Von Snapshot-Ereignissen zu Thin-Ereignissen migrieren

const express = require('express');
const stripe = require('stripe')(process.env.STRIPE_SECRET_KEY, {
  apiVersion: '2025-11-17.preview'
});

const app = express();

// New thin event endpoint
app.post(
  '/webhook/thin',
  express.raw({type: 'application/json'}),
  async (req, res) => {
    const sig = req.headers['stripe-signature'];
    const thinWebhookSecret = process.env.THIN_WEBHOOK_SECRET;

    try {
      // Verify the signature using the same method as snapshot events
      const thinNotification = stripe.webhooks.constructEvent(
        req.body,
        sig,
        thinWebhookSecret
      );

      console.log(`Verified thin event: ${thinNotification.id}`);

      // For now, just acknowledge receipt
      res.sendStatus(200);
    } catch (err) {
      console.log(`Webhook Error: ${err.message}`);
      res.status(400).send(`Webhook Error: ${err.message}`);
    }
  }
);

app.listen(3000, () => console.log('Running on port 3000'));

curl https://api.stripe.com/v2/core/event_destinations \
  -H "Authorization: Bearer sk_test_..." \
  -H "Stripe-Version: 2025-11-17.preview" \
  -d "name"="Thin Events Destination" \
  -d "type"="webhook_endpoint" \
  -d "event_payload"="thin" \
  -d "webhook_endpoint[url]"="https://yourdomain.com/webhook/thin" \
  -d "enabled_events[]"="v1.customer.created" \
  -d "enabled_events[]"="v1.payment_intent.succeeded" \
  -d "enabled_events[]"="v1.invoice.paid"

// Enable shadow mode via environment variable
const SHADOW_MODE = process.env.SHADOW_MODE !== 'false';

// Fetch the full event details
const event = await stripe.v2.core.events.retrieve(thinNotification.id);

console.log(`Processing ${event.type} (thin ID: ${event.id})`);

// For interop events, log the original snapshot event ID
if (event.snapshot_event) {
  console.log(`Correlated snapshot event: ${event.snapshot_event}`);
}

// Fetch the related object if needed
if (event.type === 'v1.customer.created') {
  const customer = await stripe.customers.retrieve(event.related_object.id);

  if (SHADOW_MODE) {
    // SHADOW MODE: Log what you would do, but don't do it yet
    console.log(`[SHADOW] Would create customer record: ${customer.id}`);
    // recordMetric('customer.created.thin', 1);
  } else {
    // Production mode: Actually write to database
    await createCustomerInDatabase(customer);
  }
}

const SHADOW_MODE = process.env.SHADOW_MODE !== 'false';  // ← NEW

app.post(
  '/webhook/thin',
  express.raw({type: 'application/json'}),
  async (req, res) => {
    const sig = req.headers['stripe-signature'];
    const thinWebhookSecret = process.env.THIN_WEBHOOK_SECRET;

    try {
      const thinNotification = stripe.webhooks.constructEvent(
        req.body,
        sig,
        thinWebhookSecret
      );

      // ← NEW: Fetch full event details
      const event = await stripe.v2.core.events.retrieve(thinNotification.id);

      console.log(`Processing ${event.type} (thin ID: ${event.id})`);

      // ← NEW: Log snapshot event ID for correlation
      if (event.snapshot_event) {
        console.log(`Correlated snapshot event: ${event.snapshot_event}`);
      }

      // ← NEW: Fetch related object and handle in shadow mode
      if (event.type === 'v1.customer.created') {
        const customer = await stripe.customers.retrieve(event.related_object.id);

        if (SHADOW_MODE) {
          console.log(`[SHADOW] Would create customer record: ${customer.id}`);
        } else {
          await createCustomerInDatabase(customer);
        }
      }

      res.sendStatus(200);
    } catch (err) {
      console.log(`Webhook Error: ${err.message}`);
      res.status(400).send(`Webhook Error: ${err.message}`);
    }
  }
);

CREATE TABLE event_idempotency (
  idempotency_key TEXT PRIMARY KEY,
  event_type TEXT NOT NULL,
  processed_at INTEGER NOT NULL
);

// Try to insert idempotency key. Returns true if successfully inserted, false if duplicate.
function tryInsertIdempotencyKey(idempotencyKey, eventType) {
  try {
    db.prepare(`
      INSERT INTO event_idempotency (idempotency_key, event_type, processed_at)
      VALUES (?, ?, ?)
    `).run(idempotencyKey, eventType, Date.now());
    return true; // Insert succeeded - event is new
  } catch (err) {
    if (err.code === 'SQLITE_CONSTRAINT') {
      return false; // Duplicate - event already processed (use your database-specific error code for unique constraint violations)
    }
    throw err; // Re-throw unexpected errors
  }
}

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

    try {
      const event = stripe.webhooks.constructEvent(
        req.body,
        sig,
        snapshotWebhookSecret
      );

      // For snapshot events, idempotency key is just the event ID
      const idempotencyKey = event.id;

      // Try to insert idempotency key. If fails (duplicate), skip processing.
      if (!tryInsertIdempotencyKey(idempotencyKey, event.type)) {
        console.log(`Already processed: ${idempotencyKey}`);
        return res.sendStatus(200);
      }

      // Process the event
      if (event.type === 'customer.created') {
        createCustomerInDatabase(event.data.object);
      }

      res.sendStatus(200);
    } catch (err) {
      console.log(`Webhook Error: ${err.message}`);
      res.status(400).send(`Webhook Error: ${err.message}`);
    }
  }
);

const SHADOW_MODE = process.env.SHADOW_MODE !== 'false';

app.post(
  '/webhook/thin',
  express.raw({type: 'application/json'}),
  async (req, res) => {
    const sig = req.headers['stripe-signature'];
    const thinWebhookSecret = process.env.THIN_WEBHOOK_SECRET;

    try {
      const thinNotification = stripe.webhooks.constructEvent(
        req.body,
        sig,
        thinWebhookSecret
      );
      const event = await stripe.v2.core.events.retrieve(thinNotification.id);

      // For thin interop events, use snapshot_event if present, otherwise event ID
      const idempotencyKey = event.snapshot_event || event.id;

      // Check idempotency first to avoid unnecessary work
      if (!SHADOW_MODE) {
        // Try to insert idempotency key. If fails (duplicate), skip processing.
        if (!tryInsertIdempotencyKey(idempotencyKey, event.type)) {
          console.log(`Already processed: ${idempotencyKey}`);
          return res.sendStatus(200);
        }
      }

      // Process the event
      if (event.type === 'v1.customer.created') {
        const customer = await stripe.customers.retrieve(event.related_object.id);

        if (!SHADOW_MODE) {
          // Process the event
          createCustomerInDatabase(customer);
        } else {
          console.log(`[SHADOW] Would create customer: ${customer.id}`);
          console.log(`[SHADOW] Idempotency key: ${idempotencyKey}`);
        }
      }

      res.sendStatus(200);
    } catch (err) {
      console.log(`Webhook Error: ${err.message}`);
      res.status(400).send(`Webhook Error: ${err.message}`);
    }
  }
);