknowledge=acknowledge,
            retain=event.retain,
            **options)

        self._wamp_session.onMessage(msg)

        if event.qos_level > 0:
            self._request_to_packetid[request] = event.packet_identifier

        returnValue(0)

    def process_publish_qos_0(self, event):
        try:
            return self._publish(event)
        except:
            self.log.failure()

    def process_publish_qos_1(self, event):
        try:
            return self._publish(event, acknowledge=True)
        except:
            self.log.failure()

    def process_puback(self, event):
        return

    def process_pubrec(self, event):
        return

    def process_pubrel(self, event):
        return

    def process_pubcomp(self, event):
        return

    def process_subscribe(self, packet):

        packet_watch = OrderedDict()
        d = Deferred()

        @d.addCallback
        def _(ign):
            self._mqtt.send_suback(packet.packet_identifier, [x["response"] for x in packet_watch.values()])
            del self._inflight_subscriptions[packet.packet_identifier]
            del self._subrequest_callbacks[packet.packet_identifier]

        self._subrequest_callbacks[packet.packet_identifier] = d
        self._inflight_subscriptions[packet.packet_identifier] = packet_watch

        for n, x in enumerate(packet.topic_requests):

            topic, match = _mqtt_topicfilter_to_wamp(x.topic_filter)

            self.log.info('process_subscribe -> topic={topic}, match={match}', topic=topic, match=match)

            request_id = util.id()

            msg = message.Subscribe(
                request=request_id,
                topic=topic,
                match=match,
                get_retained=True,
            )

            try:
                packet_watch[request_id] = {"response": -1, "topic": x.topic_filter}
                self._subrequest_to_mqtt_subrequest[request_id] = packet.packet_identifier
                self._wamp_session.onMessage(msg)
            except:
                self.log.failure()
                packet_watch[request_id] = {"response": 128}

    @inlineCallbacks
    def process_unsubscribe(self, packet):

        for topic in packet.topics:
            if topic in self._subscriptions:
                yield self._subscriptions.pop(topic).unsubscribe()

        return

    def dataReceived(self, data):
        self._mqtt.dataReceived(data)
Exemplo n.º 2
0
class WampMQTTServerProtocol(Protocol):

    log = make_logger()

    def __init__(self, reactor):
        self._mqtt = MQTTServerTwistedProtocol(self, reactor)
        self._request_to_packetid = {}
        self._waiting_for_connect = None
        self._inflight_subscriptions = {}
        self._subrequest_to_mqtt_subrequest = {}
        self._subrequest_callbacks = {}
        self._topic_lookup = {}
        self._wamp_session = None

    def on_message(self, inc_msg):

        try:
            self._on_message(inc_msg)
        except:
            self.log.failure()

    def _on_message(self, inc_msg):

        if isinstance(inc_msg, message.Challenge):
            assert inc_msg.method == u"ticket"

            msg = message.Authenticate(signature=self._pw_challenge)
            del self._pw_challenge

            self._wamp_session.onMessage(msg)

        elif isinstance(inc_msg, message.Welcome):
            self._waiting_for_connect.callback((0, False))

        elif isinstance(inc_msg, message.Abort):
            self._waiting_for_connect.callback((1, False))

        elif isinstance(inc_msg, message.Subscribed):
            # Successful subscription!
            mqtt_id = self._subrequest_to_mqtt_subrequest[inc_msg.request]
            self._inflight_subscriptions[mqtt_id][
                inc_msg.request]["response"] = 0
            self._topic_lookup[
                inc_msg.subscription] = self._inflight_subscriptions[mqtt_id][
                    inc_msg.request]["topic"]

            if -1 not in [
                    x["response"]
                    for x in self._inflight_subscriptions[mqtt_id].values()
            ]:
                self._subrequest_callbacks[mqtt_id].callback(None)

        elif (isinstance(inc_msg, message.Error)
              and inc_msg.request_type == message.Subscribe.MESSAGE_TYPE):
            # Failed subscription :(
            mqtt_id = self._subrequest_to_mqtt_subrequest[inc_msg.request]
            self._inflight_subscriptions[mqtt_id][
                inc_msg.request]["response"] = 128

            if -1 not in [
                    x["response"]
                    for x in self._inflight_subscriptions[mqtt_id].values()
            ]:
                self._subrequest_callbacks[mqtt_id].callback(None)

        elif isinstance(inc_msg, message.Event):

            topic = inc_msg.topic or self._topic_lookup[inc_msg.subscription]
            body = wamp_payload_transform(
                self._wamp_session._router._mqtt_payload_format, inc_msg)

            self._mqtt.send_publish(u"/".join(tokenise_wamp_topic(topic)),
                                    0,
                                    body,
                                    retained=inc_msg.retained or False)

        elif isinstance(inc_msg, message.Goodbye):
            if self._mqtt.transport:
                self._mqtt.transport.loseConnection()
                self._mqtt.transport = None

        else:
            print("Got something we don't understand yet:")
            print(inc_msg)

    def connectionMade(self, ignore_handshake=False):
        if ignore_handshake or not ISSLTransport.providedBy(self.transport):
            self._when_ready()

    def connectionLost(self, reason):
        if self._wamp_session:
            msg = message.Goodbye()
            self._wamp_session.onMessage(msg)
            del self._wamp_session

    def handshakeCompleted(self):
        self._when_ready()

    def _when_ready(self):
        if self._wamp_session:
            return

        self._mqtt.transport = self.transport

        self._wamp_session = RouterSession(
            self.factory._wamp_session_factory._routerFactory)
        self._wamp_session._is_mqtt = True
        self._wamp_transport = WampTransport(self.on_message, self.transport)
        self._wamp_transport.factory = self.factory
        self._wamp_session.onOpen(self._wamp_transport)

    def process_connect(self, packet):

        self._waiting_for_connect = Deferred()

        roles = {
            u"subscriber":
            role.RoleSubscriberFeatures(payload_transparency=True),
            u"publisher":
            role.RolePublisherFeatures(payload_transparency=True,
                                       x_acknowledged_event_delivery=True)
        }

        # Will be autoassigned
        realm = None
        methods = []

        if ISSLTransport.providedBy(self.transport):
            methods.append(u"tls")

        if packet.username and packet.password:
            methods.append(u"ticket")
            msg = message.Hello(realm=realm,
                                roles=roles,
                                authmethods=methods,
                                authid=packet.username)
            self._pw_challenge = packet.password

        else:
            methods.append(u"anonymous")
            msg = message.Hello(realm=realm,
                                roles=roles,
                                authmethods=methods,
                                authid=packet.client_id)

        self._wamp_session.onMessage(msg)

        if packet.flags.will:

            @self._waiting_for_connect.addCallback
            def process_will(res):

                akw = mqtt_payload_transform(
                    self._wamp_session._router._mqtt_payload_format,
                    packet.will_message)

                if not akw:
                    # Drop it I guess :(
                    return res

                args, kwargs = akw

                msg = message.Call(
                    request=util.id(),
                    procedure=u"wamp.session.add_testament",
                    args=[
                        u".".join(tokenise_mqtt_topic(packet.will_topic)),
                        args, kwargs, {
                            "retain": bool(packet.flags.will_retain)
                        }
                    ])

                self._wamp_session.onMessage(msg)

                return res

        return self._waiting_for_connect

    def _publish(self, event, options):

        request = util.id()
        msg = message.Publish(request=request,
                              topic=u".".join(
                                  tokenise_mqtt_topic(event.topic_name)),
                              payload=event.payload,
                              **options.message_attr())
        msg._mqtt_publish = True

        self._wamp_session.onMessage(msg)

        if event.qos_level > 0:
            self._request_to_packetid[request] = event.packet_identifier

        return succeed(0)

    def process_publish_qos_0(self, event):
        return self._publish(event,
                             options=PublishOptions(exclude_me=False,
                                                    retain=event.retain))

    def process_publish_qos_1(self, event):
        return self._publish(event,
                             options=PublishOptions(acknowledge=True,
                                                    exclude_me=False,
                                                    retain=event.retain))

    def process_puback(self, event):
        return

    def process_pubrec(self, event):
        return

    def process_pubrel(self, event):
        return

    def process_pubcomp(self, event):
        return

    def process_subscribe(self, packet):

        packet_watch = OrderedDict()
        d = Deferred()

        @d.addCallback
        def _(ign):
            self._mqtt.send_suback(
                packet.packet_identifier,
                [x["response"] for x in packet_watch.values()])
            del self._inflight_subscriptions[packet.packet_identifier]
            del self._subrequest_callbacks[packet.packet_identifier]

        self._subrequest_callbacks[packet.packet_identifier] = d
        self._inflight_subscriptions[packet.packet_identifier] = packet_watch

        for n, x in enumerate(packet.topic_requests):
            # fixme
            match_type = u"exact"

            request_id = util.id()

            msg = message.Subscribe(
                request=request_id,
                topic=u".".join(tokenise_mqtt_topic(x.topic_filter)),
                match=match_type,
                get_retained=True,
            )

            try:
                packet_watch[request_id] = {
                    "response": -1,
                    "topic": x.topic_filter
                }
                self._subrequest_to_mqtt_subrequest[
                    request_id] = packet.packet_identifier
                self._wamp_session.onMessage(msg)
            except Exception:
                self.log.failure()
                packet_watch[request_id] = {"response": 128}

    @inlineCallbacks
    def process_unsubscribe(self, packet):

        for topic in packet.topics:
            if topic in self._subscriptions:
                yield self._subscriptions.pop(topic).unsubscribe()

        return

    def dataReceived(self, data):
        self._mqtt.dataReceived(data)
Exemplo n.º 3
0
class WampMQTTServerProtocol(Protocol):

    log = make_logger()

    def __init__(self, reactor):
        self._mqtt = MQTTServerTwistedProtocol(self, reactor)
        self._request_to_packetid = {}
        self._waiting_for_connect = None
        self._inflight_subscriptions = {}
        self._subrequest_to_mqtt_subrequest = {}
        self._subrequest_callbacks = {}
        self._topic_lookup = {}
        self._wamp_session = None

    def on_message(self, inc_msg):

        try:
            self._on_message(inc_msg)
        except:
            self.log.failure()

    @inlineCallbacks
    def _on_message(self, inc_msg):
        self.log.debug('WampMQTTServerProtocol._on_message(inc_msg={inc_msg})',
                       inc_msg=inc_msg)

        if isinstance(inc_msg, message.Challenge):
            assert inc_msg.method == u"ticket"

            msg = message.Authenticate(signature=self._pw_challenge)
            del self._pw_challenge

            self._wamp_session.onMessage(msg)

        elif isinstance(inc_msg, message.Welcome):
            self._waiting_for_connect.callback((0, False))

        elif isinstance(inc_msg, message.Abort):
            self._waiting_for_connect.callback((1, False))

        elif isinstance(inc_msg, message.Subscribed):
            # Successful subscription!
            mqtt_id = self._subrequest_to_mqtt_subrequest[inc_msg.request]
            self._inflight_subscriptions[mqtt_id][
                inc_msg.request]["response"] = 0
            self._topic_lookup[
                inc_msg.subscription] = self._inflight_subscriptions[mqtt_id][
                    inc_msg.request]["topic"]

            if -1 not in [
                    x["response"]
                    for x in self._inflight_subscriptions[mqtt_id].values()
            ]:
                self._subrequest_callbacks[mqtt_id].callback(None)

        elif (isinstance(inc_msg, message.Error)
              and inc_msg.request_type == message.Subscribe.MESSAGE_TYPE):
            # Failed subscription :(
            mqtt_id = self._subrequest_to_mqtt_subrequest[inc_msg.request]
            self._inflight_subscriptions[mqtt_id][
                inc_msg.request]["response"] = 128

            if -1 not in [
                    x["response"]
                    for x in self._inflight_subscriptions[mqtt_id].values()
            ]:
                self._subrequest_callbacks[mqtt_id].callback(None)

        elif isinstance(inc_msg, message.Event):

            topic = inc_msg.topic or self._topic_lookup[inc_msg.subscription]

            try:
                payload_format, mapped_topic, payload = yield self.factory.transform_wamp(
                    topic, inc_msg)
            except:
                self.log.failure()
            else:
                self._mqtt.send_publish(mapped_topic,
                                        0,
                                        payload,
                                        retained=inc_msg.retained or False)

        elif isinstance(inc_msg, message.Goodbye):
            if self._mqtt.transport:
                self._mqtt.transport.loseConnection()
                self._mqtt.transport = None

        else:
            self.log.warn('cannot process unimplemented message: {inc_msg}',
                          inc_msg=inc_msg)

    def connectionMade(self, ignore_handshake=False):
        if ignore_handshake or not ISSLTransport.providedBy(self.transport):
            self._when_ready()

    def connectionLost(self, reason):
        if self._wamp_session:
            msg = message.Goodbye()
            self._wamp_session.onMessage(msg)
            del self._wamp_session

    def handshakeCompleted(self):
        self._when_ready()

    def _when_ready(self):
        if self._wamp_session:
            return

        self._mqtt.transport = self.transport

        self._wamp_session = RouterSession(
            self.factory._router_session_factory._routerFactory)
        self._wamp_transport = WampTransport(self.factory, self.on_message,
                                             self.transport)
        self._wamp_session.onOpen(self._wamp_transport)
        self._wamp_session._transport_config = self.factory._options

    def process_connect(self, packet):

        try:
            self.log.debug(
                'WampMQTTServerProtocol.process_connect(packet={packet})',
                packet=packet)

            self._waiting_for_connect = Deferred()

            roles = {
                u"subscriber":
                role.RoleSubscriberFeatures(payload_transparency=True),
                u"publisher":
                role.RolePublisherFeatures(payload_transparency=True,
                                           x_acknowledged_event_delivery=True)
            }

            realm = self.factory._options.get('realm', None)
            methods = []

            if ISSLTransport.providedBy(self.transport):
                methods.append(u"tls")

            if packet.username and packet.password:
                methods.append(u"ticket")
                msg = message.Hello(realm=realm,
                                    roles=roles,
                                    authmethods=methods,
                                    authid=packet.username)
                self._pw_challenge = packet.password

            else:
                methods.append(u"anonymous")
                msg = message.Hello(realm=realm,
                                    roles=roles,
                                    authmethods=methods,
                                    authid=packet.client_id)

            self._wamp_session.onMessage(msg)

            if packet.flags.will:

                @inlineCallbacks
                @self._waiting_for_connect.addCallback
                def process_will(res):

                    payload_format, mapped_topic, options = yield self.factory.transform_mqtt(
                        packet.will_topic, packet.will_message)

                    request = util.id()

                    msg = message.Call(request=request,
                                       procedure=u"wamp.session.add_testament",
                                       args=[
                                           mapped_topic,
                                           options.get('args', None),
                                           options.get('kwargs', None), {
                                               'retain':
                                               bool(packet.flags.will_retain)
                                           }
                                       ])

                    self._wamp_session.onMessage(msg)

                    returnValue(res)

            return self._waiting_for_connect
        except:
            self.log.failure()

    @inlineCallbacks
    def _publish(self, event, acknowledge=None):
        """
        Given a MQTT event, create a WAMP Publish message and
        forward that on the forwarding WAMP session.
        """
        try:
            payload_format, mapped_topic, options = yield self.factory.transform_mqtt(
                event.topic_name, event.payload)
        except:
            self.log.failure()
            return

        request = util.id()

        msg = message.Publish(request=request,
                              topic=mapped_topic,
                              exclude_me=False,
                              acknowledge=acknowledge,
                              retain=event.retain,
                              **options)

        self._wamp_session.onMessage(msg)

        if event.qos_level > 0:
            self._request_to_packetid[request] = event.packet_identifier

        returnValue(0)

    def process_publish_qos_0(self, event):
        try:
            return self._publish(event)
        except:
            self.log.failure()

    def process_publish_qos_1(self, event):
        try:
            return self._publish(event, acknowledge=True)
        except:
            self.log.failure()

    def process_puback(self, event):
        return

    def process_pubrec(self, event):
        return

    def process_pubrel(self, event):
        return

    def process_pubcomp(self, event):
        return

    def process_subscribe(self, packet):

        packet_watch = OrderedDict()
        d = Deferred()

        @d.addCallback
        def _(ign):
            self._mqtt.send_suback(
                packet.packet_identifier,
                [x["response"] for x in packet_watch.values()])
            del self._inflight_subscriptions[packet.packet_identifier]
            del self._subrequest_callbacks[packet.packet_identifier]

        self._subrequest_callbacks[packet.packet_identifier] = d
        self._inflight_subscriptions[packet.packet_identifier] = packet_watch

        for n, x in enumerate(packet.topic_requests):
            # fixme
            match_type = u"exact"

            request_id = util.id()

            msg = message.Subscribe(
                request=request_id,
                topic=u".".join(tokenise_mqtt_topic(x.topic_filter)),
                match=match_type,
                get_retained=True,
            )

            try:
                packet_watch[request_id] = {
                    "response": -1,
                    "topic": x.topic_filter
                }
                self._subrequest_to_mqtt_subrequest[
                    request_id] = packet.packet_identifier
                self._wamp_session.onMessage(msg)
            except:
                self.log.failure()
                packet_watch[request_id] = {"response": 128}

    @inlineCallbacks
    def process_unsubscribe(self, packet):

        for topic in packet.topics:
            if topic in self._subscriptions:
                yield self._subscriptions.pop(topic).unsubscribe()

        return

    def dataReceived(self, data):
        self._mqtt.dataReceived(data)