对127.0.0.1:80的HTTP请求失败 [英] HTTP request to 127.0.0.1:80 fails
问题描述
环境
- Android Studio最新版本
- 运行Android Nougat的Android模拟器
- MAMP用作HTTP服务器
问题
我的简单方法
Future<String> _getSimpleReply( String command, callback, errorCallback ) async {
try {
HttpClientRequest request = await _myClient.get( '127.0.0.1', 80 '/' );
HttpClientResponse response = await request.close();
await callback( response.toString() );
} on SocketException catch( e ) {
errorCallback( e.toString() );
}
}
失败，并显示错误:
cbLoginFailed :: SocketException: OS Error:
Connection refused, errno = 111, address = 127.0.0.1, port = 46414
当前使用已配置为可访问互联网的Android模拟器:
Currently using the Android emulator, which has been configured for internet access:
<uses-permission android:name="android.permission.INTERNET"/>
出于测试目的，HTTP服务器是MAMP，如果我在浏览器中输入以下链接，它将执行index.php脚本并返回一些简单的字符串:
For test purpose, the HTTP server is MAMP, which executes the index.php script and returns some simple string, if I enter this link in a browser:
http://127.0.0.1/index.php
如果我用localhost替换127.0.0.1，情况不会改变.
The situation does not change, if I replace 127.0.0.1 with localhost.
但是，如果我确实使用有效的公共FQDN 更改了127.0.0.1，则该方法可以正常工作:
But if I do change 127.0.0.1 with a valid public FQDN, the method works just fine:
doLoginSuccess :: Instance of '_HttpClientResponse'
问题
-
为什么Android模拟器/Flutter/Dart处理的127.0.0.1与有效的FQDN?
Why does the android emulator / flutter / dart handles 127.0.0.1 different than a valid FQDN?
以及如何更改此行为?
推荐答案
第一个注释指出，localhost或127.0.0.1是-在Android模拟器上运行应用程序时-实际上是本地计算机，Android应用正在执行.就Android应用而言，本地计算机是模拟的Android系统.
As pointed out by the first comment, localhost or 127.0.0.1 is - when running an app on Android emulator - in fact the local machine on which the Android app is executing. With respect of the Android app, the local machine is the emulated Android system.
因此，颤动代码中的http请求根本不会离开模拟器.由于Flutter应用程序不提供HTTP服务器，因此模拟器拒绝了http请求.
Therefore, the http request from the flutter code doesn't leave the emulator at all. Since the Flutter app doesn't provide a HTTP Server, the emulator refuses the http request.
需要更改为正在执行模拟器的主机的地址.
Android模拟器使用特殊的IP地址与其主机或主机网关进行通信.
The Android emulator uses special IP addresses to communicate with its host or the host gateway.
请查看 Android文档.
例如，主机的环回接口由以下IP标识: 10.0.2.2 因此，如果通常使用 127.0.0.1:80 ，则可以用 10.0.2.2:80 代替.
E.g., the host‘s loopback Interface is identified by this IP: 10.0.2.2
So, if normally one would use 127.0.0.1:80, one can substitute it with 10.0.2.2:80.
这篇关于对127.0.0.1:80的HTTP请求失败的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
