Slot not called for signal finished of QNetworkAccessManager

Question

I want to send a post request to a server and I do something like this:

function makePost(){
    QNetworkAccessManager *networkManager = new QNetworkAccessManager();

    qDebug()<<"1";
    bool ret = connect(networkManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(serviceRequestFinished(QNetworkReply*)));
    qDebug()<<"2: " <<ret;

    QUrl serviceUrl = QUrl("http://someurl/json");
    QNetworkRequest request(serviceUrl);
    request.setHeader(QNetworkRequest::ContentTypeHeader, "application/json");

    QString content = "";
    networkManager->post(request, content.toUtf8());
}

But the slot serviceRequestFinished() is not called at all! I must mention that I used Wireshark to track the request/response and I found that the request(post) is being sent and the server returns a response back with status 200(ok). Also the ret variable returns true, i.e. the connection between signal and slot was made successfully. Any of you have any idea why this doesn't work? Thank you!:)

EDIT

The code that cause the problem - see my answer - is this:

{    
     MyObjectWithSlot obj;
     obj.makePost();
}

Is that all your code? You dont have a CONNECT(...) to connect the signal to a slot? — PureW, Feb 10 '15 at 13:48

score 4 · Accepted Answer · edited Jun 26 '15 at 14:58

4

Ok so I found my mistake! You can downvote as much as you want my answer or question but I would like to answer if someone else has a similar problem!

Be careful! The object that has the slot should be in scope and not terminate(destroyed) before the slot is called. As you can see in the edited part of my question, the object is created, it calls a function and then it's out of scope!

{
    MyObjectWithSlot obj;
    return obj.makePost();
}

edited Jun 26 '15 at 14:58

BaCaRoZzo

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answered Feb 11 '15 at 09:53

Ispas Claudiu

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Glad it worked out. I was about to ask where you defined your serviceRequestFinished(...) – PureW Feb 11 '15 at 09:54

score 0 · Answer 2 · edited Jun 26 '15 at 15:00

0

You need to tell Qt to connect the signal finished(), which is called when post() finishes, to a slot of your choice. Something like the following:

QObject::connect(networkManager, SIGNAL(finished(QNetworkReply*)),
                 this, SLOT(replyFinished(QNetworkReply*)));

For more information about signals and slots, see this page.

edited Jun 26 '15 at 15:00

BaCaRoZzo

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answered Feb 10 '15 at 13:52

PureW

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Slot not called for signal finished of QNetworkAccessManager

2 Answers2