FreeOpcUa / opcua-client-gui

            if node is None:

                return

        if node in self._subscribed_nodes:

            logger.info("allready subscribed to event for node: %s", node)

            return

        logger.info("Subscribing to events for %s", node)

        self.window.ui.evDockWidget.raise_()

        try:

            self.uaclient.subscribe_events(node, self._handler)

        except Exception as ex:

            self.window.show_error(ex)

            raise

        else:

            self._subscribed_nodes.append(node)

    @trycatchslot

    def _unsubscribe(self):

        node = self.window.get_current_node()

        if node is None:

            return

        self._subscribed_nodes.remove(node)

        self.uaclient.unsubscribe_events(node)

    @trycatchslot

    def _update_event_model(self, event):

        self.model.appendRow([QStandardItem(str(event))])

logger = logging.getLogger(__name__)

class DataChangeHandler(QObject):

    data_change_fired = pyqtSignal(object, str, str)

    def datachange_notification(self, node, val, data):

        if data.monitored_item.Value.SourceTimestamp:

            dato = data.monitored_item.Value.SourceTimestamp.isoformat()

        elif data.monitored_item.Value.ServerTimestamp:

            dato = data.monitored_item.Value.ServerTimestamp.isoformat()

        else:

            dato = datetime.now().isoformat()

        self.data_change_fired.emit(node, str(val), dato)

class EventHandler(QObject):

    event_fired = pyqtSignal(object)

    def event_notification(self, event):

        self.event_fired.emit(event)