mainwindow.cpp Example File

secureudpclient/mainwindow.cpp

  /****************************************************************************
  **
  ** Copyright (C) 2018 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** "Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
  **
  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/

  #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();
  }