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.

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QNetworkAccessManager finished signal error