[v7] Update Venmo to Support Only Universal Links (#1489)

* Remove BTAppContextSwitcher.sharedInstance.returnURLScheme
* Remove BTVenmoClient(apiClient:) init in favor of universalLink init
* Cleanup demo app
* Remove logic around returnURLScheme in the Venmo flow since this is no longer needed
* Remove no longer needed error case
* Cleanup unit tests based on updated logic

CHANGELOG.md

@@ -9,6 +9,8 @@
   * BraintreeVenmo
     * Update `BTVenmoRequest` to make all properties accessible on the initializer only vs via the dot syntax.
     * Remove `fallbacktoWeb` property from `BTVenmoRequest`. All Venmo flows will now use universal links to switch to the Venmo app or fallback to the web flow if the Venmo app is not installed
+    * Remove `BTAppContextSwitcher.sharedInstance.returnURLScheme`
+    * `BTVenmoClient` initializer now requires a `universalLink` for switching to and from the Venmo app or web fallback flow
   * BraintreeSEPADirectDebit
     * Update `BTSEPADirectDebitRequest` to make all properties accessible on the initializer only vs via the dot syntax.
   * BraintreeLocalPayment

Demo/Application/Base/AppDelegate.swift

@@ -3,7 +3,6 @@ import BraintreeCore
 
 @UIApplicationMain class AppDelegate: UIResponder, UIApplicationDelegate {
 
-    private let returnURLScheme = "com.braintreepayments.Demo.payments"
     private let processInfoArgs = ProcessInfo.processInfo.arguments
     private let userDefaults = UserDefaults.standard
 
@@ -13,7 +12,6 @@ import BraintreeCore
     ) -> Bool {
         registerDefaultsFromSettings()
         persistDemoSettings()
-        BTAppContextSwitcher.sharedInstance.returnURLScheme = returnURLScheme
 
         userDefaults.setValue(true, forKey: "magnes.debug.mode")
 

Demo/Application/Base/PaymentButtonBaseViewController.swift

@@ -51,4 +51,20 @@ class PaymentButtonBaseViewController: BaseViewController {
         button.addTarget(self, action: action, for: .touchUpInside)
         return button
     }
+
+    // MARK: - Helpers
+
+    func buttonsStackView(label: String, views: [UIView]) -> UIStackView {
+        let titleLabel = UILabel()
+        titleLabel.text = label
+
+        let buttonsStackView = UIStackView(arrangedSubviews: [titleLabel] + views)
+        buttonsStackView.axis = .vertical
+        buttonsStackView.distribution = .fillProportionally
+        buttonsStackView.backgroundColor = .systemGray6
+        buttonsStackView.layoutMargins = UIEdgeInsets(top: 5, left: 5, bottom: 5, right: 5)
+        buttonsStackView.isLayoutMarginsRelativeArrangement = true
+
+        return buttonsStackView
+    }
 }

Demo/Application/Features/PayPalWebCheckoutViewController.swift

@@ -250,20 +250,4 @@ class PayPalWebCheckoutViewController: PaymentButtonBaseViewController {
             self.completionBlock(nonce)
         }
     }
-
-    // MARK: - Helpers
-
-    private func buttonsStackView(label: String, views: [UIView]) -> UIStackView {
-        let titleLabel = UILabel()
-        titleLabel.text = label
-
-        let buttonsStackView = UIStackView(arrangedSubviews: [titleLabel] + views)
-        buttonsStackView.axis = .vertical
-        buttonsStackView.distribution = .fillProportionally
-        buttonsStackView.backgroundColor = .systemGray6
-        buttonsStackView.layoutMargins = UIEdgeInsets(top: 5, left: 5, bottom: 5, right: 5)
-        buttonsStackView.isLayoutMarginsRelativeArrangement = true
-
-        return buttonsStackView
-    }
 }

Demo/Application/Features/ShopperInsightsViewController.swift

@@ -8,8 +8,12 @@ class ShopperInsightsViewController: PaymentButtonBaseViewController {
 
     lazy var shopperInsightsClient = BTShopperInsightsClient(apiClient: apiClient)
     lazy var payPalClient = BTPayPalClient(apiClient: apiClient)
-    lazy var venmoClient = BTVenmoClient(apiClient: apiClient)
-
+    lazy var venmoClient = BTVenmoClient(
+        apiClient: apiClient,
+        // swiftlint:disable:next force_unwrapping
+        universalLink: URL(string: "https://mobile-sdk-demo-site-838cead5d3ab.herokuapp.com/braintree-payments")!
+    )
+
     lazy var payPalVaultButton = createButton(title: "PayPal Vault", action: #selector(payPalVaultButtonTapped))
     lazy var venmoButton = createButton(title: "Venmo", action: #selector(venmoButtonTapped))
 

Demo/Application/Features/VenmoViewController.swift

@@ -7,26 +7,31 @@ class VenmoViewController: PaymentButtonBaseViewController {
     var venmoClient: BTVenmoClient!
 
     let vaultToggle = Toggle(title: "Vault")
-    let universalLinkReturnToggle = Toggle(title: "Use Universal Link Return")
 
     override func viewDidLoad() {
         super.heightConstraint = 150
         super.viewDidLoad()
-        venmoClient = BTVenmoClient(apiClient: apiClient)
+        venmoClient = BTVenmoClient(
+            apiClient: apiClient,
+            // swiftlint:disable:next force_unwrapping
+            universalLink: URL(string: "https://mobile-sdk-demo-site-838cead5d3ab.herokuapp.com/braintree-payments")!
+        )
+
         title = "Custom Venmo Button"
     }
 
     override func createPaymentButton() -> UIView {
         let venmoButton = createButton(title: "Venmo", action: #selector(tappedVenmo))
 
-        let stackView = UIStackView(arrangedSubviews: [vaultToggle, universalLinkReturnToggle, venmoButton])
-        stackView.axis = .vertical
-        stackView.spacing = 15
-        stackView.alignment = .fill
-        stackView.distribution = .fillEqually
-        stackView.translatesAutoresizingMaskIntoConstraints = false
+        let venmoStackView = buttonsStackView(label: "Venmo Payment Flow", views: [
+            vaultToggle,
+            venmoButton
+        ])
+
+        venmoStackView.spacing = 12
+        venmoStackView.translatesAutoresizingMaskIntoConstraints = false
 
-        return stackView
+        return venmoStackView
     }
 
     @objc func tappedVenmo() {
@@ -38,14 +43,6 @@ class VenmoViewController: PaymentButtonBaseViewController {
             vault: isVaultingEnabled
         )
 
-        if universalLinkReturnToggle.isOn {
-            venmoClient = BTVenmoClient(
-                apiClient: apiClient,
-                // swiftlint:disable:next force_unwrapping
-                universalLink: URL(string: "https://mobile-sdk-demo-site-838cead5d3ab.herokuapp.com/braintree-payments")!
-            )
-        }
-
         Task {
             do {
                 let venmoAccount = try await venmoClient.tokenize(venmoRequest)

SampleApps/CarthageTest/CarthageTest/ViewController.swift

@@ -24,7 +24,10 @@ class ViewController: UIViewController {
         let payPalClient = BTPayPalClient(apiClient: apiClient)
         let payPalMessagingView = BTPayPalMessagingView(apiClient: apiClient)
         let threeDSecureClient = BTThreeDSecureClient(apiClient: apiClient)
-        let venmoClient = BTVenmoClient(apiClient: apiClient)
+        let venmoClient = BTVenmoClient(
+            apiClient: apiClient,
+            universalLink: URL(string: "https://mobile-sdk-demo-site-838cead5d3ab.herokuapp.com/braintree-payments")!
+        )
         let sepaDirectDebitClient = BTSEPADirectDebitClient(apiClient: apiClient)
     }
 }

SampleApps/SPMTest/SPMTest/ViewController.swift

@@ -24,7 +24,10 @@ class ViewController: UIViewController {
         let payPalClient = BTPayPalClient(apiClient: apiClient)
         let payPalMessagingView = BTPayPalMessagingView(apiClient: apiClient)
         let threeDSecureClient = BTThreeDSecureClient(apiClient: apiClient)
-        let venmoClient = BTVenmoClient(apiClient: apiClient)
+        let venmoClient = BTVenmoClient(
+            apiClient: apiClient,
+            universalLink: URL(string: "https://mobile-sdk-demo-site-838cead5d3ab.herokuapp.com/braintree-payments")!
+        )
         let sepaDirectDebitClient = BTSEPADirectDebitClient(apiClient: apiClient)
     }
 }

Sources/BraintreeCore/BTAppContextSwitcher.swift

@@ -9,27 +9,6 @@ import UIKit
 
     /// Singleton for shared instance of `BTAppContextSwitcher`
     public static let sharedInstance = BTAppContextSwitcher()
-
-    // NEXT_MAJOR_VERSION: move this property into the feature client request where it is used
-    /// 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.
-    /// - Note: This property should only be used for the Venmo flow.
-    @available(
-        *,
-        deprecated,
-        message: "returnURLScheme is deprecated and will be removed in a future version. Use BTVenmoClient(apiClient:universalLink:)."
-    )
-    public var returnURLScheme: String {
-        get { _returnURLScheme }
-        set { _returnURLScheme = newValue }
-    }
-
-    // swiftlint:disable identifier_name
-    /// :nodoc: This method is exposed for internal Braintree use only. Do not use. It is not covered by Semantic Versioning and may change or be removed at any time.
-    /// Property for `returnURLScheme`. Created to avoid deprecation warnings upon accessing
-    /// `returnURLScheme` directly within our SDK. Use this value instead.
-    public var _returnURLScheme: String = ""
-    // swiftlint:enable identifier_name
 
     // MARK: - Private Properties
 

Sources/BraintreeVenmo/BTVenmoAppSwitchRedirectURL.swift

@@ -6,26 +6,16 @@ import BraintreeCore
 
 struct BTVenmoAppSwitchRedirectURL {
 
-    // MARK: - Internal Properties
-
-    /// The base app switch URL for Venmo. Does not include specific parameters.
-    static var baseAppSwitchURL: URL? {
-        appSwitchBaseURLComponents().url
-    }
-
     // MARK: - Private Properties
 
-    static private let xCallbackTemplate: String = "scheme://x-callback-url/path"
-
     private var queryParameters: [String: Any?] = [:]
 
     // MARK: - Initializer
 
     init(
         paymentContextID: String,
         metadata: BTClientMetadata,
-        returnURLScheme: String?,
-        universalLink: URL?,
+        universalLink: URL,
         forMerchantID merchantID: String?,
         accessToken: String?,
         bundleDisplayName: String?,
@@ -53,18 +43,11 @@ struct BTVenmoAppSwitchRedirectURL {
             "braintree_environment": environment,
             "resource_id": paymentContextID,
             "braintree_sdk_data": base64EncodedBraintreeData ?? "",
-            "customerClient": "MOBILE_APP"
+            "customerClient": "MOBILE_APP",
+            "x-success": universalLink.appendingPathComponent("success").absoluteString,
+            "x-error": universalLink.appendingPathComponent("error").absoluteString,
+            "x-cancel": universalLink.appendingPathComponent("cancel").absoluteString
         ]
-
-        if let universalLink {
-            queryParameters["x-success"] = universalLink.appendingPathComponent("success").absoluteString
-            queryParameters["x-error"] = universalLink.appendingPathComponent("error").absoluteString
-            queryParameters["x-cancel"] = universalLink.appendingPathComponent("cancel").absoluteString
-        } else if let returnURLScheme {
-            queryParameters["x-success"] = constructRedirectURL(with: returnURLScheme, result: "success")
-            queryParameters["x-error"] = constructRedirectURL(with: returnURLScheme, result: "error")
-            queryParameters["x-cancel"] = constructRedirectURL(with: returnURLScheme, result: "cancel")
-        }
     }
 
     // MARK: - Internal Methods
@@ -82,20 +65,4 @@ struct BTVenmoAppSwitchRedirectURL {
 
         return urlComponent.url
     }
-
-    // MARK: - Private Helper Methods
-
-    private func constructRedirectURL(with scheme: String, result: String) -> URL? {
-        var components = URLComponents(string: BTVenmoAppSwitchRedirectURL.xCallbackTemplate)
-        components?.scheme = scheme
-        components?.percentEncodedPath = "/vzero/auth/venmo/\(result)"
-        return components?.url
-    }
-
-    private static func appSwitchBaseURLComponents() -> URLComponents {
-        var components: URLComponents = URLComponents(string: xCallbackTemplate) ?? URLComponents()
-        components.scheme = BTCoreConstants.venmoURLScheme
-        components.percentEncodedPath = "/vzero/auth"
-        return components
-    }
 }

Sources/BraintreeVenmo/BTVenmoAppSwitchReturnURL.swift

@@ -69,6 +69,5 @@ struct BTVenmoAppSwitchReturnURL {
     /// - Returns: `true` if the url represents a Venmo Touch app switch return
     static func isValid(url: URL) -> Bool {
         (url.scheme == "https" && (url.path.contains("cancel") || url.path.contains("success") || url.path.contains("error")))
-        || (url.host == "x-callback-url" && url.path.hasPrefix("/vzero/auth/venmo/"))
     }
 }

Sources/BraintreeVenmo/BTVenmoClient.swift

@@ -29,6 +29,15 @@ import BraintreeCore
     /// Stored property used to determine whether a Venmo account nonce should be vaulted after an app switch return
     var shouldVault: Bool = false
 
+    /// Used for linking events from the client to server side request
+    /// In the Venmo flow this will be the payment context ID
+    private var payPalContextID: String?
+
+    /// Used for sending the type of flow, universal vs deeplink to FPTI
+    private var linkType: LinkType?
+
+    private var universalLink: URL
+
     /// Used internally as a holder for the completion in methods that do not pass a completion such as `handleOpen`.
     /// This allows us to set and return a completion in our methods that otherwise cannot require a completion.
     var appSwitchCompletion: (BTVenmoAccountNonce?, Error?) -> Void = { _, _ in }
@@ -39,32 +48,17 @@ import BraintreeCore
     /// We require a static reference of the client to call `handleReturnURL` and return to the app.
     static var venmoClient: BTVenmoClient?
 
-    /// Used for linking events from the client to server side request
-    /// In the Venmo flow this will be the payment context ID
-    private var payPalContextID: String?
-
-    /// Used for sending the type of flow, universal vs deeplink to FPTI
-    private var linkType: LinkType?
-
-    private var universalLink: URL?
-
     // MARK: - Initializer
 
-    /// Creates a Venmo client
-    /// - Parameter apiClient: An API client
-    @objc(initWithAPIClient:)
-    public init(apiClient: BTAPIClient) {
-        BTAppContextSwitcher.sharedInstance.register(BTVenmoClient.self)
-        self.apiClient = apiClient
-    }
-
     /// Initialize a new Venmo client instance.
     /// - Parameters:
     ///   - apiClient: The API Client
     ///   - universalLink: The URL for the Venmo app to redirect to after user authentication completes. Must be a valid HTTPS URL dedicated to Braintree app switch returns.
     @objc(initWithAPIClient:universalLink:)
-    public convenience init(apiClient: BTAPIClient, universalLink: URL) {
-        self.init(apiClient: apiClient)
+    public init(apiClient: BTAPIClient, universalLink: URL) {
+        BTAppContextSwitcher.sharedInstance.register(BTVenmoClient.self)
+
+        self.apiClient = apiClient
         self.universalLink = universalLink
     }
 
@@ -77,27 +71,9 @@ import BraintreeCore
     ///   an instance of `BTVenmoAccountNonce`; on failure or user cancelation you will receive an error.
     ///   If the user cancels out of the flow, the error code will be `.canceled`.
     @objc(tokenizeWithVenmoRequest:completion:)
-    // swiftlint:disable:next function_body_length cyclomatic_complexity
+    // swiftlint:disable:next function_body_length
     public func tokenize(_ request: BTVenmoRequest, completion: @escaping (BTVenmoAccountNonce?, Error?) -> Void) {
         apiClient.sendAnalyticsEvent(BTVenmoAnalytics.tokenizeStarted, isVaultRequest: shouldVault)
-        let returnURLScheme = BTAppContextSwitcher.sharedInstance._returnURLScheme
-
-        if returnURLScheme.isEmpty {
-            NSLog(
-                "%@ Venmo requires a return URL scheme to be configured via [BTAppContextSwitcher setReturnURLScheme:]",
-                BTLogLevelDescription.string(for: .critical)
-            )
-            notifyFailure(with: BTVenmoError.appNotAvailable, completion: completion)
-            return
-        } else if let bundleIdentifier = bundle.bundleIdentifier, !returnURLScheme.hasPrefix(bundleIdentifier) {
-            NSLog(
-                // swiftlint:disable:next line_length
-                "%@ Venmo requires [BTAppContextSwitcher setReturnURLScheme:] to be configured to begin with your app's bundle ID (%@). Currently, it is set to (%@)",
-                BTLogLevelDescription.string(for: .critical),
-                bundleIdentifier,
-                returnURLScheme
-            )
-        }
 
         apiClient.fetchOrReturnRemoteConfiguration { configuration, error in
             if let error {
@@ -164,7 +140,6 @@ import BraintreeCore
                     let appSwitchURL = try BTVenmoAppSwitchRedirectURL(
                         paymentContextID: paymentContextID,
                         metadata: metadata,
-                        returnURLScheme: returnURLScheme,
                         universalLink: self.universalLink,
                         forMerchantID: merchantProfileID,
                         accessToken: configuration.venmoAccessToken,