Rork × Stripe サブスクリプション実装 — アプリ収益化の

import { useEffect, useState } from 'react';
 
export function PricingPlans() {
  const [plans, setPlans] = useState([]);
 
  useEffect(() => {
    // バックエンドから計画一覧を取得
    fetch('/api/stripe/plans')
      .then(res => res.json())
      .then(data => setPlans(data))
      .catch(err => console.error('Failed to load plans:', err));
  }, []);
 
  const handleSubscribe = async (priceId) => {
    // ユーザーを Checkout セッションへ遷移
    const response = await fetch('/api/stripe/checkout', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ priceId })
    });
    const { sessionId } = await response.json();
 
    // Stripe Checkout へリダイレクト
    window.location.href = `https://checkout.stripe.com/pay/${sessionId}`;
  };
 
  return (
    <div className="pricing-grid">
      {plans.map(plan => (
        <div key={plan.id} className="pricing-card">
          <h2>{plan.name}</h2>
          <p className="price">
            ${plan.price_cents / 100} / 月
          </p>
          <ul className="features">
            {plan.features.map(feature => (
              <li key={feature}>{feature}</li>
            ))}
          </ul>
          <button
            onClick={() => handleSubscribe(plan.price_id)}
            className="btn-subscribe"
          >
            今すぐ登録
          </button>
        </div>
      ))}
    </div>
  );
}
 
// Expected output:
// ┌─────────────────┬─────────────────┬─────────────────┐
// │ Basic           │ Pro             │ Premium         │
// │ $9.99 / month   │ $19.99 / month  │ $49.99 / month  │
// │ ・保存数: 10    │ ・無制限保存    │ ・Pro のすべて  │
// │ ・広告あり      │ ・広告なし      │ ・優先サポート  │
// │ [登録]          │ [登録]          │ [登録]          │
// └─────────────────┴─────────────────┴─────────────────┘

import { useEffect, useState } from 'react';
 
export function UserSubscriptionStatus() {
  const [user, setUser] = useState(null);
  const [loading, setLoading] = useState(true);
 
  useEffect(() => {
    fetch('/api/user/subscription-status')
      .then(res => res.json())
      .then(data => {
        setUser(data);
        setLoading(false);
      });
  }, []);
 
  if (loading) return <p>Loading...</p>;
  if (!user) return <p>Please log in first</p>;
 
  return (
    <div className="user-subscription">
      <h2>Your Subscription</h2>
 
      {user.subscription ? (
        <>
          <p>
            Plan: <strong>{user.subscription.plan_name}</strong>
          </p>
          <p>
            Status: <strong>
              {user.subscription.status === 'active' ? '✓ Active' : '⚠ ' + user.subscription.status}
            </strong>
          </p>
          <p>
            Next billing: {new Date(user.subscription.next_billing_date).toLocaleDateString()}
          </p>
 
          <button onClick={() => handleCancelSubscription(user.subscription.id)}>
            サブスク解除
          </button>
        </>
      ) : (
        <p>You are currently on the Free plan. <a href="/pricing">Upgrade now</a></p>
      )}
    </div>
  );
}
 
const handleCancelSubscription = async (subscriptionId) => {
  const confirmed = window.confirm('解除してもよろしいですか？');
  if (!confirmed) return;
 
  await fetch('/api/stripe/cancel-subscription', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ subscriptionId })
  });
 
  alert('サブスクリプションが解除されました。');
  window.location.reload();
};
 
// Expected output:
// ┌──────────────────────────────────┐
// │ Your Subscription                │
// │ Plan: Pro                        │
// │ Status: ✓ Active                 │
// │ Next billing: Mar 28, 2026       │
// │ [サブスク解除]                   │
// └──────────────────────────────────┘

import Stripe from 'stripe';
 
const stripe = new Stripe(process.env.STRIPE_SECRET_KEY, {
  apiVersion: '2023-10-16'
});

// POST /api/stripe/checkout
app.post('/api/stripe/checkout', async (req, res) => {
  const { priceId } = req.body;
  const userId = req.user.id; // 認証ユーザーから取得
 
  try {
    const session = await stripe.checkout.sessions.create({
      payment_method_types: ['card'],
      customer_email: req.user.email,
      line_items: [
        {
          price: priceId,
          quantity: 1
        }
      ],
      mode: 'subscription',
      success_url: `${process.env.APP_URL}/success?session_id={CHECKOUT_SESSION_ID}`,
      cancel_url: `${process.env.APP_URL}/pricing`,
      // 重要: メタデータでユーザー情報を紐付け
      metadata: {
        userId: userId
      }
    });
 
    res.json({ sessionId: session.id });
  } catch (error) {
    console.error('Checkout error:', error);
    res.status(500).json({ error: error.message });
  }
});
 
// Expected output:
// POST /api/stripe/checkout
// Request: { "priceId": "price_1MqAaBxxxxxxxxx" }
// Response: { "sessionId": "cs_test_aBcDeFgHiJkLmNoPqRsT..." }

import express from 'express';
import bodyParser from 'body-parser';
 
const webhookSecret = process.env.STRIPE_WEBHOOK_SECRET;
 
// Webhook 用エンドポイント
// ⚠️ 通常の JSON パーサーではなく raw を使用（Stripe の署名検証に必須）
app.post(
  '/api/webhooks/stripe',
  bodyParser.raw({ type: 'application/json' }),
  async (req, res) => {
    const sig = req.headers['stripe-signature'];
 
    let event;
    try {
      event = stripe.webhooks.constructEvent(
        req.body,
        sig,
        webhookSecret
      );
    } catch (err) {
      console.error('Webhook signature verification failed:', err.message);
      return res.sendStatus(400);
    }
 
    // イベントタイプごとに処理分岐
    switch (event.type) {
      case 'customer.subscription.created': {
        const subscription = event.data.object;
        const userId = subscription.metadata.userId;
 
        // データベースに保存
        await db.subscription.create({
          userId,
          stripeSubscriptionId: subscription.id,
          stripePriceId: subscription.items.data[0].price.id,
          status: subscription.status,
          currentPeriodEnd: new Date(subscription.current_period_end * 1000)
        });
 
        console.log(`✓ Subscription created for user ${userId}`);
        break;
      }
 
      case 'customer.subscription.updated': {
        const subscription = event.data.object;
        const userId = subscription.metadata.userId;
 
        // ステータス更新（特に cancel_at が設定された場合）
        await db.subscription.update(
          { stripeSubscriptionId: subscription.id },
          {
            status: subscription.status,
            currentPeriodEnd: new Date(subscription.current_period_end * 1000),
            canceledAt: subscription.canceled_at
              ? new Date(subscription.canceled_at * 1000)
              : null
          }
        );
 
        console.log(`✓ Subscription updated for user ${userId}`);
        break;
      }
 
      case 'customer.subscription.deleted': {
        const subscription = event.data.object;
        const userId = subscription.metadata.userId;
 
        // サブスク削除時の処理
        await db.subscription.update(
          { stripeSubscriptionId: subscription.id },
          { status: 'canceled', deletedAt: new Date() }
        );
 
        // アプリのプロフィールを無料版に戻す
        await db.user.update(
          { id: userId },
          { tier: 'free' }
        );
 
        console.log(`✓ Subscription deleted for user ${userId}`);
        break;
      }
 
      case 'invoice.paid': {
        const invoice = event.data.object;
        console.log(`✓ Invoice paid: ${invoice.id}`);
        // 請求書送信メール等の処理
        break;
      }
 
      case 'invoice.payment_failed': {
        const invoice = event.data.object;
        console.warn(`⚠ Invoice payment failed: ${invoice.id}`);
        // リトライアラートやメール送信
        break;
      }
 
      default:
        console.log(`Unhandled event type: ${event.type}`);
    }
 
    res.sendStatus(200);
  }
);
 
// Expected output:
// Webhook イベント受信時:
// "✓ Subscription created for user 12345"
// "✓ Invoice paid: in_1MqAaBxxxxxxxxx"
// "⚠ Invoice payment failed: in_1MqBbCyyyyyyyyy"

// GET /api/user/subscription-status
app.get('/api/user/subscription-status', async (req, res) => {
  const userId = req.user.id;
 
  const subscription = await db.subscription.findFirst({
    where: { userId, status: 'active' }
  });
 
  if (!subscription) {
    return res.json({
      userId,
      subscription: null,
      tier: 'free'
    });
  }
 
  res.json({
    userId,
    subscription: {
      id: subscription.stripeSubscriptionId,
      plan_name: subscription.stripePriceId.includes('pro') ? 'Pro' : 'Basic',
      status: subscription.status,
      next_billing_date: subscription.currentPeriodEnd
    },
    tier: 'premium'
  });
});
 
// Expected output:
// {
//   "userId": "12345",
//   "subscription": {
//     "id": "sub_1MqAaBxxxxxxxxx",
//     "plan_name": "Pro",
//     "status": "active",
//     "next_billing_date": "2026-04-27T10:00:00Z"
//   },
//   "tier": "premium"
// }

// アプリ起動時に Receipt を確認
async function verifySubscriptionOnAppStart() {
  const token = localStorage.getItem('stripe_session_token');
 
  if (token) {
    const response = await fetch('/api/verify-receipt', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ token })
    });
 
    if (response.ok) {
      const { isValid, expiresAt } = await response.json();
 
      if (isValid) {
        // サブスク有効期限をチェック
        if (new Date() < new Date(expiresAt)) {
          activatePremiumFeatures();
        } else {
          // 期限切れ → 無料版に降格
          deactivatePremiumFeatures();
        }
      }
    }
  }
}
 
// Expected output:
// アプリ起動
//   ↓
// "✓ Subscription valid until: 2026-04-27"
//   ↓
// プレミアム機能を有効化

function CancelSubscriptionButton({ subscriptionId }) {
  const [showConfirm, setShowConfirm] = useState(false);
  const [selectedReason, setSelectedReason] = useState('');
 
  const handleCancel = async () => {
    // 解約理由を記録（リテンション施策の参考に）
    await fetch('/api/subscription/cancel-feedback', {
      method: 'POST',
      body: JSON.stringify({
        subscriptionId,
        cancelReason: selectedReason,
        timestamp: new Date()
      })
    });
 
    // キャンセル処理
    await fetch('/api/stripe/cancel-subscription', {
      method: 'POST',
      body: JSON.stringify({ subscriptionId })
    });
 
    setShowConfirm(false);
    alert('Your subscription has been canceled.');
  };
 
  if (!showConfirm) {
    return (
      <button onClick={() => setShowConfirm(true)} className="btn-danger">
        Cancel Subscription
      </button>
    );
  }
 
  return (
    <div className="cancel-confirmation">
      <h3>We're sorry to see you go!</h3>
 
      <p>Why are you leaving? (This helps us improve)</p>
      <select value={selectedReason} onChange={(e) => setSelectedReason(e.target.value)}>
        <option value="">-- Select a reason --</option>
        <option value="too-expensive">Too expensive</option>
        <option value="not-using">Not using enough</option>
        <option value="found-alternative">Found alternative</option>
        <option value="other">Other</option>
      </select>
 
      {selectedReason === 'too-expensive' && (
        <div className="retention-offer">
          <p>💰 We have a 50% discount available for 3 months. Would you like to try that?</p>
          <button className="btn-secondary">Apply Discount</button>
        </div>
      )}
 
      <button onClick={handleCancel} className="btn-danger-confirm">
        Confirm Cancellation
      </button>
      <button onClick={() => setShowConfirm(false)} className="btn-secondary">
        Keep My Subscription
      </button>
    </div>
  );
}
 
// Expected output:
// ┌──────────────────────────────────────┐
// │ We're sorry to see you go!           │
// │                                      │
// │ Why are you leaving?                 │
// │ [v] -- Select a reason --            │
// │     → Too expensive                  │
// │     → Not using enough               │
// │     → Found alternative              │
// │                                      │
// │ [💰 Apply Discount] [Cancel] [Back] │
// └──────────────────────────────────────┘

// 毎月実行される定期タスク
async function monthlyRetentionCheck() {
  // 来月キャンセル予定のユーザーを抽出
  const pendingCancellations = await db.subscription.findMany({
    where: {
      status: 'active',
      canceledAt: { not: null }
    }
  });
 
  for (const sub of pendingCancellations) {
    const daysUntilCancellation = Math.ceil(
      (new Date(sub.currentPeriodEnd) - new Date()) / (1000 * 60 * 60 * 24)
    );
 
    // 7日前にウィンバックメール送信
    if (daysUntilCancellation === 7) {
      await sendWinbackEmail({
        email: sub.user.email,
        plan: sub.stripePriceId,
        offer: '特別オファー: 50% OFF for 3 months'
      });
    }
  }
}
 
// Expected output:
// Retention task executed
// Found 23 pending cancellations
// Sent 23 winback emails