nicegui/website/documentation/content/more/log_documentation.py

from nicegui import ui

from ...model import UiElementDocumentation


class LogDocumentation(UiElementDocumentation, element=ui.log):

    def main_demo(self) -> None:
        from datetime import datetime

        log = ui.log(max_lines=10).classes('w-full h-20')
        ui.button('Log time', on_click=lambda: log.push(datetime.now().strftime('%X.%f')[:-5]))

    def more(self) -> None:
        @self.demo('Attach to a logger', '''
            You can attach a `ui.log` element to a Python logger object so that log messages are pushed to the log element.
        ''')
        def logger_handler():
            import logging
            from datetime import datetime

            logger = logging.getLogger()

            class LogElementHandler(logging.Handler):
                """A logging handler that emits messages to a log element."""

                def __init__(self, element: ui.log, level: int = logging.NOTSET) -> None:
                    self.element = element
                    super().__init__(level)

                def emit(self, record: logging.LogRecord) -> None:
                    try:
                        msg = self.format(record)
                        self.element.push(msg)
                    except Exception:
                        self.handleError(record)

            log = ui.log(max_lines=10).classes('w-full')
            logger.addHandler(LogElementHandler(log))
            ui.button('Log time', on_click=lambda: logger.warning(datetime.now().strftime('%X.%f')[:-5]))