WhatsApp ChatGPT Auto-Reply

Wouldn't it be great to have ChatGPT auto-reply to some of your WhatsApp messages on your behalf? Well with a combination of the (unofficial) WhatsApp client library and OpenAI client library we can.

We can do all this in under a 100 lines of code.

TLDR:
Full source code: https://github.com/jmc265/whatsapp-ai-reply

First, let's get some initialisation code down to get the WhatsApp client library connected to your WhatsApp account. The below code will also store the auth information to /mnt/auth-data so that we can restart the process and still remain connected:

import qrcode from 'qrcode-terminal';
import { Client, LocalAuth } from 'whatsapp-web.js';

const whatsAppClient = new Client({
  authStrategy: new LocalAuth({
    dataPath: '/mnt/auth-data'
  }),
  puppeteer: {
    args: ['--no-sandbox'],
  }
});

whatsAppClient.on('qr', qr => {
  qrcode.generate(qr, { small: true });
});

whatsAppClient.on('ready', () => {
  console.log('WhatsApp AI Reply is ready');
});

whatsAppClient.initialize();

Next we need to listen to reaction events. We only care about events that:

• Are sent by ourselves
• Are reactions to text-based messages (not images, audio etc.)

whatsAppClient.on('message_reaction', async (whatsAppReaction) => {
  if (whatsAppReaction.senderId !== 'xxxxxx@c.us') {
    return;
  }
  if (!whatsAppReaction.reaction || whatsAppReaction.reaction === '') {
    return;
  }
  const whatsAppMessage = await whatsAppClient.getMessageById(whatsAppReaction.msgId._serialized);
  if (whatsAppMessage.type !== MessageTypes.TEXT) {
    return;
  }
  ...
});

Lastly, let's ask GPT4 for a response to the message and send it back:

const chatCompletion = await openai.chat.completions.create({
  messages: [
    { role: 'system', content: 'You are an assistant who expands an emoji response to a message into a full text response' },
    { role: 'user', content: whatsAppMessage.body },
    { role: 'user', content: whatsAppReaction.reaction }
  ],
  model: 'gpt-4-1106-preview',
});
if (chatCompletion.choices[0].message.content) {
  await whatsAppMessage.reply(chatCompletion.choices[0].message.content);
}

And that's all the code we need!

The full source code is available at github.com/jmc265/whatsapp-ai-reply. We can wrap this up in a Dockerfile and also use Docker Compose if we want.