PhysiGo/serverless_functions/api/push-notification.ts

import { VercelRequest, VercelResponse } from '@vercel/node';
import { initializeApp, cert } from 'firebase-admin/app';
import { getFirestore } from 'firebase-admin/firestore';
import { getMessaging } from 'firebase-admin/messaging';
import { Message } from 'firebase-admin/lib/messaging/messaging-api';

const serviceAccountStringified = Buffer.from(process.env.FIREBASE_SERVICE_ACCOUNT!, 'base64').toString('ascii');
const serviceAccount = JSON.parse(serviceAccountStringified);
initializeApp({
  credential: cert(serviceAccount),
});
const firestore = getFirestore();
const messaging = getMessaging();
export default async function sendPushNotification(req: VercelRequest, res: VercelResponse) {
  const { user_id, title, body } = req.query as { user_id: string; title: string; body: string };

  const friend = await firestore
    .collection('Users')
    .doc(user_id)
    .get();
  if (!friend.exists) {
    return res.status(400).json({ error: "User doesn't exist" });
  }
  const token = friend.data()!['token'];
  const message: Message = {
    notification: {
      title,
      body,
    },
    token,
  };
  messaging
    .send(message)
    .then((response) => {
      console.log('Successfully sent message:', response);
      res.status(200);
    })
    .catch((error) => {
      console.log('Error sending message:', error);
      res.status(500).send(error);
    });
}