Example of a basic Qt TCP server¶

#include <QTcpServer>
#include <QTcpSocket>
#include <QDebug>

class MyTcpServer : public QObject
{
    Q_OBJECT
public:
    explicit MyTcpServer(QObject *parent = nullptr) : QObject(parent)
    {
        mTcpServer = new QTcpServer(this);

        connect(mTcpServer, &QTcpServer::newConnection, this, &MyTcpServer::onNewConnection);

        if (!mTcpServer->listen(QHostAddress::Any, 6000)) {
            qDebug() << "Server could not be started!";
        } else {
            qDebug() << "Server started on port 6000!";
        }
    }

private slots:
    void onNewConnection()
    {
        QTcpSocket *clientSocket = mTcpServer->nextPendingConnection();
        qDebug() << "New client connected:" << clientSocket->peerAddress().toString();

        connect(clientSocket, &QTcpSocket::readyRead, this, &MyTcpServer::onReadyRead);
        connect(clientSocket, &QTcpSocket::disconnected, this, &MyTcpServer::onClientDisconnected);

        clientSocket->write("Welcome to the Qt TCP server!\r\n");
    }

    void onReadyRead()
    {
        QTcpSocket *clientSocket = qobject_cast<QTcpSocket*>(sender());
        if (clientSocket) {
            QByteArray data = clientSocket->readAll();
            qDebug() << "Received from client:" << data;
            clientSocket->write("Echo: " + data); // Echo back the received data
        }
    }

    void onClientDisconnected()
    {
        QTcpSocket *clientSocket = qobject_cast<QTcpSocket*>(sender());
        if (clientSocket) {
            qDebug() << "Client disconnected:" << clientSocket->peerAddress().toString();
            clientSocket->deleteLater(); // Clean up the socket object
        }
    }

private:
    QTcpServer *mTcpServer;
};