Access network using QNetworkaccessmanger doesn’t work on seperate class

[dineshkumar]

Hi, i have created a c++ header file for network access and i am able access the network when i create instance in main.cpp, but it is not working(only network access like get,post… remains works fine) when i call it on a separate class.

Sync_Network.h

#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QNetworkRequest>
#include <QDebug>
#include <QUrl>
class Sync_Network:public QNetworkAccessManager{
    Q_OBJECT
    public:
        Sync_Network(QString url,QObject *parent=0):QNetworkAccessManager(parent),host(url){
connect(this,SIGNAL(finished(QNetworkReply*)),this,SLOT(showReply(QNetworkReply*)));
}
        virtual ~Sync_Network(){}
        bool Sync_Get(const QString path){
             get(QNetworkRequest(QUrl(host+""+path)));
             return status;
        }
        bool Sync_Post(QString params,QString path=""){
            QByteArray data;
            data.append(params);
            post(QNetworkRequest(QUrl(host+""+path)),data);
            return status;
        }
    protected slots:
        virtual void showReply(QNetworkReply *reply){
            if(!reply->error()) qDebug()<<reply->readAll();
            else{
                status=false;
                qDebug()<<reply->errorString();
            }
        }
    private:
        bool status;
        QString host;
};

#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QNetworkRequest>
#include <QDebug>
#include <QUrl>
class Sync_Network:public QNetworkAccessManager{
    Q_OBJECT
    public:
        Sync_Network(QString url,QObject *parent=0):QNetworkAccessManager(parent),host(url){
connect(this,SIGNAL(finished(QNetworkReply*)),this,SLOT(showReply(QNetworkReply*)));
}
        virtual ~Sync_Network(){}
        bool Sync_Get(const QString path){
             get(QNetworkRequest(QUrl(host+""+path)));
             return status;
        }
        bool Sync_Post(QString params,QString path=""){
            QByteArray data;
            data.append(params);
            post(QNetworkRequest(QUrl(host+""+path)),data);
            return status;
        }
    protected slots:
        virtual void showReply(QNetworkReply *reply){
            if(!reply->error()) qDebug()<<reply->readAll();
            else{
                status=false;
                qDebug()<<reply->errorString();
            }
        }
    private:
        bool status;
        QString host;
};

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tweet.cpp

#include "Sync_Network.h"
 
Tweet::Tweet(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::Tweet)
{
    ui->setupUi(this);
    Sync_Network s("http://www.capeconsultancy.com");
    s.Sync_Get("/aboutus");
    s.Sync_Post("<tweet><username>dinesh</username><passowrd>123456</password></tweet>");
}

#include "Sync_Network.h"
 
Tweet::Tweet(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::Tweet)
{
    ui->setupUi(this);
    Sync_Network s("http://www.capeconsultancy.com");
    s.Sync_Get("/aboutus");
    s.Sync_Post("<tweet><username>dinesh</username><passowrd>123456</password></tweet>");
}

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Please help me. Thanks in advance

[helloworld]

I think it is because 's' falls out of scope and is destroyed.. change your code to:

{
    ui->setupUi(this);
    Sync_Network* s = new Sync_Network("http://www.capeconsultancy.com", this);
    s->Sync_Get("/aboutus");
    s->Sync_Post("<tweet><username>dinesh</username><passowrd>123456</password></tweet>");
}

{
    ui->setupUi(this);
    Sync_Network* s = new Sync_Network("http://www.capeconsultancy.com", this);
    s->Sync_Get("/aboutus");
    s->Sync_Post("<tweet><username>dinesh</username><passowrd>123456</password></tweet>");
}

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Edit: That is, it is not synchronous at all, so it's not really a good solution, but it solves the problem of the signal not being emitted.

What you want is probably Sync_Get to wait before returning:

get(QNetworkRequest(QUrl(host+""+path)));
loop.exec();

get(QNetworkRequest(QUrl(host+""+path)));
loop.exec();

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then in showReply(QNetworkReply *reply), you exit the event loop:

loop.exit();

loop.exit();

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private:
      bool status;
      QString host;
      QEventLoop loop;

private:
      bool status;
      QString host;
      QEventLoop loop;

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.. then you can create your Sync_Network on the stack without it being destroyed before the reply is received.