server.cpp Example File

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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("Trolltech"));
         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("Trolltech"));
         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();
 }