Add AppStoreReceipt reader

2 files changed, 83 insertions, 0 deletions

diff --git a/ios/MullvadVPN.xcodeproj/project.pbxproj b/ios/MullvadVPN.xcodeproj/project.pbxproj
index 449a9f06cc..205cd82a43 100644
--- a/ios/MullvadVPN.xcodeproj/project.pbxproj
+++ b/ios/MullvadVPN.xcodeproj/project.pbxproj
@@ -122,6 +122,7 @@
 		58D0C7A223F1CECF00FE9BA7 /* MullvadVPNScreenshots.swift in Sources */ = {isa = PBXBuildFile; fileRef = 58D0C7A023F1CECF00FE9BA7 /* MullvadVPNScreenshots.swift */; };
 		58EC4E6C23915325003F5C5B /* Bundle+MullvadVersion.swift in Sources */ = {isa = PBXBuildFile; fileRef = 58EC4E6B23915325003F5C5B /* Bundle+MullvadVersion.swift */; };
 		58F19E35228C15BA00C7710B /* SpinnerActivityIndicatorView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 58F19E34228C15BA00C7710B /* SpinnerActivityIndicatorView.swift */; };
+		58FD5BE724192A2C00112C88 /* AppStoreReceipt.swift in Sources */ = {isa = PBXBuildFile; fileRef = 58FD5BE624192A2B00112C88 /* AppStoreReceipt.swift */; };
 		58FD5BE92419406000112C88 /* SKRequestPublisher.swift in Sources */ = {isa = PBXBuildFile; fileRef = 58FD5BE82419406000112C88 /* SKRequestPublisher.swift */; };
 /* End PBXBuildFile section */
 
@@ -259,6 +260,7 @@
 		58F19E34228C15BA00C7710B /* SpinnerActivityIndicatorView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SpinnerActivityIndicatorView.swift; sourceTree = "<group>"; };
 		58FBDAA422A52BDA00EB69A3 /* PacketTunnel-Bridging-Header.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "PacketTunnel-Bridging-Header.h"; sourceTree = "<group>"; };
 		58FBDAAA22A52DC500EB69A3 /* MullvadVPN-Bridging-Header.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "MullvadVPN-Bridging-Header.h"; sourceTree = "<group>"; };
+		58FD5BE624192A2B00112C88 /* AppStoreReceipt.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppStoreReceipt.swift; sourceTree = "<group>"; };
 		58FD5BE82419406000112C88 /* SKRequestPublisher.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SKRequestPublisher.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -351,6 +353,7 @@
 				5868585424054096000B8131 /* AppButton.swift */,
 				58CE5E63224146200008646E /* AppDelegate.swift */,
 				58BFA5CB22A7CE1F00A6173D /* ApplicationConfiguration.swift */,
+				58FD5BE624192A2B00112C88 /* AppStoreReceipt.swift */,
 				58CE5E6A224146210008646E /* Assets.xcassets */,
 				5845F839236C6A7200B2D93C /* AutoDisposableSink.swift */,
 				589AB4F6227B64450039131E /* BasicTableViewCell.swift */,
@@ -751,6 +754,7 @@
 				5888AD83227B11080051EB06 /* SelectLocationCell.swift in Sources */,
 				58CE5E66224146200008646E /* LoginViewController.swift in Sources */,
 				5877152E23981C5B001F8237 /* SettingsBasicCell.swift in Sources */,
+				58FD5BE724192A2C00112C88 /* AppStoreReceipt.swift in Sources */,
 				5835B7CC233B76CB0096D79F /* TunnelManager.swift in Sources */,
 				58ADDB3C227B1BD200FAFEA7 /* JsonRpc.swift in Sources */,
 				581CBCEE229826FD00727D7F /* StaticTableViewDataSource.swift in Sources */,
diff --git a/ios/MullvadVPN/AppStoreReceipt.swift b/ios/MullvadVPN/AppStoreReceipt.swift
new file mode 100644
index 0000000000..ecb2e8d130
--- /dev/null
+++ b/ios/MullvadVPN/AppStoreReceipt.swift
@@ -0,0 +1,79 @@
+//
+//  AppStoreReceipt.swift
+//  MullvadVPN
+//
+//  Created by pronebird on 11/03/2020.
+//  Copyright © 2020 Mullvad VPN AB. All rights reserved.
+//
+
+import Combine
+import Foundation
+import StoreKit
+
+enum AppStoreReceipt {
+    enum Error: Swift.Error {
+        /// AppStore receipt file does not exist or file URL is not available
+        case doesNotExist
+
+        /// IO error
+        case io(Swift.Error)
+
+        /// Failure to refresh the receipt from AppStore
+        case refresh(Swift.Error)
+
+        var localizedDescription: String {
+            switch self {
+            case .doesNotExist:
+                return "AppStore receipt file does not exist on disk"
+            case .io(let ioError):
+                return "Read error: \(ioError.localizedDescription)"
+            case .refresh(let refreshError):
+                return "Receipt refresh error: \(refreshError.localizedDescription)"
+            }
+        }
+    }
+
+    /// Read AppStore receipt from disk
+    static func readFromDisk() -> Result<Data, Error> {
+        guard let appStoreReceiptURL = Bundle.main.appStoreReceiptURL else {
+            return .failure(.doesNotExist)
+        }
+
+        return Result { try Data(contentsOf: appStoreReceiptURL) }
+            .mapError { (error) -> Error in
+                if let ioError = error as? CocoaError, ioError.code == .fileNoSuchFile {
+                    return .doesNotExist
+                } else {
+                    return .io(error)
+                }
+        }
+    }
+
+    /// Read AppStore receipt from disk or refresh it from the AppStore if it's missing
+    /// This call may trigger a sign in with AppStore prompt to appear
+    static func fetch(forceRefresh: Bool = false, receiptProperties: [String: Any]? = nil) -> AnyPublisher<Data, Error> {
+        let refreshReceiptPublisher = Deferred {
+            SKReceiptRefreshRequest(receiptProperties: receiptProperties)
+                .publisher
+                .mapError { .refresh($0) }
+                .flatMap({ _ -> Result<Data, Error>.Publisher in
+                    return self.readFromDisk().publisher
+                })
+        }
+
+        if forceRefresh {
+            return refreshReceiptPublisher.eraseToAnyPublisher()
+        } else {
+            return Deferred { self.readFromDisk().publisher }
+                .catch({ (readError) -> AnyPublisher<Data, Error> in
+                    // Refresh the receipt from AppStore if it's not on disk
+                    if case .doesNotExist = readError {
+                        return refreshReceiptPublisher.eraseToAnyPublisher()
+                    } else {
+                        return Fail(error: readError).eraseToAnyPublisher()
+                    }
+                })
+                .eraseToAnyPublisher()
+        }
+    }
+}