QNetworkAccessManager is not sending data part of POST request

CupaMurdosan

When sending POST data to server, from Qt application looks everything good but data part of HTTP part were not sent. In Wireshark in POST packet is visible correct "Content-Length" value but size of whole HTTP segment is only about 226 bytes (is independent on POST data size).

Here is simplified source code:

project.pro:

QT += widgets
QT -= gui
QT += network

CONFIG += c++11

TARGET = POSTrequest
CONFIG += console
CONFIG -= app_bundle

TEMPLATE = app

SOURCES += main.cpp

main.cpp:

#include <QObject>
#include <QApplication>
#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QUrl>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QNetworkAccessManager manager;
    QByteArray array = "a=aaaaaaaaaaaaaa..."; // content length > 500
    QNetworkRequest r( QUrl("http://www.server.com/index.php") );
    r.setHeader(QNetworkRequest::ContentTypeHeader, "application/x-www-form-urlencoded");

    QEventLoop loop;
    QObject::connect(&manager, SIGNAL(finished(QNetworkReply *)), &loop, SLOT(quit()));
    
    manager.post(r, array);

    loop.exec();

    return a.exec();
}

I can't find reason why data part is not send. What I doing wrong? Or, its bug?
Application is running in console.
Using Qt 5.6.0.

Paul Colby

Hi @CupaMurdosan,

Why are you instantiating your own QEventLoop?

What happens if you leave out the QEventLoop entirely (I don't think it should be necessary). Instead of connecting to the loop's quit slot, you should be able to connect to the application's quit slot directly, eg:

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    ...

    //QEventLoop loop;
    //QObject::connect(&manager, SIGNAL(finished(QNetworkReply *)), &loop, SLOT(quit()));
    QObject::connect(&manager, SIGNAL(finished(QNetworkReply *)), &a, SLOT(quit()));
    
    manager.post(r, array);

    //loop.exec();

    return a.exec();
}

Give that a go :)

SGaist

Hi and welcome to devnet,

To add to @paul-colby, you should also connect the error signal to see whether there's something wrong going on.

CupaMurdosan

Thank you guys for your replies. Problem is solved - I was wrong with wireshark - data were sent in another packet [TCP segment of a reassembled PDU].