[QL] Conform BTPayPalClient to BTAppContextSwitchClient Protocol

Demo/Application/Base/AppDelegate.swift

@@ -4,14 +4,16 @@ import BraintreeCore
 @UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate {
 
     private let returnURLScheme = "com.braintreepayments.Demo.payments"
+    private let universalLinkURL = "https://braintree-ios-demo.fly.dev/braintree-payments"
     private let processInfoArgs = ProcessInfo.processInfo.arguments
     private let userDefaults = UserDefaults.standard
 
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
         registerDefaultsFromSettings()
         persistDemoSettings()
         BTAppContextSwitcher.sharedInstance.returnURLScheme = returnURLScheme
-
+        BTAppContextSwitcher.sharedInstance.universalLink = universalLinkURL
+
         userDefaults.setValue(true, forKey: "magnes.debug.mode")
 
         return true

Demo/Application/Base/SceneDelegate.swift

@@ -27,9 +27,9 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
     }
 
     func scene(_ scene: UIScene, continue userActivity: NSUserActivity) {
-        if let returnURL = userActivity.webpageURL {
-            // TODO: implementation - pass full URL to BT SDK
+        if let returnURL = userActivity.webpageURL, returnURL.path == "/braintree-payments" {
             print("Returned to Demo app via universal link: \(returnURL)")
+            _ = BTAppContextSwitcher.sharedInstance.handleOpen(returnURL)
         }
     }
 }

Demo/Application/Features/PayPalWebCheckoutViewController.swift

@@ -86,6 +86,6 @@ class PayPalWebCheckoutViewController: PaymentButtonBaseViewController {
     }
 
     @objc func universalLinkFlow(_ sender: UIButton) {
-        UIApplication.shared.open(URL(string: "https://braintree-ios-demo.fly.dev")!)
+        UIApplication.shared.open(URL(string: "https://braintree-ios-demo.fly.dev/braintree-payments")!)
     }
 }

Sources/BraintreeCore/BTAppContextSwitcher.swift

@@ -13,7 +13,10 @@ import UIKit
     /// The URL scheme to return to this app after switching to another app or opening a SFSafariViewController.
     /// This URL scheme must be registered as a URL Type in the app's info.plist, and it must start with the app's bundle ID.
     public var returnURLScheme: String = ""
-
+
+    /// The URL to use for the PayPal universal link flow. Must contain the path `braintree-payments`.
+    public var universalLink: String = ""
+
     // MARK: - Private Properties
 
     private var appContextSwitchClients = [BTAppContextSwitchClient.Type]()

Sources/BraintreePayPal/BTPayPalClient.swift

@@ -29,6 +29,12 @@ import BraintreeDataCollector
     /// Exposed for testing, the ASWebAuthenticationSession instance used for the PayPal flow
     var webAuthenticationSession: BTWebAuthenticationSession
 
+    // MARK: - Static Properties
+
+    /// This static instance of `BTPayPalClient` is used during the app switch process.
+    /// We require a static reference of the client to call `handleReturnURL` and return to the app.
+    static var payPalClient: BTPayPalClient? = nil
+
     // MARK: - Private Properties
 
     /// Indicates if the user returned back to the merchant app from the `BTWebAuthenticationSession`
@@ -221,6 +227,12 @@ import BraintreeDataCollector
         performSwitchRequest(appSwitchURL: url, paymentType: paymentType, completion: completion)
     }
 
+    // MARK: - App Switch Methods
+
+    func handleOpen(_ url: URL) {
+        // TODO: implement handling return URL in a follow up PR
+    }
+
     // MARK: - Private Methods
 
     private func tokenize(
@@ -431,3 +443,18 @@ import BraintreeDataCollector
         completion(nil, BTPayPalError.canceled)
     }
 }
+
+extension BTPayPalClient: BTAppContextSwitchClient {
+    /// :nodoc:
+    @_documentation(visibility: private)
+    @objc public static func handleReturnURL(_ url: URL) {
+        payPalClient?.handleOpen(url)
+        BTPayPalClient.payPalClient = nil
+    }
+
+    /// :nodoc:
+    @_documentation(visibility: private)
+    @objc public static func canHandleReturnURL(_ url: URL) -> Bool {
+        url.scheme == "https" && (url.path.contains("cancel") || url.path.contains("success"))
+    }
+}

Sources/BraintreeVenmo/BTVenmoAppSwitchReturnURL.swift

@@ -68,6 +68,8 @@ struct BTVenmoAppSwitchReturnURL {
     /// - Parameter url: an app switch return URL
     /// - Returns: `true` if the url represents a Venmo Touch app switch return
     static func isValid(url: URL) -> Bool {
-        url.host == "x-callback-url" && url.path.hasPrefix("/vzero/auth/venmo/")
+        url.scheme?.caseInsensitiveCompare(BTAppContextSwitcher.sharedInstance.returnURLScheme) == .orderedSame
+        && url.host == "x-callback-url"
+        && url.path.hasPrefix("/vzero/auth/venmo/")
     }
 }

UnitTests/BraintreeCoreTests/BTAppContextSwitcher_Tests.swift

@@ -25,7 +25,7 @@ class BTAppContextSwitcher_Tests: XCTestCase {
         appSwitch.register(MockAppContextSwitchClient.self)
         let expectedURL = URL(string: "fake://url")!
 
-        BTAppContextSwitcher.sharedInstance.handleOpen(expectedURL)
+        _ = BTAppContextSwitcher.sharedInstance.handleOpen(expectedURL)
 
         XCTAssertEqual(MockAppContextSwitchClient.lastCanHandleURL!, expectedURL)
     }
@@ -80,13 +80,19 @@ class BTAppContextSwitcher_Tests: XCTestCase {
         XCTAssertFalse(handled)
         XCTAssertNil(MockAppContextSwitchClient.lastHandleReturnURL)
     }
-        
+
     func testHandleOpenURLContext_withNoAppSwitching_returnsFalse() {
         let mockURLContext = BTMockOpenURLContext(url: URL(string: "fake://url")!).mock
         let handled = BTAppContextSwitcher.sharedInstance.handleOpenURL(context: mockURLContext)
         XCTAssertFalse(handled)
     }
 
+    // MARK: - universalLink Tests
+
+    func testSetUniversalLink() {
+        BTAppContextSwitcher.sharedInstance.universalLink = "https://fake.com"
+        XCTAssertEqual(appSwitch.universalLink, "https://fake.com")
+    }
 }
 
 @objcMembers class MockAppContextSwitchClient: BTAppContextSwitchClient {

UnitTests/BraintreePayPalTests/BTPayPalClient_Tests.swift

@@ -634,6 +634,43 @@ class BTPayPalClient_Tests: XCTestCase {
         XCTAssertEqual(metaParameters["sessionId"] as? String, mockAPIClient.metadata.sessionID)
     }
 
+    // MARK: - App Switch
+
+    func testCanHandleReturnURL_whenHostIsURLScheme_returnsFalse() {
+        let url = URL(string: "fake-scheme://success")!
+        XCTAssertFalse(BTPayPalClient.canHandleReturnURL(url))
+    }
+
+    func testCanHandleReturnURL_whenPathIsInvalid_returnsFalse() {
+        let url = URL(string: "https://mycoolwebsite.com/junkpath")!
+        XCTAssertFalse(BTPayPalClient.canHandleReturnURL(url))
+    }
+
+    func testCanHandleReturnURL_whenSchemeIsHTTP_returnsFalse() {
+        let url = URL(string: "http://mycoolwebsite.com/success")!
+        XCTAssertFalse(BTPayPalClient.canHandleReturnURL(url))
+    }
+
+    func testCanHandleReturnURL_whenPathIsValidSuccess_returnsTrue() {
+        let url = URL(string: "https://mycoolwebsite.com/braintree-payments/success")!
+        XCTAssertTrue(BTPayPalClient.canHandleReturnURL(url))
+    }
+
+    func testCanHandleReturnURL_whenPathIsValidCancel_returnsTrue() {
+        let url = URL(string: "https://mycoolwebsite.com/braintree-payments/cancel")!
+        XCTAssertTrue(BTPayPalClient.canHandleReturnURL(url))
+    }
+
+    func testCanHandleReturnURL_whenPathIsValidWithQueryParameters_returnsTrue() {
+        let url = URL(string: "https://mycoolwebsite.com/braintree-payments/success?token=112233")!
+        XCTAssertTrue(BTPayPalClient.canHandleReturnURL(url))
+    }
+
+    func testHandleReturnURL_whenURLIsValid_setsBTPayPalClientToNil() {
+        BTPayPalClient.handleReturnURL(URL(string: "https://mycoolwebsite.com/braintree-payments/success")!)
+        XCTAssertNil(BTPayPalClient.payPalClient)
+    }
+
     // MARK: - Analytics
 
     func testAPIClientMetadata_hasIntegrationSetToCustom() {

UnitTests/BraintreeVenmoTests/BTVenmoClient_Tests.swift

@@ -803,7 +803,8 @@ class BTVenmoClient_Tests: XCTestCase {
         XCTAssertFalse(venmoClient.isVenmoAppInstalled())
     }
 
-    func testCanHandleReturnURL_withValidHost_andValidPath_returnsTrue() {
+    func testCanHandleReturnURL_withValidSchemeHostAndValidPath_returnsTrue() {
+        BTAppContextSwitcher.sharedInstance.returnURLScheme = "fake-scheme"
         let host = "x-callback-url"
         let path = "/vzero/auth/venmo/"
         XCTAssertTrue(BTVenmoClient.canHandleReturnURL(URL(string: "fake-scheme://\(host)\(path)fake-result")!))