wire up custom hotreload handling

Author: schultek

packages/jaspr/CHANGELOG.md

@@ -1,3 +1,7 @@
+## Unreleased breaking
+
+- Added hot-reload support.
+
 ## 0.23.1
 
 - Fixed expression compilation when debugging a client-side application with an AOT installed CLI.

packages/jaspr/lib/src/server/server_handler.dart

@@ -127,10 +127,11 @@ Handler createProxyHandler(http.Client? client) {
   final handler = proxyHandler('http://localhost:$jasprProxyPort/', client: c);
   return (req) async {
     try {
-      // Determine and pass the base path to the proxy handler so it can rewrite DWDS handler paths correctly.
-      return await handler(req.change(headers: {'jaspr_base_path': req.handlerPath}));
+      return await handler(req);
     } on http.ClientException {
       return Response(503, headers: {'Retry-After': '1'});
+    } on SocketException {
+      return Response(503, headers: {'Retry-After': '1'});
     }
   };
 }

packages/jaspr_builder/lib/src/options/client_options_builder.dart

@@ -120,6 +120,8 @@ class ClientOptionsBuilder implements Builder {
   }
 }
 
+bool _triedRunningFlutter = false;
+
 Future<List<Plugin>> loadWebPlugins(BuildStep buildStep) async {
   final pluginsDependenciesId = AssetId(buildStep.inputId.package, '.flutter-plugins-dependencies');
 
@@ -136,7 +138,8 @@ Future<List<Plugin>> loadWebPlugins(BuildStep buildStep) async {
 
   var content = await readPluginsDependencies();
 
-  if (content == null) {
+  if (content == null && !_triedRunningFlutter) {
+    _triedRunningFlutter = true;
     try {
       final result = await Process.run('flutter', ['packages', 'get']);
       if (result.exitCode != 0) {

packages/jaspr_cli/lib/src/commands/dev_command.dart

@@ -287,11 +287,6 @@ abstract class DevCommand extends BaseCommand with ProxyHelper, FlutterHelper {
 
     logger.write('Starting web compiler...', tag: Tag.cli, progress: ProgressState.running);
 
-    final webHotReload = argResults!.flag('web-hot-reload');
-    final moduleFormat = webHotReload ? 'ddc' : (argResults!.option('module-format') ?? 'ddc');
-
-    logger.write('Starting web compilers...', tag: Tag.cli, progress: ProgressState.running);
-
     final compiler = useWasm
         ? 'dart2wasm'
         : release
@@ -325,7 +320,8 @@ abstract class DevCommand extends BaseCommand with ProxyHelper, FlutterHelper {
       'refresh' => ReloadConfiguration.liveReload,
       'restart' || _ => ReloadConfiguration.hotRestart,
     };
-    final moduleFormat = this.moduleFormat ?? (reloadConfig == ReloadConfiguration.hotReload ? 'ddc' : 'amd');
+
+    final moduleFormat = reloadConfig == ReloadConfiguration.hotReload ? 'ddc' : this.moduleFormat ?? 'ddc';
     final usesDdcLibraryBundles = moduleFormat == 'ddc';
 
     List<String> additionalFlutterBuildArgs() {

packages/jaspr_cli/lib/src/dev/dev_proxy.dart

@@ -20,6 +20,7 @@ class DevProxy {
   final http.Client client;
   final Handler handler;
   final Stream<BuildResult> buildResults;
+  final ReloadConfiguration reload;
 
   final Dwds dwds;
   final ExpressionCompilerService? ddcService;
@@ -28,14 +29,16 @@ class DevProxy {
   final _clientEvents = StreamController<Map<String, dynamic>>();
   Stream<Map<String, dynamic>> get clientEvents => _clientEvents.stream;
 
-  DevProxy._(
-    this.client,
-    this.handler,
-    this.buildResults, {
+  DevProxy._({
+    required this.client,
+    required this.handler,
+    required this.buildResults,
+    required this.reload,
     required this.dwds,
     this.ddcService,
   }) {
     _listenToClientConnections();
+    _listenToBuildResults();
   }
 
   Future<void> _listenToClientConnections() async {
@@ -51,6 +54,18 @@ class DevProxy {
     }
   }
 
+  void _listenToBuildResults() async {
+    if (reload == ReloadConfiguration.hotReload) {
+      await for (final buildResult in buildResults) {
+        if (buildResult.status == BuildStatus.succeeded) {
+          for (final clientConnection in _clientConnections.values) {
+            await clientConnection.performHotReload();
+          }
+        }
+      }
+    }
+  }
+
   ClientConnection? getClientConnection(String? appId) {
     if (appId == null) return null;
     return _clientConnections[appId];
@@ -120,16 +135,19 @@ class DevProxy {
 
     final reloadedSourcesUri = Uri.parse('/reloaded_sources.json');
 
+    // We handle hot-reload ourselves, so we don't need the DDC service to do it.
+    final reloadStrategy = reload == ReloadConfiguration.hotReload ? ReloadConfiguration.none : reload;
+
     final loadStrategy = moduleFormat == 'ddc'
         ? BuildRunnerDdcLibraryBundleStrategyProvider(
-            reload,
+            reloadStrategy,
             assetReader,
             buildSettings,
             packageConfigPath: findPackageConfigFilePath(),
             reloadedSourcesUri: reloadedSourcesUri,
           ).strategy
         : BuildRunnerRequireStrategyProvider(
-            reload,
+            reloadStrategy,
             assetReader,
             buildSettings,
             packageConfigPath: findPackageConfigFilePath(),
@@ -174,7 +192,6 @@ class DevProxy {
 
     if (moduleFormat == 'ddc') {
       cascade = cascade.add((Request req) {
-        print("middleware reloaded sources: ${req.url.path}");
         if (req.url.path == 'reloaded_sources.json') {
           return Response.ok(jsonEncode(reloadedSources), headers: {'content-type': 'application/json'});
         }
@@ -188,9 +205,10 @@ class DevProxy {
     cascade = cascade.add(assetHandler);
 
     return DevProxy._(
-      client,
-      pipeline.addHandler(cascade.handler),
-      filteredBuildResults,
+      client: client,
+      handler: pipeline.addHandler(cascade.handler),
+      buildResults: filteredBuildResults,
+      reload: reload,
       dwds: dwds,
       ddcService: ddcService,
     );
@@ -287,6 +305,7 @@ class ClientConnection {
 
   void start() async {
     final appId = appConnection.request.appId;
+
     try {
       final debugConnection = _debugConnection = await dwds.debugConnection(appConnection);
       final debugUri = debugConnection.ddsUri ?? debugConnection.uri;
@@ -343,15 +362,13 @@ class ClientConnection {
   }
 
   void sendEvent(String method, Map<String, dynamic> params) {
-    print('event: $method $params');
     devProxy._clientEvents.add({'method': method, 'params': params});
   }
 
   // Mapping from service name to service method.
   final Map<String, String> _registeredMethodsForService = <String, String>{};
 
   void _onServiceEvent(vm.Event e) {
-    print('service event: ${e.kind} ${e.service} ${e.method}');
     if (e.kind == vm.EventKind.kServiceRegistered) {
       final serviceName = e.service!;
       _registeredMethodsForService[serviceName] = e.method!;
@@ -369,6 +386,20 @@ class ClientConnection {
     return response;
   }
 
+  Future<void> performHotReload() async {
+    final isolateId = (await vmService?.getVM())?.isolates?.first.id;
+    vm.ReloadReport? response;
+    for (var i = 0; i < 5; i++) {
+      response = await vmService?.reloadSources(isolateId!);
+      if (response?.success ?? false) {
+        break;
+      }
+    }
+    if (response?.success ?? false) {
+      await reassemble();
+    }
+  }
+
   Future<vm.Response?> reassemble() async {
     final reassembleMethod = _registeredMethodsForService['ext.jaspr.reassemble'] ?? 'ext.jaspr.reassemble';
     try {

packages/jaspr_cli/pubspec.yaml

@@ -53,4 +53,4 @@ dependencies:
 
 dev_dependencies:
   mocktail: ^1.0.4
-  test: ^1.22.0
+  test: ^1.22.0

pubspec.lock

@@ -194,13 +194,14 @@ packages:
     source: hosted
     version: "3.5.10"
   build_web_compilers:
-    dependency: transitive
+    dependency: "direct overridden"
     description:
-      name: build_web_compilers
-      sha256: f7020628ddf67db7619025ff64b1d3e890419410c4356a28757907db6e61a1f8
-      url: "https://pub.dev"
-    source: hosted
-    version: "4.4.15"
+      path: "builder_pkgs/build_web_compilers"
+      ref: HEAD
+      resolved-ref: f4cabecdb834819022dd845c600978b8e4ecdc38
+      url: "https://github.com/dart-lang/build"
+    source: git
+    version: "4.4.20-wip"
   built_collection:
     dependency: transitive
     description:

pubspec.yaml

@@ -33,7 +33,13 @@ dev_dependencies:
   melos: ^7.1.0
 
 dependency_overrides:
-  cli_util: 0.5.0 # Until melos upgrades to this version
+  # Until melos upgrades to this version
+  cli_util: 0.5.0 
+  # Until 4.4.20 is released
+  build_web_compilers:
+    git:
+      url: https://github.com/dart-lang/build
+      path: builder_pkgs/build_web_compilers
 
 melos:
   command: