3. Architektur

ios/Runner.xcodeproj/project.pbxproj

@@ -3,7 +3,7 @@
 	archiveVersion = 1;
 	classes = {
 	};
-	objectVersion = 50;
+	objectVersion = 54;
 	objects = {
 
 /* Begin PBXBuildFile section */
@@ -171,10 +171,12 @@
 /* Begin PBXShellScriptBuildPhase section */
 		3B06AD1E1E4923F5004D2608 /* Thin Binary */ = {
 			isa = PBXShellScriptBuildPhase;
+			alwaysOutOfDate = 1;
 			buildActionMask = 2147483647;
 			files = (
 			);
 			inputPaths = (
+				"${TARGET_BUILD_DIR}/${INFOPLIST_PATH}",
 			);
 			name = "Thin Binary";
 			outputPaths = (
@@ -185,6 +187,7 @@
 		};
 		9740EEB61CF901F6004384FC /* Run Script */ = {
 			isa = PBXShellScriptBuildPhase;
+			alwaysOutOfDate = 1;
 			buildActionMask = 2147483647;
 			files = (
 			);

lib/main.dart

@@ -1,6 +1,15 @@
 import 'package:counter_workshop/src/app.dart';
+import 'package:counter_workshop/src/features/counter/data/datasources/local/counter.db.dart';
+import 'package:counter_workshop/src/features/counter/data/datasources/remote/src/mock/counter_fake.api.dart';
+import 'package:counter_workshop/src/features/counter/data/repositories/counter.repository.dart';
 import 'package:flutter/material.dart';
 
 void main() {
-  runApp(const App());
+  final CounterRepository counterRepository =
+      CounterRepository(counterApi: CounterFakeApi(), counterDatabase: CounterDatabase());
+  runApp(
+    App(
+      counterRepository: counterRepository,
+    ),
+  );
 }

lib/src/app.dart

@@ -1,8 +1,10 @@
-import 'package:counter_workshop/src/features/counter/counter.page.dart';
+import 'package:counter_workshop/src/features/counter/data/repositories/counter.repository.dart';
+import 'package:counter_workshop/src/features/counter/presentation/counter.page.dart';
 import 'package:flutter/material.dart';
 
 class App extends StatelessWidget {
-  const App({super.key});
+  const App({required this.counterRepository, super.key});
+  final CounterRepository counterRepository;
 
   @override
   Widget build(BuildContext context) {
@@ -11,7 +13,7 @@ class App extends StatelessWidget {
       theme: ThemeData(
         primarySwatch: Colors.blue,
       ),
-      home: const CounterPage(),
+      home: CounterPage(counterRepository: counterRepository),
     );
   }
 }

lib/src/features/counter/data/datasources/local/counter.db.dart

@@ -0,0 +1,14 @@
+import 'package:counter_workshop/src/features/counter/domain/counter.model.dart';
+
+/// Locale app database like SqlLite that providers a [CounterModel]
+class CounterDatabase {
+  CounterModel _counter = CounterModel(value: 0);
+
+  CounterModel getCounter() {
+    return _counter;
+  }
+
+  storeCounter(CounterModel counter) {
+    _counter = counter;
+  }
+}

lib/src/features/counter/data/datasources/remote/converters/counter_response.converter.dart

@@ -0,0 +1,18 @@
+import 'package:counter_workshop/src/features/counter/data/datasources/remote/dtos/counter_response.dto.dart';
+import 'package:counter_workshop/src/features/counter/domain/counter.model.dart';
+
+class CounterResponseConverter {
+  CounterModel toModel(CounterResponseDto counterResponseDto) {
+    return CounterModel(
+      value: counterResponseDto.counterValue,
+      id: counterResponseDto.sysId,
+    );
+  }
+
+  CounterResponseDto toDto(CounterModel counter) {
+    return CounterResponseDto(
+      counterValue: counter.value,
+      sysId: counter.id,
+    );
+  }
+}

lib/src/features/counter/data/datasources/remote/counter.api.dart

@@ -0,0 +1,18 @@
+import 'package:counter_workshop/src/features/counter/data/datasources/remote/dtos/counter_response.dto.dart';
+import 'package:counter_workshop/src/features/counter/domain/counter.model.dart';
+
+/// The interface for a DataSource that provides access to a single [CounterModel]
+abstract class CounterApi {
+  /// Fetches a counter with the give [id]
+  ///
+  /// If no counter with the given id exits, a [CounterNotFoundException] error is thrown.
+  Future<CounterResponseDto> fetchCounter(String id);
+
+  /// Update the value [value] of a given counter [id]
+  ///
+  /// If no counter with the given id exits, a [CounterNotFoundException] error is thrown.
+  Future<void> updateCounter(String id, int value);
+}
+
+/// Error thrown when a [CounterModel] is not found.
+class CounterNotFoundException implements Exception {}

lib/src/features/counter/data/datasources/remote/dtos/counter_response.dto.dart

@@ -0,0 +1,13 @@
+class CounterResponseDto {
+  CounterResponseDto({
+    required this.sysId,
+    required this.counterValue,
+    this.createdAt,
+    this.updatedAt,
+  });
+
+  final String sysId;
+  final int counterValue;
+  final DateTime? createdAt;
+  final DateTime? updatedAt;
+}

lib/src/features/counter/data/datasources/remote/src/mock/counter_fake.api.dart

@@ -0,0 +1,36 @@
+import 'package:counter_workshop/src/features/counter/data/datasources/remote/counter.api.dart';
+import 'package:counter_workshop/src/features/counter/data/datasources/remote/dtos/counter_response.dto.dart';
+import 'package:counter_workshop/src/features/counter/domain/counter.model.dart';
+
+/// FakeApi that simulates a remote restful API which providers a [CounterModel]
+class CounterFakeApi implements CounterApi {
+  @override
+  Future<CounterResponseDto> fetchCounter(String id) {
+    // simulate a network delay
+    return Future.delayed(const Duration(milliseconds: 300), () {
+      if (id == '1') {
+        // return a dummy counter
+        return CounterResponseDto(
+          counterValue: 0,
+          sysId: '1',
+          createdAt: DateTime.now(),
+        );
+      } else {
+        // return a exception
+        throw CounterNotFoundException();
+      }
+    });
+  }
+
+  @override
+  Future<void> updateCounter(String id, int value) {
+    return Future.delayed(const Duration(milliseconds: 300), () {
+      if (id == '1') {
+        return;
+      } else {
+        // return a exception
+        throw CounterNotFoundException();
+      }
+    });
+  }
+}

lib/src/features/counter/data/datasources/remote/src/rest/counter_rest.api.dart

@@ -0,0 +1,22 @@
+import 'package:counter_workshop/src/features/counter/data/datasources/remote/counter.api.dart';
+import 'package:counter_workshop/src/features/counter/data/datasources/remote/dtos/counter_response.dto.dart';
+import 'package:counter_workshop/src/features/counter/domain/counter.model.dart';
+import 'package:http/http.dart' as http;
+
+/// Remote restful API that providers a [CounterModel]
+class CounterRestApi implements CounterApi {
+  CounterRestApi({required this.client});
+  final http.Client client;
+
+  @override
+  Future<CounterResponseDto> fetchCounter(String id) {
+    // TODO: implement fetchCounter
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<void> updateCounter(String id, int value) {
+    // TODO: implement incrementCounter
+    throw UnimplementedError();
+  }
+}

lib/src/features/counter/data/repositories/counter.repository.dart

@@ -0,0 +1,40 @@
+import 'dart:async';
+
+import 'package:counter_workshop/src/features/counter/data/datasources/local/counter.db.dart';
+import 'package:counter_workshop/src/features/counter/data/datasources/remote/counter.api.dart';
+import 'package:counter_workshop/src/features/counter/data/datasources/remote/converters/counter_response.converter.dart';
+import 'package:counter_workshop/src/features/counter/data/datasources/remote/dtos/counter_response.dto.dart';
+import 'package:counter_workshop/src/features/counter/domain/counter.model.dart';
+import 'dart:developer';
+
+class CounterRepository {
+  CounterRepository({required this.counterApi, required this.counterDatabase}) {
+    // prefill repository Counter from API
+    _fetchCounterData();
+  }
+
+  final CounterApi counterApi;
+  final CounterDatabase counterDatabase;
+  final String defaultCounterId = '1'; // TODO: allow multiple counters
+
+  Future<void> _fetchCounterData() async {
+    log('retriving default counter');
+    CounterResponseDto counterResponseDto = await counterApi.fetchCounter(defaultCounterId);
+
+    // map result to Model
+    CounterModel counterModel = CounterResponseConverter().toModel(counterResponseDto);
+
+    // store model in database
+    counterDatabase.storeCounter(counterModel);
+  }
+
+  CounterModel getCounter() {
+    return counterDatabase.getCounter();
+  }
+
+  Future<void> updateCounter({required CounterModel counterModel}) async {
+    log('updating counter: ${counterModel.id} with value: $counterModel');
+    await counterApi.updateCounter(counterModel.id, counterModel.value);
+    return;
+  }
+}

lib/src/features/counter/domain/counter.model.dart

@@ -0,0 +1,17 @@
+import 'package:equatable/equatable.dart';
+
+// ignore: must_be_immutable
+class CounterModel extends Equatable {
+  CounterModel({
+    this.value = 0,
+    this.id = '1',
+  });
+
+  /// technical counter id
+  final String id;
+
+  int value;
+
+  @override
+  List<Object?> get props => [id, value];
+}

lib/src/features/counter/presentation/counter.controller.dart

@@ -0,0 +1,16 @@
+import 'package:counter_workshop/src/features/counter/data/repositories/counter.repository.dart';
+import 'package:counter_workshop/src/features/counter/domain/counter.model.dart';
+
+class CounterController {
+  CounterController({required this.counterRepository}) {
+    counterModel = counterRepository.getCounter();
+  }
+
+  final CounterRepository counterRepository;
+  CounterModel counterModel = CounterModel();
+
+  Future<void> increment() async {
+    counterModel.value += 1;
+    counterRepository.updateCounter(counterModel: counterModel);
+  }
+}

lib/src/features/counter/counter.page.dart → lib/src/features/counter/presentation/counter.page.dart

@@ -1,18 +1,26 @@
+import 'package:counter_workshop/src/features/counter/data/repositories/counter.repository.dart';
+import 'package:counter_workshop/src/features/counter/presentation/counter.controller.dart';
 import 'package:flutter/material.dart';
 
 class CounterPage extends StatefulWidget {
-  const CounterPage({super.key});
+  const CounterPage({required this.counterRepository, super.key});
+  final CounterRepository counterRepository;
 
   @override
   State<CounterPage> createState() => _CounterPageState();
 }
 
 class _CounterPageState extends State<CounterPage> {
-  int _counter = 0;
+  late final CounterController counterController;
+  @override
+  void initState() {
+    counterController = CounterController(counterRepository: widget.counterRepository);
+    super.initState();
+  }
 
   void _incrementCounter() {
     setState(() {
-      _counter++;
+      counterController.increment();
     });
   }
 
@@ -30,7 +38,7 @@ class _CounterPageState extends State<CounterPage> {
               'You have pushed the button this many times:',
             ),
             Text(
-              '$_counter',
+              '${counterController.counterModel.value}',
               style: Theme.of(context).textTheme.headline4,
             ),
           ],