描述
我正在尝试运行一个flutter web服务器，并使用vm_service库以编程方式连接到Dart VM。web服务器已成功启动，但当我尝试侦听套接字时，我收到以下错误：
未处理的异常：WebSocketException：连接到http://localhost:1234/ws#'未升级到websocket
我的代码基于下面链接中的vm_service库示例，开发人员在这里启动Dart VM并连接到它
https://github.com/dart-lang/sdk/blob/master/pkg/vm_service/example/vm_service_tester.dart
复制步骤
错误的来源如下：
serviceClient = await vmServiceConnect(host, port, log: new StdoutLog());
完整的代码如下：
library service_tester;
import 'dart:async';
import 'dart:collection';
import 'dart:convert';
import 'dart:io';
import 'package:path/path.dart' as path;
import 'package:pedantic/pedantic.dart';
import 'package:vm_service/vm_service.dart';
import 'package:vm_service/vm_service_io.dart';
// import 'package:test/test.dart';
final String host = 'localhost';
final int port = 1234;
VmService serviceClient;
void main() async {
Directory current = Directory.current;
String sdk = path.dirname(path.dirname(Platform.resolvedExecutable));
String fsdk = path.dirname(path.dirname(Platform.resolvedExecutable));
// var flutterSDK = new Directory('C:/flutter/bin'); //FOR WINDOWS
var flutterSDK = new Directory('/opt/flutter/bin'); //FOR LINUX
print('Using sdk at ${sdk}');
print('Directory ${current.path}');
print('Directory ${flutterSDK.path}/flutter');
var commands = ["run", "--target=lib/main.dart", "-d", "web", '--web-port=${port}' ];
print('Running command: flutter ${commands.join(" ")}');
Process process = await Process.start('flutter', commands , runInShell: true);
print('dart process started: ${process.pid}');
process.exitCode.then((code) => print('vm exited: ${code}'));
process.stdout.transform(utf8.decoder).listen((v)=>print('STDOUT: $v'));
process.stderr.transform(utf8.decoder).listen((v)=>print('STDERR: $v'));
await new Future.delayed(new Duration(milliseconds: 1 * 60 * 1000));
print('nnConnecting to ${host}:${port}nn');
serviceClient = await vmServiceConnect(host, port, log: new StdoutLog());
print('nnSocket connected to ${host}:${port}nn');
// serviceClient.onSend.listen((str) => print('--> ${str}'));
// var checkResponseJsonCompatibility = true;
// serviceClient.onReceive.listen((str) =>print('<-- ${str}'));
// serviceClient.onIsolateEvent.listen((e) => print('onIsolateEvent: ${e}'));
// serviceClient.onDebugEvent.listen((e) => print('onDebugEvent: ${e}'));
// serviceClient.onGCEvent.listen((e) => print('onGCEvent: ${e}'));
// serviceClient.onStdoutEvent.listen((e) => print('onStdoutEvent: ${e}'));
// serviceClient.onStderrEvent.listen((e) => print('onStderrEvent: ${e}'));
// unawaited(serviceClient.streamListen(EventStreams.kIsolate));
// unawaited(serviceClient.streamListen(EventStreams.kDebug));
// unawaited(serviceClient.streamListen(EventStreams.kStdout));
VM vm = await serviceClient.getVM();
print('hostCPU=${vm.hostCPU}');
print(await serviceClient.getVersion());
}
class StdoutLog extends Log {
void warning(String message) => print(message);
void severe(String message) => print(message);
}
我的pubspec.yaml文件如下：
name: demo
description: A new Flutter project.
version: 1.0.0+1
environment:
sdk: ">=2.1.0 <3.0.0"
dependencies:
flutter:
sdk: flutter
vm_service: ^2.1.1
path: ^1.6.4
pedantic: ^1.8.0+1
# test: ^1.9.4
cupertino_icons: ^0.1.2
dev_dependencies:
flutter_test:
sdk: flutter
flutter:
来自flutter doctor -v的日志如下：
[✓] Flutter (Channel master, v1.12.5-pre.27, on Linux, locale en_US.UTF-8)
• Flutter version 1.12.5-pre.27 at /opt/flutter
• Framework revision 29ab6b549a (8 hours ago), 2019-11-19 11:29:35 -0800
• Engine revision ecb32952ff
• Dart version 2.7.0
[✓] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
• Android SDK at /opt/sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-28, build-tools 28.0.3
• ANDROID_HOME = /opt/sdk
• Java binary at: /usr/local/openjdk-8/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_232-b09)
• All Android licenses accepted.
[✗] Chrome - develop for the web (Cannot find chrome executable at google-chrome)
! Cannot find Chrome. Try setting CHROME_EXECUTABLE to a Chrome executable.
[!] Android Studio (not installed)
• Android Studio not found; download from https://developer.android.com/studio/index.html
(or visit https://flutter.dev/setup/#android-setup for detailed instructions).
[✓] Connected device (1 available)
• Web Server • web-server • web-javascript • Flutter Tools
! Doctor found issues in 2 categories.
错误日志
Running "flutter pub get" in project... 2.8s
Using sdk at /usr/lib/dart
Directory /project
Directory /opt/flutter/bin/flutter
Running command: flutter run --target=lib/main.dart -d web --web-port=1234
dart process started: 56
STDOUT: Downloading Web SDK...
STDOUT: 3.5s
STDOUT:
STDOUT: Launching lib/main.dart on Web Server in debug mode...
Building application for the web...
STDOUT: 31.9s
lib/main.dart is being served at http://localhost:1234/
Warning: Flutter's support for web development is not stable yet and hasn't
been thoroughly tested in production environments.
For more information see https://flutter.dev/web
STDOUT: 🔥 To hot restart changes while running, press "r". To hot restart (and refresh the browser), press "R".
For a more detailed help message, press "h". To quit, press "q".
Connecting to localhost:1234
Unhandled exception:
WebSocketException: Connection to 'http://localhost:1234/ws#' was not upgraded to websocket
#0 _WebSocketImpl.connect.<anonymous closure>.error (dart:_http/websocket_impl.dart:1052:9)
#1 _WebSocketImpl.connect.<anonymous closure> (dart:_http/websocket_impl.dart:1061:14)
#2 _RootZone.runUnary (dart:async/zone.dart:1379:54)
#3 _FutureListener.handleValue (dart:async/future_impl.dart:137:18)
#4 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:678:45)
#5 Future._propagateToListeners (dart:async/future_impl.dart:707:32)
#6 Future._completeWithValue (dart:async/future_impl.dart:522:5)
#7 Future.wait.<anonymous closure> (dart:async/future.dart:400:22)
#8 _RootZone.runUnary (dart:async/zone.dart:1379:54)
#9 _FutureListener.handleValue (dart:async/future_impl.dart:137:18)
#10 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:678:45)
#11 Future._propagateToListeners (dart:async/future_impl.dart:707:32)
#12 Future._completeWithValue (dart:async/future_impl.dart:522:5)
#13 Future._asyncComplete.<anonymous closure> (dart:async/future_impl.dart:552:7)
#14 _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
#15 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)
#16 _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:116:13)
#17 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:173:5)
似乎有一个与您的问题相关的bug文件。该漏洞仍然存在，Dart/Flutter团队尚未对其进行检查。