Dart - 发送 UDP 广播 [英] Dart - Send an UDP broadcast

问题描述

我正在寻求帮助，因为我似乎找不到使用 Dart 在本地网络内发送 UDP 广播的方法.

I'm asking for help since it seems I cannot find a way to send an UDP broadcast inside a local network using Dart.

到目前为止，我设法使用 UDP 与 RawDatagramSocket 进行通信.我可以向特定地址发送消息.

So far I managed to communicate using UDP with RawDatagramSocket. I'm able to send a message to a specific address.

我无法做的是向本地网络内的任何设备发送广播(网络掩码为 255.255.255.0)，并等待可能的(多个)答案.这是我正在使用的代码:

What I'm not able to do is to send a broadcast to any device inside a local network (network mask is 255.255.255.0), and to wait for possible (multiple) answer(s). Here is the code I'm using:

RawDatagramSocket.bind('127.0.0.1', 8889)
    .then((RawDatagramSocket udpSocket) {
        udpSocket.listen((e) {
            Datagram dg = udpSocket.receive();
            if (dg != null) {
                //stuff
            }
        });
        udpSocket.send(utf8.encode('TEST'), DESTINATION_ADDRESS, 8889);
});

我尝试用 InternetAddress.anyIPv4 替换 DESTINATION_ADDRESS，但我没有运气.我还在 RawDatagramSocket 中找到了属性 broadcastEnabled，但我找不到有关如何使用它的更多信息.

I tried to replace DESTINATION_ADDRESS with InternetAddress.anyIPv4, but I had no luck. I also found the property broadcastEnabled inside RawDatagramSocket, but I cannot find further informations about how to make use of it.

预先感谢您的帮助.

推荐答案

有两个问题:

1. 使用 InternetAddress.anyIPv4 在所有网络接口上进行绑定；

1. Use InternetAddress.anyIPv4 for binding on all network interfaces;

使用属性broadcastEnabled启用广播权限

显然使用广播地址:对于 /24 网络使用 x.y.z.255 地址.

Obviously use a broadcast address: for a /24 network use x.y.z.255 address.

此代码段有效:

import 'dart:io';
import 'dart:convert';

main() {

  var DESTINATION_ADDRESS=InternetAddress("x.y.z.255");

  RawDatagramSocket.bind(InternetAddress.anyIPv4, 8889).then((RawDatagramSocket udpSocket) {
    udpSocket.broadcastEnabled = true;
    udpSocket.listen((e) {
      Datagram dg = udpSocket.receive();
      if (dg != null) {
        print("received ${dg.data}");
      }
    });
    List<int> data =utf8.encode('TEST');
    udpSocket.send(data, DESTINATION_ADDRESS, 8889);
  });
}

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