Exceptions

Exceptions can be thrown while processing user responses. The exception text can be displayed to the user. In case of an unexpected exception, a default message will be displayed. See here for how to configure it and add custom exceptions.

ChatException will write an exception message back to the chat where the request came from.

fun BotHandling.exceptionCommand() {
    command("/exception") {
        throw ChatException("usually exception to display to the user")
    }
}

fun BotHandling.exceptionCommand() {
    command("/exception_unexpected") {
        // this message will be displayed only in logs (with stacktrace)
        throw RuntimeException("user will not see this message")
        // user will see message like "Oops! Unexpected Error. Please contact with developers."
    }
}

If an exception is thrown at some step, the bot will wait for a message from the user again and again at the same step. Until the user enters a valid response.

fun BotHandling.startCommand() {
    command("/start", next = "get_age") {
        sendMessage("Please enter your age")
    }

    step("get_age", next = "get_name") {
        // until the user enters an integer, the chain will be at this step
        val age = text.toIntOrNull() ?: throw ChatException("An integer is expected")

        sendMessage("$age years - recorded")
        sendMessage("Please enter your name")
    }

    step("get_name") {
        sendMessage("Hello, $text!")
    }
}

Last modified: 07 September 2024