Multiple definitions of slots / QNetwork implementation

Rapishiny

Hello,

I am currently trying to send HTTP requests via QNetwork.

However, I have a "multiple definitions" error in the slots used to receive responses.

That's my code:

main.cpp

#include <QCoreApplication>
#include "Httpclient.h"
#include <QTextStream>
#include <iostream>

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

    HttpClient *client = new HttpClient();
    client->HttpRequest();

    std::cout << "End program" << std::endl;

    return a.exec();
}

HttpClient.cpp

#include "Httpclient.h"
#include <QTextCodec>
#include <iostream>

HttpClient::HttpClient()
{
    QNetworkAccessManager *mgr = new QNetworkAccessManager(this);
       QNetworkRequest req;
       req.setUrl(QUrl("http://google.com"));
       req.setRawHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.154 Safari/537.36");

       this->resp = mgr->get(req);
       connect(this->resp, SIGNAL(readyRead()),                          this, SLOT(slotReadyRead()));
       connect(this->resp, SIGNAL(error(QNetworkReply::NetworkError)),   this, SLOT(slotError(QNetworkReply::NetworkError)));
       connect(this->resp, SIGNAL(sslErrors(QList<QSslError>)),          this, SLOT(slotSslErrors(QList<QSslError>)));
}

void HttpClient::HttpRequest()
{
}

void HttpClient::slotReadyRead() {
    std::vector<char> buf;
    qint64 chunk;

    QString allbuf;

    while(resp->bytesAvailable() > 0) {
        chunk = this->resp->bytesAvailable();
        if(chunk > 4096)
            chunk = 4096;

        buf.resize(chunk + 1);
        memset(& buf[0], 0, chunk + 1);

        if(chunk != resp->read(& buf[0], chunk)) {
            qDebug("-> read error");
        } else {
            qDebug("-> read ok");
        }

        allbuf += & buf[0];
    }


    std::cout << allbuf.toUtf8().constData() << std::endl;
}

void HttpClient::slotError(QNetworkReply::NetworkError) {
}

void HttpClient::slotSslErrors(QList<QSslError>) {
}

HttpClient.h

#ifndef HTTPCLIENT_H
#define HTTPCLIENT_H

#include <QtNetwork/QNetworkAccessManager>
#include <QNetworkReply>
#include <QObject>

class HttpClient : public QObject
{
    Q_OBJECT

public:
    HttpClient();
    void HttpRequest();

private:
   QNetworkAccessManager *manager;
   QNetworkRequest request;
   QNetworkReply *resp;

signals:
    void slotReadyRead();
    void slotError(QNetworkReply::NetworkError);
    void slotSslErrors(QList<QSslError> );
};

#endif // HTTPCLIENT_H

Thank you for your help.

mrjj

Hi
What does the error say exactly?
normally it points to a symbol.
Is it the HttpClient::slotReadyRead() ?

I would do.
Delete build folder and rebuild all.
If error is still there.
Then check the .pro file if any files is added twice.

Rapishiny

Sorry I forgot to put the error....

/usr/bin/ld : moc_Httpclient.o : dans la fonction « HttpClient::slotReadyRead() » :
/home/ludo/Projets_epitech/build-TestHttp-Desktop_Qt_5_13_0_GCC_64bit-Debug/moc_Httpclient.cpp:175 : définitions multiples de « HttpClient::slotReadyRead() »; Httpclient.o:/home/ludo/Projets_epitech/build-TestHttp-Desktop_Qt_5_13_0_GCC_64bit-Debug/../TestHttp/Httpclient.cpp:22 : défini pour la première fois ici
/usr/bin/ld : moc_Httpclient.o : dans la fonction « HttpClient::slotError(QNetworkReply::NetworkError) » :
/home/ludo/Projets_epitech/build-TestHttp-Desktop_Qt_5_13_0_GCC_64bit-Debug/moc_Httpclient.cpp:181 : définitions multiples de « HttpClient::slotError(QNetworkReply::NetworkError) »; Httpclient.o:/home/ludo/Projets_epitech/build-TestHttp-Desktop_Qt_5_13_0_GCC_64bit-Debug/../TestHttp/Httpclient.cpp:49 : défini pour la première fois ici
/usr/bin/ld : moc_Httpclient.o : dans la fonction « HttpClient::slotSslErrors(QList<QSslError>) » :
/home/ludo/Projets_epitech/build-TestHttp-Desktop_Qt_5_13_0_GCC_64bit-Debug/moc_Httpclient.cpp:188 : définitions multiples de « HttpClient::slotSslErrors(QList<QSslError>) »; Httpclient.o:/home/ludo/Projets_epitech/build-TestHttp-Desktop_Qt_5_13_0_GCC_64bit-Debug/../TestHttp/Httpclient.cpp:53 : défini pour la première fois ici
collect2: error: ld returned 1 exit status
make: *** [Makefile:265: TestHttp] Error 1

I still have the error when deleting the build folder

And no files added twice in my .pro file:

QT -= gui
QT += network

CONFIG += c++11 console
CONFIG -= app_bundle

# The following define makes your compiler emit warnings if you use
# any Qt feature that has been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
        Httpclient.cpp \
        main.cpp

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

HEADERS += \
    Httpclient.h
``

mrjj

Hi
Hmm it does seems fine.
Its the fullproject/code so i can put in a defualt project to check it out ?

Also, you did try to delete the build folder completely ?

Rapishiny

Yes it's the full project.

I delete the folder "build-TestHttp-Desktop_Qt_5_13_0_GCC_64bit-Debug" created when i compile my project. I think it's the good folder.

mrjj

Hi
Im just blind :)
You have them listed under signals.
But its slots.
So when you list them as signals and then gives them body you get this error :)

so
public slots:
void slotReadyRead();
void slotError(QNetworkReply::NetworkError);
void slotSslErrors(QList<QSslError> );

fixes it.
(code runs and download something)

End program
-> read ok
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>301 Moved</TITLE></HEAD><BODY>
<H1>301 Moved</H1>
The document has moved
<A HREF="http://www.google.com/">here</A>.
</BODY></HTML>

mrjj

Hi
I bumped you so you dont have to wait so long to reply.
Regarding the build folder and deleting it.
if you use Creator, you can right click and go there directly.
Then ctrl+a and then delete key :)
alt text

Rapishiny

Spend two hours on it for that kind of mistake....

In any case it works!

Thanks!

mrjj

@rapishiny
Dont think about it. Shit happens.
I looked at it for several minutes after getting/reproducing same error before
i realized it. So it was slightly hard to detect as it was more logical than hard error.

SGaist

Hi,

Just in case, you are leaking QNetworkAccessManager objects in your HttpRequest method.