Qt 5.6 | Qt Network | Fortune Client Example | client.cpp Example File

Qt 5.6.2 Reference Documentation

# client.cpp Example File

fortuneclient/client.cpp

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      #include <QtWidgets>
      #include <QtNetwork>

      #include "client.h"

      Client::Client(QWidget *parent)
          : QDialog(parent)
          , hostCombo(new QComboBox)
          , portLineEdit(new QLineEdit)
          , getFortuneButton(new QPushButton(tr("Get Fortune")))
          , tcpSocket(new QTcpSocket(this))
          , blockSize(0)
          , networkSession(Q_NULLPTR)
      {
          setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
          hostCombo->setEditable(true);
          // find out name of this machine
          QString name = QHostInfo::localHostName();
          if (!name.isEmpty()) {
              hostCombo->addItem(name);
              QString domain = QHostInfo::localDomainName();
              if (!domain.isEmpty())
                  hostCombo->addItem(name + QChar('.') + domain);
          }
          if (name != QLatin1String("localhost"))
              hostCombo->addItem(QString("localhost"));
          // find out IP addresses of this machine
          QList<QHostAddress> ipAddressesList = QNetworkInterface::allAddresses();
          // add non-localhost addresses
          for (int i = 0; i < ipAddressesList.size(); ++i) {
              if (!ipAddressesList.at(i).isLoopback())
                  hostCombo->addItem(ipAddressesList.at(i).toString());
          }
          // add localhost addresses
          for (int i = 0; i < ipAddressesList.size(); ++i) {
              if (ipAddressesList.at(i).isLoopback())
                  hostCombo->addItem(ipAddressesList.at(i).toString());
          }

          portLineEdit->setValidator(new QIntValidator(1, 65535, this));

          QLabel *hostLabel = new QLabel(tr("&Server name:"));
          hostLabel->setBuddy(hostCombo);
          QLabel *portLabel = new QLabel(tr("S&erver port:"));
          portLabel->setBuddy(portLineEdit);

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

          getFortuneButton->setDefault(true);
          getFortuneButton->setEnabled(false);

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

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

          connect(hostCombo, &QComboBox::editTextChanged,
                  this, &Client::enableGetFortuneButton);
          connect(portLineEdit, &QLineEdit::textChanged,
                  this, &Client::enableGetFortuneButton);
          connect(getFortuneButton, &QAbstractButton::clicked,
                  this, &Client::requestNewFortune);
          connect(quitButton, &QAbstractButton::clicked, this, &QWidget::close);
          connect(tcpSocket, &QIODevice::readyRead, this, &Client::readFortune);
          typedef void (QAbstractSocket::*QAbstractSocketErrorSignal)(QAbstractSocket::SocketError);
          connect(tcpSocket, static_cast<QAbstractSocketErrorSignal>(&QAbstractSocket::error),
                  this, &Client::displayError);

          QGridLayout *mainLayout = Q_NULLPTR;
          if (QGuiApplication::styleHints()->showIsFullScreen() || QGuiApplication::styleHints()->showIsMaximized()) {
              QVBoxLayout *outerVerticalLayout = new QVBoxLayout(this);
              outerVerticalLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::Ignored, QSizePolicy::MinimumExpanding));
              QHBoxLayout *outerHorizontalLayout = new QHBoxLayout;
              outerHorizontalLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::MinimumExpanding, QSizePolicy::Ignored));
              QGroupBox *groupBox = new QGroupBox(QGuiApplication::applicationDisplayName());
              mainLayout = new QGridLayout(groupBox);
              outerHorizontalLayout->addWidget(groupBox);
              outerHorizontalLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::MinimumExpanding, QSizePolicy::Ignored));
              outerVerticalLayout->addLayout(outerHorizontalLayout);
              outerVerticalLayout->addItem(new QSpacerItem(0, 0, QSizePolicy::Ignored, QSizePolicy::MinimumExpanding));
          } else {
              mainLayout = new QGridLayout(this);
          }
          mainLayout->addWidget(hostLabel, 0, 0);
          mainLayout->addWidget(hostCombo, 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);

          setWindowTitle(QGuiApplication::applicationDisplayName());
          portLineEdit->setFocus();

          QNetworkConfigurationManager manager;
          if (manager.capabilities() & QNetworkConfigurationManager::NetworkSessionRequired) {
              // Get saved network configuration
              QSettings settings(QSettings::UserScope, QLatin1String("QtProject"));
              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, &QNetworkSession::opened, this, &Client::sessionOpened);

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

      void Client::requestNewFortune()
      {
          getFortuneButton->setEnabled(false);
          blockSize = 0;
          tcpSocket->abort();
          tcpSocket->connectToHost(hostCombo->currentText(),
                                   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, &Client::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()) &&
                                       !hostCombo->currentText().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("QtProject"));
          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();
      }