feat(Auth): Add fetchCurrentDevice API (#5251)

feat(Auth): Add fetchCurrentDevice API (#5251)

packages/amplify_core/doc/lib/auth.dart

@@ -483,6 +483,17 @@ Future<void> forgetSpecificDevice(AuthDevice myDevice) async {
 }
 // #enddocregion forget-specific-device
 
+// #docregion fetch-current-device
+Future<void> fetchCurrentDevice() async {
+  try {
+    final device = await Amplify.Auth.fetchCurrentDevice();
+    safePrint('Device: $device');
+  } on AuthException catch (e) {
+    safePrint('Fetch current device failed with error: $e');
+  }
+}
+// #enddocregion fetch-current-device
+
 // #docregion fetch-devices
 Future<void> fetchAllDevices() async {
   try {

packages/amplify_core/lib/src/category/amplify_auth_category.dart

@@ -1355,6 +1355,37 @@ class AuthCategory extends AmplifyCategory<AuthPluginInterface> {
         () => defaultPlugin.rememberDevice(),
       );
 
+  /// {@template amplify_core.amplify_auth_category.fetch_current_device}
+  /// Retrieves the current device.
+  ///
+  /// For more information about device tracking, see the
+  /// [Amplify docs](https://docs.amplify.aws/flutter/build-a-backend/auth/manage-users/manage-devices/#fetch-current-device).
+  ///
+  /// ## Examples
+  ///
+  /// <?code-excerpt "doc/lib/auth.dart" region="imports"?>
+  /// ```dart
+  /// import 'package:amplify_auth_cognito/amplify_auth_cognito.dart';
+  /// import 'package:amplify_flutter/amplify_flutter.dart';
+  /// ```
+  ///
+  /// <?code-excerpt "doc/lib/auth.dart" region="fetch-current-device"?>
+  /// ```dart
+  /// Future<AuthDevice> getCurrentUserDevice() async {
+  ///   try {
+  ///     final device = await Amplify.Auth.fetchCurrentDevice();
+  ///     safePrint('Device: $device');
+  ///   } on AuthException catch (e) {
+  ///     safePrint('Fetch current device failed with error: $e');
+  ///   }
+  /// }
+  /// ```
+  /// {@endtemplate}
+  Future<AuthDevice> fetchCurrentDevice() => identifyCall(
+        AuthCategoryMethod.fetchCurrentDevice,
+        () => defaultPlugin.fetchCurrentDevice(),
+      );
+
   /// {@template amplify_core.amplify_auth_category.forget_device}
   /// Forgets the current device.
   ///

packages/amplify_core/lib/src/http/amplify_category_method.dart

@@ -52,7 +52,8 @@ enum AuthCategoryMethod with AmplifyCategoryMethod {
   setMfaPreference('49'),
   getMfaPreference('50'),
   setUpTotp('51'),
-  verifyTotpSetup('52');
+  verifyTotpSetup('52'),
+  fetchCurrentDevice('59');
 
   const AuthCategoryMethod(this.method);
 

packages/amplify_core/lib/src/plugin/amplify_auth_plugin_interface.dart

@@ -189,6 +189,11 @@ abstract class AuthPluginInterface extends AmplifyPluginInterface {
     throw UnimplementedError('forgetDevice() has not been implemented.');
   }
 
+  /// {@macro amplify_core.amplify_auth_category.fetch_current_device}
+  Future<AuthDevice> fetchCurrentDevice() {
+    throw UnimplementedError('fetchCurrentDevice() has not been implemented.');
+  }
+
   /// {@macro amplify_core.amplify_auth_category.fetch_devices}
   Future<List<AuthDevice>> fetchDevices() {
     throw UnimplementedError('fetchDevices() has not been implemented.');

packages/auth/amplify_auth_cognito/example/integration_test/device_tracking_test.dart

@@ -240,6 +240,45 @@ void main() {
         await expectLater(Amplify.Auth.rememberDevice(), completes);
       });
 
+      asyncTest('fetchCurrentDevice returns the current device', (_) async {
+        await expectLater(Amplify.Auth.fetchCurrentDevice(), completes);
+        final currentTestDevice = await Amplify.Auth.fetchCurrentDevice();
+        final currentDeviceKey = await getDeviceKey();
+        expect(currentDeviceKey, currentTestDevice.id);
+      });
+
+      asyncTest(
+          'The device from fetchCurrentDevice isnt equal to another device.',
+          (_) async {
+        final previousDeviceKey = await getDeviceKey();
+        await signOutUser();
+        await deleteDevice(cognitoUsername, previousDeviceKey!);
+        await signIn();
+        final newCurrentTestDevice = await Amplify.Auth.fetchCurrentDevice();
+        expect(newCurrentTestDevice.id, isNot(previousDeviceKey));
+      });
+
+      asyncTest(
+          'fetchCurrentDevice throws a DeviceNotTrackedException when device is forgotten.',
+          (_) async {
+        expect(await getDeviceState(), DeviceState.remembered);
+        await Amplify.Auth.forgetDevice();
+        await expectLater(
+          Amplify.Auth.fetchCurrentDevice,
+          throwsA(isA<DeviceNotTrackedException>()),
+        );
+      });
+
+      asyncTest(
+          'fetchCurrentDevice throws a SignedOutException when device signs out.',
+          (_) async {
+        await signOutUser();
+        await expectLater(
+          Amplify.Auth.fetchCurrentDevice,
+          throwsA(isA<SignedOutException>()),
+        );
+      });
+
       asyncTest('forgetDevice stops tracking', (_) async {
         expect(await getDeviceState(), DeviceState.remembered);
         await Amplify.Auth.forgetDevice();

packages/auth/amplify_auth_cognito_dart/example/lib/common.dart

@@ -104,6 +104,10 @@ Future<List<AuthUserAttribute>> fetchUserAttributes() async {
   return Amplify.Auth.fetchUserAttributes();
 }
 
+Future<AuthDevice> fetchCurrentDevice() async {
+  return Amplify.Auth.fetchCurrentDevice();
+}
+
 Future<List<AuthDevice>> fetchDevices() async {
   return Amplify.Auth.fetchDevices();
 }

packages/auth/amplify_auth_cognito_dart/lib/src/auth_plugin_impl.dart

@@ -31,6 +31,7 @@ import 'package:amplify_auth_cognito_dart/src/sdk/cognito_identity_provider.dart
         ForgotPasswordRequest,
         GetUserAttributeVerificationCodeRequest,
         GetUserRequest,
+        GetDeviceRequest,
         ListDevicesRequest,
         ResendConfirmationCodeRequest,
         UserContextDataType,
@@ -39,6 +40,7 @@ import 'package:amplify_auth_cognito_dart/src/sdk/cognito_identity_provider.dart
         VerifyUserAttributeRequest;
 import 'package:amplify_auth_cognito_dart/src/sdk/sdk_bridge.dart';
 import 'package:amplify_auth_cognito_dart/src/sdk/src/cognito_identity_provider/model/analytics_metadata_type.dart';
+import 'package:amplify_auth_cognito_dart/src/sdk/src/cognito_identity_provider/model/get_device_response.dart';
 import 'package:amplify_auth_cognito_dart/src/state/cognito_state_machine.dart';
 import 'package:amplify_auth_cognito_dart/src/state/state.dart';
 import 'package:amplify_auth_cognito_dart/src/util/cognito_iam_auth_provider.dart';
@@ -97,6 +99,7 @@ class AmplifyAuthCognitoDart extends AuthPluginInterface
   late CognitoAuthStateMachine _stateMachine = CognitoAuthStateMachine(
     dependencyManager: dependencies,
   );
+
   StreamSubscription<AuthState>? _stateMachineSubscription;
 
   /// The underlying state machine, for use in subclasses.
@@ -993,6 +996,46 @@ class AmplifyAuthCognitoDart extends AuthPluginInterface
         .result;
   }
 
+  @override
+  Future<CognitoDevice> fetchCurrentDevice() async {
+    final tokens = await stateMachine.getUserPoolTokens();
+    final deviceSecrets = await _deviceRepo.get(tokens.username);
+    final deviceKey = deviceSecrets?.deviceKey;
+    if (deviceSecrets == null || deviceKey == null) {
+      throw const DeviceNotTrackedException();
+    }
+
+    late GetDeviceResponse response;
+
+    try {
+      response = await _cognitoIdp
+          .getDevice(
+            cognito.GetDeviceRequest(
+              deviceKey: deviceKey,
+              accessToken: tokens.accessToken.raw,
+            ),
+          )
+          .result;
+    } on Exception catch (error) {
+      throw AuthException.fromException(error);
+    }
+
+    final device = response.device;
+    final attributes =
+        device.deviceAttributes ?? const <cognito.AttributeType>[];
+
+    return CognitoDevice(
+      id: deviceKey,
+      attributes: {
+        for (final attribute in attributes)
+          attribute.name: attribute.value ?? '',
+      },
+      createdDate: device.deviceCreateDate,
+      lastAuthenticatedDate: device.deviceLastAuthenticatedDate,
+      lastModifiedDate: device.deviceLastModifiedDate,
+    );
+  }
+
   @override
   Future<List<CognitoDevice>> fetchDevices() async {
     final allDevices = <CognitoDevice>[];

packages/auth/amplify_auth_cognito_test/test/plugin/fetch_current_device_test.dart

@@ -0,0 +1,96 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import 'package:amplify_auth_cognito_dart/amplify_auth_cognito_dart.dart';
+import 'package:amplify_auth_cognito_dart/src/credentials/cognito_keys.dart';
+import 'package:amplify_auth_cognito_dart/src/credentials/device_metadata_repository.dart';
+import 'package:amplify_auth_cognito_dart/src/sdk/cognito_identity_provider.dart';
+import 'package:amplify_auth_cognito_test/common/mock_clients.dart';
+import 'package:amplify_auth_cognito_test/common/mock_config.dart';
+import 'package:amplify_auth_cognito_test/common/mock_secure_storage.dart';
+import 'package:amplify_core/amplify_core.dart';
+import 'package:test/test.dart';
+
+void main() {
+  AmplifyLogger().logLevel = LogLevel.verbose;
+
+  final userPoolKeys = CognitoUserPoolKeys(userPoolConfig.appClientId);
+  final identityPoolKeys = CognitoIdentityPoolKeys(identityPoolConfig.poolId);
+  final testAuthRepo = AmplifyAuthProviderRepository();
+  final mockDevice = DeviceType(deviceKey: deviceKey);
+  final mockDeviceResponse = GetDeviceResponse(device: mockDevice);
+
+  late DeviceMetadataRepository repo;
+  late AmplifyAuthCognitoDart plugin;
+
+  group('fetchCurrentDevice', () {
+    setUp(() async {
+      final secureStorage = MockSecureStorage();
+      seedStorage(
+        secureStorage,
+        userPoolKeys: userPoolKeys,
+        identityPoolKeys: identityPoolKeys,
+        deviceKeys: CognitoDeviceKeys(userPoolConfig.appClientId, username),
+      );
+      plugin = AmplifyAuthCognitoDart(
+        secureStorageFactory: (_) => secureStorage,
+      );
+      await plugin.configure(
+        config: mockConfig,
+        authProviderRepo: testAuthRepo,
+      );
+      repo = plugin.stateMachine.getOrCreate<DeviceMetadataRepository>();
+    });
+
+    group('should successfully', () {
+      setUp(() async {
+        final mockIdp = MockCognitoIdentityProviderClient(
+          getDevice: () async => mockDeviceResponse,
+          forgetDevice: () async {},
+        );
+        plugin.stateMachine.addInstance<CognitoIdentityProviderClient>(mockIdp);
+      });
+
+      test(
+          'return the current device where the current device id is equal to the local device id',
+          () async {
+        final secrets = await repo.get(username);
+        final currentDeviceKey = secrets?.deviceKey;
+        expect(currentDeviceKey, isNotNull);
+        final currentDevice = await plugin.fetchCurrentDevice();
+        expect(currentDeviceKey, currentDevice.id);
+      });
+
+      test('throw a DeviceNotTrackedException when current device key is null',
+          () async {
+        await plugin.forgetDevice();
+        await expectLater(
+          plugin.fetchCurrentDevice,
+          throwsA(isA<DeviceNotTrackedException>()),
+        );
+      });
+    });
+
+    group('should throw', () {
+      setUp(() async {
+        final mockIdp = MockCognitoIdentityProviderClient(
+          getDevice: () async => throw AWSHttpException(
+            AWSHttpRequest.get(Uri.parse('https://aws.amazon.com/cognito/')),
+          ),
+        );
+        plugin.stateMachine.addInstance<CognitoIdentityProviderClient>(mockIdp);
+      });
+
+      test('a NetworkException', () async {
+        await expectLater(
+          plugin.fetchCurrentDevice,
+          throwsA(isA<NetworkException>()),
+        );
+      });
+    });
+
+    tearDown(() async {
+      await plugin.close();
+    });
+  });
+}

packages/test/amplify_integration_test/lib/src/stubs/amplify_auth_cognito_stub.dart

@@ -368,6 +368,13 @@ class AmplifyAuthCognitoStub extends AuthPluginInterface
     );
   }
 
+  @override
+  Future<AuthDevice> fetchCurrentDevice() async {
+    throw UnimplementedError(
+      'fetchCurrentDevice is not implemented.',
+    );
+  }
+
   @override
   Future<void> forgetDevice([AuthDevice? device]) async {
     throw UnimplementedError(
@@ -391,7 +398,6 @@ class AmplifyAuthCognitoStub extends AuthPluginInterface
 }
 
 class MockCognitoUser {
-
   factory MockCognitoUser({
     required String username,
     required String password,