Stripe Payments & SaaS Billing Systems · レッスン

非同期イベント向けWebhookの処理

Stripeからの非同期イベントに反応するWebhookを設定・処理し、決済後にアプリケーションの状態を更新する方法を学びます。

「非同期イベント向けWebhookの処理」はCoddyKit上の無料Stripe Payments & SaaS Billing Systemsレッスンです。これはレッスン2/4です。下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。これはStripe Payments & SaaS Billing Systems学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 Stripe Payments & SaaS Billing Systemsコースには全4レッスンが含まれています。

このレッスンの一部はまだ翻訳されておらず、英語で表示されています。

Payments Aren't Always Instant

When you process payments, things don't always happen instantly. Think about a bank transfer: it takes time for funds to move and clear. This is called an asynchronous event.

Your application needs a way to know when these background processes are complete or if something important changes with a payment.

Webhooks: Your Payment Alarms

This is where webhooks come in! A webhook is an automated message sent from one application to another when a specific event occurs.

They act like 'alarms' or 'notifications'.
Instead of your app constantly asking Stripe, 'Is the payment done yet?' (known as 'polling'), Stripe tells your app directly when something happens.

Stripe's Event Notifications

Stripe uses webhooks to notify your application about important events in your account. These could be:

A payment succeeding or failing.
A refund being issued.
A customer's subscription changing.

By listening to these events, your app can update its own records, send customer emails, or trigger other business logic.

Key Webhook Event Types

There are many types of webhook events, but some are crucial for payment processing:

payment_intent.succeeded: A payment has been successfully captured.
charge.refunded: A refund has been processed for a charge.
customer.subscription.updated: A customer's subscription plan or status has changed.

You choose which events your application wants to receive notifications for.

Setting Up Your Webhook Endpoint

To receive webhook events, you need to provide Stripe with a special URL on your server. This URL is called your webhook endpoint.

When an event occurs, Stripe sends an HTTP POST request to this URL, containing the event data. You configure this URL and select event types in your Stripe Dashboard.

Your Server Listens In

Your webhook endpoint is just a regular HTTP endpoint in your application. It waits for Stripe to send data. Here's a conceptual look at what such an endpoint might do:

public class WebhookController {
  @PostMapping("/stripe-webhook")
  public ResponseEntity<String> handleWebhook(@RequestBody String payload, @RequestHeader("Stripe-Signature") String sigHeader) {
    // 1. Verify the signature (CRUCIAL!)
    // 2. Parse the event payload
    // 3. Process the event based on its type
    return new ResponseEntity<>("Event received", HttpStatus.OK);
  }
}

Trust, But Verify!

Imagine someone malicious sends fake payment success messages to your webhook endpoint. Without verification, your app might mistakenly grant access to a service or ship a product without payment!

This is why webhook signature verification is absolutely critical. It ensures that incoming events truly originate from Stripe and haven't been tampered with.

Secure Your Webhook Endpoint

Stripe sends a unique signature in the Stripe-Signature header with each webhook event. You use your unique webhook secret (from your Stripe Dashboard) to compute a matching signature locally.

If the signatures match, you can trust the event. Here's how you'd use the Stripe Java library to do this:

import com.stripe.model.Event;
import com.stripe.exception.SignatureVerificationException;
import com.stripe.net.Webhook;

public class VerifyWebhook {
  public static void main(String[] args) {
    // In a real app, these come from the HTTP request:
    String jsonPayload = "{"id":"evt_test","object":"event","type":"payment_intent.succeeded"}";
    String stripeSignatureHeader = "t=1678886400,v1=5d53a9f0a... (truncated)"; // Placeholder
    String webhookSecret = "whsec_your_secret_here"; // Get this from Stripe Dashboard

    System.out.println("--- Webhook Signature Verification ---");

    try {
      Event event = Webhook.constructEvent(
          jsonPayload, stripeSignatureHeader, webhookSecret
      );

      System.out.println("✅ Webhook signature verified!");
      System.out.println("Event Type: " + event.getType());
      // Now process the 'event' object safely
    } catch (SignatureVerificationException e) {
      System.err.println("❌ Verification FAILED: " + e.getMessage());
      System.err.println("Make sure the signature and secret are correct.");
    } catch (Exception e) {
      System.err.println("An unexpected error occurred: " + e.getMessage());
    }
  }
}

Robust Event Handling

Beyond security, your webhook handler should be robust:

Respond Quickly (200 OK): Stripe expects a 200 status code within a few seconds. If not, it might retry the event.
Idempotency: Design your handler to process the same event multiple times without causing duplicate actions. Stripe might resend events.
Asynchronous Processing: Don't do heavy processing directly in the webhook endpoint. Delegate tasks to background jobs (e.g., queues) to respond quickly.

Webhook Security Question

Why is it crucial to verify the signature of incoming webhook events from Stripe?

Recap: Webhooks for Async Events

You've learned how webhooks are essential for handling asynchronous events in payment processing:

They provide real-time notifications from Stripe.
You configure an endpoint and listen for specific event types.
Signature verification is critical for security.
Robust handlers respond quickly and process events idempotently.

Mastering webhooks is key to building reliable and secure payment integrations!

よくある質問

「非同期イベント向けWebhookの処理」レッスンは無料ですか？

はい。「非同期イベント向けWebhookの処理」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、Stripe Payments & SaaS Billing Systemsコースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 Stripe Payments & SaaS Billing Systemsコースには全4レッスンが含まれています。

「非同期イベント向けWebhookの処理」で何を学びますか？

Stripeからの非同期イベントに反応するWebhookを設定・処理し、決済後にアプリケーションの状態を更新する方法を学びます。ブラウザで直接実行するハンズオンコードでStripe Payments & SaaS Billing Systemsを演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。

Stripe Payments & SaaS Billing Systemsを始めるのに経験は必要ですか？

事前経験は必要ありません。CoddyKitのStripe Payments & SaaS Billing Systemsは初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。これはレッスン2/4です。

「非同期イベント向けWebhookの処理」レッスンにはどのくらい時間がかかりますか？

ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。

このStripe Payments & SaaS Billing Systemsレッスンでコードを書いて実行できますか？

はい。すべてのStripe Payments & SaaS Billing Systemsレッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。

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