dart - 如何使用 http 库捕获 SocketException？

Question

其他人已经指出了这个问题(如 here )。尽管我可能已经理解了原因，但在使用更高级别的 http 库时，我仍然没有找到解决方案。例如:

import 'package:http/http.dart';

// yes, pwd is String, it's just a test...
Future<Response> login(String user, String pwd) {
  final authHeader = encodeBasicCredentials(user, pwd);
  return get(
    'http://192.168.0.100:8080/login',
    headers: <String, String>{
    HttpHeaders.AUTHORIZATION: authHeader,
    },
  ));
}

我找不到捕获抛出的 SocketException 的方法，例如，如果无法访问主机(在我的情况下，主机 ip 错误)。我尝试将 await 包装在 try/catch 中，或使用 Future.catchError。

这是异常的堆栈跟踪:

[ERROR:topaz/lib/tonic/logging/dart_error.cc(16)] Unhandled exception:
E/flutter ( 4036): SocketException: OS Error: Connection refused, errno = 111, address = 192.168.0.100, port = 35588
E/flutter ( 4036): #0      IOClient.send (package:http/src/io_client.dart:30:23)
E/flutter ( 4036): <asynchronous suspension>
E/flutter ( 4036): #1      BaseClient._sendUnstreamed (package:http/src/base_client.dart:171:38)
E/flutter ( 4036): <asynchronous suspension>
E/flutter ( 4036): #2      BaseClient.get (package:http/src/base_client.dart:34:5)
E/flutter ( 4036): #3      get.<anonymous closure> (package:http/http.dart:47:34)
E/flutter ( 4036): #4      _withClient (package:http/http.dart:167:20)
E/flutter ( 4036): <asynchronous suspension>
E/flutter ( 4036): #5      get (package:http/http.dart:47:3)

Answer 1

您可以将 login 更改为 async 以便您可以等待响应。这允许您捕获异常(例如，返回 null 而不是 Response)。

Future<Response> login(String user, String pwd) async {
  final String authHeader = encodeBasicCredentials(user, pwd);
  try {
    return await get(
        'http://192.168.0.100:8080/login',
        headers: {
          HttpHeaders.AUTHORIZATION: authHeader,
        },
      );
  } catch (e) {
    print(e);
    return null;
  }
}