Add support for downloading content hosted by Apple

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 All notable changes to this project will be documented in this file.
 
+## [0.13.0](https://github.com/bizz84/SwiftyStoreKit/releases/tag/0.13.0) Add support for downloading content hosted with Apple
+
+* Add support for downloading content hosted with Apple ([#343](https://github.com/bizz84/SwiftyStoreKit/pull/343), related issue: [#128](https://github.com/bizz84/SwiftyStoreKit/issues/128))
+
 ## [0.12.1](https://github.com/bizz84/SwiftyStoreKit/releases/tag/0.12.1) Assert that `completeTransactions` was called when the app launches.
 
 * Assert that `completeTransactions()` was called when the app launches ([#337](https://github.com/bizz84/SwiftyStoreKit/pull/337), related issue: [#287](https://github.com/bizz84/SwiftyStoreKit/issues/287))

README.md

@@ -255,6 +255,48 @@ SwiftyStoreKit provides three operations that can be performed **atomically** or
 * Restoring purchases
 * Completing transactions on app launch
 
+### Downloading content hosted with Apple
+
+Quoting Apple Docs:
+
+> When you create a product in iTunes Connect, you can associate one or more pieces of downloadable content with it. At runtime, when a product is purchased by a user, your app uses SKDownload objects to download the content from the App Store.
+
+> Your app never directly creates a SKDownload object. Instead, after a payment is processed, your app reads the transaction object’s downloads property to retrieve an array of SKDownload objects associated with the transaction.
+
+> To download the content, you queue a download object on the payment queue and wait for the content to be downloaded. After a download completes, read the download object’s contentURL property to get a URL to the downloaded content. Your app must process the downloaded file before completing the transaction. For example, it might copy the file into a directory whose contents are persistent. When all downloads are complete, you finish the transaction. After the transaction is finished, the download objects cannot be queued to the payment queue and any URLs to the downloaded content are invalid.
+
+To start the downloads:
+
+```swift
+SwiftyStoreKit.purchaseProduct("com.musevisions.SwiftyStoreKit.Purchase1", quantity: 1, atomically: false) { result in
+    switch result {
+    case .success(let product):
+        let downloads = purchase.transaction.downloads
+        if !downloads.isEmpty {
+            SwiftyStoreKit.start(downloads)
+        }
+    case .error(let error):
+        print("\(error)")
+    }
+}
+```
+
+To check the updated downloads, setup a `updatedDownloadsHandler` block in your AppDelegate:
+
+```swift
+SwiftyStoreKit.updatedDownloadsHandler = { downloads in
+
+    // contentURL is not nil if downloadState == .finished
+    let contentURLs = downloads.flatMap { $0.contentURL }
+    if contentURLs.count == downloads.count {
+        // process all downloaded files, then finish the transaction
+        SwiftyStoreKit.finishTransaction(downloads[0].transaction)
+    }
+}
+```
+
+To control the state of the downloads, SwiftyStoreKit offers `start()`, `pause()`, `resume()`, `cancel()` methods.
+
 ## Receipt verification
 
 According to [Apple - Delivering Products](https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/StoreKitGuide/Chapters/DeliverProduct.html#//apple_ref/doc/uid/TP40008267-CH5-SW4):

SwiftyStoreKit-iOS-Demo/AppDelegate.swift

@@ -32,19 +32,22 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
 
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool {
 
-        completeIAPTransactions()
+        setupIAP()
 
         return true
     }
 
-    func completeIAPTransactions() {
+    func setupIAP() {
 
         SwiftyStoreKit.completeTransactions(atomically: true) { purchases in
 
             for purchase in purchases {
                 switch purchase.transaction.transactionState {
                 case .purchased, .restored:
-                    if purchase.needsFinishTransaction {
+                    let downloads = purchase.transaction.downloads
+                    if !downloads.isEmpty {
+                        SwiftyStoreKit.start(downloads)
+                    } else if purchase.needsFinishTransaction {
                         // Deliver content from server, then:
                         SwiftyStoreKit.finishTransaction(purchase.transaction)
                     }
@@ -54,5 +57,15 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
                 }
             }
         }
+
+        SwiftyStoreKit.updatedDownloadsHandler = { downloads in
+
+            // contentURL is not nil if downloadState == .finished
+            let contentURLs = downloads.flatMap { $0.contentURL }
+            if contentURLs.count == downloads.count {
+                print("Saving: \(contentURLs)")
+                SwiftyStoreKit.finishTransaction(downloads[0].transaction)
+            }
+        }
     }
 }

SwiftyStoreKit-iOS-Demo/ViewController.swift

@@ -133,6 +133,10 @@ class ViewController: UIViewController {
             NetworkActivityIndicatorManager.networkOperationFinished()
 
             if case .success(let purchase) = result {
+                let downloads = purchase.transaction.downloads
+                if !downloads.isEmpty {
+                    SwiftyStoreKit.start(downloads)
+                }
                 // Deliver content from server, then:
                 if purchase.needsFinishTransaction {
                     SwiftyStoreKit.finishTransaction(purchase.transaction)
@@ -150,9 +154,14 @@ class ViewController: UIViewController {
         SwiftyStoreKit.restorePurchases(atomically: true) { results in
             NetworkActivityIndicatorManager.networkOperationFinished()
 
-            for purchase in results.restoredPurchases where purchase.needsFinishTransaction {
-                // Deliver content from server, then:
-                SwiftyStoreKit.finishTransaction(purchase.transaction)
+            for purchase in results.restoredPurchases {
+                let downloads = purchase.transaction.downloads
+                if !downloads.isEmpty {
+                    SwiftyStoreKit.start(downloads)
+                } else if purchase.needsFinishTransaction {
+                    // Deliver content from server, then:
+                    SwiftyStoreKit.finishTransaction(purchase.transaction)
+                }
             }
             self.showAlert(self.alertForRestorePurchases(results))
         }

SwiftyStoreKit/PaymentQueueController.swift

@@ -47,7 +47,12 @@ public protocol PaymentQueue: class {
     func remove(_ observer: SKPaymentTransactionObserver)
 
     func add(_ payment: SKPayment)
-
+
+    func start(_ downloads: [SKDownload])
+    func pause(_ downloads: [SKDownload])
+    func resume(_ downloads: [SKDownload])
+    func cancel(_ downloads: [SKDownload])
+
     func restoreCompletedTransactions(withApplicationUsername username: String?)
 
     func finishTransaction(_ transaction: SKPaymentTransaction)
@@ -151,7 +156,21 @@ class PaymentQueueController: NSObject, SKPaymentTransactionObserver {
         paymentQueue.finishTransaction(skTransaction)
     }
 
+    func start(_ downloads: [SKDownload]) {
+        paymentQueue.start(downloads)
+    }
+    func pause(_ downloads: [SKDownload]) {
+        paymentQueue.pause(downloads)
+    }
+    func resume(_ downloads: [SKDownload]) {
+        paymentQueue.resume(downloads)
+    }
+    func cancel(_ downloads: [SKDownload]) {
+        paymentQueue.cancel(downloads)
+    }
+
     var shouldAddStorePaymentHandler: ShouldAddStorePaymentHandler?
+    var updatedDownloadsHandler: UpdatedDownloadsHandler?
 
     // MARK: SKPaymentTransactionObserver
     func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
@@ -210,6 +229,7 @@ class PaymentQueueController: NSObject, SKPaymentTransactionObserver {
 
     func paymentQueue(_ queue: SKPaymentQueue, updatedDownloads downloads: [SKDownload]) {
 
+        updatedDownloadsHandler?(downloads)
     }
 
     func paymentQueue(_ queue: SKPaymentQueue, shouldAddStorePayment payment: SKPayment, for product: SKProduct) -> Bool {

SwiftyStoreKit/SwiftyStoreKit+Types.swift

@@ -55,6 +55,7 @@ public protocol PaymentTransaction {
     var transactionDate: Date? { get }
     var transactionState: SKPaymentTransactionState { get }
     var transactionIdentifier: String? { get }
+    var downloads: [SKDownload] { get }
 }
 
 // Add PaymentTransaction conformance to SKPaymentTransaction
@@ -80,6 +81,7 @@ public struct RestoreResults {
 }
 
 public typealias ShouldAddStorePaymentHandler = (_ payment: SKPayment, _ product: SKProduct) -> Bool
+public typealias UpdatedDownloadsHandler = (_ downloads: [SKDownload]) -> Void
 
 // MARK: Receipt verification
 

SwiftyStoreKit/SwiftyStoreKit.swift

@@ -216,6 +216,28 @@ extension SwiftyStoreKit {
             sharedInstance.paymentQueueController.shouldAddStorePaymentHandler = shouldAddStorePaymentHandler
         }
     }
+
+    /**
+     * Register a handler for paymentQueue(_:updatedDownloads:)
+     */
+    public static var updatedDownloadsHandler: UpdatedDownloadsHandler? {
+        didSet {
+            sharedInstance.paymentQueueController.updatedDownloadsHandler = updatedDownloadsHandler
+        }
+    }
+
+    public class func start(_ downloads: [SKDownload]) {
+        sharedInstance.paymentQueueController.start(downloads)
+    }
+    public class func pause(_ downloads: [SKDownload]) {
+        sharedInstance.paymentQueueController.pause(downloads)
+    }
+    public class func resume(_ downloads: [SKDownload]) {
+        sharedInstance.paymentQueueController.resume(downloads)
+    }
+    public class func cancel(_ downloads: [SKDownload]) {
+        sharedInstance.paymentQueueController.cancel(downloads)
+    }
 }
 
 extension SwiftyStoreKit {

SwiftyStoreKitTests/PaymentQueueSpy.swift

@@ -44,4 +44,20 @@ class PaymentQueueSpy: PaymentQueue {
 
         finishTransactionCalledCount += 1
     }
+
+    func start(_ downloads: [SKDownload]) {
+
+    }
+
+    func pause(_ downloads: [SKDownload]) {
+
+    }
+
+    func resume(_ downloads: [SKDownload]) {
+
+    }
+
+    func cancel(_ downloads: [SKDownload]) {
+
+    }
 }