monkey-patch object coming from callback

Question

The Python Telegram bot library utilizes callbacks/handlers. If we define this:

self.dispatcher.add_handler(CommandHandler("help", self.help))

Then self.help() will receive the args bot and update when a certain event occurs.

One of those args, bot, has a method called send_message. I want to prefix all of my bot's messages with a certain string. What I don't want:

Do it manually each time in bot.send_message. like this: send_message(text= prefix + " Hello").
Having to monkey patch the bot.send_message method, like suggested in the answer to the aforementioned question. I have several other methods besides self.help() and this doesn't seem to abide the DRY rule.

The challenge here seems to be that I'm receiving a new instance of bot each time the callback is fired.

What are my options, if any?

I'm calling bot.message() in a variety of ways (mixed args and kwargs). For example, parse_mode can be absent in some calls.

bot.send_message(
            chat_id=update.message.chat_id,
            text=txt,
            parse_mode=telegram.ParseMode.MARKDOWN,
        )

Edit your local installation of `.../site_packages/telegram/bot.py` (or whatever the filename is), and insert the desired text in the `send_message()` function. — John Gordon, Jun 17 '19 at 23:31
@JohnGordon - that sounds very naughty, is it the only DRY way? — zerohedge, Jun 17 '19 at 23:32
@JohnGordon - also, my script will have to be portable, so even that doesn't really sound too attractive. — zerohedge, Jun 17 '19 at 23:33
What function are you calling from your code? Is it `bot.send_message()`, or `bot.help()`, or some other function? — John Gordon, Jun 17 '19 at 23:37
@JohnGordon I am calling bot.send_message(), bot is an arg in self.help(), which is invoked by a callback. — zerohedge, Jun 17 '19 at 23:39

score 1 · Accepted Answer · answered Jun 17 '19 at 23:44

1

If I understand correctly, you are calling bot.send_message() directly from your code. Presumably it's something like this:

bot = Bot(...)
bot.send_message("something")

You could make your own wrapper function that takes the bot instance and the message, and inserts the desired extra text:

def send_message_plus(bot, message):
    bot.send_message("This is extra " + message)

Then you would just call the wrapper function:

send_message_plus(bot, message)

answered Jun 17 '19 at 23:44

John Gordon

`send_message()` takes (potentially) many `args` and `kwargs` – zerohedge Jun 17 '19 at 23:45
When you call it yourself, are you actually using args and kwargs? Or do you just use it with one plain string, as in your example? – John Gordon Jun 17 '19 at 23:49
1

You could modify the wrapper function to add the kwargs, but at that point it seems like less effort to forget about the wrapper function and just add the text to each call. – John Gordon Jun 18 '19 at 00:11
Yep. Thanks for your help. – zerohedge Jun 18 '19 at 00:15

1 Answers1