Fortune Server Example▲

This example is intended to be run alongside the Fortune Client example or the Blocking Fortune Client Example.

Screenshot of the Fortune Server example

It uses QTcpServer to accept incoming TCP connections, and a simple QDataStream based data transfer protocol to write a fortune to the connecting client (from the Fortune Client example), before closing the connection.

 
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class Server : public QDialog
{
    Q_OBJECT

public:
    explicit Server(QWidget *parent = nullptr);

private slots:
    void sessionOpened();
    void sendFortune();

private:
    QLabel *statusLabel = nullptr;
    QTcpServer *tcpServer = nullptr;
    QVector<QString> fortunes;
    QNetworkSession *networkSession = nullptr;
};

The server is implemented using a simple class with only one slot, for handling incoming connections.

 
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    tcpServer = new QTcpServer(this);
    if (!tcpServer->listen()) {
        QMessageBox::critical(this, tr("Fortune Server"),
                              tr("Unable to start the server: %1.")
                              .arg(tcpServer->errorString()));
        close();
        return;
    }
    QString ipAddress;
    QList<QHostAddress> ipAddressesList = QNetworkInterface::allAddresses();
    // use the first non-localhost IPv4 address
    for (int i = 0; i < ipAddressesList.size(); ++i) {
        if (ipAddressesList.at(i) != QHostAddress::LocalHost &&
            ipAddressesList.at(i).toIPv4Address()) {
            ipAddress = ipAddressesList.at(i).toString();
            break;
        }
    }
    // if we did not find one, use IPv4 localhost
    if (ipAddress.isEmpty())
        ipAddress = QHostAddress(QHostAddress::LocalHost).toString();
    statusLabel->setText(tr("The server is running on\n\nIP: %1\nport: %2\n\n"
                            "Run the Fortune Client example now.")
                         .arg(ipAddress).arg(tcpServer->serverPort()));

In its constructor, our Server object calls QTcpServer::listen() to set up a QTcpServer to listen on all addresses, on an arbitrary port. In then displays the port QTcpServer picked in a label, so that user knows which port the fortune client should connect to.

 
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fortunes << tr("You've been leading a dog's life. Stay off the furniture.")
         << tr("You've got to think about tomorrow.")
         << tr("You will be surprised by a loud noise.")
         << tr("You will feel hungry again in another hour.")
         << tr("You might have mail.")
         << tr("You cannot kill time without injuring eternity.")
         << tr("Computers are not intelligent. They only think they are.");

Our server generates a list of random fortunes that it can send to connecting clients.

 
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connect(tcpServer, &QTcpServer::newConnection,