Basic telegram bot

telegram-bot.js

addEventListener("fetch", (event) => {
  event.respondWith(
    handleRequest(event.request).catch(
      (err) => new Response(err.stack, { status: 500 })
    )
  );
})

function sendMessage(chat_id, text) {
  return fetch(`https://api.telegram.org/bot${BOT_TOKEN}/sendMessage`, {
    method: "POST",
    headers: {
      'Accept': 'application/json',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      chat_id,
      text
    })
  });
}

async function getMembers() {
  const members = await kv.get('telegram-chat-members'); 
  return new Set(members?.split(','));
}

async function saveMembers(members) {
  await kv.put('telegram-chat-members', String([...members]));
  return members;
}

// https://core.telegram.org/bots/api#getting-updates
// https://core.telegram.org/bots/api#update
// https://core.telegram.org/bots/api#message
// https://core.telegram.org/bots/api#messageentity
async function handleUpdate(update) {  
  if (update.message) {
    const members = await getMembers();
    const message = update.message;
    const from = message.from;

    // We do nothing with other bots here
    if (from.is_bot) {
      return new Response(null, { status: 204 });
    }

    else if (/^\/start$/.test(message.text)) {
      if (members.has(String(from.id))) {
        await sendMessage(message.chat.id, `Bonjour ${from.first_name}, content de te revoir !`);
      } else {
        await saveMembers(members.add(from.id));
        await sendMessage(message.chat.id, `Bienvenue ${from.first_name}`);
      }
    }

    else if (/^\/ping$/.test(message.text)) {
      await sendMessage(message.chat.id, 'pong');
    }

    else if (/(bonjour|salut|hello|yo)/i.test(message.text)) {
      await sendMessage(message.chat.id, `Bonjour ${from.first_name} 😊`);
    }

    else if (/(btc|bitcoin)/i.test(message.text)) {
      const res = await fetch('https://api.kraken.com/0/public/Ticker?pair=BTCEUR');
      const json = await res.json();
      const price = parseInt(json.result.XXBTZEUR.a[0]);
      await sendMessage(message.chat.id, `Le Bitcoin s'échange actuellement à ${price}€`);
    }
  }

  return new Response(null, { status: 204 });
}

/**
 * Many more examples available at:
 *   https://developers.cloudflare.com/workers/examples
 * @param {Request} request
 * @returns {Promise<Response>}
 */
async function handleRequest(request) {
  const { pathname } = new URL(request.url);

  if (request.method == 'POST' && pathname.startsWith("/api/hook")) {
    const token = pathname.slice(10);

    // https://core.telegram.org/bots/api#setwebhook
    // https://core.telegram.org/bots/api#deletewebhook
    if (token != BOT_HOOK_SECRET) {
      return new Response("Invalid token", { status: 401 });
    }

    return request.json().then((update) => handleUpdate(update));
  }

  return new Response(null, { status: 204 });
}