Top level deeplink handling (#1660)

* Handle link opening on the top most levels and prepare for percolating them throughout the app
* Add support for a custom app scheme
* Add specific AppRoute parsers.
* Integrate custom scheme in the AppRouteURLParser
* Switch to `element://call` and cleanup route parsing

ElementX.xcodeproj/project.pbxproj

@@ -5196,6 +5196,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
+				APP_CUSTOM_SCHEME = element;
 				APP_DISPLAY_NAME = "Element X";
 				APP_GROUP_IDENTIFIER = "group.$(BASE_APP_GROUP_IDENTIFIER)";
 				APP_NAME = ElementX;
@@ -5265,6 +5266,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
+				APP_CUSTOM_SCHEME = element;
 				APP_DISPLAY_NAME = "Element X";
 				APP_GROUP_IDENTIFIER = "group.$(BASE_APP_GROUP_IDENTIFIER)";
 				APP_NAME = ElementX;

ElementX/Sources/Application/AppCoordinator.swift

@@ -55,6 +55,7 @@ class AppCoordinator: AppCoordinatorProtocol, AuthenticationCoordinatorDelegate,
     
     let notificationManager: NotificationManagerProtocol
 
+    private let appRouteURLParser: AppRouteURLParser
     @Consumable private var storedAppRoute: AppRoute?
 
     init() {
@@ -75,6 +76,7 @@ class AppCoordinator: AppCoordinatorProtocol, AuthenticationCoordinatorDelegate,
         }
         
         self.appSettings = appSettings
+        appRouteURLParser = AppRouteURLParser(appSettings: appSettings)
         
         navigationRootCoordinator = NavigationRootCoordinator()
         
@@ -137,10 +139,10 @@ class AppCoordinator: AppCoordinatorProtocol, AuthenticationCoordinatorDelegate,
         )
     }
     
-    func handleUniversalLink(_ url: URL) {
+    func handleDeepLink(_ url: URL) -> Bool {
         // Parse into an AppRoute to redirect these in a type safe way.
         
-        if let route = AppRouteURLParser.route(from: url) {
+        if let route = appRouteURLParser.route(from: url) {
             switch route {
             case .genericCallLink(let url):
                 if let userSessionFlowCoordinator {
@@ -152,13 +154,15 @@ class AppCoordinator: AppCoordinatorProtocol, AuthenticationCoordinatorDelegate,
                 break
             }
             
-            return
+            return true
         }
         
         // Until we have an OIDC callback AppRoute, handle it manually.
         if url.absoluteString.starts(with: appSettings.oidcRedirectURL.absoluteString) {
             MXLog.error("OIDC callback through Universal Links not implemented.")
         }
+        
+        return false
     }
     
     // MARK: - AuthenticationCoordinatorDelegate

ElementX/Sources/Application/AppCoordinatorProtocol.swift

@@ -18,5 +18,5 @@ import Foundation
 
 protocol AppCoordinatorProtocol: CoordinatorProtocol {
     var notificationManager: NotificationManagerProtocol { get }
-    func handleUniversalLink(_ url: URL)
+    @discardableResult func handleDeepLink(_ url: URL) -> Bool
 }

ElementX/Sources/Application/Application.swift

@@ -35,7 +35,14 @@ struct Application: App {
         WindowGroup {
             appCoordinator.toPresentable()
                 .statusBarHidden(shouldHideStatusBar)
-                .onOpenURL { appCoordinator.handleUniversalLink($0) }
+                .environment(\.openURL, OpenURLAction { url in
+                    if appCoordinator.handleDeepLink(url) {
+                        return .handled
+                    }
+
+                    return .systemAction
+                })
+                .onOpenURL { appCoordinator.handleDeepLink($0) }
                 .introspect(.window, on: .iOS(.v16)) { window in
                     // Workaround for SwiftUI not consistently applying the tint colour to Alerts/Confirmation Dialogs.
                     window.tintColor = .compound.textActionPrimary

ElementX/Sources/Application/Navigation/AppRoutes.swift

@@ -17,6 +17,7 @@
 import Foundation
 
 enum AppRoute: Equatable {
+    case oidcCallback(url: URL)
     case roomList
     case room(roomID: String)
     case roomDetails(roomID: String)
@@ -24,32 +25,87 @@ enum AppRoute: Equatable {
     case genericCallLink(url: URL)
 }
 
-enum AppRouteURLParser {
-    private enum KnownHosts: String, CaseIterable {
-        case elementIo = "element.io"
-        case appElementIo = "app.element.io"
-        case stagingElementIo = "staging.element.io"
-        case developElementIo = "develop.element.io"
-        case mobileElementIo = "mobile.element.io"
-        case callElementIo = "call.element.io"
+struct AppRouteURLParser {
+    let urlParsers: [URLParser]
+    
+    init(appSettings: AppSettings) {
+        urlParsers = [
+            ElementAppURLParser(appSettings: appSettings),
+            ElementCallURLParser()
+        ]
     }
     
-    static func route(from url: URL) -> AppRoute? {
-        guard let urlComponents = URLComponents(url: url, resolvingAgainstBaseURL: false),
-              let host = urlComponents.host else {
-            MXLog.error("Failed parsing URL: \(url)")
-            return nil
+    func route(from url: URL) -> AppRoute? {
+        for parser in urlParsers {
+            if let appRoute = parser.route(from: url) {
+                return appRoute
+            }
         }
         
-        guard KnownHosts.allCases.map(\.rawValue).contains(host) else {
-            return .genericCallLink(url: url)
-        }
-        
-        if host == KnownHosts.callElementIo.rawValue {
-            return .genericCallLink(url: url)
-        }
-                
-        // Deep linking not supported at the moment
         return nil
     }
 }
+
+/// Represents a type that can parse a `URL` into an `AppRoute`.
+///
+/// The following Universal Links are missing parsers.
+/// - app.element.io
+/// - mobile.element.io
+protocol URLParser {
+    func route(from url: URL) -> AppRoute?
+}
+
+/// The parser for the main Element website.
+struct ElementAppURLParser: URLParser {
+    private let knownHosts = ["app.element.io", "staging.element.io", "develop.element.io"]
+    
+    let appSettings: AppSettings
+    
+    func route(from url: URL) -> AppRoute? {
+        guard let host = url.host, knownHosts.contains(host) else {
+            return nil
+        }
+        
+        let pathComponents = url.pathComponents
+        
+        // OIDC callback URL.
+        if pathComponents.count == 3, pathComponents[0] == "mobile", pathComponents[1] == "oidc" {
+            return .oidcCallback(url: url)
+        }
+        
+        return nil
+    }
+}
+
+/// The parser for Element Call links. This always returns a `.genericCallLink`
+struct ElementCallURLParser: URLParser {
+    private let knownHosts = ["call.element.io"]
+    private let customSchemeHost = "call"
+    private let customSchemeURLQueryParameterName = "url"
+    
+    func route(from url: URL) -> AppRoute? {
+        // First try processing URLs with custom schemes
+        if let scheme = url.scheme,
+           scheme == InfoPlistReader.app.appScheme {
+            guard let components = URLComponents(url: url, resolvingAgainstBaseURL: false),
+                  components.host == customSchemeHost else {
+                return nil
+            }
+            
+            guard let encodedURLString = components.queryItems?.first(where: { $0.name == customSchemeURLQueryParameterName })?.value,
+                  let callURL = URL(string: encodedURLString) else {
+                MXLog.error("Invalid custom scheme call parameters: \(url)")
+                return nil
+            }
+            
+            return .genericCallLink(url: callURL)
+        }
+        
+        // Otherwise try to interpret it as an universal link
+        guard let host = url.host, knownHosts.contains(host) else {
+            return nil
+        }
+        
+        return .genericCallLink(url: url)
+    }
+}

ElementX/Sources/FlowCoordinators/RoomFlowCoordinator.swift

@@ -83,7 +83,7 @@ class RoomFlowCoordinator: FlowCoordinatorProtocol {
             stateMachine.tryEvent(.dismissRoom, userInfo: EventUserInfo(animated: animated))
         case .invites:
             break
-        case .genericCallLink:
+        case .genericCallLink, .oidcCallback:
             break
         }
     }

ElementX/Sources/FlowCoordinators/UserSessionFlowCoordinator.swift

@@ -121,6 +121,8 @@ class UserSessionFlowCoordinator: FlowCoordinatorProtocol {
                 self.stateMachine.processEvent(.showInvitesScreen, userInfo: .init(animated: animated))
             case .genericCallLink(let url):
                 self.navigationSplitCoordinator.setSheetCoordinator(GenericCallLinkCoordinator(parameters: .init(url: url)), animated: animated)
+            case .oidcCallback:
+                break
             }
         }
     }

ElementX/Sources/Other/InfoPlistReader.swift

@@ -31,6 +31,9 @@ struct InfoPlistReader {
         static let otlpTracingURL = "otlpTracingURL"
         static let otlpTracingUsername = "otlpTracingUsername"
         static let otlpTracingPassword = "otlpTracingPassword"
+        
+        static let bundleURLTypes = "CFBundleURLTypes"
+        static let bundleURLSchemes = "CFBundleURLSchemes"
     }
     
     private enum Values {
@@ -111,6 +114,19 @@ struct InfoPlistReader {
         infoPlistValue(forKey: Keys.otlpTracingPassword)
     }
     
+    // MARK: - Custom App Scheme
+    
+    var appScheme: String {
+        let urlTypes: [[String: Any]] = infoPlistValue(forKey: Keys.bundleURLTypes)
+        
+        guard let urlSchemes = urlTypes.first?[Keys.bundleURLSchemes] as? [String],
+              let scheme = urlSchemes.first else {
+            fatalError("Invalid custon application scheme configuration")
+        }
+        
+        return scheme
+    }
+    
     // MARK: - Mention Pills
 
     /// Mention Pills UTType

ElementX/Sources/Screens/RoomScreen/RoomScreenModels.swift

@@ -56,7 +56,6 @@ enum RoomScreenViewAction {
     case itemAppeared(itemID: TimelineItemIdentifier)
     case itemDisappeared(itemID: TimelineItemIdentifier)
     case itemTapped(itemID: TimelineItemIdentifier)
-    case linkClicked(url: URL)
     case toggleReaction(key: String, itemID: TimelineItemIdentifier)
     case sendReadReceiptIfNeeded(TimelineItemIdentifier)
     case paginateBackwards

ElementX/Sources/Screens/RoomScreen/RoomScreenViewModel.swift

@@ -104,8 +104,6 @@ class RoomScreenViewModel: RoomScreenViewModelType, RoomScreenViewModelProtocol
             Task { await timelineController.processItemDisappearance(id) }
         case .itemTapped(let id):
             Task { await itemTapped(with: id) }
-        case .linkClicked(let url):
-            MXLog.warning("Link clicked: \(url)")
         case .toggleReaction(let emoji, let itemId):
             Task { await timelineController.toggleReaction(emoji, to: itemId) }
         case .sendReadReceiptIfNeeded(let lastVisibleItemID):

ElementX/Sources/Screens/Settings/NotificationSettingsScreen/NotificationSettingsScreenModels.swift

@@ -86,7 +86,6 @@ struct NotificationSettingsScreenStrings {
 }
 
 enum NotificationSettingsScreenViewAction {
-    case linkClicked(url: URL)
     case changedEnableNotifications
     case groupChatsTapped
     case directChatsTapped

ElementX/Sources/Screens/Settings/NotificationSettingsScreen/NotificationSettingsScreenViewModel.swift

@@ -57,8 +57,6 @@ class NotificationSettingsScreenViewModel: NotificationSettingsScreenViewModelTy
     
     override func process(viewAction: NotificationSettingsScreenViewAction) {
         switch viewAction {
-        case .linkClicked(let url):
-            MXLog.warning("Link clicked: \(url)")
         case .changedEnableNotifications:
             toggleNotifications()
         case .groupChatsTapped:

ElementX/Sources/Screens/Settings/NotificationSettingsScreen/View/NotificationSettingsScreen.swift

@@ -79,10 +79,6 @@ struct NotificationSettingsScreen: View {
                 }
                 .padding(.horizontal, ListRowPadding.horizontal)
                 .padding(.vertical, 8)
-                .environment(\.openURL, OpenURLAction { url in
-                    context.send(viewAction: .linkClicked(url: url))
-                    return .systemAction
-                })
             })
         }
     }

ElementX/Sources/Services/Timeline/TimelineItems/RoomTimelineItemView.swift

@@ -30,10 +30,6 @@ struct RoomTimelineItemView: View {
             .onDisappear {
                 context.send(viewAction: .itemDisappeared(itemID: viewState.identifier))
             }
-            .environment(\.openURL, OpenURLAction { url in
-                context.send(viewAction: .linkClicked(url: url))
-                return .systemAction
-            })
     }
 
     @ViewBuilder private var timelineView: some View {

ElementX/Sources/UITests/UITestsAppCoordinator.swift

@@ -61,7 +61,7 @@ class UITestsAppCoordinator: AppCoordinatorProtocol {
         navigationRootCoordinator.toPresentable()
     }
     
-    func handleUniversalLink(_ url: URL) {
+    func handleDeepLink(_ url: URL) -> Bool {
         fatalError("Not implemented.")
     }
 }

ElementX/Sources/UnitTests/UnitTestsAppCoordinator.swift

@@ -37,7 +37,7 @@ class UnitTestsAppCoordinator: AppCoordinatorProtocol {
         AnyView(ProgressView("Running Unit Tests"))
     }
     
-    func handleUniversalLink(_ url: URL) {
+    func handleDeepLink(_ url: URL) -> Bool {
         fatalError("Not implemented.")
     }
 }

ElementX/SupportingFiles/Info.plist

@@ -35,6 +35,19 @@
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
 	<string>$(MARKETING_VERSION)</string>
+	<key>CFBundleURLTypes</key>
+	<array>
+		<dict>
+			<key>CFBundleTypeRole</key>
+			<string>Editor</string>
+			<key>CFBundleURLName</key>
+			<string>$(BASE_BUNDLE_IDENTIFIER)</string>
+			<key>CFBundleURLSchemes</key>
+			<array>
+				<string>$(APP_CUSTOM_SCHEME)</string>
+			</array>
+		</dict>
+	</array>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 	<key>ITSAppUsesNonExemptEncryption</key>

ElementX/SupportingFiles/target.yml

@@ -54,6 +54,15 @@ targets:
         CFBundleDisplayName: $(APP_DISPLAY_NAME)
         CFBundleShortVersionString: $(MARKETING_VERSION)
         CFBundleVersion: $(CURRENT_PROJECT_VERSION)
+        CFBundleURLTypes: [
+          {
+            CFBundleTypeRole: Editor,
+            CFBundleURLName: $(BASE_BUNDLE_IDENTIFIER),
+            CFBundleURLSchemes: [
+              $(APP_CUSTOM_SCHEME)
+            ]
+          }
+        ]
         UISupportedInterfaceOrientations: [
           UIInterfaceOrientationPortrait,
           UIInterfaceOrientationPortraitUpsideDown,

project.yml

@@ -28,6 +28,7 @@ settings:
   BASE_BUNDLE_IDENTIFIER: io.element.elementx
   APP_NAME: ElementX
   APP_DISPLAY_NAME: Element X
+  APP_CUSTOM_SCHEME: element
   KEYCHAIN_ACCESS_GROUP_IDENTIFIER: $(AppIdentifierPrefix)$(BASE_BUNDLE_IDENTIFIER)
   MARKETING_VERSION: 1.2.9
   CURRENT_PROJECT_VERSION: 1