Recover abandoned carts

curl https://api.stripe.com/v1/checkout/sessions \
  -u "
sk_test_4eC39HqLyjWDarjtT1zdp7dc
:" \
  -d "line_items[0][price]"=
{{PRICE_ID}} \
  -d "line_items[0][quantity]"=2 \
  -d customer=
{{CUSTOMER_ID}} \
  -d mode=payment \
  --data-urlencode success_url="https://example.com/success" \
  -d "consent_collection[promotions]"=auto

curl https://api.stripe.com/v1/checkout/sessions \
  -u "
sk_test_4eC39HqLyjWDarjtT1zdp7dc
:" \
  -d "line_items[0][price]"=
{{PRICE_ID}} \
  -d "line_items[0][quantity]"=1 \
  -d mode=payment \
  --data-urlencode success_url="https://example.com/success" \
  -d customer=
{{CUSTOMER_ID}} \
  -d "consent_collection[promotions]"=auto \
  -d "after_expiration[recovery][enabled]"=true \
  -d "after_expiration[recovery][allow_promotion_codes]"=true

// Find your endpoint's secret in your Dashboard's webhook settings
const endpointSecret = 'whsec_...';

// Using Express
const app = require('express')();

// Use body-parser to retrieve the raw body as a buffer
const bodyParser = require('body-parser');

const sendRecoveryEmail = (email, recoveryUrl) => {
  // TODO: fill me in
  console.log("Sending recovery email", email, recoveryUrl);
}

app.post('/webhook', bodyParser.raw({type: 'application/json'}), (request, response) => {
  const payload = request.body;
  const sig = request.headers['stripe-signature'];

  let event;

  try {
    event = stripe.webhooks.constructEvent(payload, sig, endpointSecret);
  } catch (err) {
    return response.status(400).send(`Webhook Error: ${err.message}`);
  }

  // Handle the checkout.session.expired event
  if (event.type === 'checkout.session.expired') {
    const session = event.data.object;

    // When a Checkout Session expires, the customer's email isn't returned in
    // the webhook payload unless they give consent for promotional content
    const email = session.customer_details?.email
    const recoveryUrl = session.after_expiration?.recovery?.url

    // Do nothing if the Checkout Session has no email or recovery URL
    if (!email || !recoveryUrl) {
      return response.status(200).end();
    }

    // Check if the customer has consented to promotional emails and
    // avoid spamming people who abandon Checkout multiple times
    if (
      session.consent?.promotions === 'opt_in'
      && !hasSentRecoveryEmailToCustomer(email)
    ) {
      sendRecoveryEmail(email, recoveryUrl)
    }
  }
  response.status(200).end();
});