downloader.cpp Example File

 /****************************************************************************
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
 ** Contact: http://www.qt.io/licensing/
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** 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 <QFileDialog>
 #include <QMessageBox>
 #include <QNetworkRequest>
 #include <QNetworkReply>
 #include "downloader.h"

 Downloader::Downloader(QWidget *parentWidget, QNetworkAccessManager *manager)
     : QObject(parentWidget), manager(manager), parentWidget(parentWidget)
 {
 }

 QString Downloader::chooseSaveFile(const QUrl &url)
 {
     QString fileName = url.path().split("/").last();
     if (!path.isEmpty())
         fileName = QDir(path).filePath(fileName);

     return QFileDialog::getSaveFileName(parentWidget, tr("Save File"), fileName);
 }

 void Downloader::startDownload(const QNetworkRequest &request)
 {
     downloads[request.url().toString()] = chooseSaveFile(request.url());

     QNetworkReply *reply = manager->get(request);
     connect(reply, SIGNAL(finished()), this, SLOT(finishDownload()));
 }

 void Downloader::saveFile(QNetworkReply *reply)
 {
     QString newPath = downloads[reply->url().toString()];

     if (newPath.isEmpty())
         newPath = chooseSaveFile(reply->url());

     if (!newPath.isEmpty()) {
         QFile file(newPath);
         if (file.open(QIODevice::WriteOnly)) {
             file.write(reply->readAll());
             file.close();
             path = QDir(newPath).dirName();
             QMessageBox::information(parentWidget, tr("Download Completed"),
                                      tr("Saved '%1'.").arg(newPath));
         } else
             QMessageBox::warning(parentWidget, tr("Download Failed"),
                                  tr("Failed to save the file."));
     }
 }

 void Downloader::finishDownload()
 {
     QNetworkReply *reply = static_cast<QNetworkReply *>(sender());
     saveFile(reply);
     downloads.remove(reply->url().toString());
     reply->deleteLater();
 }