mainwindow.cpp Example File

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 #include <QtCore>
 #include <QtNetwork>

 #include "addressdialog.h"
 #include "association.h"
 #include "mainwindow.h"
 #include "ui_mainwindow.h"

 #include <utility>

 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent),
       ui(new Ui::MainWindow),
       nameTemplate(QStringLiteral("Alice (clone number %1)"))
 {
     ui->setupUi(this);
     updateUi();
 }

 MainWindow::~MainWindow()
 {
     delete ui;
 }


 const QString colorizer(QStringLiteral("<font color=\"%1\">%2</font><br>"));

 void MainWindow::addErrorMessage(const QString &message)
 {
     ui->clientMessages->insertHtml(colorizer.arg(QStringLiteral("Crimson"), message));
 }

 void MainWindow::addWarningMessage(const QString &message)
 {
     ui->clientMessages->insertHtml(colorizer.arg(QStringLiteral("DarkOrange"), message));
 }

 void MainWindow::addInfoMessage(const QString &message)
 {
     ui->clientMessages->insertHtml(colorizer.arg(QStringLiteral("DarkBlue"), message));
 }

 void MainWindow::addServerResponse(const QString &clientInfo, const QByteArray &datagram,
                                    const QByteArray &plainText)
 {
     static const QString messageColor = QStringLiteral("DarkMagenta");
     static const QString formatter = QStringLiteral("<br>---------------"
                                                     "<br>%1 received a DTLS datagram:<br> %2"
                                                     "<br>As plain text:<br> %3");

     const QString html = formatter.arg(clientInfo, QString::fromUtf8(datagram.toHex(' ')),
                                        QString::fromUtf8(plainText));
     ui->serverMessages->insertHtml(colorizer.arg(messageColor, html));
 }


 void MainWindow::on_connectButton_clicked()
 {
     if (lookupId != -1) {
         QHostInfo::abortHostLookup(lookupId);
         lookupId = -1;
         port = 0;
         updateUi();
         return;
     }

     AddressDialog dialog;
     if (dialog.exec() != QDialog::Accepted)
         return;

     const QString hostName = dialog.remoteName();
     if (hostName.isEmpty())
         return addWarningMessage(tr("Host name or address required to connect"));

     port = dialog.remotePort();
     QHostAddress remoteAddress;
     if (remoteAddress.setAddress(hostName))
         return startNewConnection(remoteAddress);

     addInfoMessage(tr("Looking up the host ..."));
     lookupId = QHostInfo::lookupHost(hostName, this, SLOT(lookupFinished(QHostInfo)));
     updateUi();
 }

 void MainWindow::updateUi()
 {
     ui->connectButton->setText(lookupId == -1 ? tr("Connect ...") : tr("Cancel lookup"));
     ui->shutdownButton->setEnabled(connections.size() != 0);
 }

 void MainWindow::lookupFinished(const QHostInfo &hostInfo)
 {
     if (hostInfo.lookupId() != lookupId)
         return;

     lookupId = -1;
     updateUi();

     if (hostInfo.error() != QHostInfo::NoError) {
         addErrorMessage(hostInfo.errorString());
         return;
     }

     const QList<QHostAddress> foundAddresses = hostInfo.addresses();
     if (foundAddresses.empty()) {
         addWarningMessage(tr("Host not found"));
         return;
     }

     const auto remoteAddress = foundAddresses.at(0);
     addInfoMessage(tr("Connecting to: %1").arg(remoteAddress.toString()));
     startNewConnection(remoteAddress);
 }

 void MainWindow::startNewConnection(const QHostAddress &address)
 {
     AssocPtr newConnection(new DtlsAssociation(address, port, nameTemplate.arg(nextId)));
     connect(newConnection.data(), &DtlsAssociation::errorMessage, this, &MainWindow::addErrorMessage);
     connect(newConnection.data(), &DtlsAssociation::warningMessage, this, &MainWindow::addWarningMessage);
     connect(newConnection.data(), &DtlsAssociation::infoMessage, this, &MainWindow::addInfoMessage);
     connect(newConnection.data(), &DtlsAssociation::serverResponse, this, &MainWindow::addServerResponse);
     connections.push_back(std::move(newConnection));
     connections.back()->startHandshake();
     updateUi();

     ++nextId;
 }

 void MainWindow::on_shutdownButton_clicked()
 {
     connections.clear();
     updateUi();
 }