Problem with curl writefunction

**januszmk** · 26th July 2011, 11:47

Hello.
I have little problem.
I have functions:

Qt Code:

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size_t WriteData(void *ptr, size_t size, size_t nmemb, FILE *stream) {
    size_t written;
    written = fwrite(ptr, size, nmemb, stream);
    return written;
}
int MainWindow::progress_func(void* ptr, double TotalToDownload, double NowDownloaded, double TotalToUpload, double NowUploaded)
{
    ui->progressBar->setMaximum(TotalToDownload);
    ui->progressBar->setValue(NowDownloaded);
    double speed;
    curl_easy_getinfo(curl, CURLINFO_SPEED_DOWNLOAD, &speed);
    ui->label_2->setText(QString("PrÄ™dkoÅ›Ä‡: %0").arg(speed));
    return NowDownloaded;
}
bool MainWindow::downloadFile(QString url, QString filename)
{
    FILE *fp;
    fp = fopen(filename.toStdString().c_str(), "wb");
    ui->label->setText(filename);
    ui->label_2->setText("Predkosc: 0 KB/s");
    curl = curl_easy_init();
    curl_easy_setopt(curl, CURLOPT_AUTOREFERER, 1);
    curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
    curl_easy_setopt(curl, CURLOPT_USERAGENT, "User-Agent: Mozilla/5.0 (compatible;)");
    curl_easy_setopt(curl, CURLOPT_COOKIEFILE, "cookie");
    curl_easy_setopt(curl, CURLOPT_COOKIEJAR, "cookie");
    curl_easy_setopt(curl, CURLOPT_HEADER, 1);
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteData);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
    curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0);
    curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
    curl_easy_setopt(curl, CURLOPT_URL, url.toStdString().c_str());
    curl_easy_setopt(curl, CURLOPT_NOPROGRESS, FALSE);
    curl_easy_setopt(curl, CURLOPT_PROGRESSFUNCTION, &MainWindow::progress_func);
    curl_easy_setopt(curl, CURLOPT_PROGRESSDATA, this);
    status = curl_easy_perform(curl);
    if(status !=0)
        qDebug() << QString("curl_easy_perform() error: %0").arg(curl_easy_strerror(status));
    curl_easy_cleanup(curl);
    fclose(fp);
    return true;
}

size_t WriteData(void *ptr, size_t size, size_t nmemb, FILE *stream) {
    size_t written;
    written = fwrite(ptr, size, nmemb, stream);
    return written;
}
int MainWindow::progress_func(void* ptr, double TotalToDownload, double NowDownloaded, double TotalToUpload, double NowUploaded)
{
    ui->progressBar->setMaximum(TotalToDownload);
    ui->progressBar->setValue(NowDownloaded);
    double speed;
    curl_easy_getinfo(curl, CURLINFO_SPEED_DOWNLOAD, &speed);
    ui->label_2->setText(QString("PrÄ™dkoÅ›Ä‡: %0").arg(speed));
    return NowDownloaded;
}
bool MainWindow::downloadFile(QString url, QString filename)
{
    FILE *fp;
    fp = fopen(filename.toStdString().c_str(), "wb");
    ui->label->setText(filename);
    ui->label_2->setText("Predkosc: 0 KB/s");
    curl = curl_easy_init();
    curl_easy_setopt(curl, CURLOPT_AUTOREFERER, 1);
    curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
    curl_easy_setopt(curl, CURLOPT_USERAGENT, "User-Agent: Mozilla/5.0 (compatible;)");
    curl_easy_setopt(curl, CURLOPT_COOKIEFILE, "cookie");
    curl_easy_setopt(curl, CURLOPT_COOKIEJAR, "cookie");
    curl_easy_setopt(curl, CURLOPT_HEADER, 1);
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteData);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, fp);
    curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0);
    curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
    curl_easy_setopt(curl, CURLOPT_URL, url.toStdString().c_str());
    curl_easy_setopt(curl, CURLOPT_NOPROGRESS, FALSE);
    curl_easy_setopt(curl, CURLOPT_PROGRESSFUNCTION, &MainWindow::progress_func);
    curl_easy_setopt(curl, CURLOPT_PROGRESSDATA, this);
    status = curl_easy_perform(curl);
    if(status !=0)
        qDebug() << QString("curl_easy_perform() error: %0").arg(curl_easy_strerror(status));
    curl_easy_cleanup(curl);
    fclose(fp);
    return true;
}

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When I try to download a file, window of my aplication is frozen(?) until downloading is not finished.
Could you suggest what could I do to make this work?
Sory for my bad english
Janusz

**mcosta** · 26th July 2011, 17:00

A solution could be to execute this function in a separate thread.

Why you use CURL and not QtNetwork?

**januszmk** · 26th July 2011, 19:23

Thanks, when I execute function in another thread, it's start working. But progress function is still not working:

Qt Code:

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int MainWindow::progress_func(void* ptr, double TotalToDownload, double NowDownloaded, double TotalToUpload, double NowUploaded)
{
 
    int total = (int)TotalToDownload;
 
    ui->progressBar->setMaximum(total);
    int now = (int)NowDownloaded;
    ui->progressBar->setValue(now);
    qDebug() << QString("%0 : %1").arg(now).arg(total);
    double speed;
    curl_easy_getinfo(curl, CURLINFO_SPEED_DOWNLOAD, &speed);
    int speed1 = (int)speed;
    ui->label_2->setText(QString("Predkosc: %0 B/s").arg(speed1));
 //   qDebug() << speed;
    return NowDownloaded;
}

int MainWindow::progress_func(void* ptr, double TotalToDownload, double NowDownloaded, double TotalToUpload, double NowUploaded)
{

    int total = (int)TotalToDownload;

    ui->progressBar->setMaximum(total);
    int now = (int)NowDownloaded;
    ui->progressBar->setValue(now);
    qDebug() << QString("%0 : %1").arg(now).arg(total);
    double speed;
    curl_easy_getinfo(curl, CURLINFO_SPEED_DOWNLOAD, &speed);
    int speed1 = (int)speed;
    ui->label_2->setText(QString("Predkosc: %0 B/s").arg(speed1));
 //   qDebug() << speed;
    return NowDownloaded;
}

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now and total always = 0 why?
I am using curl because I have more experience with curl (from php), and in QtNetwork even if I used cookies, websites detect then I have disabled cookies.

**mcosta** · 26th July 2011, 19:31

First of all, these line are wrong

Qt Code:

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qDebug() << QString("%0 : %1").arg(now).arg(total);
ui->label_2->setText(QString("Predkosc: %0 B/s").arg(speed1));

qDebug() << QString("%0 : %1").arg(now).arg(total);
ui->label_2->setText(QString("Predkosc: %0 B/s").arg(speed1));

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the placeholder for arg are 1 based so you have to rewrite them as

Qt Code:

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qDebug() << QString("%1 : %2").arg(now).arg(total);
ui->label_2->setText(QString("Predkosc: %1 B/s").arg(speed1));

qDebug() << QString("%1 : %2").arg(now).arg(total);
ui->label_2->setText(QString("Predkosc: %1 B/s").arg(speed1));

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**januszmk** · 26th July 2011, 19:39

With arg there are no problem, because speed1 is showing property, but when I update progressbar, then i don't get property value. the value of double variable is something like that: "5.39501e-315" and when I am converting like that:

Qt Code:

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int var = (int)doublevar;

int var = (int)doublevar;

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then I get value 0

Edit:
I tried to do this like that:

Qt Code:

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int total = 100;
double temp = NowDownloaded/TotalToDownload;
temp = temp*100;
int total = round(temp);

int total = 100;
double temp = NowDownloaded/TotalToDownload;
temp = temp*100;
int total = round(temp);

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But when I downloading file, then on the start i get 99% and when i get couple of hundred KB (total is 19MB) then I get 100%

**januszmk** · 27th July 2011, 08:17

I make this work by:

Qt Code:

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double bytesRead;
    curl_easy_getinfo(curl, CURLINFO_SIZE_DOWNLOAD, &bytesRead);
    double totaltoread;
    curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &totaltoread);

double bytesRead;
    curl_easy_getinfo(curl, CURLINFO_SIZE_DOWNLOAD, &bytesRead);
    double totaltoread;
    curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &totaltoread);

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Thanks for all