server.cpp Example File

fortuneserver/server.cpp
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#include <QtWidgets>
#include <QtNetwork>

#include <stdlib.h>

#include "server.h"

Server::Server(QWidget *parent)
:   QDialog(parent), tcpServer(0), networkSession(0)
{
    statusLabel = new QLabel;
    quitButton = new QPushButton(tr("Quit"));
    quitButton->setAutoDefault(false);

    QNetworkConfigurationManager manager;
    if (manager.capabilities() & QNetworkConfigurationManager::NetworkSessionRequired) {
        // Get saved network configuration
        QSettings settings(QSettings::UserScope, QLatin1String("QtProject"));
        settings.beginGroup(QLatin1String("QtNetwork"));
        const QString id = settings.value(QLatin1String("DefaultNetworkConfiguration")).toString();
        settings.endGroup();

        // If the saved network configuration is not currently discovered use the system default
        QNetworkConfiguration config = manager.configurationFromIdentifier(id);
        if ((config.state() & QNetworkConfiguration::Discovered) !=
            QNetworkConfiguration::Discovered) {
            config = manager.defaultConfiguration();
        }

        networkSession = new QNetworkSession(config, this);
        connect(networkSession, SIGNAL(opened()), this, SLOT(sessionOpened()));

        statusLabel->setText(tr("Opening network session."));
        networkSession->open();
    } else {
        sessionOpened();
    }

        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.");

        connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
        connect(tcpServer, SIGNAL(newConnection()), this, SLOT(sendFortune()));

        QHBoxLayout *buttonLayout = new QHBoxLayout;
        buttonLayout->addStretch(1);
        buttonLayout->addWidget(quitButton);
        buttonLayout->addStretch(1);

        QVBoxLayout *mainLayout = new QVBoxLayout;
        mainLayout->addWidget(statusLabel);
        mainLayout->addLayout(buttonLayout);
        setLayout(mainLayout);

        setWindowTitle(tr("Fortune Server"));
}

void Server::sessionOpened()
{
    // Save the used configuration
    if (networkSession) {
        QNetworkConfiguration config = networkSession->configuration();
        QString id;
        if (config.type() == QNetworkConfiguration::UserChoice)
            id = networkSession->sessionProperty(QLatin1String("UserChoiceConfiguration")).toString();
        else
            id = config.identifier();

        QSettings settings(QSettings::UserScope, QLatin1String("QtProject"));
        settings.beginGroup(QLatin1String("QtNetwork"));
        settings.setValue(QLatin1String("DefaultNetworkConfiguration"), id);
        settings.endGroup();
    }

    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()));
}

void Server::sendFortune()
{
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_4_0);
    out << (quint16)0;
    out << fortunes.at(qrand() % fortunes.size());
    out.device()->seek(0);
    out << (quint16)(block.size() - sizeof(quint16));

    QTcpSocket *clientConnection = tcpServer->nextPendingConnection();
    connect(clientConnection, SIGNAL(disconnected()),
            clientConnection, SLOT(deleteLater()));

    clientConnection->write(block);
    clientConnection->disconnectFromHost();
}