Add a server endpoint for serving devtools extensions

packages/devtools_app/lib/src/app.dart

@@ -4,12 +4,12 @@
 
 import 'dart:async';
 
+import 'package:devtools_shared/devtools_extensions.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
 import 'example/conditional_screen.dart';
-import 'extensions/extension_model.dart';
 import 'extensions/extension_screen.dart';
 import 'framework/framework_core.dart';
 import 'framework/home_screen.dart';

packages/devtools_app/lib/src/extensions/embedded/controller.dart

@@ -3,9 +3,9 @@
 // found in the LICENSE file.
 
 import 'package:devtools_extensions/api.dart';
+import 'package:devtools_shared/devtools_extensions.dart';
 
 import '../../shared/primitives/auto_dispose.dart';
-import '../extension_model.dart';
 import '_controller_desktop.dart' if (dart.library.html) '_controller_web.dart';
 
 EmbeddedExtensionControllerImpl createEmbeddedExtensionController(

packages/devtools_app/lib/src/extensions/extension_screen.dart

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:devtools_shared/devtools_extensions.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 
@@ -13,7 +14,6 @@ import '../shared/screen.dart';
 import '../shared/theme.dart';
 import 'embedded/controller.dart';
 import 'embedded/view.dart';
-import 'extension_model.dart';
 
 class ExtensionScreen extends Screen {
   ExtensionScreen(this.extensionConfig)
@@ -155,3 +155,10 @@ class EmbeddedExtensionHeader extends StatelessWidget {
     );
   }
 }
+
+extension ExtensionConfigExtension on DevToolsExtensionConfig {
+  IconData get icon => IconData(
+        materialIconCodePoint,
+        fontFamily: 'MaterialIcons',
+      );
+}

packages/devtools_app/lib/src/extensions/extension_service.dart

@@ -2,11 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:devtools_shared/devtools_extensions.dart';
 import 'package:flutter/foundation.dart';
 
 import '../shared/globals.dart';
 import '../shared/primitives/auto_dispose.dart';
-import 'extension_model.dart';
 
 class ExtensionService extends DisposableController
     with AutoDisposeControllerMixin {
@@ -28,3 +28,28 @@ class ExtensionService extends DisposableController
         debugExtensions.sublist(0, _count++ % (debugExtensions.length + 1));
   }
 }
+
+// TODO(kenz): remove these once the DevTools extensions feature has shipped.
+final List<DevToolsExtensionConfig> debugExtensions = [
+  DevToolsExtensionConfig.parse({
+    DevToolsExtensionConfig.nameKey: 'foo',
+    DevToolsExtensionConfig.issueTrackerKey: 'www.google.com',
+    DevToolsExtensionConfig.versionKey: '1.0.0',
+    DevToolsExtensionConfig.pathKey: '/path/to/foo',
+  }),
+  DevToolsExtensionConfig.parse({
+    DevToolsExtensionConfig.nameKey: 'bar',
+    DevToolsExtensionConfig.issueTrackerKey: 'www.google.com',
+    DevToolsExtensionConfig.versionKey: '2.0.0',
+    DevToolsExtensionConfig.materialIconCodePointKey: 0xe638,
+    DevToolsExtensionConfig.pathKey: '/path/to/bar',
+  }),
+  DevToolsExtensionConfig.parse({
+    DevToolsExtensionConfig.nameKey: 'provider',
+    DevToolsExtensionConfig.issueTrackerKey:
+        'https://github.com/rrousselGit/provider/issues',
+    DevToolsExtensionConfig.versionKey: '3.0.0',
+    DevToolsExtensionConfig.materialIconCodePointKey: 0xe50a,
+    DevToolsExtensionConfig.pathKey: '/path/to/provider',
+  }),
+];

packages/devtools_app/lib/src/shared/config_specific/server/_server_stub.dart

@@ -6,6 +6,8 @@
 // ignore_for_file: avoid-unused-parameters
 import 'dart:async';
 
+import 'package:devtools_shared/devtools_extensions.dart';
+
 import '../../primitives/utils.dart';
 
 const unsupportedMessage =
@@ -75,6 +77,12 @@ Future<DevToolsJsonFile?> requestTestAppSizeFile(String path) async {
   throw Exception(unsupportedMessage);
 }
 
+Future<List<DevToolsExtensionConfig>> refreshAvailableExtensions(
+  String? rootPath,
+) async {
+  return [];
+}
+
 void logWarning() {
   throw Exception(unsupportedMessage);
 }

packages/devtools_app/lib/src/shared/config_specific/server/_server_web.dart

@@ -8,6 +8,7 @@ import 'dart:convert';
 // ignore: avoid_web_libraries_in_flutter, as designed
 import 'dart:html';
 
+import 'package:devtools_shared/devtools_extensions.dart';
 import 'package:devtools_shared/devtools_shared.dart';
 import 'package:logging/logging.dart';
 
@@ -337,6 +338,31 @@ DevToolsJsonFile _devToolsJsonFileFromResponse(
   );
 }
 
+Future<List<DevToolsExtensionConfig>> refreshAvailableExtensions(
+  String? rootPath,
+) async {
+  if (isDevToolsServerAvailable) {
+    final uri = Uri(
+      path: apiServeAvailableExtensions,
+      queryParameters: {extensionRootPathPropertyName: rootPath},
+    );
+    final resp = await request(uri.toString());
+    if (resp?.status == HttpStatus.ok) {
+      final parsedResult = json.decode(resp!.responseText!);
+      final extensionsAsJson =
+          (parsedResult[extensionsResultPropertyName]! as List<Object?>)
+              .cast<Map<String, Object?>>();
+      return extensionsAsJson
+          .map((p) => DevToolsExtensionConfig.parse(p))
+          .toList();
+    } else {
+      logWarning(resp, apiServeAvailableExtensions);
+      return [];
+    }
+  }
+  return [];
+}
+
 void logWarning(HttpRequest? response, String apiType, [String? respText]) {
   _log.warning(
     'HttpRequest $apiType failed status = ${response?.status}'

packages/devtools_app/test/extensions/extension_screen_test.dart

@@ -4,8 +4,8 @@
 
 import 'package:devtools_app/devtools_app.dart';
 import 'package:devtools_app/src/extensions/embedded/view.dart';
-import 'package:devtools_app/src/extensions/extension_model.dart';
 import 'package:devtools_app/src/extensions/extension_screen.dart';
+import 'package:devtools_shared/src/extensions/extension_model.dart';
 import 'package:devtools_test/devtools_test.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';

packages/devtools_shared/lib/devtools_extensions.dart

@@ -0,0 +1,6 @@
+// Copyright 2023 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+export 'src/extensions/extension_manager.dart';
+export 'src/extensions/extension_model.dart';

packages/devtools_shared/lib/src/devtools_api.dart

@@ -64,3 +64,12 @@ const String apiGetTestAppSizeFile = '${apiPrefix}getTestAppSizeFile';
 const String baseAppSizeFilePropertyName = 'appSizeBase';
 
 const String testAppSizeFilePropertyName = 'appSizeTest';
+
+/// Serves any available extensions and returns a list of their configurations
+/// to DevTools.
+const String apiServeAvailableExtensions =
+    '${apiPrefix}serveAvailableExtensions';
+
+const extensionRootPathPropertyName = 'rootPath';
+
+const extensionsResultPropertyName = 'extensions';

packages/devtools_shared/lib/src/extensions/extension_manager.dart

@@ -0,0 +1,129 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:io';
+
+import 'package:io/io.dart';
+import 'package:path/path.dart' as path;
+
+import 'extension_model.dart';
+
+/// Location where DevTools extension assets will be served, relative to where
+/// DevTools assets are served (build/).
+const extensionRequestPath = 'devtools_extensions';
+
+/// The location for the DevTools extension, relative to the parent package's
+/// root.
+const extensionLocation = 'extension/devtools';
+
+/// The default location for the DevTools extension, relative to
+/// `<parent_package_root>/extension/devtools/`.
+const extensionBuildDefault = 'build';
+
+class ExtensionsManager {
+  ExtensionsManager({required this.buildDir});
+
+  final String buildDir;
+
+  String get servedExtensionsPath => path.join(buildDir, extensionRequestPath);
+
+  final devtoolsExtensions = <DevToolsExtensionConfig>[];
+
+  void serveAvailableExtensions(String? rootPath) {
+    devtoolsExtensions.clear();
+
+    if (rootPath != null) {
+      // TODO(kenz): use 'findExtensions' from package:extension_discovery once it
+      // is published.
+      // final extensions = findExtensions(
+      //   'devtools',
+      //   packageConfig: '$rootPath/.dart_tool/package_config.json',
+      // );
+      final extensions = <Extension>[];
+      for (final extension in extensions) {
+        final config = extension.config;
+        if (config is! Map) {
+          // Fail gracefully. Invalid content in the extension's config.json.
+          continue;
+        }
+        final configAsMap = config as Map<String, Object?>;
+
+        // This should be relative to the 'extension/devtools/' directory and
+        // defaults to 'build';
+        final relativeExtensionLocation =
+            configAsMap['buildLocation'] as String? ?? 'build';
+
+        // TODO(kenz): this is hacky. Unclear if this will work for windows.
+        var rootWithoutFile = extension.rootUri.toString();
+        if (rootWithoutFile.startsWith('file:///Users')) {
+          rootWithoutFile = rootWithoutFile.replaceFirst('file:///', '/');
+        }
+
+        final location = path.join(
+          rootWithoutFile,
+          extensionLocation,
+          relativeExtensionLocation,
+        );
+
+        try {
+          final pluginConfig = DevToolsExtensionConfig.parse({
+            ...configAsMap,
+            DevToolsExtensionConfig.pathKey: location,
+          });
+          devtoolsExtensions.add(pluginConfig);
+        } on StateError catch (e) {
+          print(e.message);
+          continue;
+        }
+      }
+    }
+
+    _resetServedPluginsDir();
+    for (final extension in devtoolsExtensions) {
+      _moveToServedExtensionsDir(extension.name, extension.path);
+    }
+  }
+
+  void _resetServedPluginsDir() {
+    final buildDirectory = Directory(buildDir);
+    if (!buildDirectory.existsSync()) {
+      throw Exception('The build directory does not exist.');
+    }
+
+    // Destroy and recreate the 'devtools_extensions' directory where extension
+    // assets are served.
+    final servedExtensionsDir = Directory(servedExtensionsPath);
+    if (servedExtensionsDir.existsSync()) {
+      servedExtensionsDir.deleteSync(recursive: true);
+    }
+    servedExtensionsDir.createSync();
+  }
+
+  void _moveToServedExtensionsDir(
+    String extensionPackageName,
+    String extensionPath,
+  ) {
+    final newExtensionPath =
+        path.join(servedExtensionsPath, extensionPackageName);
+    copyPathSync(extensionPath, newExtensionPath);
+  }
+}
+
+/// TODO(kenz): remove this class. This is copied from
+/// package:extension_discovery, which is drafed here: 
+/// https://github.com/dart-lang/tools/pull/129. Remove this temporary copy once
+/// package:extension_discovery is published.
+class _Extension {
+  _Extension._({
+    required this.package,
+    required this.rootUri,
+    required this.packageUri,
+    required this.config,
+  });
+
+  final String package;
+  final Uri rootUri;
+  final Uri packageUri;
+  final Object? config;
+}