iOS Universal Links for Navigator2.0/Router with FlutterDeepLinkingEnabled

[abegehr]

Steps to Reproduce

1. Create a new flutter app.
2. Setup the iOS config as outlined here: https://flutter.dev/docs/development/ui/navigation/deep-linking. Including setting FlutterDeepLinkingEnabled to true in the Info.plist
3. Create a simple MaterialApp.router() with a routeInformationParser that simply prints to the console (the app uses the beamer package for the routerDelegate, whereas the point here is that the routeInformationParser does not get called on deep link open) :

class App extends StatelessWidget {
  final routerDelegate = BeamerRouterDelegate(
    locationBuilder: BeamerLocationBuilder(
      beamLocations: [
        WelcomeLocation(),
      ],
    ),
    initialPath: WelcomeLocation.name,
  );

  @override
  Widget build(BuildContext context) {
    return MaterialApp.router(
        routeInformationParser: SimpleParser(),
        routerDelegate: routerDelegate,
    );
  }
}

class SimpleParser extends RouteInformationParser<Object> {
  @override
  Future<Object> parseRouteInformation(
      RouteInformation routeInformation) async {
    print('Deep Link – routeInformation: $routeInformation');
    return Future.value(Object());
  }
}

4. Run the app and open a deep link.

Expected results:

SimpleParser.parseRouteInformation() gets called and a console log is printed for each deep link open when the app is running as is specified in the behavior section of the docs: https://flutter.dev/docs/development/ui/navigation/deep-linking#behavior

Actual results:

SimpleParser.parseRouteInformation() gets called once on initial open and then does not got called when opening a deep link.
The deep link is registered somehow, since Analytics does notice the deep link open (see screenshot):

Logs

log.txt

Analyzing smallgroups...                                                
No issues found! (ran in 5.3s)

[✓] Flutter (Channel dev, 2.3.0-1.0.pre, on macOS 11.3.1 20E241 darwin-x64, locale en-DE)
    • Flutter version 2.3.0-1.0.pre at /Users/anton/development/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision d97f41caed (2 weeks ago), 2021-04-30 12:35:21 -0700
    • Engine revision e7939e091e
    • Dart version 2.14.0 (build 2.14.0-48.0.dev)

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at /Users/anton/Library/Android/sdk
    • Platform android-30, build-tools 30.0.3
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.5, Build version 12E262
    • CocoaPods version 1.10.1

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 4.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)

[✓] VS Code
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.22.0

[✓] Connected device (2 available)
    • macOS (desktop) • macos  • darwin-x64     • macOS 11.3.1 20E241 darwin-x64
    • Chrome (web)    • chrome • web-javascript • Google Chrome 90.0.4430.212
    ! Error: Anton’s iPhone is not connected. Xcode will continue when Anton’s iPhone is connected. (code -13)

• No issues found!

• I have just disconnected the iOS device but was testing on it before.

[abegehr]

Using getInitialLink() and linkStream from uni_links and navigating on a deep link works. After reading https://flutter.dev/docs/development/ui/navigation/deep-linking#migrating-from-plugin-based-deep-linking, I was under the impression that the FlutterDeepLinkingEnabled flag would mean there is no need to handle incoming deep links manually. Is this not correct? What does FlutterDeepLinkingEnabled do in that case?

[slovnicki]

Hi @abegehr

I followed the instructions at https://flutter.dev/docs/development/ui/navigation/deep-linking by adding

<!-- Deep linking -->
<meta-data android:name="flutter_deeplinking_enabled" android:value="true" />
<intent-filter android:autoVerify="true">
    <action android:name="android.intent.action.VIEW" />
    <category android:name="android.intent.category.DEFAULT" />
    <category android:name="android.intent.category.BROWSABLE" />
    <data android:scheme="http" android:host="localhost" />
    <data android:scheme="https" />
</intent-filter>

to the AndroidManifest.xml of beamer's example app and it worked with no changes to the app's lib/ folder.

Then I went on to define a SimpleParser similar to yours that also prints the incoming link;

class SimpleParser extends RouteInformationParser<BeamState> {
  @override
  SynchronousFuture<BeamState> parseRouteInformation(
      RouteInformation routeInformation) {
    print('incoming link: ${routeInformation.location}');
    final uri = Uri.parse(routeInformation.location ?? '/');
    return SynchronousFuture(BeamState.fromUri(uri));
  }

  @override
  RouteInformation restoreRouteInformation(BeamState beamState) {
    return RouteInformation(location: beamState.uri.toString());
  }
}

This also works as shown in the below gif.

It's important that parser and delegate operate on same type of object, in this case - BeamState.
NOTE: Beamer versions <0.13.0 would operate on Uri instead, so SimpleParser should be tweaked accordingly.

[abegehr]

Hey @slovnicki, thanks for checking this out! I have confirmed that this does work with a custom URL schema on iOS as well. It does however not work with iOS universal links.

I have built a minimal example with MaterialApp.router() and beamer here: https://github.com/abegehr/flutter_beamer_deep_linking/tree/6261f9fb4d0f1cf1197684d7abdebe90ac64049b
To get the universal links to open the app, I had to publish the app to iOS App Store Connect and install a version via TestFlight. The apple-app-site-association file is hosted on Firebase hosting: http://flutterbeamerdeeplinking.web.app/apple-app-site-association (also deployed through the minimal repo example above).
While universal links do open the app, they do not navigate. Custom schema links do trigger a navigation. I have tried both custom url schema and universal links with and without /#. You can see in this screen recording that only option 3 (custom schema, no /# navigates to book 13:

RPReplay_Final1621203339.mov

[slovnicki]

This is a very valuable investigation @abegehr 👍
I'm wondering what will other people comment on this as I don't have any experience in iOS universal links.

[abegehr]

BeamerParser.onParse() does not get called for iOS universal links: https://github.com/abegehr/flutter_beamer_deep_linking/tree/3f1b72901655472f6b7e1441d72cfb84cae81ebd
I will now try an implementation without beamer.

[abegehr]

I validated that this is not a beamer package issue. Here is a minimal example based on the medium article's books example (that does not use the beamer package: https://github.com/abegehr/flutter_beamer_deep_linking/tree/0c3a5a0c2760f08ebaa63ab1831e4b8bd73f5705
On line 12 of main.dart, I'm logging routeInformation.location in BookRouteInformationParser.parseRouteInformation(routeInformation). Flutter does log routeInformation.location as /books/13 when I click the custom schema link flutterbeamerdeeplinking://flutterbeamerdeeplinking.web.app/books/13, but not if I click the universal link https://flutterbeamerdeeplinking.web.app/books/13 (both links open the app). Therefore, I assume Flutter deep linking currently does not support iOS universal links but only custom schema links.

[abegehr]

One work around to get deep linking to work with iOS universal links currently is to use a package like uri_links and navigate manually on getInitialLink() and new entries to linkStream.

[abegehr]

I've also tried setting the URL Scheme to https:

This does not seep to work for https://flutterbeamerdeeplinking.web.app/books/13 either and shouldn't be required for associated domains (universal links): https://developer.apple.com/documentation/xcode/supporting-associated-domains

[TahaTesser]

Hi @abegehr
I'm not familiar with deep linking on iOS, since you've provided all the details needed, I feel safe to label issue
Thanks for filiing the issue!