firebase functions iOS サブスク更新をチェックして最新レシートをFirestoreに保存する

purchase.js

exports.verifySubscriptionIos = functions.pubsub.schedule('0 1 * * 0').timeZone('Asia/Tokyo').onRun(async (context) => {
  // 該当レシートを検索
  const now = Date.now();
  const termTime = 24 * 60 * 60 * 1000; // 24時間間隔でチェックするため
  const minTime = now - termTime;

  const receiptsSnapshot = await admin.firestore().collectionGroup("receipts")
    .where("expires_date_ms", "<=", now)
    .where("expires_date_ms", ">", minTime)
    .orderBy("expires_date_ms")
    .orderBy("transaction_id")
    .get();

  if (receiptsSnapshot.empty) {
    console.log('result: DOCUMENT_NOT_FOUND');
    return { result: DOCUMENT_NOT_FOUND };
  }

  console.log('Find target receipts.');

  receiptsSnapshot.forEach(async doc => {
    // receipt_data を使って検証する
    const verificationData = doc.data().receipt_data;
    const latestReceipt = await verifyReceiptIos(verificationData, null);

    if (latestReceipt === null || latestReceipt === undefined) {
      console.log('result: INVALID_RECEIPT');
      return { result: INVALID_RECEIPT };
    }

    // 期限内であることを確認する
    const expireDate = Number(latestReceipt["expires_date_ms"]);
    if (now < expireDate) {
      // Firestoreに保存する
      const userRef = doc.ref.parent.parent;
      const receiptRef = userRef.collection('receipts').doc();

      const result = await receiptRef.set({
        receipt_data : verificationData,
        product_id : latestReceipt["product_id"],
        transaction_id : latestReceipt["transaction_id"],
        purchase_date_ms : parseInt(latestReceipt["purchase_date_ms"]),
        purchase_date : latestReceipt["purchase_date"],
        expires_date_ms : parseInt(latestReceipt["expires_date_ms"]),
        expires_date : latestReceipt["expires_date"],
        created_at: Firestore.FieldValue.serverTimestamp(),
      });
      console.log('firestore set document, SUCCESS.');
      return { result: SUCCESS };
    } else {
      console.log('Last receipt is expired, maybe stopped subscription.');
      return { result: EXPIRED };
    }
  });

  // DONE
  console.log("DONE verifySubscriptionIos.");
  return null;
});