firebase functions verifyIos iOS 購入を検証してFirestoreに保存する

purchase.js

exports.verifyIos = functions.https.onCall(async (data, context) => {
  if (context.auth === null) {
    return { result: NO_AUTH };
  }

  const uid = context.auth.uid;
  const verificationData = data["data"];

  const latestReceipt = await verifyReceiptIos(
    verificationData,
    context.auth
  );
  if (latestReceipt === null || latestReceipt === undefined) {
    return { result: INVALID_RECEIPT };
  }

  // 同じTransactionIdが存在するか確認し、購入情報が既に登録済みでないか確認する
  const queryId = await admin.firestore().collectionGroup("receipts")
    .where("transaction_id", "==", latestReceipt["transaction_id"])
    .get();

  if (!queryId.empty) {
    return { result: ALREADY_EXIST };
  }

  // Firestoreに保存する
  const receiptRef = admin.firestore()
    .collection('users').doc(uid).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(),
  });

  // 期限内であることを確認する
  const now = Date.now();
  const expireDate = Number(latestReceipt["expires_date_ms"]);
  if (now < expireDate) {
    return { result: SUCCESS };
  } else {
    return { result: EXPIRED };
  }
});