Add support for connecting a debug version of DevTools to the DevTools server.

Requires flutter/devtools#8621.

Bug: flutter/devtools#6486
Change-Id: I57b6a6d1551831d89cc7d007376291e8cffd920e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/366421
Reviewed-by: Ben Konyi <[email protected]>
Commit-Queue: Ben Konyi <[email protected]>
Reviewed-by: Elliott Brooks <[email protected]>

Author: kenzieschmoll

pkg/dds/.gitignore

@@ -3,3 +3,5 @@
 .packages
 build/
 pubspec.lock
+*.code-workspace
+logs/

pkg/dds/lib/devtools_server.dart

@@ -299,7 +299,7 @@ class DevToolsServer {
     );
 
     handler ??= await defaultHandler(
-      buildDir: customDevToolsPath!,
+      buildDir: customDevToolsPath,
       clientManager: clientManager,
       dtd: dtdInfo,
       devtoolsExtensionsManager: ExtensionsManager(),
@@ -336,6 +336,16 @@ class DevToolsServer {
       server.defaultResponseHeaders.add('origin-agent-cluster', '?1');
     }
 
+    // This is only true when the DevTools server is started through the
+    // tool/devtools_server/serve_local.dart script. This is required to allow
+    // connecting a debug instance of DevTools app to a running DevTools server.
+    if (Platform.script.toString().endsWith('serve_local.dart')) {
+      server.defaultResponseHeaders.add(
+        HttpHeaders.accessControlAllowOriginHeader,
+        '*',
+      );
+    }
+
     // Ensure browsers don't cache older versions of the app.
     server.defaultResponseHeaders.add(
       HttpHeaders.cacheControlHeader,

pkg/dds/lib/src/devtools/handler.dart

@@ -42,7 +42,7 @@ import 'utils.dart';
 /// client that is not the DevTools server (e.g. an IDE).
 FutureOr<Handler> defaultHandler({
   DartDevelopmentServiceImpl? dds,
-  required String buildDir,
+  String? buildDir,
   ClientManager? clientManager,
   Handler? notFoundHandler,
   DtdInfo? dtd,
@@ -55,15 +55,6 @@ FutureOr<Handler> defaultHandler({
     appRoot = '/${dds!.authCode}$appRoot';
   }
 
-  const defaultDocument = 'index.html';
-  final indexFile = File(path.join(buildDir, defaultDocument));
-
-  // Serves the static web assets for DevTools.
-  final devtoolsStaticAssetHandler = createStaticHandler(
-    buildDir,
-    defaultDocument: defaultDocument,
-  );
-
   /// A wrapper around [devtoolsStaticAssetHandler] that handles serving
   /// index.html up for / and non-file requests like /memory, /inspector, etc.
   /// with the correct base href for the DevTools root.
@@ -106,6 +97,12 @@ FutureOr<Handler> defaultHandler({
       }
     }
 
+    if (buildDir == null) {
+      return Response.notFound('No build directory was specified.');
+    }
+
+    const defaultDocument = 'index.html';
+    final indexFile = File(path.join(buildDir, defaultDocument));
     final isValidRootPage = pathSegments.isEmpty ||
         (pathSegments.length == 1 && !pathSegments[0].contains('.'));
 
@@ -118,6 +115,11 @@ FutureOr<Handler> defaultHandler({
       );
     }
 
+    // Serves the static web assets for DevTools.
+    final devtoolsStaticAssetHandler = createStaticHandler(
+      buildDir,
+      defaultDocument: defaultDocument,
+    );
     return devtoolsStaticAssetHandler(request);
   }
 

pkg/dds/tool/devtools_server/serve_local.dart

@@ -15,15 +15,16 @@ void main(List<String> args) {
       argDevToolsBuild,
       help: 'The location of the DevTools build to serve from DevTools server '
           '(e.g. --devtools-build=absolute/path/to/devtools/build).',
-      mandatory: true,
     );
 
   try {
     final ArgResults argResults = argParser.parse(args);
     unawaited(
       DevToolsServer().serveDevToolsWithArgs(
         _removeDevToolsBuildOption(args),
-        customDevToolsPath: argResults[argDevToolsBuild],
+        customDevToolsPath: argResults.wasParsed(argDevToolsBuild)
+            ? argResults[argDevToolsBuild]
+            : null,
       ),
     );
   } on FormatException catch (e) {