Webhook 서명 검증 실패 해결하기

import express from 'express';
import Stripe from 'stripe';

const app = express();
const stripe = new Stripe(process.env.STRIPE_SECRET_KEY || '');

app.post('/webhook/stripe', express.raw({ type: 'application/json' }), (req, res) => {
  const signature = req.headers['stripe-signature'];
  const secret = process.env.STRIPE_WEBHOOK_SECRET || '';

  try {
    const event = stripe.webhooks.constructEvent(req.body, String(signature), secret);
    // TODO: handle event with idempotency check
    res.status(200).send('ok');
  } catch (err) {
    res.status(400).send('signature verification failed');
  }
});