Qt Reference Documentation

# client.cpp Example File

ipc/localfortuneclient/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)
     {
         hostLabel = new QLabel(tr("&Server name:"));
         hostLineEdit = new QLineEdit("fortune");

         hostLabel->setBuddy(hostLineEdit);

         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);

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

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

         socket = new QLocalSocket(this);

         connect(hostLineEdit, SIGNAL(textChanged(QString)),
                 this, SLOT(enableGetFortuneButton()));
         connect(getFortuneButton, SIGNAL(clicked()),
                 this, SLOT(requestNewFortune()));
         connect(quitButton, SIGNAL(clicked()), this, SLOT(close()));
         connect(socket, SIGNAL(readyRead()), this, SLOT(readFortune()));
         connect(socket, SIGNAL(error(QLocalSocket::LocalSocketError)),
                 this, SLOT(displayError(QLocalSocket::LocalSocketError)));

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

         setWindowTitle(tr("Fortune Client"));
         hostLineEdit->setFocus();
     }

     void Client::requestNewFortune()
     {
         getFortuneButton->setEnabled(false);
         blockSize = 0;
         socket->abort();
         socket->connectToServer(hostLineEdit->text());
     }

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

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

         if (in.atEnd())
             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(QLocalSocket::LocalSocketError socketError)
     {
         switch (socketError) {
         case QLocalSocket::ServerNotFoundError:
             QMessageBox::information(this, tr("Fortune Client"),
                                      tr("The host was not found. Please check the "
                                         "host name and port settings."));
             break;
         case QLocalSocket::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;
         case QLocalSocket::PeerClosedError:
             break;
         default:
             QMessageBox::information(this, tr("Fortune Client"),
                                      tr("The following error occurred: %1.")
                                      .arg(socket->errorString()));
         }

         getFortuneButton->setEnabled(true);
     }

     void Client::enableGetFortuneButton()
     {
         getFortuneButton->setEnabled(!hostLineEdit->text().isEmpty());
     }