pkg/dds/lib/devtools_server.dart - sdk.git - Git at Google

 // Copyright (c) 2022, 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:async';
 import 'dart:io';

 import 'package:args/args.dart';
 import 'package:browser_launcher/browser_launcher.dart';
 import 'package:devtools_shared/devtools_shared.dart';
 import 'package:http_multi_server/http_multi_server.dart';
 import 'package:path/path.dart' as path;
 import 'package:shelf/shelf.dart' as shelf;
 import 'package:shelf/shelf_io.dart' as shelf;

 import 'src/devtools/client.dart';
 import 'src/devtools/handler.dart';
 import 'src/devtools/machine_mode_command_handler.dart';
 import 'src/devtools/memory_profile.dart';
 import 'src/devtools/utils.dart';
 import 'src/utils/console.dart';

 class DevToolsServer {
   static const protocolVersion = '1.1.0';
   static const defaultTryPorts = 10;
   static const commandDescription =
       'Open DevTools (optionally connecting to an existing application).';

   static const argHelp = 'help';
   static const argVmUri = 'vm-uri';
   static const argEnableNotifications = 'enable-notifications';
   static const argAllowEmbedding = 'allow-embedding';
   static const argAppSizeBase = 'appSizeBase';
   static const argAppSizeTest = 'appSizeTest';
   static const argHeadlessMode = 'headless';
   static const argDebugMode = 'debug';
   static const argLaunchBrowser = 'launch-browser';
   static const argMachine = 'machine';
   static const argHost = 'host';
   static const argPort = 'port';
   static const argProfileMemory = 'record-memory-profile';
   static const argTryPorts = 'try-ports';
   static const argVerbose = 'verbose';
   static const argVersion = 'version';
   static const launchDevToolsService = 'launchDevTools';

   MachineModeCommandHandler? _machineModeCommandHandler;
   late ClientManager clientManager;
   final bool _isChromeOS = File('/dev/.cros_milestone').existsSync();

   /// Builds an arg parser for the DevTools server.
   ///
   /// [includeHelpOption] should be set to false if this arg parser will be used
   /// in a Command subclass.
   static ArgParser buildArgParser({
     bool verbose = false,
     bool includeHelpOption = true,
   }) {
     final argParser = ArgParser();

     if (includeHelpOption) {
       argParser.addFlag(
         argHelp,
         negatable: false,
         abbr: 'h',
         help: 'Prints help output.',
       );
     }
     argParser
       ..addFlag(
         argVersion,
         negatable: false,
         help: 'Prints the DevTools version.',
       )
       ..addFlag(
         argVerbose,
         negatable: false,
         abbr: 'v',
         help: 'Output more informational messages.',
       )
       ..addOption(
         argHost,
         valueHelp: 'host',
         help: 'Hostname to serve DevTools on (defaults to localhost).',
       )
       ..addOption(
         argPort,
         defaultsTo: '9100',
         valueHelp: 'port',
         help: 'Port to serve DevTools on; specify 0 to automatically use any '
             'available port.',
       )
       ..addFlag(
         argLaunchBrowser,
         help:
             'Launches DevTools in a browser immediately at start.\n(defaults to on unless in --machine mode)',
       )
       ..addFlag(
         argMachine,
         negatable: false,
         help: 'Sets output format to JSON for consumption in tools.',
       )
       ..addSeparator('Memory profiling options:')
       ..addOption(
         argProfileMemory,
         valueHelp: 'file',
         defaultsTo: 'memory_samples.json',
         help:
             'Start devtools headlessly and write memory profiling samples to the '
             'indicated file.',
       );

     if (verbose) {
       argParser.addSeparator('App size options:');
     }

     // TODO(devoncarew): --appSizeBase and --appSizeTest should be renamed to
     // something like --app-size-base and --app-size-test; #3146.
     argParser
       ..addOption(
         argAppSizeBase,
         valueHelp: 'appSizeBase',
         help: 'Path to the base app size file used for app size debugging.',
         hide: !verbose,
       )
       ..addOption(
         argAppSizeTest,
         valueHelp: 'appSizeTest',
         help:
             'Path to the test app size file used for app size debugging.\nThis '
             'file should only be specified if --$argAppSizeBase is also specified.',
         hide: !verbose,
       );

     if (verbose) {
       argParser.addSeparator('Advanced options:');
     }

     // Args to show for verbose mode.
     argParser
       ..addOption(
         argTryPorts,
         defaultsTo: DevToolsServer.defaultTryPorts.toString(),
         valueHelp: 'count',
         help: 'The number of ascending ports to try binding to before failing '
             'with an error. ',
         hide: !verbose,
       )
       ..addFlag(
         argEnableNotifications,
         negatable: false,
         help: 'Requests notification permissions immediately when a client '
             'connects back to the server.',
         hide: !verbose,
       )
       ..addFlag(
         argAllowEmbedding,
         help: 'Allow embedding DevTools inside an iframe.',
         hide: !verbose,
       )
       ..addFlag(
         argHeadlessMode,
         negatable: false,
         help: 'Causes the server to spawn Chrome in headless mode for use in '
             'automated testing.',
         hide: !verbose,
       );

     // Deprecated and hidden args.
     // TODO: Remove this - prefer that clients use the rest arg.
     argParser
       ..addOption(
         argVmUri,
         defaultsTo: '',
         help: 'VM Service protocol URI.',
         hide: true,
       )

       // Development only args.
       ..addFlag(
         argDebugMode,
         negatable: false,
         help: 'Run a debug build of the DevTools web frontend.',
         hide: true,
       );

     return argParser;
   }

   /// Serves DevTools.
   ///
   /// `handler` is the [shelf.Handler] that the server will use for all requests.
   /// If null, [defaultHandler] will be used. Defaults to null.
   ///
   /// `customDevToolsPath` is a path to a directory containing a pre-built
   /// DevTools application.
   ///
   // Note: this method is used by the Dart CLI and by package:dwds.
   Future<HttpServer?> serveDevTools({
     bool enableStdinCommands = true,
     bool machineMode = false,
     bool debugMode = false,
     bool launchBrowser = false,
     bool enableNotifications = false,
     bool allowEmbedding = true,
     bool headlessMode = false,
     bool verboseMode = false,
     String? hostname,
     String? customDevToolsPath,
     int port = 0,
     int numPortsToTry = defaultTryPorts,
     shelf.Handler? handler,
     String? serviceProtocolUri,
     String? profileFilename,
     String? appSizeBase,
     String? appSizeTest,
   }) async {
     hostname ??= 'localhost';

     // Collect profiling information.
     if (profileFilename != null && serviceProtocolUri != null) {
       final Uri? vmServiceUri = Uri.tryParse(serviceProtocolUri);
       if (vmServiceUri != null) {
         await _hookupMemoryProfiling(
           vmServiceUri,
           profileFilename,
           verboseMode,
         );
       }
       return null;
     }

     if (machineMode) {
       assert(
         enableStdinCommands,
         'machineMode only works with enableStdinCommands.',
       );
     }

     clientManager = ClientManager(
       requestNotificationPermissions: enableNotifications,
     );
     handler ??= await defaultHandler(
       buildDir: customDevToolsPath!,
       clientManager: clientManager,
     );

     HttpServer? server;
     SocketException? ex;
     while (server == null && numPortsToTry >= 0) {
       // If we have tried [numPortsToTry] ports and still have not been able to
       // connect, try port 0 to find a random available port.
       if (numPortsToTry == 0) port = 0;

       try {
         server = await HttpMultiServer.bind(hostname, port);
       } on SocketException catch (e) {
         ex = e;
         numPortsToTry--;
         port++;
       }
     }

     // Re-throw the last exception if we failed to bind.
     if (server == null && ex != null) {
       throw ex;
     }

     final _server = server!;
     if (allowEmbedding) {
       _server.defaultResponseHeaders.remove('x-frame-options', 'SAMEORIGIN');
       // The origin-agent-cluster header is required to support the embedding of
       // Dart DevTools in Chrome DevTools.
       _server.defaultResponseHeaders.add('origin-agent-cluster', '?1');
     }

     // Ensure browsers don't cache older versions of the app.
     _server.defaultResponseHeaders.add(
       HttpHeaders.cacheControlHeader,
       'max-age=0',
     );

     // Serve requests in an error zone to prevent failures
     // when running from another error zone.
     runZonedGuarded(
       () => shelf.serveRequests(_server, handler!),
       (e, _) => print('Error serving requests: $e'),
     );

     final devToolsUrl = 'http://${_server.address.host}:${_server.port}';

     if (launchBrowser) {
       if (serviceProtocolUri != null) {
         serviceProtocolUri =
             normalizeVmServiceUri(serviceProtocolUri).toString();
       }

       final queryParameters = {
         if (serviceProtocolUri != null) 'uri': serviceProtocolUri,
         if (appSizeBase != null) 'appSizeBase': appSizeBase,
         if (appSizeTest != null) 'appSizeTest': appSizeTest,
       };
       String url = Uri.parse(devToolsUrl)
           .replace(queryParameters: queryParameters)
           .toString();

       // If app size parameters are present, open to the standalone `appsize`
       // page, regardless if there is a vm service uri specified. We only check
       // for the presence of [appSizeBase] here because [appSizeTest] may or may
       // not be specified (it should only be present for diffs). If [appSizeTest]
       // is present without [appSizeBase], we will ignore the parameter.
       if (appSizeBase != null) {
         final startQueryParamIndex = url.indexOf('?');
         if (startQueryParamIndex != -1) {
           url = '${url.substring(0, startQueryParamIndex)}'
               '/#/appsize'
               '${url.substring(startQueryParamIndex)}';
         }
       }

       try {
         await Chrome.start([url]);
       } catch (e) {
         print('Unable to launch Chrome: $e\n');
       }
     }

     if (enableStdinCommands) {
       String message = '''Serving DevTools at $devToolsUrl.

           Hit ctrl-c to terminate the server.''';
       if (!machineMode && debugMode) {
         // Add bold to help find the correct url to open.
         message = ConsoleUtils.bold('$message\n');
       }

       DevToolsUtils.printOutput(
         message,
         {
           'event': 'server.started',
           // TODO(dantup): Remove this `method` field when we're sure VS Code
           // users are all on a newer version that uses `event`. We incorrectly
           // used `method` for the original releases.
           'method': 'server.started',
           'params': {
             'host': _server.address.host,
             'port': _server.port,
             'pid': pid,
             'protocolVersion': protocolVersion,
           }
         },
         machineMode: machineMode,
       );

       if (machineMode) {
         _machineModeCommandHandler = MachineModeCommandHandler(server: this);
         await _machineModeCommandHandler!.initialize(
           devToolsUrl: devToolsUrl,
           headlessMode: headlessMode,
         );
       }
     }

     return server;
   }

   void _printUsage(ArgParser argParser) {
     print(commandDescription);
     print('\nUsage: devtools [arguments] [service protocol uri]');
     print(argParser.usage);
   }

   /// Wraps [serveDevTools] `arguments` parsed, as from the command line.
   ///
   /// For more information on `handler`, see [serveDevTools].
   // Note: this method is used in google3 as well as by DevTools' main method.
   Future<HttpServer?> serveDevToolsWithArgs(
     List<String> arguments, {
     shelf.Handler? handler,
     String? customDevToolsPath,
   }) async {
     ArgResults args;
     final verbose = arguments.contains('-v') || arguments.contains('--verbose');
     final argParser = buildArgParser(verbose: verbose);
     try {
       args = argParser.parse(arguments);
     } on FormatException catch (e) {
       print(e.message);
       print('');
       _printUsage(argParser);
       return null;
     }

     return await _serveDevToolsWithArgs(
       args,
       verbose,
       handler: handler,
       customDevToolsPath: customDevToolsPath,
     );
   }

   Future<HttpServer?> _serveDevToolsWithArgs(
     ArgResults args,
     bool verbose, {
     shelf.Handler? handler,
     String? customDevToolsPath,
   }) async {
     final help = args[argHelp];
     final bool version = args[argVersion];
     final bool machineMode = args[argMachine];
     // launchBrowser defaults based on machine-mode if not explicitly supplied.
     final bool launchBrowser = args.wasParsed(argLaunchBrowser)
         ? args[argLaunchBrowser]
         : !machineMode;
     final bool enableNotifications = args[argEnableNotifications];
     final bool allowEmbedding =
         args.wasParsed(argAllowEmbedding) ? args[argAllowEmbedding] : true;

     final port = args[argPort] != null ? int.tryParse(args[argPort]) ?? 0 : 0;

     final bool headlessMode = args[argHeadlessMode];
     final bool debugMode = args[argDebugMode];

     final numPortsToTry = args[argTryPorts] != null
         ? int.tryParse(args[argTryPorts]) ?? 0
         : defaultTryPorts;

     final bool verboseMode = args[argVerbose];
     final String? hostname = args[argHost];
     final String? appSizeBase = args[argAppSizeBase];
     final String? appSizeTest = args[argAppSizeTest];

     if (help) {
       print(
           'Dart DevTools version ${await DevToolsUtils.getVersion(customDevToolsPath ?? "")}');
       print('');
       _printUsage(buildArgParser(verbose: verbose));
       return null;
     }

     if (version) {
       final versionStr =
           await DevToolsUtils.getVersion(customDevToolsPath ?? '');
       DevToolsUtils.printOutput(
         'Dart DevTools version $versionStr',
         {
           'version': versionStr,
         },
         machineMode: machineMode,
       );
       return null;
     }

     // Prefer getting the VM URI from the rest args; fall back on the 'vm-url'
     // option otherwise.
     String? serviceProtocolUri;
     if (args.rest.isNotEmpty) {
       serviceProtocolUri = args.rest.first;
     } else if (args.wasParsed(argVmUri)) {
       serviceProtocolUri = args[argVmUri];
     }

     // Support collecting profile data.
     String? profileFilename;
     if (args.wasParsed(argProfileMemory)) {
       profileFilename = args[argProfileMemory];
     }
     if (profileFilename != null && !path.isAbsolute(profileFilename)) {
       profileFilename = path.absolute(profileFilename);
     }

     return serveDevTools(
       machineMode: machineMode,
       debugMode: debugMode,
       launchBrowser: launchBrowser,
       enableNotifications: enableNotifications,
       allowEmbedding: allowEmbedding,
       port: port,
       headlessMode: headlessMode,
       numPortsToTry: numPortsToTry,
       handler: handler,
       customDevToolsPath: customDevToolsPath,
       serviceProtocolUri: serviceProtocolUri,
       profileFilename: profileFilename,
       verboseMode: verboseMode,
       hostname: hostname,
       appSizeBase: appSizeBase,
       appSizeTest: appSizeTest,
     );
   }

   Future<Map<String, dynamic>> launchDevTools(
     Map<String, dynamic> params,
     Uri vmServiceUri,
     String devToolsUrl,
     bool headlessMode,
     bool machineMode,
   ) async {
     // First see if we have an existing DevTools client open that we can
     // reuse.
     final canReuse =
         params.containsKey('reuseWindows') && params['reuseWindows'] == true;
     final shouldNotify =
         params.containsKey('notify') && params['notify'] == true;
     final page = params['page'];
     if (canReuse &&
         _tryReuseExistingDevToolsInstance(
           vmServiceUri,
           page,
           shouldNotify,
         )) {
       _emitLaunchEvent(
         reused: true,
         notified: shouldNotify,
         pid: null,
         machineMode: machineMode,
       );
       return {
         'reused': true,
         'notified': shouldNotify,
       };
     }

     final uriParams = <String, dynamic>{};

     // Copy over queryParams passed by the client
     params['queryParams']?.forEach((key, value) => uriParams[key] = value);

     // Add the URI to the VM service
     uriParams['uri'] = vmServiceUri.toString();

     final devToolsUri = Uri.parse(devToolsUrl);
     final uriToLaunch = _buildUriToLaunch(uriParams, page, devToolsUri);

     // TODO(dantup): When ChromeOS has support for tunneling all ports we can
     // change this to always use the native browser for ChromeOS and may wish to
     // handle this inside `browser_launcher`; https://crbug.com/848063.
     final useNativeBrowser = _isChromeOS &&
         _isAccessibleToChromeOSNativeBrowser(devToolsUri) &&
         _isAccessibleToChromeOSNativeBrowser(vmServiceUri);
     int? browserPid;
     if (useNativeBrowser) {
       await Process.start('x-www-browser', [uriToLaunch.toString()]);
     } else {
       final args = headlessMode
           ? [
               '--headless',
               // When running headless, Chrome will quit immediately after loading
               // the page unless we have the debug port open.
               '--remote-debugging-port=9223',
               '--disable-gpu',
               '--no-sandbox',
             ]
           : <String>[];
       final proc = await Chrome.start([uriToLaunch.toString()], args: args);
       browserPid = proc.pid;
     }
     _emitLaunchEvent(
         reused: false,
         notified: false,
         pid: browserPid!,
         machineMode: machineMode);
     return {
       'reused': false,
       'notified': false,
       'pid': browserPid,
     };
   }

   Future<void> _hookupMemoryProfiling(
     Uri observatoryUri,
     String profileFile, [
     bool verboseMode = false,
   ]) async {
     final service = await DevToolsUtils.connectToVmService(observatoryUri);
     if (service == null) {
       return;
     }

     final memoryProfiler = MemoryProfile(service, profileFile, verboseMode);
     memoryProfiler.startPolling();

     print('Writing memory profile samples to $profileFile...');
   }

   bool _tryReuseExistingDevToolsInstance(
     Uri vmServiceUri,
     String? page,
     bool notifyUser,
   ) {
     // First try to find a client that's already connected to this VM service,
     // and just send the user a notification for that one.
     final existingClient =
         clientManager.findExistingConnectedReusableClient(vmServiceUri);
     if (existingClient != null) {
       try {
         if (page != null) {
           existingClient.showPage(page);
         }
         if (notifyUser) {
           existingClient.notify();
         }
         return true;
       } catch (e) {
         print('Failed to reuse existing connected DevTools client');
         print(e);
       }
     }

     final reusableClient = clientManager.findReusableClient();
     if (reusableClient != null) {
       try {
         reusableClient.connectToVmService(vmServiceUri, notifyUser);
         return true;
       } catch (e) {
         print('Failed to reuse existing DevTools client');
         print(e);
       }
     }
     return false;
   }

   String _buildUriToLaunch(
     Map<String, dynamic> uriParams,
     String? page,
     Uri devToolsUri,
   ) {
     final queryStringNameValues = [];
     uriParams.forEach((key, value) => queryStringNameValues.add(
         '${Uri.encodeQueryComponent(key)}=${Uri.encodeQueryComponent(value)}'));

     if (page != null) {
       queryStringNameValues.add('page=${Uri.encodeQueryComponent(page)}');
     }

     return devToolsUri
         .replace(
             path: '${devToolsUri.path.isEmpty ? '/' : devToolsUri.path}',
             fragment: '?${queryStringNameValues.join('&')}')
         .toString();
   }

   /// Prints a launch event to stdout so consumers of the DevTools server
   /// can see when clients are being launched/reused.
   void _emitLaunchEvent(
       {required bool reused,
       required bool notified,
       required int? pid,
       required bool machineMode}) {
     DevToolsUtils.printOutput(
       null,
       {
         'event': 'client.launch',
         'params': {
           'reused': reused,
           'notified': notified,
           'pid': pid,
         },
       },
       machineMode: machineMode,
     );
   }

   bool _isAccessibleToChromeOSNativeBrowser(Uri uri) {
     const tunneledPorts = {
       8000,
       8008,
       8080,
       8085,
       8888,
       9005,
       3000,
       4200,
       5000
     };
     return uri.hasPort && tunneledPorts.contains(uri.port);
   }
 }
	// Copyright (c) 2022, 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:async';
	import 'dart:io';

	import 'package:args/args.dart';
	import 'package:browser_launcher/browser_launcher.dart';
	import 'package:devtools_shared/devtools_shared.dart';
	import 'package:http_multi_server/http_multi_server.dart';
	import 'package:path/path.dart' as path;
	import 'package:shelf/shelf.dart' as shelf;
	import 'package:shelf/shelf_io.dart' as shelf;

	import 'src/devtools/client.dart';
	import 'src/devtools/handler.dart';
	import 'src/devtools/machine_mode_command_handler.dart';
	import 'src/devtools/memory_profile.dart';
	import 'src/devtools/utils.dart';
	import 'src/utils/console.dart';

	class DevToolsServer {
	static const protocolVersion = '1.1.0';
	static const defaultTryPorts = 10;
	static const commandDescription =
	'Open DevTools (optionally connecting to an existing application).';

	static const argHelp = 'help';
	static const argVmUri = 'vm-uri';
	static const argEnableNotifications = 'enable-notifications';
	static const argAllowEmbedding = 'allow-embedding';
	static const argAppSizeBase = 'appSizeBase';
	static const argAppSizeTest = 'appSizeTest';
	static const argHeadlessMode = 'headless';
	static const argDebugMode = 'debug';
	static const argLaunchBrowser = 'launch-browser';
	static const argMachine = 'machine';
	static const argHost = 'host';
	static const argPort = 'port';
	static const argProfileMemory = 'record-memory-profile';
	static const argTryPorts = 'try-ports';
	static const argVerbose = 'verbose';
	static const argVersion = 'version';
	static const launchDevToolsService = 'launchDevTools';

	MachineModeCommandHandler? _machineModeCommandHandler;
	late ClientManager clientManager;
	final bool _isChromeOS = File('/dev/.cros_milestone').existsSync();

	/// Builds an arg parser for the DevTools server.
	///
	/// [includeHelpOption] should be set to false if this arg parser will be used
	/// in a Command subclass.
	static ArgParser buildArgParser({
	bool verbose = false,
	bool includeHelpOption = true,
	}) {
	final argParser = ArgParser();

	if (includeHelpOption) {
	argParser.addFlag(
	argHelp,
	negatable: false,
	abbr: 'h',
	help: 'Prints help output.',
	);
	}
	argParser
	..addFlag(
	argVersion,
	negatable: false,
	help: 'Prints the DevTools version.',
	)
	..addFlag(
	argVerbose,
	negatable: false,
	abbr: 'v',
	help: 'Output more informational messages.',
	)
	..addOption(
	argHost,
	valueHelp: 'host',
	help: 'Hostname to serve DevTools on (defaults to localhost).',
	)
	..addOption(
	argPort,
	defaultsTo: '9100',
	valueHelp: 'port',
	help: 'Port to serve DevTools on; specify 0 to automatically use any '
	'available port.',
	)
	..addFlag(
	argLaunchBrowser,
	help:
	'Launches DevTools in a browser immediately at start.\n(defaults to on unless in --machine mode)',
	)
	..addFlag(
	argMachine,
	negatable: false,
	help: 'Sets output format to JSON for consumption in tools.',
	)
	..addSeparator('Memory profiling options:')
	..addOption(
	argProfileMemory,
	valueHelp: 'file',
	defaultsTo: 'memory_samples.json',
	help:
	'Start devtools headlessly and write memory profiling samples to the '
	'indicated file.',
	);

	if (verbose) {
	argParser.addSeparator('App size options:');
	}

	// TODO(devoncarew): --appSizeBase and --appSizeTest should be renamed to
	// something like --app-size-base and --app-size-test; #3146.
	argParser
	..addOption(
	argAppSizeBase,
	valueHelp: 'appSizeBase',
	help: 'Path to the base app size file used for app size debugging.',
	hide: !verbose,
	)
	..addOption(
	argAppSizeTest,
	valueHelp: 'appSizeTest',
	help:
	'Path to the test app size file used for app size debugging.\nThis '
	'file should only be specified if --$argAppSizeBase is also specified.',
	hide: !verbose,
	);

	if (verbose) {
	argParser.addSeparator('Advanced options:');
	}

	// Args to show for verbose mode.
	argParser
	..addOption(
	argTryPorts,
	defaultsTo: DevToolsServer.defaultTryPorts.toString(),
	valueHelp: 'count',
	help: 'The number of ascending ports to try binding to before failing '
	'with an error. ',
	hide: !verbose,
	)
	..addFlag(
	argEnableNotifications,
	negatable: false,
	help: 'Requests notification permissions immediately when a client '
	'connects back to the server.',
	hide: !verbose,
	)
	..addFlag(
	argAllowEmbedding,
	help: 'Allow embedding DevTools inside an iframe.',
	hide: !verbose,
	)
	..addFlag(
	argHeadlessMode,
	negatable: false,
	help: 'Causes the server to spawn Chrome in headless mode for use in '
	'automated testing.',
	hide: !verbose,
	);

	// Deprecated and hidden args.
	// TODO: Remove this - prefer that clients use the rest arg.
	argParser
	..addOption(
	argVmUri,
	defaultsTo: '',
	help: 'VM Service protocol URI.',
	hide: true,
	)

	// Development only args.
	..addFlag(
	argDebugMode,
	negatable: false,
	help: 'Run a debug build of the DevTools web frontend.',
	hide: true,
	);

	return argParser;
	}

	/// Serves DevTools.
	///
	/// `handler` is the [shelf.Handler] that the server will use for all requests.
	/// If null, [defaultHandler] will be used. Defaults to null.
	///
	/// `customDevToolsPath` is a path to a directory containing a pre-built
	/// DevTools application.
	///
	// Note: this method is used by the Dart CLI and by package:dwds.
	Future<HttpServer?> serveDevTools({
	bool enableStdinCommands = true,
	bool machineMode = false,
	bool debugMode = false,
	bool launchBrowser = false,
	bool enableNotifications = false,
	bool allowEmbedding = true,
	bool headlessMode = false,
	bool verboseMode = false,
	String? hostname,
	String? customDevToolsPath,
	int port = 0,
	int numPortsToTry = defaultTryPorts,
	shelf.Handler? handler,
	String? serviceProtocolUri,
	String? profileFilename,
	String? appSizeBase,
	String? appSizeTest,
	}) async {
	hostname ??= 'localhost';

	// Collect profiling information.
	if (profileFilename != null && serviceProtocolUri != null) {
	final Uri? vmServiceUri = Uri.tryParse(serviceProtocolUri);
	if (vmServiceUri != null) {
	await _hookupMemoryProfiling(
	vmServiceUri,
	profileFilename,
	verboseMode,
	);
	}
	return null;
	}

	if (machineMode) {
	assert(
	enableStdinCommands,
	'machineMode only works with enableStdinCommands.',
	);
	}

	clientManager = ClientManager(
	requestNotificationPermissions: enableNotifications,
	);
	handler ??= await defaultHandler(
	buildDir: customDevToolsPath!,
	clientManager: clientManager,
	);

	HttpServer? server;
	SocketException? ex;
	while (server == null && numPortsToTry >= 0) {
	// If we have tried [numPortsToTry] ports and still have not been able to
	// connect, try port 0 to find a random available port.
	if (numPortsToTry == 0) port = 0;

	try {
	server = await HttpMultiServer.bind(hostname, port);
	} on SocketException catch (e) {
	ex = e;
	numPortsToTry--;
	port++;
	}
	}

	// Re-throw the last exception if we failed to bind.
	if (server == null && ex != null) {
	throw ex;
	}

	final _server = server!;
	if (allowEmbedding) {
	_server.defaultResponseHeaders.remove('x-frame-options', 'SAMEORIGIN');
	// The origin-agent-cluster header is required to support the embedding of
	// Dart DevTools in Chrome DevTools.
	_server.defaultResponseHeaders.add('origin-agent-cluster', '?1');
	}

	// Ensure browsers don't cache older versions of the app.
	_server.defaultResponseHeaders.add(
	HttpHeaders.cacheControlHeader,
	'max-age=0',
	);

	// Serve requests in an error zone to prevent failures
	// when running from another error zone.
	runZonedGuarded(
	() => shelf.serveRequests(_server, handler!),
	(e, _) => print('Error serving requests: $e'),
	);

	final devToolsUrl = 'http://${_server.address.host}:${_server.port}';

	if (launchBrowser) {
	if (serviceProtocolUri != null) {
	serviceProtocolUri =
	normalizeVmServiceUri(serviceProtocolUri).toString();
	}

	final queryParameters = {
	if (serviceProtocolUri != null) 'uri': serviceProtocolUri,
	if (appSizeBase != null) 'appSizeBase': appSizeBase,
	if (appSizeTest != null) 'appSizeTest': appSizeTest,
	};
	String url = Uri.parse(devToolsUrl)
	.replace(queryParameters: queryParameters)
	.toString();

	// If app size parameters are present, open to the standalone `appsize`
	// page, regardless if there is a vm service uri specified. We only check
	// for the presence of [appSizeBase] here because [appSizeTest] may or may
	// not be specified (it should only be present for diffs). If [appSizeTest]
	// is present without [appSizeBase], we will ignore the parameter.
	if (appSizeBase != null) {
	final startQueryParamIndex = url.indexOf('?');
	if (startQueryParamIndex != -1) {
	url = '${url.substring(0, startQueryParamIndex)}'
	'/#/appsize'
	'${url.substring(startQueryParamIndex)}';
	}
	}

	try {
	await Chrome.start([url]);
	} catch (e) {
	print('Unable to launch Chrome: $e\n');
	}
	}

	if (enableStdinCommands) {
	String message = '''Serving DevTools at $devToolsUrl.

	Hit ctrl-c to terminate the server.''';
	if (!machineMode && debugMode) {
	// Add bold to help find the correct url to open.
	message = ConsoleUtils.bold('$message\n');
	}

	DevToolsUtils.printOutput(
	message,
	{
	'event': 'server.started',
	// TODO(dantup): Remove this `method` field when we're sure VS Code
	// users are all on a newer version that uses `event`. We incorrectly
	// used `method` for the original releases.
	'method': 'server.started',
	'params': {
	'host': _server.address.host,
	'port': _server.port,
	'pid': pid,
	'protocolVersion': protocolVersion,
	}
	},
	machineMode: machineMode,
	);

	if (machineMode) {
	_machineModeCommandHandler = MachineModeCommandHandler(server: this);
	await _machineModeCommandHandler!.initialize(
	devToolsUrl: devToolsUrl,
	headlessMode: headlessMode,
	);
	}
	}

	return server;
	}

	void _printUsage(ArgParser argParser) {
	print(commandDescription);
	print('\nUsage: devtools [arguments] [service protocol uri]');
	print(argParser.usage);
	}

	/// Wraps [serveDevTools] `arguments` parsed, as from the command line.
	///
	/// For more information on `handler`, see [serveDevTools].
	// Note: this method is used in google3 as well as by DevTools' main method.
	Future<HttpServer?> serveDevToolsWithArgs(
	List<String> arguments, {
	shelf.Handler? handler,
	String? customDevToolsPath,
	}) async {
	ArgResults args;
	final verbose = arguments.contains('-v') \|\| arguments.contains('--verbose');
	final argParser = buildArgParser(verbose: verbose);
	try {
	args = argParser.parse(arguments);
	} on FormatException catch (e) {
	print(e.message);
	print('');
	_printUsage(argParser);
	return null;
	}

	return await _serveDevToolsWithArgs(
	args,
	verbose,
	handler: handler,
	customDevToolsPath: customDevToolsPath,
	);
	}

	Future<HttpServer?> _serveDevToolsWithArgs(
	ArgResults args,
	bool verbose, {
	shelf.Handler? handler,
	String? customDevToolsPath,
	}) async {
	final help = args[argHelp];
	final bool version = args[argVersion];
	final bool machineMode = args[argMachine];
	// launchBrowser defaults based on machine-mode if not explicitly supplied.
	final bool launchBrowser = args.wasParsed(argLaunchBrowser)
	? args[argLaunchBrowser]
	: !machineMode;
	final bool enableNotifications = args[argEnableNotifications];
	final bool allowEmbedding =
	args.wasParsed(argAllowEmbedding) ? args[argAllowEmbedding] : true;

	final port = args[argPort] != null ? int.tryParse(args[argPort]) ?? 0 : 0;

	final bool headlessMode = args[argHeadlessMode];
	final bool debugMode = args[argDebugMode];

	final numPortsToTry = args[argTryPorts] != null
	? int.tryParse(args[argTryPorts]) ?? 0
	: defaultTryPorts;

	final bool verboseMode = args[argVerbose];
	final String? hostname = args[argHost];
	final String? appSizeBase = args[argAppSizeBase];
	final String? appSizeTest = args[argAppSizeTest];

	if (help) {
	print(
	'Dart DevTools version ${await DevToolsUtils.getVersion(customDevToolsPath ?? "")}');
	print('');
	_printUsage(buildArgParser(verbose: verbose));
	return null;
	}

	if (version) {
	final versionStr =
	await DevToolsUtils.getVersion(customDevToolsPath ?? '');
	DevToolsUtils.printOutput(
	'Dart DevTools version $versionStr',
	{
	'version': versionStr,
	},
	machineMode: machineMode,
	);
	return null;
	}

	// Prefer getting the VM URI from the rest args; fall back on the 'vm-url'
	// option otherwise.
	String? serviceProtocolUri;
	if (args.rest.isNotEmpty) {
	serviceProtocolUri = args.rest.first;
	} else if (args.wasParsed(argVmUri)) {
	serviceProtocolUri = args[argVmUri];
	}

	// Support collecting profile data.
	String? profileFilename;
	if (args.wasParsed(argProfileMemory)) {
	profileFilename = args[argProfileMemory];
	}
	if (profileFilename != null && !path.isAbsolute(profileFilename)) {
	profileFilename = path.absolute(profileFilename);
	}

	return serveDevTools(
	machineMode: machineMode,
	debugMode: debugMode,
	launchBrowser: launchBrowser,
	enableNotifications: enableNotifications,
	allowEmbedding: allowEmbedding,
	port: port,
	headlessMode: headlessMode,
	numPortsToTry: numPortsToTry,
	handler: handler,
	customDevToolsPath: customDevToolsPath,
	serviceProtocolUri: serviceProtocolUri,
	profileFilename: profileFilename,
	verboseMode: verboseMode,
	hostname: hostname,
	appSizeBase: appSizeBase,
	appSizeTest: appSizeTest,
	);
	}

	Future<Map<String, dynamic>> launchDevTools(
	Map<String, dynamic> params,
	Uri vmServiceUri,
	String devToolsUrl,
	bool headlessMode,
	bool machineMode,
	) async {
	// First see if we have an existing DevTools client open that we can
	// reuse.
	final canReuse =
	params.containsKey('reuseWindows') && params['reuseWindows'] == true;
	final shouldNotify =
	params.containsKey('notify') && params['notify'] == true;
	final page = params['page'];
	if (canReuse &&
	_tryReuseExistingDevToolsInstance(
	vmServiceUri,
	page,
	shouldNotify,
	)) {
	_emitLaunchEvent(
	reused: true,
	notified: shouldNotify,
	pid: null,
	machineMode: machineMode,
	);
	return {
	'reused': true,
	'notified': shouldNotify,
	};
	}

	final uriParams = <String, dynamic>{};

	// Copy over queryParams passed by the client
	params['queryParams']?.forEach((key, value) => uriParams[key] = value);

	// Add the URI to the VM service
	uriParams['uri'] = vmServiceUri.toString();

	final devToolsUri = Uri.parse(devToolsUrl);
	final uriToLaunch = _buildUriToLaunch(uriParams, page, devToolsUri);

	// TODO(dantup): When ChromeOS has support for tunneling all ports we can
	// change this to always use the native browser for ChromeOS and may wish to
	// handle this inside `browser_launcher`; https://crbug.com/848063.
	final useNativeBrowser = _isChromeOS &&
	_isAccessibleToChromeOSNativeBrowser(devToolsUri) &&
	_isAccessibleToChromeOSNativeBrowser(vmServiceUri);
	int? browserPid;
	if (useNativeBrowser) {
	await Process.start('x-www-browser', [uriToLaunch.toString()]);
	} else {
	final args = headlessMode
	? [
	'--headless',
	// When running headless, Chrome will quit immediately after loading
	// the page unless we have the debug port open.
	'--remote-debugging-port=9223',
	'--disable-gpu',
	'--no-sandbox',
	]
	: <String>[];
	final proc = await Chrome.start([uriToLaunch.toString()], args: args);
	browserPid = proc.pid;
	}
	_emitLaunchEvent(
	reused: false,
	notified: false,
	pid: browserPid!,
	machineMode: machineMode);
	return {
	'reused': false,
	'notified': false,
	'pid': browserPid,
	};
	}

	Future<void> _hookupMemoryProfiling(
	Uri observatoryUri,
	String profileFile, [
	bool verboseMode = false,
	]) async {
	final service = await DevToolsUtils.connectToVmService(observatoryUri);
	if (service == null) {
	return;
	}

	final memoryProfiler = MemoryProfile(service, profileFile, verboseMode);
	memoryProfiler.startPolling();

	print('Writing memory profile samples to $profileFile...');
	}

	bool _tryReuseExistingDevToolsInstance(
	Uri vmServiceUri,
	String? page,
	bool notifyUser,
	) {
	// First try to find a client that's already connected to this VM service,
	// and just send the user a notification for that one.
	final existingClient =
	clientManager.findExistingConnectedReusableClient(vmServiceUri);
	if (existingClient != null) {
	try {
	if (page != null) {
	existingClient.showPage(page);
	}
	if (notifyUser) {
	existingClient.notify();
	}
	return true;
	} catch (e) {
	print('Failed to reuse existing connected DevTools client');
	print(e);
	}
	}

	final reusableClient = clientManager.findReusableClient();
	if (reusableClient != null) {
	try {
	reusableClient.connectToVmService(vmServiceUri, notifyUser);
	return true;
	} catch (e) {
	print('Failed to reuse existing DevTools client');
	print(e);
	}
	}
	return false;
	}

	String _buildUriToLaunch(
	Map<String, dynamic> uriParams,
	String? page,
	Uri devToolsUri,
	) {
	final queryStringNameValues = [];
	uriParams.forEach((key, value) => queryStringNameValues.add(
	'${Uri.encodeQueryComponent(key)}=${Uri.encodeQueryComponent(value)}'));

	if (page != null) {
	queryStringNameValues.add('page=${Uri.encodeQueryComponent(page)}');
	}

	return devToolsUri
	.replace(
	path: '${devToolsUri.path.isEmpty ? '/' : devToolsUri.path}',
	fragment: '?${queryStringNameValues.join('&')}')
	.toString();
	}

	/// Prints a launch event to stdout so consumers of the DevTools server
	/// can see when clients are being launched/reused.
	void _emitLaunchEvent(
	{required bool reused,
	required bool notified,
	required int? pid,
	required bool machineMode}) {
	DevToolsUtils.printOutput(
	null,
	{
	'event': 'client.launch',
	'params': {
	'reused': reused,
	'notified': notified,
	'pid': pid,
	},
	},
	machineMode: machineMode,
	);
	}

	bool _isAccessibleToChromeOSNativeBrowser(Uri uri) {
	const tunneledPorts = {
	8000,
	8008,
	8080,
	8085,
	8888,
	9005,
	3000,
	4200,
	5000
	};
	return uri.hasPort && tunneledPorts.contains(uri.port);
	}
	}