[Swift] Add support for window.open delegation

platforms/swift/Samples/MobileBuyIntegration/MobileBuyIntegration/Sources/App/AppDelegate.swift

@@ -48,7 +48,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
         ShopifyCheckoutKit.configure {
             $0.colorScheme = .automatic
             $0.tintColor = ColorPalette.primaryColor
-            $0.preloading.enabled = true
+            $0.preloading.enabled = false
             $0.logger = FileLogger("log.txt")
             $0.logLevel = checkoutKitLogLevel
         }

platforms/swift/Samples/MobileBuyIntegration/MobileBuyIntegration/Sources/CheckoutProtocolClient.swift

@@ -21,27 +21,69 @@
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
+import SafariServices
 import ShopifyCheckoutProtocol
+import UIKit
 
-enum CheckoutProtocolClient {
-    static let shared = CheckoutProtocol.Client()
-        .on(CheckoutProtocol.start) { checkout in
-            print("[UCP] ec.start: \(checkout.id)")
-        }
-        .on(CheckoutProtocol.complete) { checkout in
-            print("[UCP] ec.complete: \(checkout.order?.id ?? "unknown")")
-            CartManager.shared.resetCart()
-        }
-        .on(CheckoutProtocol.lineItemsChange) { checkout in
-            print("[UCP] ec.line_items.change: \(checkout.id)")
-        }
-        .on(CheckoutProtocol.messagesChange) { checkout in
-            print("[UCP] ec.messages.change: \(checkout.id)")
-        }
-        .on(CheckoutProtocol.totalsChange) { checkout in
-            print("[UCP] ec.totals.change: \(checkout.id)")
+extension CheckoutProtocol.Client {
+    @MainActor
+    static func with(windowOpen: WindowOpenHandlerOption) -> CheckoutProtocol.Client {
+        let base = CheckoutProtocol.Client()
+            .on(CheckoutProtocol.start) { checkout in
+                print("[UCP] ec.start: \(checkout.id)")
+            }
+            .on(CheckoutProtocol.complete) { checkout in
+                print("[UCP] ec.complete: \(checkout.order?.id ?? "unknown")")
+                CartManager.shared.resetCart()
+            }
+            .on(CheckoutProtocol.lineItemsChange) { checkout in
+                print("[UCP] ec.line_items.change: \(checkout.id)")
+            }
+            .on(CheckoutProtocol.messagesChange) { checkout in
+                print("[UCP] ec.messages.change: \(checkout.id)")
+            }
+            .on(CheckoutProtocol.totalsChange) { checkout in
+                print("[UCP] ec.totals.change: \(checkout.id)")
+            }
+            .on(CheckoutProtocol.error) { error in
+                print("[UCP] ec.error: \(error.messages.first?.content ?? "(no message)")")
+            }
+
+        switch windowOpen {
+        case .default:
+            return base
+        case .safariViewController:
+            return base.on(CheckoutProtocol.windowOpen) { request in
+                let scheme = request.url.scheme?.lowercased()
+
+                print("[UCP] ec.window_open (\(scheme ?? ""))")
+
+                guard scheme == "http" || scheme == "https" else {
+                    return .rejected(reason: "unsupported URL scheme")
+                }
+
+                guard let presenter = UIApplication.shared.foregroundActiveWindow?.topMostViewController() else {
+                    return .rejected(reason: "no presenter available")
+                }
+
+                let safari = SFSafariViewController(url: request.url)
+                presenter.present(safari, animated: true)
+                return .success
+            }
         }
-        .on(CheckoutProtocol.error) { error in
-            print("[UCP] ec.error: \(error.messages.first?.content ?? "(no message)")")
+    }
+}
+
+extension UIApplication {
+    fileprivate var foregroundActiveWindow: UIWindow? {
+        let activeScenes = connectedScenes
+            .compactMap { $0 as? UIWindowScene }
+            .filter { $0.activationState == .foregroundActive }
+
+        if #available(iOS 15.0, *) {
+            return activeScenes.compactMap(\.keyWindow).first
+        } else {
+            return activeScenes.flatMap(\.windows).first { $0.isKeyWindow }
         }
+    }
 }

platforms/swift/Samples/MobileBuyIntegration/MobileBuyIntegration/Sources/Localizable.xcstrings

@@ -186,6 +186,10 @@
     },
     "Version" : {
 
+    },
+    "Window open handler" : {
+      "comment" : "A label for the selection of the window open handler in the settings.",
+      "isCommentAutoGenerated" : true
     },
     "Your cart is empty." : {
 

platforms/swift/Samples/MobileBuyIntegration/MobileBuyIntegration/Sources/Scenes/Cart/CartView.swift

@@ -37,11 +37,16 @@ struct CartView: View {
 
     @ObservedObject var cartManager: CartManager = .shared
 
-    private let client = CheckoutProtocolClient.shared
-
     @AppStorage(AppStorageKeys.applePayStyle.rawValue)
     var applePayStyle: ApplePayStyleOption = .automatic
 
+    @AppStorage(AppStorageKeys.windowOpenHandler.rawValue)
+    var windowOpenHandler: WindowOpenHandlerOption = .default
+
+    private var client: CheckoutProtocol.Client {
+        .with(windowOpen: windowOpenHandler)
+    }
+
     var body: some View {
         if let lines = cartManager.cart?.lines.nodes {
             ZStack(alignment: .bottom) {

platforms/swift/Samples/MobileBuyIntegration/MobileBuyIntegration/Sources/Scenes/SettingsView.swift

@@ -31,6 +31,19 @@ enum AppStorageKeys: String {
     case checkoutKitLogLevel
     case buyerIdentityMode
     case applePayStyle
+    case windowOpenHandler
+}
+
+enum WindowOpenHandlerOption: String, CaseIterable {
+    case `default`
+    case safariViewController
+
+    var title: String {
+        switch self {
+        case .default: return "Default (UIApplication.open)"
+        case .safariViewController: return "SFSafariViewController"
+        }
+    }
 }
 
 struct SettingsView: View {
@@ -48,6 +61,9 @@ struct SettingsView: View {
     @AppStorage(AppStorageKeys.applePayStyle.rawValue)
     var applePayStyle: ApplePayStyleOption = .automatic
 
+    @AppStorage(AppStorageKeys.windowOpenHandler.rawValue)
+    var windowOpenHandler: WindowOpenHandlerOption = .default
+
     @State private var preloadingEnabled = ShopifyCheckoutKit.configuration.preloading.enabled
     @State private var logs: [String?] = LogReader.shared.readLogs() ?? []
     @State private var selectedColorScheme = ShopifyCheckoutKit.configuration.colorScheme
@@ -61,6 +77,13 @@ struct SettingsView: View {
                         .onChange(of: preloadingEnabled) { newValue in
                             ShopifyCheckoutKit.configuration.preloading.enabled = newValue
                         }
+
+                    Picker("Window open handler", selection: $windowOpenHandler) {
+                        ForEach(WindowOpenHandlerOption.allCases, id: \.self) { option in
+                            Text(option.title).tag(option)
+                        }
+                    }
+                    .pickerStyle(.menu)
                 }
 
                 Section(

platforms/swift/Sources/ShopifyCheckoutKit/CheckoutCommunicationProtocol.swift

@@ -21,8 +21,13 @@
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
+#if !COCOAPODS
+    import ShopifyCheckoutProtocol
+#endif
 import Foundation
 
 public protocol CheckoutCommunicationProtocol: Sendable {
     func process(_ message: String) async -> String?
 }
+
+extension CheckoutProtocol.Client: CheckoutCommunicationProtocol {}

platforms/swift/Sources/ShopifyCheckoutKit/CheckoutWebView.swift

@@ -30,7 +30,6 @@ import WebKit
 protocol CheckoutWebViewDelegate: AnyObject {
     func checkoutViewDidStartNavigation()
     func checkoutViewDidFinishNavigation()
-    func checkoutViewDidClickLink(url: URL)
     func checkoutViewDidFailWithError(error: CheckoutError)
 }
 
@@ -254,29 +253,53 @@ extension CheckoutWebView: WKScriptMessageHandler {
             return
         }
 
-        guard let client else {
-            return
-        }
-
         Task {
-            if let response = await client.process(body) {
+            if let response = await client?.process(body) {
+                checkoutBridge.sendResponse(self, messageBody: response)
+                return
+            }
+
+            if let response = await CheckoutWebView.defaultsClient.process(body) {
                 checkoutBridge.sendResponse(self, messageBody: response)
             }
         }
     }
+
+    /// Kit-owned client that handles delegations the consumer did not register.
+    /// Today the only default is `window.open`, which falls back to
+    /// `UIApplication.shared.open(...)` after a `canOpenURL` check.
+    static let defaultsClient = CheckoutProtocol.Client()
+        .on(CheckoutProtocol.windowOpen) { request in
+            guard UIApplication.shared.canOpenURL(request.url) else {
+                return .rejected(reason: "canOpenURL returned false")
+            }
+            UIApplication.shared.open(request.url)
+            return .success
+        }
 }
 
 extension CheckoutWebView: WKNavigationDelegate {
     func webView(_: WKWebView, decidePolicyFor action: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) {
+        // Handle rare cases where the url is nil
         guard let url = action.request.url else {
             decisionHandler(.allow)
             return
         }
 
-        if isExternalLink(action) || CheckoutURL(from: url).isDeepLink() {
-            OSLogger.shared.debug("External or deep link clicked: \(url.absoluteString) - request intercepted")
-            viewDelegate?.checkoutViewDidClickLink(url: removeExternalParam(url))
-            decisionHandler(.cancel)
+        // Handle non-HTTP links triggered on external surfaces by opening them with UIApplication
+        // Scenarios include:
+        // 	- mailto:, tel: etc
+        // 	- Deep links on offsite payment sites
+        //
+        if CheckoutURL(from: url).isDeepLink() {
+            if UIApplication.shared.canOpenURL(url) {
+                UIApplication.shared.open(url)
+                OSLogger.shared.debug("Deep link intercepted: \(url.absoluteString) - allowed")
+                return decisionHandler(.allow)
+            } else {
+                OSLogger.shared.debug("Deep link intercepted: \(url.absoluteString) - rejected")
+                return decisionHandler(.cancel)
+            }
             return
         }
 
@@ -401,27 +424,6 @@ extension CheckoutWebView: WKNavigationDelegate {
         )
     }
 
-    private func isExternalLink(_ action: WKNavigationAction) -> Bool {
-        if action.navigationType == .linkActivated && action.targetFrame == nil {
-            return true
-        }
-
-        guard let url = action.request.url else { return false }
-        guard let url = URLComponents(url: url, resolvingAgainstBaseURL: false) else { return false }
-
-        guard let openExternally = url.queryItems?.first(where: { $0.name == "open_externally" })?.value else { return false }
-
-        return openExternally.lowercased() == "true" || openExternally == "1"
-    }
-
-    private func removeExternalParam(_ url: URL) -> URL {
-        guard var urlComponents = URLComponents(url: url, resolvingAgainstBaseURL: false) else {
-            return url
-        }
-        urlComponents.queryItems = urlComponents.queryItems?.filter { !($0.name == "open_externally") }
-        return urlComponents.url ?? url
-    }
-
     private func isCheckout(url: URL?) -> Bool {
         return self.url == url
     }

platforms/swift/Sources/ShopifyCheckoutKit/CheckoutWebViewController.swift

@@ -247,12 +247,6 @@ extension CheckoutWebViewController: CheckoutWebViewDelegate {
         return isRecoverableError() && isWithinRetryLimit && error.isRecoverable
     }
 
-    func checkoutViewDidClickLink(url: URL) {
-        if UIApplication.shared.canOpenURL(url) {
-            UIApplication.shared.open(url)
-        }
-    }
-
     private func isRecoverableError() -> Bool {
         return !CheckoutURL(from: checkoutURL).isMultipassURL()
     }