I spend all the RAM downloading a file

leonardogsu

Hi,
Im new in QT and when I try to download a file (9GB) I spend all my RAM, I would like to know how can I store the temporaly file in the hard drive instead to the RAM. If the size of the file is smaller than my system available RAM, I be able to download it.
Im using the code from bogotobongo
thanks!

//
#ifndef DOWNLOADER_H
#define DOWNLOADER_H

#include <QObject>
#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QNetworkReply>
#include <QUrl>
#include <QDateTime>
#include <QFile>
#include <QDebug>


class Downloader : public QObject
{
    Q_OBJECT
public:
    explicit Downloader(QObject *parent = 0);

    void doDownload();

signals:

public slots:
    void replyFinished (QNetworkReply *reply);

private:
   QNetworkAccessManager *manager;

};

//void Downloader::doDownload()
{
    manager = new QNetworkAccessManager(this);

    connect(manager, SIGNAL(finished(QNetworkReply*)),
            this, SLOT(replyFinished(QNetworkReply*)));

    manager->get(QNetworkRequest(QUrl("http://bogotobogo.com")));
}

//void Downloader::replyFinished (QNetworkReply *reply)
{
    if(reply->error())
    {
        qDebug() << "ERROR!";
        qDebug() << reply->errorString();
    }
    else
    {
        qDebug() << reply->header(QNetworkRequest::ContentTypeHeader).toString();
        qDebug() << reply->header(QNetworkRequest::LastModifiedHeader).toDateTime().toString();;
        qDebug() << reply->header(QNetworkRequest::ContentLengthHeader).toULongLong();
        qDebug() << reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
        qDebug() << reply->attribute(QNetworkRequest::HttpReasonPhraseAttribute).toString();

        QFile *file = new QFile("C:/Qt/Dummy/downloaded.txt");
        if(file->open(QFile::Append))
        {
            file->write(reply->readAll());
            file->flush();
            file->close();
        }
        delete file;
    }

    reply->deleteLater();
}

Paul Colby

Hi @leonardogsu,

Connect to the QNetworkReply::downloadProgress() signal, and write (append) the available bytes to a temporary file in that slot. Then use that temporary file however you like once QNetworkReply::finished() is emitted.

Cheers.

? Offline

Hi! The following...

 manager->get(QNetworkRequest(QUrl("http://bogotobogo.com")));

... returns a QNetworkReply *. QNetworkReply inherits from QIODevice; and you'd usually use [signal] void QIODevice::readyRead() and [virtual] qint64 QIODevice::bytesAvailable() const to react to incoming data.

Edit: The good old Fortune Client Example shows how to do it; it uses a QTcpSocket but that makes no difference as both, QTcpSocket and QNetworkReply, are QIODevices.