Qt 5.6 | Qt Core | Local Fortune Client Example | client.cpp Example File

Qt 5.6.2 Reference Documentation

# client.cpp Example File

ipc/localfortuneclient/client.cpp

      /****************************************************************************
      **
      ** Copyright (C) 2015 The Qt Company Ltd.
      ** Contact: http://www.qt.io/licensing/
      **
      ** 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 The Qt Company Ltd 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 <QtWidgets>
      #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."));
          statusLabel->setWordWrap(true);

          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());
      }