client.cpp Example File

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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());
  }