QNetworkAccessManager - There is an extra "finished" signal at the end

Qtooc

Hello,

When I use a QNetworkAccessManager to download files I receive an extra / unwanted finished event.
If I want to download 2 files, my finished slot is called 3 times...
And the code is very simple...
I don't see what is wrong.

My class stores a vector of urls and variables for the current download :

std::vector<QUrl> m_vectorUrl;

std::vector<QUrl>::iterator m_currentUrlIt; // iterator on the url
QFile *m_currentFile; // to save the downloaded document
QNetworkReply *m_currentReply = nullptr;

To download all the urls :

void TestNetworkManager::DownloadAllUrls()
{
    m_currentUrlIt = std::begin(m_vectorUrl);
    DownloadUrl();
}

To download an url :

void TestNetworkManager::DownloadUrl()
{
    // No more url to read in the vector
    if (m_currentUrlIt == std::end(m_vectorUrl))
        return;

    // get url in url vector
    QUrl url = *m_currentUrlIt;

    // open file to save the download
    QString basename = url.host();
    m_currentFile = new QFile(basename);
    m_currentFile->open(QIODevice::WriteOnly);

    // Init download
    QNetworkRequest request(url);
    m_currentReply = m_netManager.get(request);

    connect(&m_netManager, &QNetworkAccessManager::finished, this, &TestNetworkManager::Finished);
    connect(m_currentReply, &QIODevice::readyRead, this,  &TestNetworkManager::ReadData);
}

The ReadData function :

void TestNetworkManager::ReadData()
{
    m_currentFile->write(m_currentReply->readAll());
}

The Finished function closes the file, increments the iterator to the next url in the vector and calls again DownloadUrl ():

void TestNetworkManager::Finished(QNetworkReply *r)
{
    // Close file
    m_currentFile->close();

    // prepare current values for the next url
    delete m_currentFile;
    m_currentReply->deleteLater();
    m_currentUrlIt++; // next url in url vector

    // download next url
    DownloadUrl();
}

If my vector contains 2 urls the Finished function is called 3 times.
And at the third time m_currentFile was deleted, the iterator is at the end of the vector, etc...

When DownloadAllUrls is called my DownloadUrl is called 3 times :
1- by DownloadAllUrls at the start
2- by the first Finished slot call
3- by the second Finished call : in this case DownloadUrl returns at the beginning and the connect functions are not called.

I don't know why my Finished slot is called 3 times...
Do you have an idea ?

Thanks for your help

Pablo J. Rogina

@Qtooc said in QNetworkAccessManager - There is an extra "finished" signal at the end:

connect(&m_netManager, &QNetworkAccessManager::finished, this, &TestNetworkManager::Finished);

It's not clear to me if that connection() happens inside the DownloadUrl() method.

If so, I guess that you're duplicating the connections. You have ONE QNAM so it's enough connecting only once the finished() signal...

Qtooc

Oh ! You have found immediatly !
If i had used the finished signal of the QNetworkReply the connect could be in my DownloadUrl function I think.
But I used the QNetworkManager without really thinking at what I was doing.

Thank you Pablo for your help !