static Future start()

in dwds/lib/dwds.dart [97:200]
89 lines of code
6 McCabe index (conditional complexity)

  static Future<Dwds> start({
    @required AssetReader assetReader,
    @required Stream<BuildResult> buildResults,
    @required ConnectionProvider chromeConnection,
    @required LoadStrategy loadStrategy,
    @required bool enableDebugging,
    // TODO(annagrin): make expressionCompiler argument required
    // [issue 881](https://github.com/dart-lang/webdev/issues/881)
    ExpressionCompiler expressionCompiler,
    bool enableDebugExtension,
    String hostname,
    bool useSseForDebugProxy,
    bool useSseForDebugBackend,
    bool useSseForInjectedClient,
    UrlEncoder urlEncoder,
    bool spawnDds,
    // TODO(elliette): DevTools is inconsistently capitalized throughout this
    // file. Change all occurances of devtools/Devtools to devTools/DevTools.
    bool enableDevtoolsLaunch,
    DevtoolsLauncher devtoolsLauncher,
    bool launchDevToolsInNewWindow,
    Uri sdkDir,
    Uri librariesPath,
    bool emitDebugEvents,
  }) async {
    hostname ??= 'localhost';
    enableDebugging ??= true;
    enableDebugExtension ??= false;
    useSseForDebugProxy ??= true;
    useSseForDebugBackend ??= true;
    useSseForInjectedClient ??= true;
    enableDevtoolsLaunch ??= true;
    launchDevToolsInNewWindow ??= true;
    spawnDds ??= true;
    globalLoadStrategy = loadStrategy;
    emitDebugEvents ??= true;

    await DartUri.initialize(sdkDir: sdkDir, librariesPath: librariesPath);

    DevTools devTools;
    Future<String> extensionUri;
    ExtensionBackend extensionBackend;
    if (enableDebugExtension) {
      final handler = useSseForDebugBackend
          ? SseSocketHandler(SseHandler(Uri.parse('/\$debug'),
              // Proxy servers may actively kill long standing connections.
              // Allow for clients to reconnect in a short window. Making the
              // window too long may cause issues if the user closes a debug
              // session and initites a new one during the keepAlive window.
              keepAlive: const Duration(seconds: 5)))
          : WebSocketSocketHandler();

      extensionBackend = await ExtensionBackend.start(handler, hostname);
      extensionUri = Future.value(Uri(
              scheme: useSseForDebugBackend ? 'http' : 'ws',
              host: extensionBackend.hostname,
              port: extensionBackend.port,
              path: r'$debug')
          .toString());
      if (urlEncoder != null) extensionUri = urlEncoder(await extensionUri);
    }

    var serveDevTools = devtoolsLauncher != null;
    if (serveDevTools) {
      devTools = await devtoolsLauncher(hostname);
      var uri =
          Uri(scheme: 'http', host: devTools.hostname, port: devTools.port);
      _logger.info('Serving DevTools at $uri\n');
    }

    var injected = DwdsInjector(
      loadStrategy,
      useSseForInjectedClient: useSseForInjectedClient,
      extensionUri: extensionUri,
      enableDevtoolsLaunch: enableDevtoolsLaunch,
      emitDebugEvents: emitDebugEvents,
    );

    var devHandler = DevHandler(
      chromeConnection,
      buildResults,
      devTools,
      assetReader,
      loadStrategy,
      hostname,
      extensionBackend,
      urlEncoder,
      useSseForDebugProxy,
      useSseForInjectedClient,
      serveDevTools,
      expressionCompiler,
      injected,
      spawnDds,
      launchDevToolsInNewWindow,
    );

    return Dwds._(
      injected.middleware,
      devTools,
      devHandler,
      assetReader,
      enableDebugging,
    );
  }