add login via qr code

Author: Leptopoda

android/app/build.gradle

@@ -36,7 +36,7 @@ android {
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "com.nextcloud_cookbook_flutter"
-        minSdkVersion 19
+        minSdkVersion 20
         targetSdkVersion flutter.targetSdkVersion
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName

lib/src/blocs/login/login_bloc.dart

@@ -7,6 +7,7 @@ import 'package:nextcloud/nextcloud.dart';
 import 'package:nextcloud_cookbook_flutter/src/blocs/authentication/authentication_bloc.dart';
 import 'package:nextcloud_cookbook_flutter/src/models/app_authentication.dart';
 import 'package:nextcloud_cookbook_flutter/src/services/services.dart';
+import 'package:nextcloud_cookbook_flutter/src/util/nextcloud_login_qr_util.dart';
 import 'package:nextcloud_cookbook_flutter/src/util/url_validator.dart';
 
 part 'login_event.dart';
@@ -17,6 +18,7 @@ class LoginBloc extends Bloc<LoginEvent, LoginState> {
     required this.authenticationBloc,
   }) : super(const LoginState()) {
     on<LoginFlowStart>(_mapLoginFlowStartEventToState);
+    on<LoginQRScenned>(_mapLoginQRScannedEventToState);
   }
   final UserRepository userRepository = UserRepository();
   final AuthenticationBloc authenticationBloc;
@@ -54,4 +56,27 @@ class LoginBloc extends Bloc<LoginEvent, LoginState> {
       emit(LoginState(status: LoginStatus.failure, error: e.toString()));
     }
   }
+
+  Future<void> _mapLoginQRScannedEventToState(
+    LoginQRScenned event,
+    Emitter<LoginState> emit,
+  ) async {
+    assert(event.uri.isScheme('nc'));
+    try {
+      final auth = parseNCLoginQR(event.uri);
+
+      authenticationBloc.add(
+        LoggedIn(
+          appAuthentication: AppAuthentication(
+            server: auth['server']!,
+            loginName: auth['user']!,
+            appPassword: auth['password']!,
+            isSelfSignedCertificate: false,
+          ),
+        ),
+      );
+    } catch (e) {
+      emit(LoginState(status: LoginStatus.failure, error: e.toString()));
+    }
+  }
 }

lib/src/blocs/login/login_event.dart

@@ -12,3 +12,9 @@ class LoginFlowStart extends LoginEvent {
 
   final String serverURL;
 }
+
+class LoginQRScenned extends LoginEvent {
+  const LoginQRScenned(this.uri);
+
+  final Uri uri;
+}

lib/src/screens/login_qr_screen.dart

@@ -0,0 +1,67 @@
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:qr_code_scanner/qr_code_scanner.dart';
+
+class LoginQrScreen extends StatefulWidget {
+  const LoginQrScreen({super.key});
+
+  @override
+  State<LoginQrScreen> createState() => _LoginQrScreenState();
+}
+
+class _LoginQrScreenState extends State<LoginQrScreen> {
+  final GlobalKey qrKey = GlobalKey(debugLabel: 'QR');
+  Barcode? result;
+  QRViewController? controller;
+
+  @override
+  void reassemble() {
+    super.reassemble();
+    if (Platform.isAndroid) {
+      controller!.pauseCamera();
+    } else if (Platform.isIOS) {
+      controller!.resumeCamera();
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+
+    return Scaffold(
+      appBar: AppBar(),
+      body: QRView(
+        formatsAllowed: const [
+          BarcodeFormat.qrcode,
+        ],
+        overlay: QrScannerOverlayShape(
+          borderColor: theme.colorScheme.primaryContainer,
+          borderWidth: 15,
+          borderRadius: 10,
+        ),
+        key: qrKey,
+        onQRViewCreated: _onQRViewCreated,
+      ),
+    );
+  }
+
+  void _onQRViewCreated(QRViewController controller) {
+    this.controller = controller;
+    controller.scannedDataStream.listen((scanData) {
+      final code = scanData.code;
+      if (code != null && code.isNotEmpty) {
+        final uri = Uri.tryParse(code);
+        if (uri != null && uri.isScheme('nc')) {
+          Navigator.of(context).pop(uri);
+        }
+      }
+    });
+  }
+
+  @override
+  void dispose() {
+    controller?.dispose();
+    super.dispose();
+  }
+}

lib/src/screens/login_screen.dart

@@ -5,6 +5,7 @@ import 'package:flutter_translate/flutter_translate.dart';
 import 'package:nextcloud_cookbook_flutter/src/blocs/authentication/authentication_bloc.dart';
 
 import 'package:nextcloud_cookbook_flutter/src/blocs/login/login_bloc.dart';
+import 'package:nextcloud_cookbook_flutter/src/screens/login_qr_screen.dart';
 import 'package:nextcloud_cookbook_flutter/src/util/url_validator.dart';
 import 'package:vector_graphics/vector_graphics.dart';
 import 'package:webview_flutter/webview_flutter.dart';
@@ -37,6 +38,16 @@ class _LoginPageState extends State<LoginPage> {
     super.didChangeDependencies();
   }
 
+  Future<void> _authenticateQR() async {
+    final uri = await Navigator.of(context).push<Uri>(
+      MaterialPageRoute(builder: (_) => const LoginQrScreen()),
+    );
+
+    if (uri != null) {
+      _loginBloc.add(LoginQRScenned(uri));
+    }
+  }
+
   @override
   Widget build(BuildContext context) => BlocBuilder<LoginBloc, LoginState>(
         bloc: _loginBloc,
@@ -130,9 +141,9 @@ class _LoginPageState extends State<LoginPage> {
                             },
                           ),
                         ),
-                        const IconButton(
-                          onPressed: null,
-                          icon: Icon(
+                        IconButton(
+                          onPressed: _authenticateQR,
+                          icon: const Icon(
                             Icons.qr_code_scanner,
                             size: 40,
                           ),

lib/src/util/nextcloud_login_qr_util.dart

@@ -0,0 +1,18 @@
+/// Parses the content of a LoginQr
+///
+/// The result will be like:
+/// ```dart
+/// {
+///  'user': 'admin',
+///  'password': 'superSecret',
+///  'server': 'https://example.com',
+/// }
+/// ```
+Map<String, String> parseNCLoginQR(Uri uri) {
+  return uri.path.split('&').map((e) {
+    final parts = e.split(':');
+    final key = parts[0].replaceFirst(RegExp('/'), '');
+    parts.removeAt(0);
+    return {key: parts.join(':')};
+  }).fold({}, (p, e) => p..addAll(e));
+}

pubspec.yaml

@@ -104,6 +104,7 @@ dependencies:
   flutter_native_splash: ^2.2.19
   webview_flutter: ^4.0.7
   vector_graphics: ^1.1.4
+  qr_code_scanner: ^1.0.1
 
 dev_dependencies:
   flutter_launcher_icons: ^0.12.0

test/models/nextcloud_login_qr_util_test.dart

@@ -0,0 +1,19 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:nextcloud_cookbook_flutter/src/util/nextcloud_login_qr_util.dart';
+
+void main() {
+  const username = 'admin';
+  const password = 'superSecret';
+  const server = 'https://example.com';
+
+  final content =
+      Uri.parse('nc://login/user:$username&password:$password&server:$server');
+
+  test('parseNCLoginQR', () {
+    expect(parseNCLoginQR(content), {
+      'user': username,
+      'password': password,
+      'server': server,
+    });
+  });
+}