StoreKit – In App Purchases Implement in iOS App

Debabrata Roy

25 November 2019

Introduction:

StoreKit Support in-app purchases and interactions with the App Store. Storekit provides 3 major services which are:

In-App Purchase.
Apple Music.
Recommendations and reviews.

Today I am going to discuss the In-App Purchases and see the process of integrating In-App Purchase in iOS application with Swift 5.0. In-App Purchase or IAP for short is a feature that gives developers the ability to sell content to the end-user after their app has been downloaded.

Click on My APP option.
choose the app where you want to add IAP services
Now client on the feature option your app and app plus button to create the SKProduct.
And all app options which is needs for iTunes and set prise and discount if you want.
Note: product id should be unique and app bundle id should prefix of this id. For example, the app bundle is com.test.ios and you want to add monthly subscription in your app then you can use com.test.ios.monthly for your SKProduct id.

Steps 4: Now configure IAP service in your app. Open Xcode and create a new product and enable In-App purchase form capabilities

Step 5: Create an enum to manage app product ids.

enum IAPProduct : String {
    case week = "com.test.ios.weekly"
    case month = "com.test.ios.monthly"
    case year = "com.test.ios.yearly"
}

enum IAPProduct : String {

case week = "com.test.ios.weekly"

case month = "com.test.ios.monthly"

case year = "com.test.ios.yearly"

}

Steps 6: Now create an IAP service class.

import StoreKit
class IPAService: NSObject {
    static var shared = IPAService()
    var products = [SKProduct]()
    var paymentQueue = SKPaymentQueue.default()
    private override init() {
    
    }
   
}

import StoreKit

class IPAService: NSObject {

static var shared = IPAService()

var products = [SKProduct]()

var paymentQueue = SKPaymentQueue.default()

private override init() {

}

Step 7: create a method which for requests all information regarding the SKProduct.

   func getProduct(){
        let products : Set = [IAPProduct.week.rawValue,IAPProduct.month.rawValue,IAPProduct.year.rawValue]
        let request = SKProductsRequest(productIdentifiers: products)
        request.delegate = self
        request.start()
        paymentQueue.add(self)
        paymentQueue.restoreCompletedTransactions()
    }

func getProduct(){

let products : Set = [IAPProduct.week.rawValue,IAPProduct.month.rawValue,IAPProduct.year.rawValue]

let request = SKProductsRequest(productIdentifiers: products)

request.delegate = self

request.start()

paymentQueue.add(self)

paymentQueue.restoreCompletedTransactions()

}

Steps 8: implement SKProductsRequestDelegate which handles the request and Store all the SKProduct in a variable which help for future use.

extension IPAService: SKProductsRequestDelegate{
    func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
        for product in response.products{
        print(product.productIdentifier)
    }
        products = response.products
    }
}

extension IPAService: SKProductsRequestDelegate{

func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) {

for product in response.products{

print(product.productIdentifier)

}

products = response.products

}

Step 9: Call the getProduct() from the viewController or where you want to call.

IPAService.shared.getProduct()

1	IPAService.shared.getProduct()

Now you can check SKProduct details on the console.

Steps 10: Now create a purchase request for creating the transaction.

func purchase(product:IAPProduct){
    guard let productToPurchase = products.first(where: {$0.productIdentifier == product.rawValue}) else {
        return
     }
    let payment = SKPayment(product: productToPurchase)
    paymentQueue.add(payment)
}

func purchase(product:IAPProduct){

guard let productToPurchase = products.first(where: {$0.productIdentifier == product.rawValue}) else {

return

}

let payment = SKPayment(product: productToPurchase)

paymentQueue.add(payment)

}

Step 11: Implement SKPaymentTransactionObserver which provides us information about the transaction is successful or failed.

extension IPAService:SKPaymentTransactionObserver{
    func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
        for transaction in transactions{
            print(transaction.transactionState.status(), transaction.payment.productIdentifier)
            switch transaction.transactionState {
            case .purchasing: break;
            case .purchased:
                Purchase.isBuy = true
                queue.finishTransaction(transaction)
            case .restored:
                Purchase.isBuy = true
                queue.finishTransaction(transaction)
            default:
                queue.finishTransaction(transaction)
            }
        }
    }
    
   func paymentQueue(_ queue: SKPaymentQueue, restoreCompletedTransactionsFailedWithError error: Error) {
    
   }
}

extension IPAService:SKPaymentTransactionObserver{

func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {

for transaction in transactions{

print(transaction.transactionState.status(), transaction.payment.productIdentifier)

switch transaction.transactionState {

case .purchasing: break;

case .purchased:

Purchase.isBuy = true

queue.finishTransaction(transaction)

case .restored:

Purchase.isBuy = true

queue.finishTransaction(transaction)

default:

queue.finishTransaction(transaction)

}

func paymentQueue(_ queue: SKPaymentQueue, restoreCompletedTransactionsFailedWithError error: Error) {

}

SKPaymentTransactionState only provides an enum value and now we will convert this enum value to a readable message.

extension SKPaymentTransactionState{
    func status() -> String{
        switch self {
        case .deferred: return "deferred"
        case .failed: return "failed"
        case .purchased: return "purchased"
        case .purchasing: return "purchasing"
        case .restored: return "restored"
        @unknown default:
            return "unknown"
        }
    }
}

extension SKPaymentTransactionState{

func status() -> String{

switch self {

case .deferred: return "deferred"

case .failed: return "failed"

case .purchased: return "purchased"

case .purchasing: return "purchasing"

case .restored: return "restored"

@unknown default:

return "unknown"

}

Steps 12: Now call the purchase methods.

IPAService.shared.purchase(product: .week)

1	IPAService.shared.purchase(product: .week)

Thank You!!!

Introduction:

Types Of In-App Purchases: