Telegram Bot with Telegraf.js - Send messages to chat

Question

I want to create a Telegram Bot with Node.js and I am using Telegraf for it. I know I can answer to messages like this:

app.hears('hi', (ctx) => ctx.reply('Hey there!'))

But how can I send a message without getting a message before? I want to read a file and always when the file got changed I want to send a message.

const Telegraf = require('telegraf');
var fs = require('fs');

const app = new Telegraf(process.env.BOT_TOKEN);

var filePath = "C:\\path\\to\\my\\file.txt";

fs.watchFile(filePath, function() {
    file = fs.readFileSync(filePath);

    // Send message to chat or group with the file content here

    console.log("File content at: " + new Date() + " is: \n" + file);
})

Would be nice if someone can help me with it.

Marnamarne

Having a similar situation xD funny how that usecase is not as straightforward as it is thought to be... So as far as I got it - I need to have the chatID of course if the chat is initially startet just when the bot is running I may get the chatId from the ctx object. But what if the bot just later connects from the service? Do I have to manually find out that specific chatId and provide it to the Bot hardcodedly? – Shennashensi

Answer 1

You can use app.telegram.sendMessage for that, see following snippet.

const Telegraf = require('telegraf');
var fs = require('fs');

const app = new Telegraf(process.env.BOT_TOKEN);

var filePath = "C:\\path\\to\\my\\file.txt";

fs.watchFile(filePath, function() {
  file = fs.readFileSync(filePath);
  app.telegram.sendMessage(chatId, "File content at: " + new Date() + " is: \n" + file);
})

Bithia

Ok ty. But I have to add a chat ID as parameter. Do you know how I can get it? – Marnamarne

Found it: api.telegram.org/bot[BOT-TOKEN]/getUpdates -> chat -> id – Marnamarne

I get a 400 Bad Request: chat not found when trying to send a message – Panslavism

Answer 2

app.on('message', function (ctx, next) {
    ctx.telegram.sendMessage(ctx.message.chat.id,
      "File content at: " + new Date() + " is: \n" + file
    )
});

Stichomythia