[tools][web] Make Plugin Registrant file ephemeral. (#102185)

Author: ditman

dev/bots/service_worker_test.dart

@@ -231,7 +231,6 @@ Future<void> runWebServiceWorkerTest({
       'main.dart.js': 1,
       'flutter_service_worker.js': 1,
       'assets/FontManifest.json': 1,
-      'assets/NOTICES': 1,
       'assets/AssetManifest.json': 1,
       'CLOSE': 1,
       // In headless mode Chrome does not load 'manifest.json' and 'favicon.ico'.
@@ -273,7 +272,6 @@ Future<void> runWebServiceWorkerTest({
         'flutter.js': 1,
       'flutter_service_worker.js': 2,
       'main.dart.js': 1,
-      'assets/NOTICES': 1,
       'assets/AssetManifest.json': 1,
       'assets/FontManifest.json': 1,
       'CLOSE': 1,
@@ -305,7 +303,6 @@ Future<void> runWebServiceWorkerTest({
       'main.dart.js': 2,
       'assets/FontManifest.json': 2,
       'flutter_service_worker.js': 1,
-      'assets/NOTICES': 1,
       'assets/AssetManifest.json': 1,
       'CLOSE': 1,
       // In headless mode Chrome does not load 'manifest.json' and 'favicon.ico'.
@@ -358,7 +355,6 @@ Future<void> runWebServiceWorkerTest({
         'flutter.js': 1,
       'flutter_service_worker.js': 2,
       'main.dart.js': 2,
-      'assets/NOTICES': 1,
       'assets/AssetManifest.json': 1,
       'assets/FontManifest.json': 2,
       'CLOSE': 1,

packages/flutter_tools/lib/src/build_system/targets/web.dart

@@ -15,9 +15,12 @@ import '../../cache.dart';
 import '../../convert.dart';
 import '../../dart/language_version.dart';
 import '../../dart/package_map.dart';
+import '../../flutter_plugins.dart';
 import '../../globals.dart' as globals;
 import '../../project.dart';
-import '../../web/flutter_js.dart' as flutter_js;
+import '../../web/file_generators/flutter_js.dart' as flutter_js;
+import '../../web/file_generators/flutter_service_worker_js.dart';
+import '../../web/file_generators/main_dart.dart' as main_dart;
 import '../build_system.dart';
 import '../depfile.dart';
 import '../exceptions.dart';
@@ -50,15 +53,6 @@ const String kSourceMapsEnabled = 'SourceMaps';
 /// Whether the dart2js native null assertions are enabled.
 const String kNativeNullAssertions = 'NativeNullAssertions';
 
-/// The caching strategy for the generated service worker.
-enum ServiceWorkerStrategy {
-  /// Download the app shell eagerly and all other assets lazily.
-  /// Prefer the offline cached version.
-  offlineFirst,
-  /// Do not generate a service worker,
-  none,
-}
-
 const String kOfflineFirst = 'offline-first';
 const String kNoneWorker = 'none';
 
@@ -97,7 +91,6 @@ class WebEntrypointTarget extends Target {
   @override
   Future<void> build(Environment environment) async {
     final String? targetFile = environment.defines[kTargetFile];
-    final bool hasWebPlugins = environment.defines[kHasWebPlugins] == 'true';
     final Uri importUri = environment.fileSystem.file(targetFile).absolute.uri;
     // TODO(zanderso): support configuration of this file.
     const String packageFile = '.packages';
@@ -124,50 +117,15 @@ class WebEntrypointTarget extends Target {
     final String importedEntrypoint = packageConfig.toPackageUri(importUri)?.toString()
       ?? importUri.toString();
 
-    String? generatedImport;
-    if (hasWebPlugins) {
-      final Uri generatedUri = environment.projectDir
-        .childDirectory('lib')
-        .childFile('generated_plugin_registrant.dart')
-        .absolute
-        .uri;
-      generatedImport = packageConfig.toPackageUri(generatedUri)?.toString()
-        ?? generatedUri.toString();
-    }
+    await injectBuildTimePluginFiles(flutterProject, webPlatform: true, destination: environment.buildDir);
+    // The below works because `injectBuildTimePluginFiles` is configured to write
+    // the web_plugin_registrant.dart file alongside the generated main.dart
+    const String generatedImport = 'web_plugin_registrant.dart';
 
-    final String contents = <String>[
-        '// @dart=${languageVersion.major}.${languageVersion.minor}',
-        '// Flutter web bootstrap script for $importedEntrypoint.',
-        '',
-        "import 'dart:ui' as ui;",
-        "import 'dart:async';",
-        '',
-        "import '$importedEntrypoint' as entrypoint;",
-        if (hasWebPlugins)
-          "import 'package:flutter_web_plugins/flutter_web_plugins.dart';",
-        if (hasWebPlugins)
-          "import '$generatedImport';",
-        '',
-        'typedef _UnaryFunction = dynamic Function(List<String> args);',
-        'typedef _NullaryFunction = dynamic Function();',
-        '',
-        'Future<void> main() async {',
-        '  await ui.webOnlyWarmupEngine(',
-        '    runApp: () {',
-        '      if (entrypoint.main is _UnaryFunction) {',
-        '        return (entrypoint.main as _UnaryFunction)(<String>[]);',
-        '      }',
-        '      return (entrypoint.main as _NullaryFunction)();',
-        '    },',
-        if (hasWebPlugins) ...<String>[
-        '    registerPlugins: () {',
-        '      registerPlugins(webPluginRegistrar);',
-        '    },',
-        ],
-        '  );',
-        '}',
-        '',
-      ].join('\n');
+    final String contents = main_dart.generateMainDartFile(importedEntrypoint,
+      languageVersion: languageVersion,
+      pluginRegistrantEntrypoint: generatedImport,
+    );
 
     environment.buildDir.childFile('main.dart')
       .writeAsStringSync(contents);
@@ -547,7 +505,6 @@ class WebServiceWorker extends Target {
       <String>[
         'main.dart.js',
         'index.html',
-        'assets/NOTICES',
         if (urlToHash.containsKey('assets/AssetManifest.json'))
           'assets/AssetManifest.json',
         if (urlToHash.containsKey('assets/FontManifest.json'))
@@ -567,194 +524,3 @@ class WebServiceWorker extends Target {
     );
   }
 }
-
-/// Generate a service worker with an app-specific cache name a map of
-/// resource files.
-///
-/// The tool embeds file hashes directly into the worker so that the byte for byte
-/// invalidation will automatically reactivate workers whenever a new
-/// version is deployed.
-String generateServiceWorker(
-  Map<String, String> resources,
-  List<String> coreBundle, {
-  required ServiceWorkerStrategy serviceWorkerStrategy,
-}) {
-  if (serviceWorkerStrategy == ServiceWorkerStrategy.none) {
-    return '';
-  }
-  return '''
-'use strict';
-const MANIFEST = 'flutter-app-manifest';
-const TEMP = 'flutter-temp-cache';
-const CACHE_NAME = 'flutter-app-cache';
-const RESOURCES = {
-  ${resources.entries.map((MapEntry<String, String> entry) => '"${entry.key}": "${entry.value}"').join(",\n")}
-};
-
-// The application shell files that are downloaded before a service worker can
-// start.
-const CORE = [
-  ${coreBundle.map((String file) => '"$file"').join(',\n')}];
-// During install, the TEMP cache is populated with the application shell files.
-self.addEventListener("install", (event) => {
-  self.skipWaiting();
-  return event.waitUntil(
-    caches.open(TEMP).then((cache) => {
-      return cache.addAll(
-        CORE.map((value) => new Request(value, {'cache': 'reload'})));
-    })
-  );
-});
-
-// During activate, the cache is populated with the temp files downloaded in
-// install. If this service worker is upgrading from one with a saved
-// MANIFEST, then use this to retain unchanged resource files.
-self.addEventListener("activate", function(event) {
-  return event.waitUntil(async function() {
-    try {
-      var contentCache = await caches.open(CACHE_NAME);
-      var tempCache = await caches.open(TEMP);
-      var manifestCache = await caches.open(MANIFEST);
-      var manifest = await manifestCache.match('manifest');
-      // When there is no prior manifest, clear the entire cache.
-      if (!manifest) {
-        await caches.delete(CACHE_NAME);
-        contentCache = await caches.open(CACHE_NAME);
-        for (var request of await tempCache.keys()) {
-          var response = await tempCache.match(request);
-          await contentCache.put(request, response);
-        }
-        await caches.delete(TEMP);
-        // Save the manifest to make future upgrades efficient.
-        await manifestCache.put('manifest', new Response(JSON.stringify(RESOURCES)));
-        return;
-      }
-      var oldManifest = await manifest.json();
-      var origin = self.location.origin;
-      for (var request of await contentCache.keys()) {
-        var key = request.url.substring(origin.length + 1);
-        if (key == "") {
-          key = "/";
-        }
-        // If a resource from the old manifest is not in the new cache, or if
-        // the MD5 sum has changed, delete it. Otherwise the resource is left
-        // in the cache and can be reused by the new service worker.
-        if (!RESOURCES[key] || RESOURCES[key] != oldManifest[key]) {
-          await contentCache.delete(request);
-        }
-      }
-      // Populate the cache with the app shell TEMP files, potentially overwriting
-      // cache files preserved above.
-      for (var request of await tempCache.keys()) {
-        var response = await tempCache.match(request);
-        await contentCache.put(request, response);
-      }
-      await caches.delete(TEMP);
-      // Save the manifest to make future upgrades efficient.
-      await manifestCache.put('manifest', new Response(JSON.stringify(RESOURCES)));
-      return;
-    } catch (err) {
-      // On an unhandled exception the state of the cache cannot be guaranteed.
-      console.error('Failed to upgrade service worker: ' + err);
-      await caches.delete(CACHE_NAME);
-      await caches.delete(TEMP);
-      await caches.delete(MANIFEST);
-    }
-  }());
-});
-
-// The fetch handler redirects requests for RESOURCE files to the service
-// worker cache.
-self.addEventListener("fetch", (event) => {
-  if (event.request.method !== 'GET') {
-    return;
-  }
-  var origin = self.location.origin;
-  var key = event.request.url.substring(origin.length + 1);
-  // Redirect URLs to the index.html
-  if (key.indexOf('?v=') != -1) {
-    key = key.split('?v=')[0];
-  }
-  if (event.request.url == origin || event.request.url.startsWith(origin + '/#') || key == '') {
-    key = '/';
-  }
-  // If the URL is not the RESOURCE list then return to signal that the
-  // browser should take over.
-  if (!RESOURCES[key]) {
-    return;
-  }
-  // If the URL is the index.html, perform an online-first request.
-  if (key == '/') {
-    return onlineFirst(event);
-  }
-  event.respondWith(caches.open(CACHE_NAME)
-    .then((cache) =>  {
-      return cache.match(event.request).then((response) => {
-        // Either respond with the cached resource, or perform a fetch and
-        // lazily populate the cache.
-        return response || fetch(event.request).then((response) => {
-          cache.put(event.request, response.clone());
-          return response;
-        });
-      })
-    })
-  );
-});
-
-self.addEventListener('message', (event) => {
-  // SkipWaiting can be used to immediately activate a waiting service worker.
-  // This will also require a page refresh triggered by the main worker.
-  if (event.data === 'skipWaiting') {
-    self.skipWaiting();
-    return;
-  }
-  if (event.data === 'downloadOffline') {
-    downloadOffline();
-    return;
-  }
-});
-
-// Download offline will check the RESOURCES for all files not in the cache
-// and populate them.
-async function downloadOffline() {
-  var resources = [];
-  var contentCache = await caches.open(CACHE_NAME);
-  var currentContent = {};
-  for (var request of await contentCache.keys()) {
-    var key = request.url.substring(origin.length + 1);
-    if (key == "") {
-      key = "/";
-    }
-    currentContent[key] = true;
-  }
-  for (var resourceKey of Object.keys(RESOURCES)) {
-    if (!currentContent[resourceKey]) {
-      resources.push(resourceKey);
-    }
-  }
-  return contentCache.addAll(resources);
-}
-
-// Attempt to download the resource online before falling back to
-// the offline cache.
-function onlineFirst(event) {
-  return event.respondWith(
-    fetch(event.request).then((response) => {
-      return caches.open(CACHE_NAME).then((cache) => {
-        cache.put(event.request, response.clone());
-        return response;
-      });
-    }).catch((error) => {
-      return caches.open(CACHE_NAME).then((cache) => {
-        return cache.match(event.request).then((response) => {
-          if (response != null) {
-            return response;
-          }
-          throw error;
-        });
-      });
-    })
-  );
-}
-''';
-}