Sending a message with a python telegram bot without a command from the user?

Question

Is there a way to send a message (call a function), without a command from the bot's user? For example when a certain condition is met?

Currently I have only been able to call a function with a command.

I have been trying the following:

from telegram.ext import Updater, CommandHandler, CallbackContext
from telegram import Update
from datetime import datetime
import telebot as tb
import logging

bot = tb.TeleBot(API_KEY)

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


def messager(update: Update, context: CallbackContext) -> None:
    """this function messages at a specific time"""
    update.message.reply_text("message back")

if __name__ == "__main__":
    updater = Updater(API_KEY)

    dispatcher = updater.dispatcher

    dispatcher.add_handler(CommandHandler("message", messager))

    condition = False #I have been changing this when testing
    if (condition == True):
        messager() # how to call messager here? how to pass update and context arguments?

    updater.start_polling()
    updater.idle()

Any possible way to achieve this would be great.

Answer 1

You cannot call a function using update and context since there is no update from the telegram servers to act on. In other words there is no event to perform a callback on.

Depending on what you want to do you could use a MessageHandler instead of a CommandHandler to reply to any message with Filters to filter out which ones to reply to

or if you want to send a message every time you start your bot and you know who to send a message to (ie you have their chat_id ) you can do

if condition:
    updater.bot.send_message(chat_id=CHAT_ID, text="message back")

or if you just want to send a message every time some user starts a chat with your bot you could use the start command which is sent by default to start a chat with a bot