Add code sharing sample (#1444)

* code-sharing boilerplate

* initial commit of code-sharing logic

* documentation improvements

* added code-sharing to samples.yaml

* Updated counter UI to visually indicate communication with the server

* added code_sharing to CI

* CI changes to code_sharing

* fixed test with DI

* formatting

* added shared module to CI

* adds forgotten CI change

code_sharing/server/.dockerignore

@@ -0,0 +1,9 @@
+.dockerignore
+Dockerfile
+build/
+.dart_tool/
+.git/
+.github/
+.gitignore
+.idea/
+.packages

code_sharing/server/.gitignore

@@ -0,0 +1,6 @@
+# Files and directories created by pub.
+.dart_tool/
+.packages
+
+# Conventional directory for build output.
+build/

code_sharing/server/CHANGELOG.md

@@ -0,0 +1,3 @@
+## 1.0.0
+
+- Initial version.

code_sharing/server/Dockerfile

@@ -0,0 +1,20 @@
+# Use latest stable channel SDK.
+FROM dart:stable AS build
+
+# Resolve app dependencies.
+WORKDIR /app
+COPY . .
+RUN dart pub get
+
+# AOT compile app.
+RUN dart compile exe bin/server.dart -o bin/server
+
+# Build minimal serving image from AOT-compiled `/server`
+# and the pre-built AOT-runtime in the `/runtime/` directory of the base image.
+FROM scratch
+COPY --from=build /runtime/ /
+COPY --from=build /app/bin/server /app/bin/
+
+# Start server.
+EXPOSE 8080
+CMD ["/app/bin/server"]

code_sharing/server/README.md

@@ -0,0 +1,49 @@
+A server app built using [Shelf](https://pub.dev/packages/shelf),
+configured to enable running with [Docker](https://www.docker.com/).
+
+This sample code handles HTTP GET requests to `/` and `/echo/<message>`
+
+# Running the sample
+
+## Running with the Dart SDK
+
+You can run the example with the [Dart SDK](https://dart.dev/get-dart)
+like this:
+
+```
+$ dart run bin/server.dart
+Server listening on port 8080
+```
+
+And then from a second terminal:
+```
+$ curl http://0.0.0.0:8080
+Hello, World!
+$ curl http://0.0.0.0:8080/echo/I_love_Dart
+I_love_Dart
+```
+
+## Running with Docker
+
+If you have [Docker Desktop](https://www.docker.com/get-started) installed, you
+can build and run with the `docker` command:
+
+```
+$ docker build . -t myserver
+$ docker run -it -p 8080:8080 myserver
+Server listening on port 8080
+```
+
+And then from a second terminal:
+```
+$ curl http://0.0.0.0:8080
+Hello, World!
+$ curl http://0.0.0.0:8080/echo/I_love_Dart
+I_love_Dart
+```
+
+You should see the logging printed in the first terminal:
+```
+2021-05-06T15:47:04.620417  0:00:00.000158 GET     [200] /
+2021-05-06T15:47:08.392928  0:00:00.001216 GET     [200] /echo/I_love_Dart
+```

code_sharing/server/analysis_options.yaml

@@ -0,0 +1,30 @@
+# This file configures the static analysis results for your project (errors,
+# warnings, and lints).
+#
+# This enables the 'recommended' set of lints from `package:lints`.
+# This set helps identify many issues that may lead to problems when running
+# or consuming Dart code, and enforces writing Dart using a single, idiomatic
+# style and format.
+#
+# If you want a smaller set of lints you can change this to specify
+# 'package:lints/core.yaml'. These are just the most critical lints
+# (the recommended set includes the core lints).
+# The core lints are also what is used by pub.dev for scoring packages.
+
+include: package:lints/recommended.yaml
+
+# Uncomment the following section to specify additional rules.
+
+# linter:
+#   rules:
+#     - camel_case_types
+
+# analyzer:
+#   exclude:
+#     - path/to/excluded/files/**
+
+# For more information about the core and recommended set of lints, see
+# https://dart.dev/go/core-lints
+
+# For additional information about configuring this file, see
+# https://dart.dev/guides/language/analysis-options

code_sharing/server/bin/server.dart

@@ -0,0 +1,36 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:shared/shared.dart';
+import 'package:shelf/shelf.dart';
+import 'package:shelf/shelf_io.dart';
+import 'package:shelf_router/shelf_router.dart';
+
+int count = 0;
+
+// Configure routes.
+final _router = Router()
+  ..post('/', _incrementHandler)
+  ..get('/', _getValueHandler);
+
+Future<Response> _incrementHandler(Request request) async {
+  final incr = Increment.fromJson(json.decode(await request.readAsString()));
+  count += incr.by;
+  return Response.ok(json.encode(Count(count).toJson()));
+}
+
+Response _getValueHandler(Request request) =>
+    Response.ok(json.encode(Count(count).toJson()));
+
+void main(List<String> args) async {
+  // Use any available host or container IP (usually `0.0.0.0`).
+  final ip = InternetAddress.anyIPv4;
+
+  // Configure a pipeline that logs requests.
+  final handler = Pipeline().addMiddleware(logRequests()).addHandler(_router);
+
+  // For running in containers, we respect the PORT environment variable.
+  final port = int.parse(Platform.environment['PORT'] ?? '8080');
+  final server = await serve(handler, ip, port);
+  print('Server listening on port ${server.port}');
+}

code_sharing/server/pubspec.yaml

@@ -0,0 +1,19 @@
+name: server
+description: A server app using the shelf package and Docker.
+version: 1.0.0
+publish_to: "none"
+
+environment:
+  sdk: ">=2.18.1 <3.0.0"
+
+dependencies:
+  args: ^2.0.0
+  shelf: ^1.1.0
+  shelf_router: ^1.0.0
+  shared:
+    path: ./shared
+
+dev_dependencies:
+  http: ^0.13.0
+  lints: ^2.0.0
+  test: ^1.15.0

code_sharing/server/shared/.gitignore

@@ -0,0 +1,10 @@
+# Files and directories created by pub.
+.dart_tool/
+.packages
+
+# Conventional directory for build outputs.
+build/
+
+# Omit committing pubspec.lock for library packages; see
+# https://dart.dev/guides/libraries/private-files#pubspeclock.
+pubspec.lock

code_sharing/server/shared/CHANGELOG.md

@@ -0,0 +1,3 @@
+## 1.0.0
+
+- Initial version.

code_sharing/server/shared/README.md

@@ -0,0 +1,39 @@
+<!-- 
+This README describes the package. If you publish this package to pub.dev,
+this README's contents appear on the landing page for your package.
+
+For information about how to write a good package README, see the guide for
+[writing package pages](https://dart.dev/guides/libraries/writing-package-pages). 
+
+For general information about developing packages, see the Dart guide for
+[creating packages](https://dart.dev/guides/libraries/create-library-packages)
+and the Flutter guide for
+[developing packages and plugins](https://flutter.dev/developing-packages). 
+-->
+
+TODO: Put a short description of the package here that helps potential users
+know whether this package might be useful for them.
+
+## Features
+
+TODO: List what your package can do. Maybe include images, gifs, or videos.
+
+## Getting started
+
+TODO: List prerequisites and provide or point to information on how to
+start using the package.
+
+## Usage
+
+TODO: Include short and useful examples for package users. Add longer examples
+to `/example` folder. 
+
+```dart
+const like = 'sample';
+```
+
+## Additional information
+
+TODO: Tell users more about the package: where to find more information, how to 
+contribute to the package, how to file issues, what response they can expect 
+from the package authors, and more.

code_sharing/server/shared/analysis_options.yaml

@@ -0,0 +1,29 @@
+# This file configures the static analysis results for your project (errors,
+# warnings, and lints).
+#
+# This enables the 'recommended' set of lints from `package:lints`.
+# This set helps identify many issues that may lead to problems when running
+# or consuming Dart code, and enforces writing Dart using a single, idiomatic
+# style and format.
+#
+# If you want a smaller set of lints you can change this to specify
+# 'package:lints/core.yaml'. These are just the most critical lints
+# (the recommended set includes the core lints).
+# The core lints are also what is used by pub.dev for scoring packages.
+
+include: package:lints/recommended.yaml
+
+# Uncomment the following section to specify additional rules.
+
+# linter:
+#   rules:
+#     - camel_case_types
+
+analyzer:
+  exclude:
+    - "**/*.g.dart"
+# For more information about the core and recommended set of lints, see
+# https://dart.dev/go/core-lints
+
+# For additional information about configuring this file, see
+# https://dart.dev/guides/language/analysis-options

code_sharing/server/shared/lib/shared.dart

@@ -0,0 +1,4 @@
+/// Common data models required by our client and server.
+library shared;
+
+export 'src/models.dart';

code_sharing/server/shared/lib/src/models.dart

@@ -0,0 +1,19 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+part 'models.freezed.dart';
+part 'models.g.dart';
+
+@Freezed()
+class Increment with _$Increment {
+  const factory Increment({required int by}) = _Increment;
+
+  factory Increment.fromJson(Map<String, dynamic> json) =>
+      _$IncrementFromJson(json);
+}
+
+@Freezed()
+class Count with _$Count {
+  const factory Count(int value) = _Count;
+
+  factory Count.fromJson(Map<String, dynamic> json) => _$CountFromJson(json);
+}

code_sharing/server/shared/lib/src/models.freezed.dart

@@ -0,0 +1,271 @@
+// coverage:ignore-file
+// GENERATED CODE - DO NOT MODIFY BY HAND
+// ignore_for_file: type=lint
+// ignore_for_file: unused_element, deprecated_member_use, deprecated_member_use_from_same_package, use_function_type_syntax_for_parameters, unnecessary_const, avoid_init_to_null, invalid_override_different_default_values_named, prefer_expression_function_bodies, annotate_overrides, invalid_annotation_target
+
+part of 'models.dart';
+
+// **************************************************************************
+// FreezedGenerator
+// **************************************************************************
+
+T _$identity<T>(T value) => value;
+
+final _privateConstructorUsedError = UnsupportedError(
+    'It seems like you constructed your class using `MyClass._()`. This constructor is only meant to be used by freezed and you are not supposed to need it nor use it.\nPlease check the documentation here for more information: https://github.com/rrousselGit/freezed#custom-getters-and-methods');
+
+Increment _$IncrementFromJson(Map<String, dynamic> json) {
+  return _Increment.fromJson(json);
+}
+
+/// @nodoc
+mixin _$Increment {
+  int get by => throw _privateConstructorUsedError;
+
+  Map<String, dynamic> toJson() => throw _privateConstructorUsedError;
+  @JsonKey(ignore: true)
+  $IncrementCopyWith<Increment> get copyWith =>
+      throw _privateConstructorUsedError;
+}
+
+/// @nodoc
+abstract class $IncrementCopyWith<$Res> {
+  factory $IncrementCopyWith(Increment value, $Res Function(Increment) then) =
+      _$IncrementCopyWithImpl<$Res>;
+  $Res call({int by});
+}
+
+/// @nodoc
+class _$IncrementCopyWithImpl<$Res> implements $IncrementCopyWith<$Res> {
+  _$IncrementCopyWithImpl(this._value, this._then);
+
+  final Increment _value;
+  // ignore: unused_field
+  final $Res Function(Increment) _then;
+
+  @override
+  $Res call({
+    Object? by = freezed,
+  }) {
+    return _then(_value.copyWith(
+      by: by == freezed
+          ? _value.by
+          : by // ignore: cast_nullable_to_non_nullable
+              as int,
+    ));
+  }
+}
+
+/// @nodoc
+abstract class _$$_IncrementCopyWith<$Res> implements $IncrementCopyWith<$Res> {
+  factory _$$_IncrementCopyWith(
+          _$_Increment value, $Res Function(_$_Increment) then) =
+      __$$_IncrementCopyWithImpl<$Res>;
+  @override
+  $Res call({int by});
+}
+
+/// @nodoc
+class __$$_IncrementCopyWithImpl<$Res> extends _$IncrementCopyWithImpl<$Res>
+    implements _$$_IncrementCopyWith<$Res> {
+  __$$_IncrementCopyWithImpl(
+      _$_Increment _value, $Res Function(_$_Increment) _then)
+      : super(_value, (v) => _then(v as _$_Increment));
+
+  @override
+  _$_Increment get _value => super._value as _$_Increment;
+
+  @override
+  $Res call({
+    Object? by = freezed,
+  }) {
+    return _then(_$_Increment(
+      by: by == freezed
+          ? _value.by
+          : by // ignore: cast_nullable_to_non_nullable
+              as int,
+    ));
+  }
+}
+
+/// @nodoc
+@JsonSerializable()
+class _$_Increment implements _Increment {
+  const _$_Increment({required this.by});
+
+  factory _$_Increment.fromJson(Map<String, dynamic> json) =>
+      _$$_IncrementFromJson(json);
+
+  @override
+  final int by;
+
+  @override
+  String toString() {
+    return 'Increment(by: $by)';
+  }
+
+  @override
+  bool operator ==(dynamic other) {
+    return identical(this, other) ||
+        (other.runtimeType == runtimeType &&
+            other is _$_Increment &&
+            const DeepCollectionEquality().equals(other.by, by));
+  }
+
+  @JsonKey(ignore: true)
+  @override
+  int get hashCode =>
+      Object.hash(runtimeType, const DeepCollectionEquality().hash(by));
+
+  @JsonKey(ignore: true)
+  @override
+  _$$_IncrementCopyWith<_$_Increment> get copyWith =>
+      __$$_IncrementCopyWithImpl<_$_Increment>(this, _$identity);
+
+  @override
+  Map<String, dynamic> toJson() {
+    return _$$_IncrementToJson(
+      this,
+    );
+  }
+}
+
+abstract class _Increment implements Increment {
+  const factory _Increment({required final int by}) = _$_Increment;
+
+  factory _Increment.fromJson(Map<String, dynamic> json) =
+      _$_Increment.fromJson;
+
+  @override
+  int get by;
+  @override
+  @JsonKey(ignore: true)
+  _$$_IncrementCopyWith<_$_Increment> get copyWith =>
+      throw _privateConstructorUsedError;
+}
+
+Count _$CountFromJson(Map<String, dynamic> json) {
+  return _Count.fromJson(json);
+}
+
+/// @nodoc
+mixin _$Count {
+  int get value => throw _privateConstructorUsedError;
+
+  Map<String, dynamic> toJson() => throw _privateConstructorUsedError;
+  @JsonKey(ignore: true)
+  $CountCopyWith<Count> get copyWith => throw _privateConstructorUsedError;
+}
+
+/// @nodoc
+abstract class $CountCopyWith<$Res> {
+  factory $CountCopyWith(Count value, $Res Function(Count) then) =
+      _$CountCopyWithImpl<$Res>;
+  $Res call({int value});
+}
+
+/// @nodoc
+class _$CountCopyWithImpl<$Res> implements $CountCopyWith<$Res> {
+  _$CountCopyWithImpl(this._value, this._then);
+
+  final Count _value;
+  // ignore: unused_field
+  final $Res Function(Count) _then;
+
+  @override
+  $Res call({
+    Object? value = freezed,
+  }) {
+    return _then(_value.copyWith(
+      value: value == freezed
+          ? _value.value
+          : value // ignore: cast_nullable_to_non_nullable
+              as int,
+    ));
+  }
+}
+
+/// @nodoc
+abstract class _$$_CountCopyWith<$Res> implements $CountCopyWith<$Res> {
+  factory _$$_CountCopyWith(_$_Count value, $Res Function(_$_Count) then) =
+      __$$_CountCopyWithImpl<$Res>;
+  @override
+  $Res call({int value});
+}
+
+/// @nodoc
+class __$$_CountCopyWithImpl<$Res> extends _$CountCopyWithImpl<$Res>
+    implements _$$_CountCopyWith<$Res> {
+  __$$_CountCopyWithImpl(_$_Count _value, $Res Function(_$_Count) _then)
+      : super(_value, (v) => _then(v as _$_Count));
+
+  @override
+  _$_Count get _value => super._value as _$_Count;
+
+  @override
+  $Res call({
+    Object? value = freezed,
+  }) {
+    return _then(_$_Count(
+      value == freezed
+          ? _value.value
+          : value // ignore: cast_nullable_to_non_nullable
+              as int,
+    ));
+  }
+}
+
+/// @nodoc
+@JsonSerializable()
+class _$_Count implements _Count {
+  const _$_Count(this.value);
+
+  factory _$_Count.fromJson(Map<String, dynamic> json) =>
+      _$$_CountFromJson(json);
+
+  @override
+  final int value;
+
+  @override
+  String toString() {
+    return 'Count(value: $value)';
+  }
+
+  @override
+  bool operator ==(dynamic other) {
+    return identical(this, other) ||
+        (other.runtimeType == runtimeType &&
+            other is _$_Count &&
+            const DeepCollectionEquality().equals(other.value, value));
+  }
+
+  @JsonKey(ignore: true)
+  @override
+  int get hashCode =>
+      Object.hash(runtimeType, const DeepCollectionEquality().hash(value));
+
+  @JsonKey(ignore: true)
+  @override
+  _$$_CountCopyWith<_$_Count> get copyWith =>
+      __$$_CountCopyWithImpl<_$_Count>(this, _$identity);
+
+  @override
+  Map<String, dynamic> toJson() {
+    return _$$_CountToJson(
+      this,
+    );
+  }
+}
+
+abstract class _Count implements Count {
+  const factory _Count(final int value) = _$_Count;
+
+  factory _Count.fromJson(Map<String, dynamic> json) = _$_Count.fromJson;
+
+  @override
+  int get value;
+  @override
+  @JsonKey(ignore: true)
+  _$$_CountCopyWith<_$_Count> get copyWith =>
+      throw _privateConstructorUsedError;
+}

code_sharing/server/shared/lib/src/models.g.dart

@@ -0,0 +1,24 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'models.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+_$_Increment _$$_IncrementFromJson(Map<String, dynamic> json) => _$_Increment(
+      by: json['by'] as int,
+    );
+
+Map<String, dynamic> _$$_IncrementToJson(_$_Increment instance) =>
+    <String, dynamic>{
+      'by': instance.by,
+    };
+
+_$_Count _$$_CountFromJson(Map<String, dynamic> json) => _$_Count(
+      json['value'] as int,
+    );
+
+Map<String, dynamic> _$$_CountToJson(_$_Count instance) => <String, dynamic>{
+      'value': instance.value,
+    };

code_sharing/server/shared/pubspec.yaml

@@ -0,0 +1,17 @@
+name: shared
+description: Common data models required by our client and server
+version: 1.0.0
+
+environment:
+  sdk: ">=2.18.1 <3.0.0"
+
+dependencies:
+  freezed_annotation: ^2.1.0
+  json_annotation: ^4.7.0
+
+dev_dependencies:
+  build_runner: ^2.2.1
+  freezed: ^2.1.1
+  json_serializable: ^6.4.0
+  lints: ^2.0.0
+  test: ^1.16.0

code_sharing/server/shared/test/shared_test.dart

@@ -0,0 +1,17 @@
+import 'package:shared/shared.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('Increment serialization', () {
+    expect(Increment(by: 3).toJson(), <String, dynamic>{'by': 3});
+  });
+  test('Increment derialization', () {
+    expect(Increment.fromJson(<String, dynamic>{'by': 5}), Increment(by: 5));
+  });
+  test('Count serialization', () {
+    expect(Count(3).toJson(), <String, dynamic>{'value': 3});
+  });
+  test('Count derialization', () {
+    expect(Count.fromJson(<String, dynamic>{'value': 5}), Count(5));
+  });
+}

code_sharing/server/test/server_test.dart

@@ -0,0 +1,40 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:http/http.dart';
+import 'package:test/test.dart';
+
+// Manual test:
+// $ dart bin/server.dart
+// $ curl -X POST -d '{"by": 1}' -H "Content-Type: application/json" localhost:8080/
+
+void main() {
+  final port = '8080';
+  final host = 'http://0.0.0.0:$port';
+  late Process p;
+
+  setUp(() async {
+    p = await Process.start(
+      'dart',
+      ['run', 'bin/server.dart'],
+      environment: {'PORT': port},
+    );
+    // Wait for server to start and print to stdout.
+    await p.stdout.first;
+  });
+
+  tearDown(() => p.kill());
+
+  test('Increment', () async {
+    final response = await post(Uri.parse('$host/'), body: '{"by": 1}');
+    expect(response.statusCode, 200);
+    expect(response.body, '{"value":1}');
+  });
+
+  test('Get', () async {
+    final response = await get(Uri.parse('$host/'));
+    expect(response.statusCode, 200);
+    final resp = json.decode(response.body) as Map;
+    expect(resp.containsKey('value'), true);
+  });
+}