client.cpp Example File
^{network/fortuneclient/client.cpp}

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    ** Copyright (C) 2004-2006 Trolltech ASA. All rights reserved.
    **
    ** This file is part of the documentation of the Qt Toolkit.
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    ** License version 2.0 as published by the Free Software Foundation
    ** and appearing in the file LICENSE.GPL included in the packaging of
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    #include <QtGui>
    #include <QtNetwork>

    #include "client.h"

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

        hostLineEdit = new QLineEdit("Localhost");
        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"));

        tcpSocket = new QTcpSocket(this);

        connect(hostLineEdit, SIGNAL(textChanged(const QString &)),
                this, SLOT(enableGetFortuneButton()));
        connect(portLineEdit, SIGNAL(textChanged(const 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)));

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

        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->addLayout(buttonLayout, 3, 0, 1, 2);
        setLayout(mainLayout);

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

    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(!hostLineEdit->text().isEmpty()
                                     && !portLineEdit->text().isEmpty());
    }