- Qt 5.5
- Qt Network
- Secure Socket Client Example
- sslclient.cpp Example File
- Qt 5.5.1 Reference Documentation

# sslclient.cpp Example File

securesocketclient/sslclient.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
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    ** This file is part of the examples of the Qt Toolkit.
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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());
    }