Qt 5.11 | Qt Network | Secure Socket Client Example | sslclient.cpp Example File

Qt 5.11.3 Reference Documentation

# sslclient.cpp Example File

securesocketclient/sslclient.cpp

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      #include "certificateinfo.h"
      #include "sslclient.h"

      #include "ui_sslclient.h"
      #include "ui_sslerrors.h"

      #include <QtCore>

      SslClient::SslClient(QWidget *parent)
          : QWidget(parent)
      {
          setupUi();
          setupSecureSocket();
      }

      SslClient::~SslClient()
      {
          delete form;
      }

      void SslClient::updateEnabledState()
      {
          const bool unconnected = socket->state() == QAbstractSocket::UnconnectedState;
          form->hostNameEdit->setReadOnly(!unconnected);
          form->hostNameEdit->setFocusPolicy(unconnected ? Qt::StrongFocus : Qt::NoFocus);
          form->hostNameLabel->setEnabled(unconnected);
          form->portBox->setEnabled(unconnected);
          form->portLabel->setEnabled(unconnected);
          form->connectButton->setEnabled(unconnected && !form->hostNameEdit->text().isEmpty());

          const bool connected = socket->state() == QAbstractSocket::ConnectedState;
          form->sessionOutput->setEnabled(connected);
          form->sessionInput->setEnabled(connected);
          form->sessionInputLabel->setEnabled(connected);
          form->sendButton->setEnabled(connected);
      }

      void SslClient::secureConnect()
      {
          socket->connectToHostEncrypted(form->hostNameEdit->text(), form->portBox->value());
          updateEnabledState();
      }

      void SslClient::socketStateChanged(QAbstractSocket::SocketState state)
      {
          if (executingDialog)
              return;

          updateEnabledState();

          if (state == QAbstractSocket::UnconnectedState) {
              form->sessionInput->clear();
              form->hostNameEdit->setPalette(QPalette());
              form->hostNameEdit->setFocus();
              form->cipherLabel->setText(tr("<none>"));
              padLock->hide();
          }
      }

      void SslClient::socketEncrypted()
      {
          form->sessionOutput->clear();
          form->sessionInput->setFocus();

          QPalette palette;
          palette.setColor(QPalette::Base, QColor(255, 255, 192));
          form->hostNameEdit->setPalette(palette);

          const QSslCipher cipher = socket->sessionCipher();
          const QString cipherInfo = QString("%1, %2 (%3/%4)").arg(cipher.authenticationMethod())
                                             .arg(cipher.name()).arg(cipher.usedBits())
                                             .arg(cipher.supportedBits());;
          form->cipherLabel->setText(cipherInfo);
          padLock->show();
      }

      void SslClient::socketReadyRead()
      {
          appendString(QString::fromUtf8(socket->readAll()));
      }

      void SslClient::sendData()
      {
          const QString input = form->sessionInput->text();
          appendString(input + '\n');
          socket->write(input.toUtf8() + "\r\n");
          form->sessionInput->clear();
      }

      void SslClient::socketError(QAbstractSocket::SocketError)
      {
          if (handlingSocketError)
              return;

          handlingSocketError = true;
          QMessageBox::critical(this, tr("Connection error"), socket->errorString());
          handlingSocketError = false;
      }

      void SslClient::sslErrors(const QList<QSslError> &errors)
      {
          QDialog errorDialog(this);
          Ui_SslErrors ui;
          ui.setupUi(&errorDialog);
          connect(ui.certificateChainButton, &QPushButton::clicked,
                  this, &SslClient::displayCertificateInfo);

          for (const auto &error : errors)
              ui.sslErrorList->addItem(error.errorString());

          executingDialog = true;
          if (errorDialog.exec() == QDialog::Accepted)
              socket->ignoreSslErrors();
          executingDialog = false;

          // did the socket state change?
          if (socket->state() != QAbstractSocket::ConnectedState)
              socketStateChanged(socket->state());
      }

      void SslClient::displayCertificateInfo()
      {
          CertificateInfo info;
          info.setCertificateChain(socket->peerCertificateChain());
          info.exec();
      }

      void SslClient::setupUi()
      {
          if (form)
              return;

          form = new Ui_Form;
          form->setupUi(this);
          form->hostNameEdit->setSelection(0, form->hostNameEdit->text().size());
          form->sessionOutput->setHtml(tr("&lt;not connected&gt;"));

          connect(form->hostNameEdit, SIGNAL(textChanged(QString)),
                  this, SLOT(updateEnabledState()));
          connect(form->connectButton, SIGNAL(clicked()),
                  this, SLOT(secureConnect()));
          connect(form->sendButton, SIGNAL(clicked()),
                  this, SLOT(sendData()));

          padLock = new QToolButton;
          padLock->setIcon(QIcon(":/encrypted.png"));
          connect(padLock, SIGNAL(clicked()), this, SLOT(displayCertificateInfo()));

      #if QT_CONFIG(cursor)
          padLock->setCursor(Qt::ArrowCursor);
      #endif
          padLock->setToolTip(tr("Display encryption details."));

          const int extent = form->hostNameEdit->height() - 2;
          padLock->resize(extent, extent);
          padLock->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Ignored);

          QHBoxLayout *layout = new QHBoxLayout(form->hostNameEdit);
          layout->setMargin(form->hostNameEdit->style()->pixelMetric(QStyle::PM_DefaultFrameWidth));
          layout->setSpacing(0);
          layout->addStretch();
          layout->addWidget(padLock);

          form->hostNameEdit->setLayout(layout);
          padLock->hide();
      }

      void SslClient::setupSecureSocket()
      {
          if (socket)
              return;

          socket = new QSslSocket(this);

          connect(socket, SIGNAL(stateChanged(QAbstractSocket::SocketState)),
                  this, SLOT(socketStateChanged(QAbstractSocket::SocketState)));
          connect(socket, SIGNAL(encrypted()),
                  this, SLOT(socketEncrypted()));
          connect(socket, SIGNAL(error(QAbstractSocket::SocketError)),
                  this, SLOT(socketError(QAbstractSocket::SocketError)));
          connect(socket, SIGNAL(sslErrors(QList<QSslError>)),
                  this, SLOT(sslErrors(QList<QSslError>)));
          connect(socket, SIGNAL(readyRead()),
                  this, SLOT(socketReadyRead()));

      }

      void SslClient::appendString(const QString &line)
      {
          QTextCursor cursor(form->sessionOutput->textCursor());
          cursor.movePosition(QTextCursor::End);
          cursor.insertText(line);
          form->sessionOutput->verticalScrollBar()->setValue(form->sessionOutput->verticalScrollBar()->maximum());
      }