joemasilotti · joemasilotti · Oct 15, 2023 · Oct 15, 2023 · Nov 1, 2023 · Nov 2, 2023
diff --git a/Demo/Server/app/javascript/controllers/alerts_controller.js b/Demo/Server/app/javascript/controllers/alerts_controller.js
@@ -0,0 +1,14 @@
+import { Controller } from "@hotwired/stimulus"
+
+export default class extends Controller {
+  showAlert(event) {
+    event.preventDefault()
+    alert(event.currentTarget.dataset["title"])
+  }
+
+  showConfirm(event) {
+    event.preventDefault()
+    const result = confirm(event.currentTarget.dataset["title"])
+    alert(`You ${result ? "confirmed" : "cancelled"} the dialog.`)
+  }
+}
diff --git a/Demo/Server/app/javascript/controllers/index.js b/Demo/Server/app/javascript/controllers/index.js
@@ -3,3 +3,6 @@
 // ./bin/rails generate stimulus controllerName
 
 import { application } from "./application"
+
+import AlertsController from "./alerts_controller"
+application.register("alerts", AlertsController)
diff --git a/Demo/Server/app/views/layouts/application.html.erb b/Demo/Server/app/views/layouts/application.html.erb
@@ -12,7 +12,7 @@
     <%= hotwire_livereload_tags if Rails.env.development? %>
   </head>
 
-  <body class="<%= "turbo-native" if turbo_native_app? %>">
+  <body class="mb-5 <%= "turbo-native" if turbo_native_app? %>">
     <%= render "shared/navbar" %>
     <main class="container">
       <%= render "shared/flash" %>

diff --git a/Demo/Server/app/views/navigations/_item.html.erb b/Demo/Server/app/views/navigations/_item.html.erb
@@ -5,7 +5,7 @@
 
   <div class="w-100 mx-auto">
     <p class="fs-5 mb-0"><%= name %></p>
-    <p class="mb-0 text-muted"><%= description %></p>
+    <p class="mb-0 text-muted"><%= local_assigns[:description] || yield %></p>
   </div>
 
   <div class="col flex-grow-0 flex-shrink-1 my-auto">

diff --git a/Demo/Server/app/views/navigations/show.html.erb b/Demo/Server/app/views/navigations/show.html.erb
@@ -3,7 +3,7 @@
 <p class="my-3">This screen was pushed onto the navigation stack.</p>
 <p>This is the default behavior, no custom options are required.</p>
 
-<div class="list-group list-group-flush mx-n3 sm:mx-0">
+<div class="list-group list-group-flush mx-n3 sm:mx-0" data-controller="alerts">
   <%= render "navigations/item",
     path: second_navigation_path,
     icon: "bi-arrow-right",
@@ -34,4 +34,20 @@
     icon: "bi-bug",
     name: "Error handling",
     description: "Visit a page that does not exist (404)." %>
+
+  <%= render "navigations/item",
+    path: "#",
+    icon: "bi-exclamation-circle",
+    name: "JavaScript alert dialog",
+    data: {action: "alerts#showAlert", title: "A JavaScript alert."} do %>
+    Present a JavaScript <code>alert()</code>.
+  <% end %>
+
+  <%= render "navigations/item",
+    path: "#",
+    icon: "bi-question-circle",
+    name: "JavaScript confirm dialog",
+    data: {action: "alerts#showConfirm", title: "Are you sure?"} do %>
+    Present a JavaScript <code>confirm()</code>, like via <code>data-turbo-confirm</code>.
+  <% end %>
 </div>
diff --git a/Demo/Server/app/views/resources/show.html.erb b/Demo/Server/app/views/resources/show.html.erb
@@ -5,5 +5,5 @@
 
 <div class="btn-group d-flex d-sm-inline-flex mt-4" role="group">
   <%= link_to "Edit resource", edit_resource_path(@resource), class: "btn btn-outline-secondary" %>
-  <%= link_to "Delete resource", resource_path(@resource), data: {turbo_method: :delete}, class: "btn btn-outline-danger" %>
+  <%= link_to "Delete resource", resource_path(@resource), data: {turbo_method: :delete, turbo_confirm: "Delete this resource?"}, class: "btn btn-outline-danger" %>
 </div>
diff --git a/Sources/TurboNavigationDelegate.swift b/Sources/TurboNavigationDelegate.swift
@@ -5,10 +5,8 @@ import WebKit
 /// Implement to be notified when certain navigations are performed
 /// or to render a native controller instead of a Turbo web visit.
 public protocol TurboNavigationDelegate: AnyObject {
-    typealias RetryBlock = () -> Void
-
-    /// Respond to authentication challenge presented by web servers behing basic auth.
-    func didReceiveAuthenticationChallenge(_ challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)
+    /// Optional. Override to provide a custom implementation of `WKUIDelegate`, like handling JavaScript alerts.
+    var webViewDelegate: WKUIDelegate? { get }
 
     /// Optional. Accept or reject a visit proposal.
     /// If accepted, you may provide a view controller to be displayed, otherwise a new `VisitableViewController` is displayed.
@@ -19,48 +17,31 @@ public protocol TurboNavigationDelegate: AnyObject {
     /// - Returns: how to react to the visit proposal
     func handle(proposal: VisitProposal) -> ProposalResult
 
-    /// Optional. An error occurred loading the request, present it to the user.
-    /// Retry the request by executing the closure.
-    /// If not implemented, will present the error's localized description and a Retry button.
-    func visitableDidFailRequest(_ visitable: Visitable, error: Error, retry: @escaping RetryBlock)
-
-    /// Optional. Implement to customize handling of external URLs.
-    /// If not implemented, will present `SFSafariViewController` as a modal and load the URL.
-    func openExternalURL(_ url: URL, from controller: UIViewController)
+    // MARK: - SessionDelegate overrides
+    /// Optional. Implement these functions when via an extension.
 
-    /// Optional. Implement to become the web view's navigation delegate after the initial cold boot visit is completed.
-    /// https://github.com/hotwired/turbo-ios/blob/main/Docs/Overview.md#becoming-the-web-views-navigation-delegate
+    func session(_ session: Session, didReceiveAuthenticationChallenge challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void)
     func sessionDidLoadWebView(_ session: Session)
 
-    /// Optional. Useful for interacting with the web view after the page loads.
+    func sessionDidStartRequest(_ session: Session)
     func sessionDidFinishRequest(_ session: Session)
+    func sessionDidStartFormSubmission(_ session: Session)
 }
 
 public extension TurboNavigationDelegate {
-    func handle(proposal: VisitProposal) -> ProposalResult { .accept }
+    var webViewDelegate: WKUIDelegate? { nil }
 
-    func visitableDidFailRequest(_ visitable: Visitable, error: Error, retry: @escaping RetryBlock) {
-        if let errorPresenter = visitable as? ErrorPresenter {
-            errorPresenter.presentError(error) {
-                retry()
-            }
-        }
-    }
+    func handle(proposal: VisitProposal) -> ProposalResult { .accept }
 
-    func openExternalURL(_ url: URL, from controller: UIViewController) {
-        let safariViewController = SFSafariViewController(url: url)
-        safariViewController.modalPresentationStyle = .pageSheet
-        if #available(iOS 15.0, *) {
-            safariViewController.preferredControlTintColor = .tintColor
-        }
-        controller.present(safariViewController, animated: true)
-    }
+    // MARK: - SessionDelegate
 
-    func didReceiveAuthenticationChallenge(_ challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
+    func session(_ session: Session, didReceiveAuthenticationChallenge challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
         completionHandler(.performDefaultHandling, nil)
     }
 
-    func sessionDidFinishRequest(_ session: Session) {}
-
     func sessionDidLoadWebView(_ session: Session) {}
+
+    func sessionDidStartRequest(_ session: Session) {}
+    func sessionDidFinishRequest(_ session: Session) {}
+    func sessionDidStartFormSubmission(_ session: Session) {}
 }
diff --git a/Sources/TurboNavigator.swift b/Sources/TurboNavigator.swift
@@ -5,63 +5,43 @@ import WebKit
 
 /// Handles navigation to new URLs using the following rules:
 /// https://github.com/joemasilotti/TurboNavigator#handled-flows
-public class TurboNavigator {
+public class TurboNavigator: NSObject {
     /// Default initializer.
     /// - Parameters:
-    ///   - delegate: handle custom controller routing
-    ///   - pathConfiguration: assigned to internal `Session` instances for custom configuration
-    ///   - navigationController: optional: override the main navigation stack
-    ///   - modalNavigationController: optional: override the modal navigation stack
-    public init(delegate: TurboNavigationDelegate,
-                pathConfiguration: PathConfiguration? = nil,
-                navigationController: UINavigationController = UINavigationController(),
-                modalNavigationController: UINavigationController = UINavigationController())
+    ///   - delegate: Handle custom controller routing.
+    ///   - pathConfiguration: Optional. Remotely configure settings and path rules.
+    ///   - navigationController: Optional. Override the main navigation stack.
+    ///   - modalNavigationController: Optional. Override the modal navigation stack.
+    public init(
+        delegate: TurboNavigationDelegate,
+        pathConfiguration: PathConfiguration? = nil,
+        navigationController: UINavigationController = UINavigationController(),
+        modalNavigationController: UINavigationController = UINavigationController())
     {
-        self.session = Session(webView: TurboConfig.shared.makeWebView())
-        self.modalSession = Session(webView: TurboConfig.shared.makeWebView())
         self.delegate = delegate
+        self.pathConfiguration = pathConfiguration
         self.navigationController = navigationController
         self.modalNavigationController = modalNavigationController
-
-        session.delegate = self
-        modalSession.delegate = self
-        session.pathConfiguration = pathConfiguration
-        modalSession.pathConfiguration = pathConfiguration
+        super.init()
     }
 
-    /// Provide `Turbo.Session` instances with preconfigured path configurations and delegates.
-    /// Note that TurboNavigationDelegate.controller(_:forProposal:) will no longer be called.
-    /// - Parameters:
-    ///   - preconfiguredMainSession: a session whose delegate is not `TurboNavigator`
-    ///   - preconfiguredModalSession: a session whose delegate is not `TurboNavigator`
-    ///   - delegate: handle non-routing behavior, like custom error handling
-    ///   - navigationController: optional: override the main navigation stack
-    ///   - modalNavigationController: optional: override the modal navigation stack
-    public init(preconfiguredMainSession: Turbo.Session,
-                preconfiguredModalSession: Turbo.Session,
-                delegate: TurboNavigationDelegate,
-                navigationController: UINavigationController = UINavigationController(),
-                modalNavigationController: UINavigationController = UINavigationController())
-    {
-        self.session = preconfiguredMainSession
-        self.modalSession = preconfiguredModalSession
-        self.navigationController = navigationController
-        self.modalNavigationController = modalNavigationController
+    /// Set this as the `rootViewController` of your application's `UIWindow`.
+    public var rootViewController: UIViewController { navigationController }
 
-        self.delegate = delegate
+    /// `navigationController` or `modalNavigationController`, whichever is being shown.
+    public var currentNavigationController: UINavigationController {
+        navigationController.presentedViewController != nil ? modalNavigationController : navigationController
     }
 
-    public var rootViewController: UIViewController { navigationController }
-    public let navigationController: UINavigationController
-    public let modalNavigationController: UINavigationController
-
+    /// Follows rules from `pathConfiguration` to route a `URL` to the stack.
     public func route(_ url: URL) {
         let options = VisitOptions(action: .advance, response: nil)
         let properties = session.pathConfiguration?.properties(for: url) ?? PathProperties()
         let proposal = VisitProposal(url: url, options: options, properties: properties)
         route(proposal)
     }
 
+    /// Follows rules from `pathConfiguration` to route a `VisitProposal` to the stack.
     public func route(_ proposal: VisitProposal) {
         guard let controller = controller(for: proposal) else { return }
 
@@ -89,8 +69,11 @@ public class TurboNavigator {
 
     // MARK: Internal
 
-    let session: Session
-    let modalSession: Session
+    let navigationController: UINavigationController
+    let modalNavigationController: UINavigationController
+
+    lazy var session = makeSession()
+    lazy var modalSession = makeSession()
 
     // MARK: Private
 
@@ -100,6 +83,15 @@ public class TurboNavigator {
     }
 
     private unowned let delegate: TurboNavigationDelegate
+    private let pathConfiguration: PathConfiguration?
+
+    private func makeSession() -> Session {
+        let session = Session(webView: TurboConfig.shared.makeWebView())
+        session.delegate = self
+        session.pathConfiguration = pathConfiguration
+        session.webView.uiDelegate = delegate.webViewDelegate ?? self
+        return session
+    }
 
     private func controller(for proposal: VisitProposal) -> UIViewController? {
         switch delegate.handle(proposal: proposal) {
@@ -248,30 +240,68 @@ extension TurboNavigator: SessionDelegate {
     }
 
     public func session(_ session: Session, openExternalURL url: URL) {
-        let controller = session === modalSession ? modalNavigationController : navigationController
-        delegate.openExternalURL(url, from: controller)
+        let safariViewController = SFSafariViewController(url: url)
+        safariViewController.modalPresentationStyle = .pageSheet
+        if #available(iOS 15.0, *) {
+            safariViewController.preferredControlTintColor = .tintColor
+        }
+        currentNavigationController.visibleViewController?.present(safariViewController, animated: true)
     }
 
     public func session(_ session: Session, didFailRequestForVisitable visitable: Visitable, error: Error) {
-        delegate.visitableDidFailRequest(visitable, error: error) {
-            session.reload()
+        if let errorPresenter = visitable as? ErrorPresenter {
+            errorPresenter.presentError(error) {
+                session.reload()
+            }
         }
     }
 
     public func sessionWebViewProcessDidTerminate(_ session: Session) {
         session.reload()
     }
 
+    // MARK: SessionDelegate → TurboNavigationDelegate
+
     public func session(_ session: Session, didReceiveAuthenticationChallenge challenge: URLAuthenticationChallenge, completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
-        delegate.didReceiveAuthenticationChallenge(challenge, completionHandler: completionHandler)
+        delegate.session(session, didReceiveAuthenticationChallenge: challenge, completionHandler: completionHandler)
+    }
+
+    public func sessionDidLoadWebView(_ session: Session) {
+        delegate.sessionDidLoadWebView(session)
+    }
+
+    public func sessionDidStartRequest(_ session: Session) {
+        delegate.sessionDidStartRequest(session)
     }
 
     public func sessionDidFinishRequest(_ session: Session) {
         delegate.sessionDidFinishRequest(session)
     }
 
-    public func sessionDidLoadWebView(_ session: Session) {
-        session.webView.navigationDelegate = session
-        delegate.sessionDidLoadWebView(session)
+    public func sessionDidStartFormSubmission(_ session: Session) {
+        delegate.sessionDidStartFormSubmission(session)
+    }
+}
+
+// MARK: - WKUIDelegate
+
+extension TurboNavigator: WKUIDelegate {
+    public func webView(_ webView: WKWebView, runJavaScriptAlertPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping () -> Void) {
+        let alert = UIAlertController(title: message, message: nil, preferredStyle: .alert)
+        alert.addAction(UIAlertAction(title: "Close", style: .default) { _ in
+            completionHandler()
+        })
+        currentNavigationController.visibleViewController?.present(alert, animated: true)
+    }
+
+    public func webView(_ webView: WKWebView, runJavaScriptConfirmPanelWithMessage message: String, initiatedByFrame frame: WKFrameInfo, completionHandler: @escaping (Bool) -> Void) {
+        let alert = UIAlertController(title: message, message: nil, preferredStyle: .alert)
+        alert.addAction(UIAlertAction(title: "OK", style: .destructive) { _ in
+            completionHandler(true)
+        })
+        alert.addAction(UIAlertAction(title: "Cancel", style: .cancel) { _ in
+            completionHandler(false)
+        })
+        currentNavigationController.visibleViewController?.present(alert, animated: true)
     }
 }
diff --git a/Tests/TurboNavigationDelegateTests.swift b/Tests/TurboNavigationDelegateTests.swift
@@ -12,16 +12,6 @@ final class TurboNavigationDelegateTests: XCTestCase {
         XCTAssertEqual(result, .accept)
     }
 
-    func test_openExternalURL_presentsSafariViewController() throws {
-        let url = URL(string: "https://example.com")!
-        let controller = TestableNavigationController()
-
-        delegate.openExternalURL(url, from: controller)
-
-        XCTAssert(controller.presentedViewController is SFSafariViewController)
-        XCTAssertEqual(controller.modalPresentationStyle, .pageSheet)
-    }
-
     // MARK: Private
 
     private let delegate = DefaultDelegate()

diff --git a/Tests/TurboNavigatorTests.swift b/Tests/TurboNavigatorTests.swift
@@ -245,6 +245,22 @@ final class TurboNavigatorTests: XCTestCase {
         XCTAssertNotEqual(navigator.session.activeVisitable?.visitableURL, proposal.url)
     }
 
+    func test_currentNavigationController_startsAsRoot() {
+        XCTAssertIdentical(navigator.currentNavigationController, navigator.navigationController)
+    }
+
+    func test_currentNavigationController_modalPresented_isModal() {
+        navigator.route(VisitProposal(path: "/one"))
+        navigator.route(VisitProposal(path: "/two", context: .modal))
+        XCTAssertIdentical(navigator.currentNavigationController, navigator.modalNavigationController)
+    }
+
+    func test_currentNavigationController_mainNavigation_isRoot() {
+        navigator.route(VisitProposal(path: "/one", context: .modal))
+        navigator.route(VisitProposal(path: "/two"))
+        XCTAssertIdentical(navigator.currentNavigationController, navigator.navigationController)
+    }
+
     // MARK: Private
 
     private enum Context {