1

因此，UDP 服务器显然只是侦听某个端口并处理带有源 IP 和 PORT 的字节数组：

// In this code, listener is QUdpSocket*
FileServer::FileServer(QObject *parent)
    : QObject(parent)
    , listener(new QUdpSocket(this))
{
    // bind to listening port
    listener->bind(QHostAddress::Any, 6660);

    connect(listener, &QUdpSocket::readyRead,
            this, &FileServer::readPendingDatagrams, Qt::QueuedConnection);
}

void FileServer::readPendingDatagrams()
{
    while (listener->hasPendingDatagrams()) {
        // This is how this is done in new QT
        //QNetworkDatagram datagram = listener->receiveDatagram();
        //processTheDatagram(datagram);
        // This is how it is done in old QT
        QByteArray datagram;
        datagram.resize(listener->pendingDatagramSize());
        QHostAddress sender;
        quint16 senderPort;

        listener->readDatagram(datagram.data(), datagram.size(),
                                &sender, &senderPort);
        processDatagram(datagram, sender, senderPort);
    }
}

非常好。这实际上有效，正如我使用这个 python 片段验证的那样：

import socket
host="127.0.0.1"
port=6660
udp_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
udp_sock.sendto(b'PING', (host, port))

字节数组甚至包含“PING”。所以我正要写一个客户端。我假设客户端将简单地使用QUdpSocket::sendDatagram. 但是他怎么能收到数据呢？

首先我想我会打电话bind(SERVER_ADDRESS_HERE, 6660)。但显然他们不能都在同一个端口上监听。

那么如何为上面的服务器编写一个客户端呢？

4

1 回答 1

0

您可以在接收数据时使用套接字的信号 readyread() 来执行插槽：

//put this in the MainWindow costructor
connect(socket, SIGNAL(readyread()), SLOT(slot()));

请记住进行绑定以开始从端口接收数据：

//this is the code to make the bind
socket->bind(port);

在插槽中，您可以编写此代码，将您收到的内容保存在 QString 中：

void MainWindow::slot(){

    QString data = "";
    while(socket->hasPendingDatagrams()) {

        QByteArray datagram;
        datagram.resize(socket->pendingDatagramSize());
        QHostAddress senderIP;
        quint64 senderPort;
        socket->readDatagram(datagram.data(), datagram.size(), &senderIP, &senderPort);

        //if you want to check if the sender was the server you can control senderIp

        data += QString(datagram);
    }
}
于 2017-04-15T17:01:18.950 回答