RevenueCat vs StoreKit 2 (kendi altyapın) 比較

// RevenueCat - エンタイトルメント確認と購入(iOS SDK 5.x)
import RevenueCat

func configureRevenueCat() {
    Purchases.logLevel = .debug
    Purchases.configure(withAPIKey: "appl_XXXXXXXXXXXX")
}

func unlockProIfEntitled() async {
    do {
        let customerInfo = try await Purchases.shared.customerInfo()
        if customerInfo.entitlements["pro"]?.isActive == true {
            print("Pro エンタイトルメント有効")
        }
    } catch {
        print("customerInfo エラー: \(error)")
    }
}

func purchasePro() async {
    do {
        let offerings = try await Purchases.shared.offerings()
        guard let package = offerings.current?.availablePackages.first else { return }

        let result = try await Purchases.shared.purchase(package: package)
        if result.customerInfo.entitlements["pro"]?.isActive == true {
            print("購入成功、Pro 有効")
        }
    } catch {
        print("購入エラー: \(error)")
    }
}

// StoreKit 2 - トランザクションの監視とエンタイトルメント確認(自前基盤)
import StoreKit

func listenForTransactions() -> Task<Void, Error> {
    Task.detached {
        for await result in Transaction.updates {
            switch result {
            case .verified(let transaction):
                await grantEntitlement(for: transaction)
                await transaction.finish()
            case .unverified(_, let error):
                print("検証失敗: \(error)")
            }
        }
    }
}

func checkCurrentEntitlement() async -> Bool {
    for await result in Transaction.currentEntitlements {
        guard case .verified(let transaction) = result else { continue }
        if transaction.productID == "pro_monthly" {
            return true
        }
    }
    return false
}

func purchase(product: Product) async throws {
    let result = try await product.purchase()
    switch result {
    case .success(let verification):
        guard case .verified(let transaction) = verification else { return }
        await grantEntitlement(for: transaction)
        await transaction.finish()
    case .userCancelled, .pending:
        break
    @unknown default:
        break
    }
}

func grantEntitlement(for transaction: Transaction) async {
    // サーバーにJWSを送信し、App Store Server APIでクロス検証する
}