Re: [Cppcms-users] CppCMS and QT

[Artyom <art...@ya...>]

> 
> my actual problem is that i want to use the  QNetworkAccessManager in a 
> cppcms application object to perform an external  https call which is 
> required for an authentication to an external 3rd party  provider. 
> actually i do something like this in the cppcms application  object:
> 
> QNetworkAccessManager * nmgr = new  QNetworkAccessManager();
> QNetworkReply * nrep =  nmgr->get(QNetworkRequest(url));
> if(!nrep->waitForReadyRead(30000))  {
>      // read failed
> } else {
>      QByteArray json  = nrep->readAll();
>      // do something with the json  data..
> }
> 
> when i run this i get the following runtime error from  qt:
> 
> QObject::startTimer: QTimer can only be used with threads started  with 
> QThread
> 
> this must originate inside the waitForReadyRead call  since the 
> QNetworkAccessManager works asynchronous..
> 
> the problem  according to the error message must be that the thread is 
> not created  through QThread and therefore misses some supplemental data 
> which hinders  QTimer on working. so my first thought was to gt the 
> cppcms application  somehow inside a QThread. of course i have no idea if 
> that's possible at  all..

I had found this:

http://doc.trolltech.com/qq/qq27-responsive-guis.html#waitinginalocaleventloop

Basically it is an example you may use as draft.

You need to have QCoreApplication created.

This simple example taken from Qt site works fine, even
not from the main thread:

#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QNetworkRequest>
#include <QUrl>
#include <QEventLoop>
#include <QTimer>
#include <QCoreApplication>
#include <iostream>


void *func(void *)
{
    QNetworkAccessManager manager;
    QEventLoop q;
    QTimer tT;

    tT.setSingleShot(true);
    QObject::connect(&tT, SIGNAL(timeout()), &q, SLOT(quit()));
    QObject::connect(&manager, SIGNAL(finished(QNetworkReply*)),
            &q, SLOT(quit()));
    QNetworkReply *reply = manager.get(QNetworkRequest(
                   QUrl("http://www.google.com")));

    tT.start(5000); // 5s timeout
    q.exec();

    if(tT.isActive()){
        // download complete
        std::cout << reply->readAll().data() << std::endl;
        tT.stop();
    } else {
        std::cout << "Timeout" << std::endl;
        // timeout
    }
    return 0;

}


int main(int argc,char **argv)
{
    QCoreApplication app(argc,argv);
    pthread_t pid;
    pthread_create(&pid,0,func,0);
    pthread_join(pid,0);

}

Best,
  Artyom