Merge pull request 'Update README' (#2) from develop into main

Reviewed-on: #2

.gitignore

@@ -1,29 +1,46 @@
-# ---> Dart
+# Miscellaneous
-# See https://www.dartlang.org/guides/libraries/private-files
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.buildlog/
+.history
+.svn/
 
-# Files and directories created by pub
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+**/ios/Flutter/.last_build_id
 .dart_tool/
-.packages
-build/
-# If you're building an application, you may want to check-in your pubspec.lock
-pubspec.lock
-
-# Directory created by dartdoc
-# If you don't generate documentation locally you can remove this line.
-doc/api/
-
-# dotenv environment variables file
-.env*
-
-# Avoid committing generated Javascript files:
-*.dart.js
-*.info.json      # Produced by the --dump-info flag.
-*.js             # When generated by dart2js. Don't specify *.js if your
-                 # project includes source files written in JavaScript.
-*.js_
-*.js.deps
-*.js.map
-
 .flutter-plugins
 .flutter-plugins-dependencies
+.packages
+.pub-cache/
+.pub/
+/build/
 
+# Web related
+lib/generated_plugin_registrant.dart
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json
+
+# Android Studio will place build artifacts here
+/android/app/debug
+/android/app/profile
+/android/app/release

.metadata

@@ -0,0 +1,10 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: 77d935af4db863f6abd0b9c31c7e6df2a13de57b
+  channel: stable
+
+project_type: app

Dockerfile

@@ -0,0 +1,28 @@
+FROM ubuntu:20.04 AS build
+
+RUN apt update
+RUN apt install -y curl git wget unzip tree
+RUN apt clean
+    # download Flutter SDK from Flutter Github repo \
+RUN git clone https://github.com/flutter/flutter.git /usr/local/flutter
+
+# Set flutter environment path
+ENV PATH="/usr/local/flutter/bin:/usr/local/flutter/bin/cache/dart-sdk/bin:${PATH}"
+
+RUN flutter doctor
+RUN flutter channel master
+RUN flutter upgrade
+RUN flutter config --enable-web
+
+RUN mkdir /app/
+COPY . /app/
+WORKDIR /app/
+RUN flutter build web && ls -lha
+
+FROM nginx:alpine AS final
+RUN apk update && apk add tree
+RUN tree
+WORKDIR /usr/share/nginx/html
+COPY --from=build /app/build/web .
+COPY nginx.conf /etc/nginx/nginx.conf
+RUN tree

README.md

@@ -1,2 +1,48 @@
-# flutter-pwa-test
+# flutter_pwa_test
 
+A Flutter PWA test.
+
+## Getting Started
+
+Build with Flutter 2.8.1 from channel stable.
+
+## Run as docker container
+
+### Build the docker image
+
+```bash
+cd <directory container the Dockerfile, i.e. the root of the project>
+docker build -t <image-name> .
+```
+
+### Transfer the image to another machine
+
+If you intent to run the container on a different machine, either upload it to a registry of your choice or save it as a tar-file and copy it as needed. If you intent to upload it to a registry, make sure you name it accordingly, e.g. docker.example.com/flutter-pwa-test:latest.
+
+```bash
+docker push <image-name>
+```
+
+```bash
+docker save -o <file-name>.tar <image-name>
+```
+
+To import the tar-file on another machine:
+
+```bash
+docker load -i <file-name>.tar
+```
+
+### Run the image
+
+You can either run the image from the cli or using docker compose:
+
+```bash
+docker run --rm -p 5000:80 --restart unless-stopped --name flutter-pwa-test <image-name>
+```
+
+Assuming you are in the root of the project containing the `docker-compose.yml` file. Otherwise specify the file using the `-f` flag.
+
+```bash
+docker-compose up -d
+```

analysis_options.yaml

@@ -0,0 +1,29 @@
+# This file configures the analyzer, which statically analyzes Dart code to
+# check for errors, warnings, and lints.
+#
+# The issues identified by the analyzer are surfaced in the UI of Dart-enabled
+# IDEs (https://dart.dev/tools#ides-and-editors). The analyzer can also be
+# invoked from the command line by running `flutter analyze`.
+
+# The following line activates a set of recommended lints for Flutter apps,
+# packages, and plugins designed to encourage good coding practices.
+include: package:flutter_lints/flutter.yaml
+
+linter:
+  # The lint rules applied to this project can be customized in the
+  # section below to disable rules from the `package:flutter_lints/flutter.yaml`
+  # included above or to enable additional rules. A list of all available lints
+  # and their documentation is published at
+  # https://dart-lang.github.io/linter/lints/index.html.
+  #
+  # Instead of disabling a lint rule for the entire project in the
+  # section below, it can also be suppressed for a single line of code
+  # or a specific dart file by using the `// ignore: name_of_lint` and
+  # `// ignore_for_file: name_of_lint` syntax on the line or in the file
+  # producing the lint.
+  rules:
+    # avoid_print: false  # Uncomment to disable the `avoid_print` rule
+    # prefer_single_quotes: true  # Uncomment to enable the `prefer_single_quotes` rule
+
+# Additional information about this file can be found at
+# https://dart.dev/guides/language/analysis-options

docker-compose.yml

@@ -0,0 +1,9 @@
+version: '3.8'
+
+services:
+  app:
+    image: docker.nuyken.dev/flutter-pwa:test
+    container_name: flutter-pwa-test
+    restart: unless-stopped
+    ports:
+      - "5000:80"

lib/Content.dart

@@ -0,0 +1,91 @@
+import 'package:flutter/material.dart';
+import 'package:geolocator/geolocator.dart';
+
+class Content extends StatefulWidget {
+  const Content({Key? key}) : super(key: key);
+
+  @override
+  _ContentState createState() => _ContentState();
+}
+
+class _ContentState extends State<Content> {
+  String? _coordinates;
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Column(
+        mainAxisAlignment: MainAxisAlignment.center,
+        children: [
+          ElevatedButton(
+            child: Text("Test coordinates"),
+            onPressed: () async {
+              try {
+                _coordinates = (await _getLocationAsync()).toString();
+                setState(() {});
+              } catch (e) {
+                _coordinates = e.toString();
+                setState(() {});
+              }
+            },
+          ),
+          _coordinates != null
+              ? Text(_coordinates!.toString())
+              : const SizedBox(),
+        ],
+      ),
+    );
+  }
+
+  Future<Position> _getLocationAsync() async {
+    bool serviceEnabled;
+    LocationPermission permission;
+
+    showDialog<void>(
+      context: context,
+      builder: (BuildContext dialogContext) {
+        return const SimpleDialog(
+          children: [
+            Center(
+              child: CircularProgressIndicator(),
+            ),
+          ],
+        );
+      },
+    );
+
+    // Test if location services are enabled.
+    serviceEnabled = await Geolocator.isLocationServiceEnabled();
+    if (!serviceEnabled) {
+      // Location services are not enabled don't continue
+      // accessing the position and request users of the
+      // App to enable the location services.
+      return Future.error('Location services are disabled.');
+    }
+
+    permission = await Geolocator.checkPermission();
+    if (permission == LocationPermission.denied) {
+      permission = await Geolocator.requestPermission();
+      if (permission == LocationPermission.denied) {
+        // Permissions are denied, next time you could try
+        // requesting permissions again (this is also where
+        // Android's shouldShowRequestPermissionRationale
+        // returned true. According to Android guidelines
+        // your App should show an explanatory UI now.
+        return Future.error('Location permissions are denied');
+      }
+    }
+
+    if (permission == LocationPermission.deniedForever) {
+      // Permissions are denied forever, handle appropriately.
+      return Future.error(
+          'Location permissions are permanently denied, we cannot request permissions.');
+    }
+
+    // When we reach here, permissions are granted and we can
+    // continue accessing the position of the device.
+    var position = await Geolocator.getCurrentPosition();
+    Navigator.pop(context);
+    return position;
+  }
+}

lib/login.dart

@@ -0,0 +1,66 @@
+import 'dart:convert';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_pwa_test/Content.dart';
+
+class Login extends StatelessWidget {
+  static const String _password = "SGVsbG9Xb3JsZCE=";
+
+  Login({Key? key, required this.loginCallback}) : super(key: key);
+  
+  final VoidCallback loginCallback;
+
+  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Form(
+        key: _formKey,
+        autovalidateMode: AutovalidateMode.disabled,
+        child: Column(
+          children: [
+            Container(
+              constraints: const BoxConstraints(maxWidth: 500),
+              child: TextFormField(
+                decoration: const InputDecoration(
+                  labelText: "Password",
+                  hintText: "Password",
+                  alignLabelWithHint: true,
+                  border: OutlineInputBorder(),
+                ),
+                validator: (s) {
+                  if (s == null) {
+                    return "Please provide a value";
+                  }
+
+                  var encoded = base64Encode(utf8.encode(s));
+                  print(encoded);
+                  if (encoded != _password) {
+                    return "Password is wrong";
+                  }
+
+                  return null;
+                },
+              ),
+            ),
+            const SizedBox(height: 16.0),
+            ElevatedButton(
+              onPressed: () async {
+                var result = _formKey.currentState?.validate();
+                if (result == null || !result) {
+                  print(
+                      "Could not validate password because of an internal error");
+                  return;
+                }
+
+                loginCallback();
+              },
+              child: const Text("Ok"),
+            )
+          ],
+        ),
+      ),
+    );
+  }
+}

lib/main.dart

@@ -0,0 +1,59 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_pwa_test/Content.dart';
+import 'package:flutter_pwa_test/login.dart';
+
+void main() {
+  runApp(const MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: 'Flutter Demo',
+      theme: ThemeData(
+        primarySwatch: Colors.blue,
+      ),
+      debugShowCheckedModeBanner: false,
+      home: const MyHomePage(title: 'Flutter Demo Home Page'),
+    );
+  }
+}
+
+class MyHomePage extends StatefulWidget {
+  const MyHomePage({Key? key, required this.title}) : super(key: key);
+
+  final String title;
+
+  @override
+  State<MyHomePage> createState() => _MyHomePageState();
+}
+
+class _MyHomePageState extends State<MyHomePage> {
+  late Widget _content;
+
+  @override
+  void initState() {
+    super.initState();
+    _content = Login(loginCallback: () {
+      setState(() {
+        _content = const Content();
+      });
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text(widget.title),
+      ),
+      body: Padding(
+        padding: const EdgeInsets.all(16.0),
+        child: _content,
+      ),
+    );
+  }
+}

nginx.conf

@@ -0,0 +1,13 @@
+events { }
+http {
+    include mime.types;
+
+    server {
+        listen 80;
+
+        location / {
+            root /usr/share/nginx/html;
+            try_files $uri $uri/ /index.html =404;
+        }
+    }
+}

pubspec.lock

@@ -0,0 +1,222 @@
+# Generated by pub
+# See https://dart.dev/tools/pub/glossary#lockfile
+packages:
+  async:
+    dependency: transitive
+    description:
+      name: async
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.8.2"
+  boolean_selector:
+    dependency: transitive
+    description:
+      name: boolean_selector
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.0"
+  characters:
+    dependency: transitive
+    description:
+      name: characters
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0"
+  charcode:
+    dependency: transitive
+    description:
+      name: charcode
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.3.1"
+  clock:
+    dependency: transitive
+    description:
+      name: clock
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.0"
+  collection:
+    dependency: transitive
+    description:
+      name: collection
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.15.0"
+  cupertino_icons:
+    dependency: "direct main"
+    description:
+      name: cupertino_icons
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.4"
+  fake_async:
+    dependency: transitive
+    description:
+      name: fake_async
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0"
+  flutter:
+    dependency: "direct main"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  flutter_lints:
+    dependency: "direct dev"
+    description:
+      name: flutter_lints
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.4"
+  flutter_test:
+    dependency: "direct dev"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  flutter_web_plugins:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
+  geolocator:
+    dependency: "direct main"
+    description:
+      name: geolocator
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "8.0.3"
+  geolocator_android:
+    dependency: transitive
+    description:
+      name: geolocator_android
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.2"
+  geolocator_apple:
+    dependency: transitive
+    description:
+      name: geolocator_apple
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.1"
+  geolocator_platform_interface:
+    dependency: transitive
+    description:
+      name: geolocator_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "4.0.1"
+  geolocator_web:
+    dependency: transitive
+    description:
+      name: geolocator_web
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.4"
+  js:
+    dependency: transitive
+    description:
+      name: js
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.6.3"
+  lints:
+    dependency: transitive
+    description:
+      name: lints
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.1"
+  matcher:
+    dependency: transitive
+    description:
+      name: matcher
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.12.11"
+  meta:
+    dependency: transitive
+    description:
+      name: meta
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.7.0"
+  path:
+    dependency: transitive
+    description:
+      name: path
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.8.0"
+  plugin_platform_interface:
+    dependency: transitive
+    description:
+      name: plugin_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.2"
+  sky_engine:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.99"
+  source_span:
+    dependency: transitive
+    description:
+      name: source_span
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.8.1"
+  stack_trace:
+    dependency: transitive
+    description:
+      name: stack_trace
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.10.0"
+  stream_channel:
+    dependency: transitive
+    description:
+      name: stream_channel
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.0"
+  string_scanner:
+    dependency: transitive
+    description:
+      name: string_scanner
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.0"
+  term_glyph:
+    dependency: transitive
+    description:
+      name: term_glyph
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0"
+  test_api:
+    dependency: transitive
+    description:
+      name: test_api
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.4.3"
+  typed_data:
+    dependency: transitive
+    description:
+      name: typed_data
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.3.0"
+  vector_math:
+    dependency: transitive
+    description:
+      name: vector_math
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.1"
+sdks:
+  dart: ">=2.15.1 <3.0.0"
+  flutter: ">=1.20.0"

pubspec.yaml

@@ -0,0 +1,90 @@
+name: flutter_pwa_test
+description: A Flutter PWA test
+
+# The following line prevents the package from being accidentally published to
+# pub.dev using `flutter pub publish`. This is preferred for private packages.
+publish_to: 'none' # Remove this line if you wish to publish to pub.dev
+
+# The following defines the version and build number for your application.
+# A version number is three numbers separated by dots, like 1.2.43
+# followed by an optional build number separated by a +.
+# Both the version and the builder number may be overridden in flutter
+# build by specifying --build-name and --build-number, respectively.
+# In Android, build-name is used as versionName while build-number used as versionCode.
+# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
+# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
+# Read more about iOS versioning at
+# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
+version: 1.0.0+1
+
+environment:
+  sdk: ">=2.15.1 <3.0.0"
+
+# Dependencies specify other packages that your package needs in order to work.
+# To automatically upgrade your package dependencies to the latest versions
+# consider running `flutter pub upgrade --major-versions`. Alternatively,
+# dependencies can be manually updated by changing the version numbers below to
+# the latest version available on pub.dev. To see which dependencies have newer
+# versions available, run `flutter pub outdated`.
+dependencies:
+  flutter:
+    sdk: flutter
+
+
+  # The following adds the Cupertino Icons font to your application.
+  # Use with the CupertinoIcons class for iOS style icons.
+  cupertino_icons: ^1.0.2
+  geolocator: ^8.0.3
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+
+  # The "flutter_lints" package below contains a set of recommended lints to
+  # encourage good coding practices. The lint set provided by the package is
+  # activated in the `analysis_options.yaml` file located at the root of your
+  # package. See that file for information about deactivating specific lint
+  # rules and activating additional ones.
+  flutter_lints: ^1.0.0
+
+# For information on the generic Dart part of this file, see the
+# following page: https://dart.dev/tools/pub/pubspec
+
+# The following section is specific to Flutter.
+flutter:
+
+  # The following line ensures that the Material Icons font is
+  # included with your application, so that you can use the icons in
+  # the material Icons class.
+  uses-material-design: true
+
+  # To add assets to your application, add an assets section, like this:
+  # assets:
+  #   - images/a_dot_burr.jpeg
+  #   - images/a_dot_ham.jpeg
+
+  # An image asset can refer to one or more resolution-specific "variants", see
+  # https://flutter.dev/assets-and-images/#resolution-aware.
+
+  # For details regarding adding assets from package dependencies, see
+  # https://flutter.dev/assets-and-images/#from-packages
+
+  # To add custom fonts to your application, add a fonts section here,
+  # in this "flutter" section. Each entry in this list should have a
+  # "family" key with the font family name, and a "fonts" key with a
+  # list giving the asset and other descriptors for the font. For
+  # example:
+  # fonts:
+  #   - family: Schyler
+  #     fonts:
+  #       - asset: fonts/Schyler-Regular.ttf
+  #       - asset: fonts/Schyler-Italic.ttf
+  #         style: italic
+  #   - family: Trajan Pro
+  #     fonts:
+  #       - asset: fonts/TrajanPro.ttf
+  #       - asset: fonts/TrajanPro_Bold.ttf
+  #         weight: 700
+  #
+  # For details regarding fonts from package dependencies,
+  # see https://flutter.dev/custom-fonts/#from-packages

test/widget_test.dart

@@ -0,0 +1,30 @@
+// This is a basic Flutter widget test.
+//
+// To perform an interaction with a widget in your test, use the WidgetTester
+// utility that Flutter provides. For example, you can send tap and scroll
+// gestures. You can also use WidgetTester to find child widgets in the widget
+// tree, read text, and verify that the values of widget properties are correct.
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:flutter_pwa_test/main.dart';
+
+void main() {
+  testWidgets('Counter increments smoke test', (WidgetTester tester) async {
+    // Build our app and trigger a frame.
+    await tester.pumpWidget(const MyApp());
+
+    // Verify that our counter starts at 0.
+    expect(find.text('0'), findsOneWidget);
+    expect(find.text('1'), findsNothing);
+
+    // Tap the '+' icon and trigger a frame.
+    await tester.tap(find.byIcon(Icons.add));
+    await tester.pump();
+
+    // Verify that our counter has incremented.
+    expect(find.text('0'), findsNothing);
+    expect(find.text('1'), findsOneWidget);
+  });
+}

web/index.html

@@ -0,0 +1,104 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <!--
+    If you are serving your web app in a path other than the root, change the
+    href value below to reflect the base path you are serving from.
+
+    The path provided below has to start and end with a slash "/" in order for
+    it to work correctly.
+
+    For more details:
+    * https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base
+
+    This is a placeholder for base href that will be replaced by the value of
+    the `--base-href` argument provided to `flutter build`.
+  -->
+  <base href="$FLUTTER_BASE_HREF">
+
+  <meta charset="UTF-8">
+  <meta content="IE=Edge" http-equiv="X-UA-Compatible">
+  <meta name="description" content="A Flutter PWA test">
+
+  <!-- iOS meta tags & icons -->
+  <meta name="apple-mobile-web-app-capable" content="yes">
+  <meta name="apple-mobile-web-app-status-bar-style" content="black">
+  <meta name="apple-mobile-web-app-title" content="flutter_pwa_test">
+  <link rel="apple-touch-icon" href="icons/Icon-192.png">
+
+  <!-- Favicon -->
+  <link rel="icon" type="image/png" href="favicon.png"/>
+
+  <title>flutter_pwa_test</title>
+  <link rel="manifest" href="manifest.json">
+</head>
+<body>
+  <!-- This script installs service_worker.js to provide PWA functionality to
+       application. For more information, see:
+       https://developers.google.com/web/fundamentals/primers/service-workers -->
+  <script>
+    var serviceWorkerVersion = null;
+    var scriptLoaded = false;
+    function loadMainDartJs() {
+      if (scriptLoaded) {
+        return;
+      }
+      scriptLoaded = true;
+      var scriptTag = document.createElement('script');
+      scriptTag.src = 'main.dart.js';
+      scriptTag.type = 'application/javascript';
+      document.body.append(scriptTag);
+    }
+
+    if ('serviceWorker' in navigator) {
+      // Service workers are supported. Use them.
+      window.addEventListener('load', function () {
+        // Wait for registration to finish before dropping the <script> tag.
+        // Otherwise, the browser will load the script multiple times,
+        // potentially different versions.
+        var serviceWorkerUrl = 'flutter_service_worker.js?v=' + serviceWorkerVersion;
+        navigator.serviceWorker.register(serviceWorkerUrl)
+          .then((reg) => {
+            function waitForActivation(serviceWorker) {
+              serviceWorker.addEventListener('statechange', () => {
+                if (serviceWorker.state == 'activated') {
+                  console.log('Installed new service worker.');
+                  loadMainDartJs();
+                }
+              });
+            }
+            if (!reg.active && (reg.installing || reg.waiting)) {
+              // No active web worker and we have installed or are installing
+              // one for the first time. Simply wait for it to activate.
+              waitForActivation(reg.installing || reg.waiting);
+            } else if (!reg.active.scriptURL.endsWith(serviceWorkerVersion)) {
+              // When the app updates the serviceWorkerVersion changes, so we
+              // need to ask the service worker to update.
+              console.log('New service worker available.');
+              reg.update();
+              waitForActivation(reg.installing);
+            } else {
+              // Existing service worker is still good.
+              console.log('Loading app from service worker.');
+              loadMainDartJs();
+            }
+          });
+
+        // If service worker doesn't succeed in a reasonable amount of time,
+        // fallback to plaint <script> tag.
+        setTimeout(() => {
+          if (!scriptLoaded) {
+            console.warn(
+              'Failed to load app from service worker. Falling back to plain <script> tag.',
+            );
+            loadMainDartJs();
+          }
+        }, 4000);
+      });
+    } else {
+      // Service workers not supported. Just drop the <script> tag.
+      loadMainDartJs();
+    }
+  </script>
+</body>
+</html>

web/manifest.json

@@ -0,0 +1,35 @@
+{
+    "name": "flutter_pwa_test",
+    "short_name": "flutter_pwa_test",
+    "start_url": ".",
+    "display": "standalone",
+    "background_color": "#0175C2",
+    "theme_color": "#0175C2",
+    "description": "A Flutter PWA test",
+    "orientation": "portrait-primary",
+    "prefer_related_applications": false,
+    "icons": [
+        {
+            "src": "icons/Icon-192.png",
+            "sizes": "192x192",
+            "type": "image/png"
+        },
+        {
+            "src": "icons/Icon-512.png",
+            "sizes": "512x512",
+            "type": "image/png"
+        },
+        {
+            "src": "icons/Icon-maskable-192.png",
+            "sizes": "192x192",
+            "type": "image/png",
+            "purpose": "maskable"
+        },
+        {
+            "src": "icons/Icon-maskable-512.png",
+            "sizes": "512x512",
+            "type": "image/png",
+            "purpose": "maskable"
+        }
+    ]
+}