neon,app: Handle qrcode login from other apps

packages/app/android/app/src/main/AndroidManifest.xml

@@ -28,6 +28,13 @@
                 <action android:name="android.intent.action.MAIN"/>
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
+            <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="nc" android:host="login" />
+            </intent-filter>
         </activity>
         <receiver android:enabled="true"  android:name=".EmbeddedDistributor" android:exported="false">
             <intent-filter>

packages/neon/neon/lib/src/pages/login_qrcode.dart

@@ -1,7 +1,10 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_zxing/flutter_zxing.dart';
 import 'package:neon/src/router.dart';
 import 'package:neon/src/utils/exceptions.dart';
+import 'package:neon/src/utils/login_qrcode.dart';
 import 'package:neon/src/widgets/exception.dart';
 
 class LoginQrcodePage extends StatefulWidget {
@@ -14,7 +17,6 @@ class LoginQrcodePage extends StatefulWidget {
 }
 
 class _LoginQrcodePageState extends State<LoginQrcodePage> {
-  final _urlRegex = RegExp(r'^nc://login/user:(.*)&password:(.*)&server:(.*)$');
   String? _lastErrorURL;
 
   @override
@@ -35,22 +37,11 @@ class _LoginQrcodePageState extends State<LoginQrcodePage> {
               if (url == null) {
                 throw InvalidQrcodeException();
               }
-              final match = _urlRegex.allMatches(url).single;
+              final match = LoginQrcode.tryParse(url);
-              if (match.groupCount != 3) {
+              if (match == null) {
                 throw InvalidQrcodeException();
               }
-              final loginName = match.group(1)!;
+              await processLoginQrcode(context, match);
-              final password = match.group(2)!;
-              final serverURL = match.group(3)!;
-
-              final result = await LoginCheckServerStatusRoute(serverURL: serverURL).push<bool>(context);
-              if ((result ?? false) && mounted) {
-                LoginCheckAccountRoute(
-                  serverURL: serverURL,
-                  loginName: loginName,
-                  password: password,
-                ).pushReplacement(context);
-              }
             } catch (e, s) {
               if (_lastErrorURL != url) {
                 debugPrint(e.toString());
@@ -64,3 +55,52 @@ class _LoginQrcodePageState extends State<LoginQrcodePage> {
         ),
       );
 }
+
+class LoginQrcodeIntermediatePage extends StatefulWidget {
+  const LoginQrcodeIntermediatePage({
+    required this.serverURL,
+    required this.loginName,
+    required this.password,
+    super.key,
+  });
+
+  final String serverURL;
+  final String loginName;
+  final String password;
+
+  @override
+  State<LoginQrcodeIntermediatePage> createState() => _LoginQrcodeIntermediatePageState();
+}
+
+class _LoginQrcodeIntermediatePageState extends State<LoginQrcodeIntermediatePage> {
+  @override
+  void initState() {
+    super.initState();
+    WidgetsBinding.instance.addPostFrameCallback((final _) {
+      unawaited(
+        processLoginQrcode(
+          context,
+          LoginQrcode(
+            server: widget.serverURL,
+            user: widget.loginName,
+            password: widget.password,
+          ),
+        ),
+      );
+    });
+  }
+
+  @override
+  Widget build(final BuildContext context) => const SizedBox();
+}
+
+Future processLoginQrcode(final BuildContext context, final LoginQrcode qrcode) async {
+  final result = await LoginCheckServerStatusRoute(serverURL: qrcode.server).push<bool>(context);
+  if ((result ?? false) && context.mounted) {
+    LoginCheckAccountRoute(
+      serverURL: qrcode.server,
+      loginName: qrcode.user,
+      password: qrcode.password,
+    ).pushReplacement(context);
+  }
+}

packages/neon/neon/lib/src/router.dart

@@ -13,6 +13,7 @@ import 'package:neon/src/pages/login_flow.dart';
 import 'package:neon/src/pages/login_qrcode.dart';
 import 'package:neon/src/pages/nextcloud_app_settings.dart';
 import 'package:neon/src/pages/settings.dart';
+import 'package:neon/src/utils/login_qrcode.dart';
 import 'package:neon/src/utils/stream_listenable.dart';
 import 'package:provider/provider.dart';
 
@@ -30,6 +31,15 @@ class AppRouter extends GoRouter {
           redirect: (final context, final state) {
             final account = accountsBloc.activeAccount.valueOrNull;
 
+            final loginQrcode = LoginQrcode.tryParse(state.location);
+            if (loginQrcode != null) {
+              return LoginQrcodeIntermediateRoute(
+                serverURL: loginQrcode.server,
+                loginName: loginQrcode.user,
+                password: loginQrcode.password,
+              ).location;
+            }
+
             // redirect to loginscreen when no account is logged in
             if (account == null && !state.location.startsWith(const LoginRoute().location)) {
               return const LoginRoute().location;
@@ -110,6 +120,10 @@ class HomeRoute extends GoRouteData {
       path: 'qrcode',
       name: 'loginQrcode',
     ),
+    TypedGoRoute<LoginQrcodeIntermediateRoute>(
+      path: 'qrcode/intermediate/:serverURL/:loginName/:password',
+      name: 'loginQrcodeIntermediate',
+    ),
     TypedGoRoute<LoginCheckServerStatusRoute>(
       path: 'check/server/:serverURL',
       name: 'checkServerStatus',
@@ -150,6 +164,26 @@ class LoginQrcodeRoute extends GoRouteData {
   Widget build(final BuildContext context, final GoRouterState state) => const LoginQrcodePage();
 }
 
+@immutable
+class LoginQrcodeIntermediateRoute extends GoRouteData {
+  const LoginQrcodeIntermediateRoute({
+    required this.serverURL,
+    required this.loginName,
+    required this.password,
+  });
+
+  final String serverURL;
+  final String loginName;
+  final String password;
+
+  @override
+  Widget build(final BuildContext context, final GoRouterState state) => LoginQrcodeIntermediatePage(
+        serverURL: serverURL,
+        loginName: loginName,
+        password: password,
+      );
+}
+
 @immutable
 class LoginCheckServerStatusRoute extends GoRouteData {
   const LoginCheckServerStatusRoute({

packages/neon/neon/lib/src/router.g.dart

@@ -130,6 +130,11 @@ RouteBase get $loginRoute => GoRouteData.$route(
           name: 'loginQrcode',
           factory: $LoginQrcodeRouteExtension._fromState,
         ),
+        GoRouteData.$route(
+          path: 'qrcode/intermediate/:serverURL/:loginName/:password',
+          name: 'loginQrcodeIntermediate',
+          factory: $LoginQrcodeIntermediateRouteExtension._fromState,
+        ),
         GoRouteData.$route(
           path: 'check/server/:serverURL',
           name: 'checkServerStatus',
@@ -192,6 +197,24 @@ extension $LoginQrcodeRouteExtension on LoginQrcodeRoute {
   void pushReplacement(BuildContext context) => context.pushReplacement(location);
 }
 
+extension $LoginQrcodeIntermediateRouteExtension on LoginQrcodeIntermediateRoute {
+  static LoginQrcodeIntermediateRoute _fromState(GoRouterState state) => LoginQrcodeIntermediateRoute(
+        serverURL: state.pathParameters['serverURL']!,
+        loginName: state.pathParameters['loginName']!,
+        password: state.pathParameters['password']!,
+      );
+
+  String get location => GoRouteData.$location(
+        '/login/qrcode/intermediate/${Uri.encodeComponent(serverURL)}/${Uri.encodeComponent(loginName)}/${Uri.encodeComponent(password)}',
+      );
+
+  void go(BuildContext context) => context.go(location);
+
+  Future<T?> push<T>(BuildContext context) => context.push<T>(location);
+
+  void pushReplacement(BuildContext context) => context.pushReplacement(location);
+}
+
 extension $LoginCheckServerStatusRouteExtension on LoginCheckServerStatusRoute {
   static LoginCheckServerStatusRoute _fromState(GoRouterState state) => LoginCheckServerStatusRoute(
         serverURL: state.pathParameters['serverURL']!,

packages/neon/neon/lib/src/utils/login_qrcode.dart

@@ -0,0 +1,47 @@
+import 'package:meta/meta.dart';
+
+@internal
+class LoginQrcode {
+  LoginQrcode({
+    required this.server,
+    required this.user,
+    required this.password,
+  });
+
+  static final _loginQrcodeUrlRegex = RegExp(r'^nc://login/user:(.*)&password:(.*)&server:(.*)$');
+  static final _loginQrcodePathRegex = RegExp(r'^/user:(.*)&password:(.*)&server:(.*)$');
+
+  static LoginQrcode parse(final String url) {
+    for (final regex in [_loginQrcodeUrlRegex, _loginQrcodePathRegex]) {
+      final matches = regex.allMatches(url);
+      if (matches.isEmpty) {
+        continue;
+      }
+
+      final match = matches.single;
+      if (match.groupCount != 3) {
+        continue;
+      }
+
+      return LoginQrcode(
+        server: match.group(3)!,
+        user: match.group(1)!,
+        password: match.group(2)!,
+      );
+    }
+
+    throw const FormatException();
+  }
+
+  static LoginQrcode? tryParse(final String url) {
+    try {
+      return parse(url);
+    } on FormatException {
+      return null;
+    }
+  }
+
+  final String server;
+  final String user;
+  final String password;
+}