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#include <QCoreApplication>

#include <QFile>

#include <QFileInfo>

#include <QList>

#include <QNetworkAccessManager>

#include <QNetworkRequest>

#include <QNetworkReply>

#include <QStringList>

#include <QTimer>

#include <QUrl>

#include <stdio.h>

class DownloadManager: public QObject

{

    Q_OBJECT

    QNetworkAccessManager manager;

    QList<QNetworkReply *> currentDownloads;

public:

    DownloadManager();

    void doDownload(const QUrl &url);

    QString saveFileName(const QUrl &url);

    bool saveToDisk(const QString &filename, QIODevice *data);

public slots:

    void execute();

    void downloadFinished(QNetworkReply *reply);

};

DownloadManager::DownloadManager()

{

    connect(&manager, SIGNAL(finished(QNetworkReply*)),

            SLOT(downloadFinished(QNetworkReply*)));

}

void DownloadManager::doDownload(const QUrl &url)

{

    QNetworkRequest request(url);

    QNetworkReply *reply = manager.get(request);

    currentDownloads.append(reply);

}

QString DownloadManager::saveFileName(const QUrl &url)

{

    QString path = url.path();

    QString basename = QFileInfo(path).fileName();

    if (basename.isEmpty())

        basename = "download";

    if (QFile::exists(basename)) {

        // already exists, don't overwrite

        int i = 0;

        basename += '.';

        while (QFile::exists(basename + QString::number(i)))

            ++i;

        basename += QString::number(i);

    }

    return basename;

}

bool DownloadManager::saveToDisk(const QString &filename, QIODevice *data)

{

    QFile file(filename);

    if (!file.open(QIODevice::WriteOnly)) {

        fprintf(stderr, "Could not open %s for writing: %s\n",

                qPrintable(filename),

                qPrintable(file.errorString()));

        return false;

    }

    file.write(data->readAll());

    file.close();

    return true;

}

void DownloadManager::execute()

{

    QStringList args = QCoreApplication::instance()->arguments();

    args.takeFirst();           // skip the first argument, which is the program's name

    if (args.isEmpty()) {

        printf("Qt Download example - downloads all URLs in parallel\n"

               "Usage: download url1 [url2... urlN]\n"

               "\n"

               "Downloads the URLs passed in the command-line to the local directory\n"

               "If the target file already exists, a .0, .1, .2, etc. is appended to\n"

               "differentiate.\n");

        QCoreApplication::instance()->quit();

        return;

    }

    foreach (QString arg, args) {

        QUrl url = QUrl::fromEncoded(arg.toLocal8Bit());

        doDownload(url);

    }

}

void DownloadManager::downloadFinished(QNetworkReply *reply)

{

    QUrl url = reply->url();

    if (reply->error()) {

        fprintf(stderr, "Download of %s failed: %s\n",

                url.toEncoded().constData(),

                qPrintable(reply->errorString()));

    } else {

        QString filename = saveFileName(url);

        if (saveToDisk(filename, reply))

            printf("Download of %s succeded (saved to %s)\n",

                   url.toEncoded().constData(), qPrintable(filename));

    }

    currentDownloads.removeAll(reply);

    reply->deleteLater();

    if (currentDownloads.isEmpty())

        // all downloads finished

        QCoreApplication::instance()->quit();

}

int main(int argc, char **argv)

{

    QCoreApplication app(argc, argv);

    DownloadManager manager;

    QTimer::singleShot(0, &manager, SLOT(execute()));

    app.exec();

}

#include "main.moc"