Qt Reference Documentation

# client.cpp Example File

network/fortuneclient/client.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** You may use this file under the terms of the BSD license as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
     **     the names of its contributors may be used to endorse or promote
     **     products derived from this software without specific prior written
     **     permission.
     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #include <QtGui>
     #include <QtNetwork>

     #include "client.h"

     Client::Client(QWidget *parent)
     :   QDialog(parent), networkSession(0)
     {
         hostLabel = new QLabel(tr("&Server name:"));
         portLabel = new QLabel(tr("S&erver port:"));

         // find out which IP to connect to
         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();

         hostLineEdit = new QLineEdit(ipAddress);
         portLineEdit = new QLineEdit;
         portLineEdit->setValidator(new QIntValidator(1, 65535, this));

         hostLabel->setBuddy(hostLineEdit);
         portLabel->setBuddy(portLineEdit);

         statusLabel = new QLabel(tr("This examples requires that you run the "
                                     "Fortune Server example as well."));

         getFortuneButton = new QPushButton(tr("Get Fortune"));
         getFortuneButton->setDefault(true);
         getFortuneButton->setEnabled(false);

         quitButton = new QPushButton(tr("Quit"));

         buttonBox = new QDialogButtonBox;
         buttonBox->addButton(getFortuneButton, QDialogButtonBox::ActionRole);
         buttonBox->addButton(quitButton, QDialogButtonBox::RejectRole);

         tcpSocket = new QTcpSocket(this);

         connect(hostLineEdit, SIGNAL(textChanged(QString)),
                 this, SLOT(enableGetFortuneButton()));
         connect(portLineEdit, SIGNAL(textChanged(QString)),
                 this, SLOT(enableGetFortuneButton()));
         connect(getFortuneButton, SIGNAL(clicked()),
                 this, SLOT(requestNewFortune()));
         connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
         connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(readFortune()));
         connect(tcpSocket, SIGNAL(error(QAbstractSocket::SocketError)),
                 this, SLOT(displayError(QAbstractSocket::SocketError)));

         QGridLayout *mainLayout = new QGridLayout;
         mainLayout->addWidget(hostLabel, 0, 0);
         mainLayout->addWidget(hostLineEdit, 0, 1);
         mainLayout->addWidget(portLabel, 1, 0);
         mainLayout->addWidget(portLineEdit, 1, 1);
         mainLayout->addWidget(statusLabel, 2, 0, 1, 2);
         mainLayout->addWidget(buttonBox, 3, 0, 1, 2);
         setLayout(mainLayout);

         setWindowTitle(tr("Fortune Client"));
         portLineEdit->setFocus();

         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()));

             getFortuneButton->setEnabled(false);
             statusLabel->setText(tr("Opening network session."));
             networkSession->open();
         }
     }

     void Client::requestNewFortune()
     {
         getFortuneButton->setEnabled(false);
         blockSize = 0;
         tcpSocket->abort();
         tcpSocket->connectToHost(hostLineEdit->text(),
                                  portLineEdit->text().toInt());
     }

     void Client::readFortune()
     {
         QDataStream in(tcpSocket);
         in.setVersion(QDataStream::Qt_4_0);

         if (blockSize == 0) {
             if (tcpSocket->bytesAvailable() < (int)sizeof(quint16))
                 return;

             in >> blockSize;
         }

         if (tcpSocket->bytesAvailable() < blockSize)
             return;

         QString nextFortune;
         in >> nextFortune;

         if (nextFortune == currentFortune) {
             QTimer::singleShot(0, this, SLOT(requestNewFortune()));
             return;
         }

         currentFortune = nextFortune;
         statusLabel->setText(currentFortune);
         getFortuneButton->setEnabled(true);
     }

     void Client::displayError(QAbstractSocket::SocketError socketError)
     {
         switch (socketError) {
         case QAbstractSocket::RemoteHostClosedError:
             break;
         case QAbstractSocket::HostNotFoundError:
             QMessageBox::information(this, tr("Fortune Client"),
                                      tr("The host was not found. Please check the "
                                         "host name and port settings."));
             break;
         case QAbstractSocket::ConnectionRefusedError:
             QMessageBox::information(this, tr("Fortune Client"),
                                      tr("The connection was refused by the peer. "
                                         "Make sure the fortune server is running, "
                                         "and check that the host name and port "
                                         "settings are correct."));
             break;
         default:
             QMessageBox::information(this, tr("Fortune Client"),
                                      tr("The following error occurred: %1.")
                                      .arg(tcpSocket->errorString()));
         }

         getFortuneButton->setEnabled(true);
     }

     void Client::enableGetFortuneButton()
     {
         getFortuneButton->setEnabled((!networkSession || networkSession->isOpen()) &&
                                      !hostLineEdit->text().isEmpty() &&
                                      !portLineEdit->text().isEmpty());

     }

     void Client::sessionOpened()
     {
         // Save the used configuration
         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();

         statusLabel->setText(tr("This examples requires that you run the "
                                 "Fortune Server example as well."));

         enableGetFortuneButton();
     }