baseimage-tutorial-framework/lib/tfw/builtins/frontend_event_handler.py

from tfw.networking import Scope
from tfw.components import FrontendMessageStorage


class FrontendEventHandler:
    keys = ['message', 'queueMessages', 'dashboard', 'console']

    def __init__(self):
        self.server_connector = None
        self.keys = [*type(self).keys, 'recover']
        self._frontend_message_storage = FrontendMessageStorage(type(self).keys)

    def send_message(self, message):
        self.server_connector.send_message(message, scope=Scope.WEBSOCKET)

    def handle_event(self, message, _):
        self._frontend_message_storage.save_message(message)
        if message['key'] == 'recover':
            self.recover_frontend()
        self.send_message(message)

    def recover_frontend(self):
        for message in self._frontend_message_storage.messages:
            self.send_message(message)