Qt 5.11 | Qt Core | Local Fortune Client Example | client.cpp Example File

Qt 5.11.3 Reference Documentation

# client.cpp Example File

ipc/localfortuneclient/client.cpp

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      #include <QtWidgets>
      #include <QtNetwork>

      #include "client.h"

      Client::Client(QWidget *parent)
          : QDialog(parent),
            hostLineEdit(new QLineEdit("fortune")),
            getFortuneButton(new QPushButton(tr("Get Fortune"))),
            statusLabel(new QLabel(tr("This examples requires that you run the "
                                      "Local Fortune Server example as well."))),
            socket(new QLocalSocket(this))
      {
          setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
          QLabel *hostLabel = new QLabel(tr("&Server name:"));
          hostLabel->setBuddy(hostLineEdit);

          statusLabel->setWordWrap(true);

          getFortuneButton->setDefault(true);
          QPushButton *quitButton = new QPushButton(tr("Quit"));

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

          in.setDevice(socket);
          in.setVersion(QDataStream::Qt_5_10);

          connect(hostLineEdit, &QLineEdit::textChanged,
                  this, &Client::enableGetFortuneButton);
          connect(getFortuneButton, &QPushButton::clicked,
                  this, &Client::requestNewFortune);
          connect(quitButton, &QPushButton::clicked, this, &Client::close);
          connect(socket, &QLocalSocket::readyRead, this, &Client::readFortune);
          connect(socket, QOverload<QLocalSocket::LocalSocketError>::of(&QLocalSocket::error),
                  this, &Client::displayError);

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

          setWindowTitle(QGuiApplication::applicationDisplayName());
          hostLineEdit->setFocus();
      }

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

      void Client::readFortune()
      {
          if (blockSize == 0) {
              // Relies on the fact that QDataStream serializes a quint32 into
              // sizeof(quint32) bytes
              if (socket->bytesAvailable() < (int)sizeof(quint32))
                  return;
              in >> blockSize;
          }

          if (socket->bytesAvailable() < blockSize || in.atEnd())
              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(QLocalSocket::LocalSocketError socketError)
      {
          switch (socketError) {
          case QLocalSocket::ServerNotFoundError:
              QMessageBox::information(this, tr("Local Fortune Client"),
                                       tr("The host was not found. Please make sure "
                                          "that the server is running and that the "
                                          "server name is correct."));
              break;
          case QLocalSocket::ConnectionRefusedError:
              QMessageBox::information(this, tr("Local Fortune Client"),
                                       tr("The connection was refused by the peer. "
                                          "Make sure the fortune server is running, "
                                          "and check that the server name "
                                          "is correct."));
              break;
          case QLocalSocket::PeerClosedError:
              break;
          default:
              QMessageBox::information(this, tr("Local Fortune Client"),
                                       tr("The following error occurred: %1.")
                                       .arg(socket->errorString()));
          }

          getFortuneButton->setEnabled(true);
      }

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