node.js - 如何从 Flutter 发出纯文本 http(而非 https)请求

Question

出于测试目的，我想禁用加密，以便我可以使用 http 而不是 https 将我的 Flutter 应用程序连接到在本地主机上运行的服务器。 I've already been able to do it with https ，但我遇到了 http 崩溃，因为默认情况下 Android 和 iOS 都不允许纯文本请求。

这是我的错误:

E/flutter ( 9119): [ERROR:flutter/shell/common/shell.cc(186)] Dart Error: Unhandled exception:
E/flutter ( 9119): SocketException: OS Error: Connection refused, errno = 111, address = 10.0.2.2, port = 40738
E/flutter ( 9119): #0      IOClient.send (package:http/src/io_client.dart:33:23)
E/flutter ( 9119): <asynchronous suspension>
E/flutter ( 9119): #1      BaseClient._sendUnstreamed (package:http/src/base_client.dart:169:38)
E/flutter ( 9119): <asynchronous suspension>
E/flutter ( 9119): #2      BaseClient.get (package:http/src/base_client.dart:32:7)
E/flutter ( 9119): #3      get.<anonymous closure> (package:http/http.dart:46:36)
E/flutter ( 9119): #4      _withClient (package:http/http.dart:166:20)
E/flutter ( 9119): <asynchronous suspension>
E/flutter ( 9119): #5      get (package:http/http.dart:46:5)
E/flutter ( 9119): #6      _makeGetRequest (package:flutter_client/main.dart:64:29)
E/flutter ( 9119): <asynchronous suspension>
E/flutter ( 9119): #7      BodyWidgetState.build.<anonymous closure> (package:flutter_client/main.dart:48:19)
E/flutter ( 9119): #8      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:507:14)
E/flutter ( 9119): #9      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:562:30)
E/flutter ( 9119): #10     GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:102:24)
E/flutter ( 9119): #11     TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:242:9)
E/flutter ( 9119): #12     TapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:175:7)
E/flutter ( 9119): #13     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:315:9)
E/flutter ( 9119): #14     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:73:12)
E/flutter ( 9119): #15     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:101:11)
E/flutter ( 9119): #16     _WidgetsFlutterBinding&BindingBase&GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:180:19)
E/flutter ( 9119): #17     _WidgetsFlutterBinding&BindingBase&GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:158:22)
E/flutter ( 9119): #18     _WidgetsFlutterBinding&BindingBase&GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:138:7)
E/flutter ( 9119): #19     _WidgetsFlutterBinding&BindingBase&GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:101:7)
E/flutter ( 9119): #20     _WidgetsFlutterBinding&BindingBase&GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:85:7)
E/flutter ( 9119): #21     _invoke1 (dart:ui/hooks.dart:173:13)
E/flutter ( 9119): #22     _dispatchPointerDataPacket (dart:ui/hooks.dart:127:5)

在 Android 中，我可以通过向 list 添加设置来禁用加密:

android:usesCleartextTraffic="true"

在 iOS 中，我可以通过向 Info.plist 添加设置来执行相同的操作:

<key>NSAppTransportSecurity</key>
<dict>
    <key>NSAllowsArbitraryLoads</key>
    <true/>
</dict>

但我不知道如何在 Flutter 中做到这一点。

补充代码

Flutter main.dart

import 'package:flutter/material.dart';
import 'package:http/http.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Node server demo',
      debugShowCheckedModeBanner: false,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: Scaffold(
        appBar: AppBar(title: Text('Flutter Client')),
        body: BodyWidget(),
      ),
    );
  }
}

class BodyWidget extends StatefulWidget {
  @override
  BodyWidgetState createState() {
    return new BodyWidgetState();
  }
}

class BodyWidgetState extends State<BodyWidget> {
  String serverResponse = 'Server response';

  @override
  Widget build(BuildContext context) {

    return Padding(
      padding: const EdgeInsets.all(32.0),
      child: Align(
        alignment: Alignment.topCenter,
        child: SizedBox(
          width: 200,
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.center,
            children: <Widget>[
              RaisedButton(
                child: Text('Send request to server'),
                onPressed: () {
                  _makeGetRequest();
                },
              ),
              Padding(
                padding: const EdgeInsets.all(8.0),
                child: Text(serverResponse),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

_makeGetRequest() async {
  Response response = await get('http://10.0.2.2:3000');

  int statusCode = response.statusCode;
  Map<String, String> headers = response.headers;
  String contentType = headers['content-type'];
  String json = response.body;

  print(statusCode);
  print(headers);
  print(contentType);
  print(json);
}

flutter pubspec.yaml

name: flutter_client
description: Flutter client to test Node.js server
version: 1.0.0+1

environment:
  sdk: ">=2.1.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter
  http: ^0.12.0+1

dev_dependencies:
  flutter_test:
    sdk: flutter

flutter:
  uses-material-design: true

Node.js 应用程序.js

const http = require('http');

const hostname = '127.0.0.1';
const port = 3000;

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello World\n');
});

server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});

使用 Android 9 模拟器 (API 28) 进行测试。

更新 1:

我尝试将 android:usesCleartextTraffic="true" 添加到 Flutter 中的 Android list ，但这并没有阻止 Dart 错误。

更新 2:

我在我的代码中使用 https 而不是 http。我更新了上面的内容并更改为新的错误消息。

更新 3

嗯，Flutter 有一个更新 (1.2.2)，我升级了。然后我重新启动了 Android Studio。现在，仅使用上面的代码，它就可以正常工作了。我不知道是什么导致了异常。难道Flutter不需要https？

Answer 1

创建一个新的httpclient并禁用证书检查

HttpClient httpClient = new HttpClient()
..badCertificateCallback =
    ((X509Certificate cert, String host, int port) => true);
IOClient ioClient = new IOClient(httpClient);
ioClient.get(url);