Dart UDP客户端/服务器 [英] Dart UDP client/server

问题描述

我一直在尝试通过使用RawDatagramSocket来实现udp客户端，但是我有点受阻.我无法发送或接收任何数据.据我所知，这是Dart中的一项相当新的功能，除了tcp之外，我找不到任何示例.

I've been trying to implement a udp client by using the RawDatagramSocket but I'm kind of stuck. I can neither send or receive any data. It's a pretty new feature in Dart as far as I know and I can't find any examples except for tcp.

此外，我也不知道是否有错误或任何错误，但是看来我只能绑定到本地主机.尝试绑定到另一台计算机的IPV4地址时，我收到一个套接字异常(由于某些无效的IP地址而导致无法创建数据报套接字).我尝试了tcp套接字，将数据连接并发送到用c#实现的tcp服务器(在dart代码在Mac OS上运行时)，没有问题.

Also, I don't know if there is a bug or anything, but it seems like I can only bind to the localhost. When trying to bind to another computer IPV4 address, I receive a socket exception (failure to create datagram socket due to some invalid IP address). I've tried the tcp socket, connecting and sending data to a tcp server implemented in c# (while the dart code was running on Mac OS), without a problem.

任何从事过该工作并且可以提供一个很好的例子的人吗?

Anyone who has worked on it and can provide a nice example?

我的代码:

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

void main() {
  var data = "Hello, World";
  var codec = new Utf8Codec();
  List<int> dataToSend = codec.encode(data);
  //var address = new InternetAddress('172.16.32.73');
  var address = new InternetAddress('127.0.0.1');
  RawDatagramSocket.bind(address, 16123).then((udpSocket) {
    udpSocket.listen((e) {
      print(e.toString());
      Datagram dg = udpSocket.receive();
      if(dg != null) 
        dg.data.forEach((x) => print(x));

    });
    udpSocket.send(dataToSend, new InternetAddress('172.16.32.73'), 16123);
    print('Did send data on the stream..');
  });
}

编辑

忙了几天，但是在更彻底地阅读了API规范之后，并在下面的注释中提供了一些帮助，我了解到，由于它是单发侦听器，因此每次发送时都必须将writeEventsEnabled设置为true..鉴于Günter，Fox32和Tomas的评论，其余的更改非常简单.

Been busy for a couple of days but after reading the API spec more thoroughly, and with some help from the comments below, I learned that, since it's a one-shot listener, the writeEventsEnabled must be set to true for every send. The rest of the changes are pretty straightforward given the comments by Günter, Fox32 and Tomas.

我还没有测试过将其设置为服务器，但是我认为这只是绑定到首选端口的问题(而不是下面的示例中的0).该服务器是在Windows 8.1上以C#实施的，而Dart VM是在Mac OS X上运行的.

I haven't tested to set it up as a server yet but I assume that's just a matter of binding to the preferred port (instead of 0 as in the example below). The server was implemented in C# on a Windows 8.1, while the Dart VM was running on Mac OS X.

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

void connect(InternetAddress clientAddress, int port) {
  Future.wait([RawDatagramSocket.bind(InternetAddress.ANY_IP_V4, 0)]).then((values) {
    RawDatagramSocket udpSocket = values[0];
    udpSocket.listen((RawSocketEvent e) {
      print(e);
      switch(e) {
        case RawSocketEvent.READ :
          Datagram dg = udpSocket.receive();
          if(dg != null) {
            dg.data.forEach((x) => print(x));
          }
          udpSocket.writeEventsEnabled = true;
          break;
        case RawSocketEvent.WRITE : 
          udpSocket.send(new Utf8Codec().encode('Hello from client'), clientAddress, port);
          break;
        case RawSocketEvent.CLOSED : 
          print('Client disconnected.');
      }
    });
  });
}

void main() {
  print("Connecting to server..");
  var address = new InternetAddress('172.16.32.71');
  int port = 16123;
  connect(address, port);
}

推荐答案

我不知道这是否是正确的方法，但是它对我有用.

I don't know if this is the right way to do it, but it got it working for me.

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

void main() {
  var data = "Hello, World";
  var codec = new Utf8Codec();
  List<int> dataToSend = codec.encode(data);
  var addressesIListenFrom = InternetAddress.anyIPv4;
  int portIListenOn = 16123; //0 is random
  RawDatagramSocket.bind(addressesIListenFrom, portIListenOn)
    .then((RawDatagramSocket udpSocket) {
    udpSocket.forEach((RawSocketEvent event) {
      if(event == RawSocketEvent.read) {
        Datagram dg = udpSocket.receive();
        dg.data.forEach((x) => print(x));
      }
    });
    udpSocket.send(dataToSend, addressesIListenFrom, portIListenOn);
    print('Did send data on the stream..');
  });
}

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