从UDP连接接收结构化数据

本文关键字：结构化 数据 UDP 连接 | 更新日期: 2023-09-27 18:02:19

我使用Kolor应用程序播放3D电影。这个应用程序在UDP端口上发送播放器状态。

UDP消息可以被任何其他应用程序使用。例如，3D音频引擎可以使用这些信息根据Kolor Eyes制作的视频播放产生3D声音。

UDP消息是JSON格式(http://www.json.org/)。所以你必须使用JSON解析器来解码消息。

下面是UDP消息的当前结构:

"id": "ked" --- message identifier
"yaw": float --- yaw in radians
"pitch": float --- pitch in radians
"roll": float --- roll in radians
"url": string --- current video url
"state": enum --- playback state, integer possible values are : 0 (StoppedState), 1 (PlayingState), 2 (PausedState)
"position": int --- current video playback position in milliseconds

我创建了c#应用程序从UDP端口接收数据并将其转换为ASCII字符串

static void Main(string[] args)
{         
    int localPort = 7755;
    IPEndPoint remoteSender = new IPEndPoint(IPAddress.Any, 0);                 
    // Create UDP client
    UdpClient client = new UdpClient(localPort);
    UdpState state = new UdpState(client, remoteSender);
    // Start async receiving
    client.BeginReceive(new AsyncCallback(DataReceived), state);
    // Wait for any key to terminate application
    Console.ReadKey();
    client.Close();
}
private static void DataReceived(IAsyncResult ar)
{
    UdpClient c = (UdpClient)((UdpState)ar.AsyncState).c;
    IPEndPoint wantedIpEndPoint = (IPEndPoint)((UdpState)(ar.AsyncState)).e;
    IPEndPoint receivedIpEndPoint = new IPEndPoint(IPAddress.Any, 0);
    Byte[] receiveBytes = c.EndReceive(ar, ref receivedIpEndPoint);
    // Check sender
    bool isRightHost = (wantedIpEndPoint.Address.Equals(receivedIpEndPoint.Address)) || wantedIpEndPoint.Address.Equals(IPAddress.Any);
    bool isRightPort = (wantedIpEndPoint.Port == receivedIpEndPoint.Port) || wantedIpEndPoint.Port == 0;
    if (isRightHost && isRightPort)
    {               
        string receivedText = Encoding.Default.GetString(receyiveBytes);
        Console.WriteLine(receivedText);
    }
    // Restart listening for udp data packages
    c.BeginReceive(new AsyncCallback(DataReceived), ar.AsyncState);
}

但是控制台的输出结果显示不正确

  qbjs☺   E   ☼   ¬   >☻  ☻ id♥ ked   ↕♣  ♣ pitch         U← position  '    ♦ roll
  ♥ url   ) file:///C:/Users/iman/Desktop/FIN_hi2.mp4 '¶  ♥ yaw           ♀   ∟
  0   @   T   `   ~

从UDP连接接收结构化数据

KolorEyes发送的消息不编码为JSON，而是一些二进制衍生物。

它可能是Qt二进制Json (qbjs)，但我找不到关于它的太多信息。

Qt5在内部将JSON文档转换为二进制表示，这就是通过UDP传输的内容。http://doc.qt.io/qt-5/qjsondocument.html

这给了我JSON文档，在Qt5应用程序:

void MainWindow::initSocket()
{
    udpSocket = new QUdpSocket(this);
    udpSocket->bind(QHostAddress::LocalHost, 7755);
    connect(udpSocket, SIGNAL(readyRead()),
            this, SLOT(readPendingDatagrams()));
}
void MainWindow::readPendingDatagrams()
{
    while (udpSocket->hasPendingDatagrams()) {
        QByteArray datagram;
        datagram.resize(udpSocket->pendingDatagramSize());
        QHostAddress sender;
        quint16 senderPort;
        udpSocket->readDatagram(datagram.data(), datagram.size(),
                            &sender, &senderPort);
        QJsonDocument document = QJsonDocument::fromBinaryData(datagram);
        qDebug() << document;
    }
}
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