Qt 5.6 | Qt Network | Secure Socket Client Example | sslclient.cpp Example File

Qt 5.6.2 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 <QtWidgets/QScrollBar>
      #include <QtWidgets/QStyle>
      #include <QtWidgets/QToolButton>
      #include <QtWidgets/QMessageBox>
      #include <QtNetwork/QSslCipher>

      SslClient::SslClient(QWidget *parent)
          : QWidget(parent), socket(0), padLock(0), executingDialog(false)
      {
          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()));
      }

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

      void SslClient::updateEnabledState()
      {
          bool unconnected = !socket || 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());

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

      void SslClient::secureConnect()
      {
          if (!socket) {
              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()));
          }

          socket->connectToHostEncrypted(form->hostNameEdit->text(), form->portBox->value());
          updateEnabledState();
      }

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

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

      void SslClient::socketEncrypted()
      {
          if (!socket)
              return;                 // might have disconnected already

          form->sessionOutput->clear();
          form->sessionInput->setFocus();

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

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

          if (!padLock) {
              padLock = new QToolButton;
              padLock->setIcon(QIcon(":/encrypted.png"));
      #ifndef QT_NO_CURSOR
              padLock->setCursor(Qt::ArrowCursor);
      #endif
              padLock->setToolTip(tr("Display encryption details."));

              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);

              connect(padLock, SIGNAL(clicked()),
                      this, SLOT(displayCertificateInfo()));
          } else {
              padLock->show();
          }
      }

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

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

      void SslClient::socketError(QAbstractSocket::SocketError)
      {
          QMessageBox::critical(this, tr("Connection error"), socket->errorString());
      }

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

          foreach (const QSslError &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 = new CertificateInfo(this);
          info->setCertificateChain(socket->peerCertificateChain());
          info->exec();
          info->deleteLater();
      }

      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());
      }