how to send message when start private chat with python telegram bot

Question

I want to write a telegram bot. I want my bot to send a message when any user start chat in the private chat with my bot.

here is my code

def start_chat(update: Update, context: CallbackContext):
    context.bot.send_message(
        chat_id=update.effective_chat.id,
        text=f"Welcome, nice to meet you{os.linesep}"
             f"/what would you like me to do?{os.linesep}"
    )
bot = Updater(token=token, use_context=True)
bot.dispatcher.add_handler(MessageHandler(Filters.text, start_chat))

is there a filter or perhaps a handler that can alert me only in the first message in the private chat?

Answer 1

When a user starts a bot, /start command will be sent to bot from user. Therefore, you have to add CommandHandler instead of MessageHandler.

Here's the modified code of yours:

def start_chat(update: Update, context: CallbackContext):
    context.bot.send_message(
        chat_id=update.effective_chat.id,
        text=f"Welcome, nice to meet you{os.linesep}"
             f"/what would you like me to do?{os.linesep}"
    )
bot = Updater(token=token, use_context=True)
bot.dispatcher.add_handler(CommandHandler('start', start_chat))

Or you could also use MessageHandler with Filters.regex('^/start$') to capture the /start command.

bot.dispatcher.add_handler(MessageHandler(Filters.regex('^/start$'), start_chat))