blob: f28549647c76334ce55c1c87a65f7dcf10e9a90f [file] [log] [blame]
// Copyright 2014 The Flutter Authors. 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 'package:meta/meta.dart';
import 'package:platform/platform.dart';
import 'package:process/process.dart';
import 'package:webkit_inspection_protocol/webkit_inspection_protocol.dart';
import '../base/common.dart';
import '../base/file_system.dart';
import '../base/io.dart';
import '../base/logger.dart';
import '../base/os.dart';
import '../convert.dart';
/// An environment variable used to override the location of chrome.
const String kChromeEnvironment = 'CHROME_EXECUTABLE';
/// The expected executable name on linux.
const String kLinuxExecutable = 'google-chrome';
/// The expected executable name on macOS.
const String kMacOSExecutable =
'/Applications/Google Chrome';
/// The expected executable name on Windows.
const String kWindowsExecutable = r'Google\Chrome\Application\chrome.exe';
/// Find the chrome executable on the current platform.
/// Does not verify whether the executable exists.
String findChromeExecutable(Platform platform, FileSystem fileSystem) {
if (platform.environment.containsKey(kChromeEnvironment)) {
return platform.environment[kChromeEnvironment];
if (platform.isLinux) {
return kLinuxExecutable;
if (platform.isMacOS) {
return kMacOSExecutable;
if (platform.isWindows) {
/// The possible locations where the chrome executable can be located on windows.
final List<String> kWindowsPrefixes = <String>[
final String windowsPrefix = kWindowsPrefixes.firstWhere((String prefix) {
if (prefix == null) {
return false;
final String path = fileSystem.path.join(prefix, kWindowsExecutable);
return fileSystem.file(path).existsSync();
}, orElse: () => '.');
return fileSystem.path.join(windowsPrefix, kWindowsExecutable);
throwToolExit('Platform ${platform.operatingSystem} is not supported.');
return null;
void resetChromeForTesting() {
ChromeLauncher._currentCompleter = Completer<Chrome>();
void launchChromeInstance(Chrome chrome) {
/// Responsible for launching chrome with devtools configured.
class ChromeLauncher {
const ChromeLauncher({
@required FileSystem fileSystem,
@required Platform platform,
@required ProcessManager processManager,
@required OperatingSystemUtils operatingSystemUtils,
@required Logger logger,
}) : _fileSystem = fileSystem,
_platform = platform,
_processManager = processManager,
_operatingSystemUtils = operatingSystemUtils,
_logger = logger;
final FileSystem _fileSystem;
final Platform _platform;
final ProcessManager _processManager;
final OperatingSystemUtils _operatingSystemUtils;
final Logger _logger;
static bool get hasChromeInstance => _currentCompleter.isCompleted;
static Completer<Chrome> _currentCompleter = Completer<Chrome>();
/// Whether we can locate the chrome executable.
bool canFindChrome() {
final String chrome = findChromeExecutable(_platform, _fileSystem);
try {
return _processManager.canRun(chrome);
} on ArgumentError {
return false;
/// Launch the chrome browser to a particular `host` page.
/// `headless` defaults to false, and controls whether we open a headless or
/// a `headfull` browser.
/// `debugPort` is Chrome's debugging protocol port. If null, a random free
/// port is picked automatically.
/// `skipCheck` does not attempt to make a devtools connection before returning.
Future<Chrome> launch(String url, { bool headless = false, int debugPort, bool skipCheck = false, Directory dataDir }) async {
// This is a JSON file which contains configuration from the
// browser session, such as window position. It is located
// under the Chrome data-dir folder.
final String preferencesPath = _fileSystem.path.join('Default', 'preferences');
final String chromeExecutable = findChromeExecutable(_platform, _fileSystem);
final Directory activeDataDir = _fileSystem.systemTempDirectory.createTempSync('flutter_tool.');
// Seed data dir with previous state.
final File savedPreferencesFile = _fileSystem.file(_fileSystem.path.join(dataDir?.path ?? '', preferencesPath));
final File destinationFile = _fileSystem.file(_fileSystem.path.join(activeDataDir.path, preferencesPath));
if (dataDir != null) {
if (savedPreferencesFile.existsSync()) {
destinationFile.parent.createSync(recursive: true);
final int port = debugPort ?? await _operatingSystemUtils.findFreePort();
final List<String> args = <String>[
// Using a tmp directory ensures that a new instance of chrome launches
// allowing for the remote debug port to be enabled.
// When the DevTools has focus we don't want to slow down the application.
// Since we are using a temp profile, disable features that slow the
// Chrome launch.
if (headless)
...<String>['--headless', '--disable-gpu', '--no-sandbox', '--window-size=2400,1800'],
final Process process = await _processManager.start(args);
// When the process exits, copy the user settings back to the provided
// data-dir.
if (dataDir != null) {
unawaited(process.exitCode.whenComplete(() {
if (destinationFile.existsSync()) {
savedPreferencesFile.parent.createSync(recursive: true);
// If the file contains a crash string, remove it to hide
// the popup on next run.
final String contents = destinationFile.readAsStringSync();
.replaceFirst('"exit_type":"Crashed"', '"exit_type":"Normal"'));
.transform(const LineSplitter())
.listen((String line) {
_logger.printTrace('[CHROME]: $line');
// Wait until the DevTools are listening before trying to connect.
await process.stderr
.transform(const LineSplitter())
.map((String line) {
return line;
.firstWhere((String line) => line.startsWith('DevTools listening'), orElse: () {
return 'Failed to spawn stderr';
final Uri remoteDebuggerUri = await _getRemoteDebuggerUrl(Uri.parse('http://localhost:$port'));
return _connect(Chrome._(
ChromeConnection('localhost', port),
url: url,
process: process,
remoteDebuggerUri: remoteDebuggerUri,
), skipCheck);
static Future<Chrome> _connect(Chrome chrome, bool skipCheck) async {
if (_currentCompleter.isCompleted) {
throwToolExit('Only one instance of chrome can be started.');
// The connection is lazy. Try a simple call to make sure the provided
// connection is valid.
if (!skipCheck) {
try {
await chrome.chromeConnection.getTabs();
} catch (e) {
await chrome.close();
'Unable to connect to Chrome debug port: ${chrome.debugPort}\n $e');
return chrome;
static Future<Chrome> get connectedInstance => _currentCompleter.future;
/// Returns the full URL of the Chrome remote debugger for the main page.
/// This takes the [base] remote debugger URL (which points to a browser-wide
/// page) and uses its JSON API to find the resolved URL for debugging the host
/// page.
Future<Uri> _getRemoteDebuggerUrl(Uri base) async {
try {
final HttpClient client = HttpClient();
final HttpClientRequest request = await client.getUrl(base.resolve('/json/list'));
final HttpClientResponse response = await request.close();
final List<dynamic> jsonObject = await json.fuse(utf8).decoder.bind(response).single as List<dynamic>;
return base.resolve(jsonObject.first['devtoolsFrontendUrl'] as String);
} catch (_) {
// If we fail to talk to the remote debugger protocol, give up and return
// the raw URL rather than crashing.
return base;
/// A class for managing an instance of Chrome.
class Chrome {
this.chromeConnection, {
Process process,
}) : _process = process;
final String url;
final int debugPort;
final Process _process;
final ChromeConnection chromeConnection;
final Uri remoteDebuggerUri;
static Completer<Chrome> _currentCompleter = Completer<Chrome>();
Future<void> get onExit => _currentCompleter.future;
Future<void> close() async {
if (_currentCompleter.isCompleted) {
_currentCompleter = Completer<Chrome>();
await _process?.exitCode;