QNetworkAccessManager finished signal error

[4j1th]

I want to download a token from server, I download files from the server before but this time the only change is the code is in a new header and source file.

updater.h :

#ifndef UPDATER_H
#define UPDATER_H

#include <QObject>
#include <QNetworkReply>
#include <QSettings>

class Updater : public QObject
{
    Q_OBJECT // Enable slots and signals

public:
    Updater();
    ~Updater();

private slots:
    void getTokenFinished(QNetworkReply* replay);

private:
    void getToken();

    void statusCheck();

    QString token;

    QSettings settings;
};

#endif // UPDATER_H

updater.cpp :

#include "updater.h"

#include <QDebug>
#include <QNetworkAccessManager>

Updater::Updater()
{
    this->getToken();
}

Updater::~Updater()
{

}

void Updater::getToken()
{
    QNetworkAccessManager *manager = new QNetworkAccessManager(this);
    QNetworkRequest request;

    request.setUrl(QUrl("http://localhost/cdms/pro/index.php/update/token?version=3.14&"
                        "lisenceRegis=1&onlineRegis=1&parishId=1"));

    request.setRawHeader("User-Agent", "MyOwnBrowser 1.0");
    QNetworkReply *replay = manager->get(request);
    qDebug() << request.url();

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

void Updater::getTokenFinished(QNetworkReply* replay)
{
    qDebug() << "finished";
    // Checking replay
    if (replay->isReadable()) {
        // Checking errors
        if(replay->error() == QNetworkReply::NoError) {
            QByteArray strreplay = replay->readAll();

            qDebug() << strreplay;
            if(strreplay != "0") {
                token = strreplay;
                qDebug() << token;
            }
        }
    }
}

void Updater::statusCheck()
{
}

php :

$token = "dfsdfs";
echo $token;

No error in build or running the code. finished signal isn't emitted or 'void Updater::getTokenFinished(QNetworkReply* replay)' didn't run.

[ccleung]

You should connect the readyRead() and error() signals of QNetworkReply *replay.

Please see the documentation: http://doc.qt.io/qt-5/qnetworkaccessmanager.html

[4j1th]

@ccleung but I don't get any signals

[mcosta]

HI,

is your request recevied from the running web server?

What is your environment? (Qt version, OS, ...)

[4j1th]

@mcosta I test the url on a browser and it worked, it's a LAMP server

environment : Qt 5.4.1, Ubuntu 12.04

the same code is run on main window class fine but I can't run the same network request on custom resource/header. I want to write the data updating section code on a different resource/header file.

[mcosta]

Hi,

when you run your Qt code, can you see the request on the server side? (apache access_log file for instance)?

what about remove the custom header? something changes?

[SGaist]

Hi,

Any chance of having something like:

void MyCoolClass::getUpate()
{
    Updater updater;
    updater.getToken();
}

?

[4j1th]

@mcosta Removed the header part but nothing on access log. I think the QNetworkAccessManager no even sending any request.

[4j1th]

@SGaist No luck.

[4j1th]

@SGaist @mcosta I think I got a clue, In

void MyCoolClass::getUpate()
{
     Updater updater;
     updater.getToken();
    
     this->runUpdate();
}

if I run both then only 'this->runUpdate();' call will work if commented out 'this->runUpdate();' then 'updater.getToken();' works.

void MyCoolClass::runUpdate()
{
    
    QNetworkAccessManager *manager = new QNetworkAccessManager(this);
    request.setUrl(QUrl("http://localhost/cdms/pro/index.php/update/linux?version=4.14&"
                        "lisenceRegis=1&onlineRegis=1"));

    QNetworkReply *reply = manager->get(request);

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


void CDMS::replyFinished(QNetworkReply * replay)
{

    // Checking replay
    if (replay->isReadable()) {

        // Checking errors
        if(replay->error() == QNetworkReply::NoError) {
            QByteArray strreplay = replay->readAll();

            // update ststus check
            if(strreplay != "0") {
               } else {
                ui->statusBar->showMessage("No new updates found", 10000);

                // run update on intervel in 30Minute
                QTimer::singleShot(1800000, this, SLOT(updateOnlineTimer()));

               
                // Run update on data and settings
                //Updater updateCDMSdata;
                //updateCDMSdata.getToken();

            }

        } else {
            ui->statusBar->showMessage(replay->errorString(), 10000);

            // run update on intervel in 1Minute
            QTimer::singleShot(60000, this, SLOT(updateOnlineTimer()));
        }
    }
}

I want to call the 'Updater' when the 'runUpdate' download finished.

[jsulm]

You create a local instance of Updater in this method:

void MyCoolClass::getUpate()
{
     Updater updater;
     updater.getToken();
    
     this->runUpdate();
}

As soon as this method finishes updater goes out of scope and is destroyed. That's why nothing is called. You must keep the instance until it finishes its work.

[4j1th]

Replace with this works fine

void MyCoolClass::getUpate()
{

 Updater *updateCDMSdata = new Updater;

 this->runUpdate();

}

[jsulm]

But now you have a memory leak: you do not delete updateCDMSdata

[SGaist]

To add to @jsulm, what does runUpdate do ? Call a function on updateCDMSdata ? If so you are lucky id doesn't crash.

If you will be using Updater several times then make it a member of your MyCoolClass object and don't forget to handle its deletion.

[4j1th]

@SGaist , runUpdate used to update the software and updateCDMSdata used to update data. I want to run data update when there is no software update, first check software update then from the 'finished(QNetworkReply*)' signal data update started.

I need to call updater several times, so I think use Updater as a member and delete on MyCoolClass::~MyCoolClass() is a better idea ?

[SGaist]

Since it's a QObject you can use the parent/child paradigm to let Qt handle the deletion for you.