Exception Handling

In python-telegram-bot, we have error handlers that take care of all TelegramError exceptions that are risen, so you can react to them. Example: You're trying to send a message, but the user blocked the bot. An Unauthorized exception, a subclass of TelegramError, will be raised and delivered to your error handler, so you can delete it from your conversation list, if you keep one.

Example code:

from telegram.error import TelegramError, Unauthorized, TimedOut, NetworkError

def error_callback(bot, update, error):
    try:
        raise error
    except Unauthorized:
        # remove update.message.chat_id from conversation list
    except TimedOut:
        # handle slow connection problems
    except NetworkError:
        # handle other connection problems
    except TelegramError:
        # handle all other telegram related errors

dispatcher.addErrorHandler(error_callback)

Other exceptions

If a handler raises an uncaught exception that is no TelegramError (e.g. an IndexError), the exception will be caught and logged by the Dispatcher, so that the bot does not crash but you still have an indication of it and can address the issue. To take advantage of this, it is imperative to set up the logging module.

Example code:

logging.basicConfig(
        format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
        level=logging.INFO)