How do I implement the automatic reply feature with a telegram bot

Question

So I am building a bot that will accept a date string with a command like this /add-date 1997.

I also want to handle it properly when users send the command without the date like this /add-date. I have been looking for a way to copy the strategy of some other bots like @vkmusic_bot that handle this case in the following way:

1, upon receiving the /song command, the bot will send this message

What song are you looking for?

2, It will automatically prepare a reply at the bottom field tagged to the first reply of the bot.

Now given a song title, it will do the same thing that it would have had the user sent /song [song title]. Manually replying to the What song are you looking for? text has the same effect.

This only works in groups though.

I can't figure out how they're doing this. Would love to get any help on this 🙏

Also, I am building the bot on node.js with the node-telegram-bot-api

Answer 1

Your question is a bit unclear. I'm assuming you want to implement a similar behaviour on the bot such that it to handle the /date command in two ways:

• If a date is provided (e.g., /date 08/05/2000), process it immediately.
• If no date is given (just /date), ask the user for a date before processing.

Here's the code for that:

// Create RegEx for the format of your choice. The following will accept DD/MM/YYYY
const dateRegex = /\d{1,2}\/\d{1,2}\/\d{2,4}/

bot.on("message", (msg) => {
    /// Ignore if the message is not /date command
    if (!msg.text?.startsWith("/date")) return;

    // Checks if the command is exactly "/date" without the date specified.
    if (msg.text == "/date") {
        bot.sendMessage(msg.chat.id, "Send me a date to continue.", {
            reply_markup: {
                force_reply: true, // Automatically goes to reply to this particular message
            }
        });
        return;
    }

    /// If the command contains a date, extract it with the specified regex and process it
    const match = dateRegex.match(msg.text);
    const date = match[0];
    if (date) {
        processDate(date);
    }
});

// Process incoming date message (this will be executed when the user sends the date alone - also as a reply to the bot's message)
bot.onText(dateRegex, (msg) => {
    const match = dateRegex.match(msg.text);
    const date = match[0];
    processDate(date);
})

// A method to process the date
function processDate(date) {
    // ...
}

Hope this helps!