QTcpSocket how to return QString - qt

Question

I have a service: GWT client calls QT QTcpSocket function that make a request to a device and gets responses(it cannot be only the one response. I should waiting for all of them).
According to the QT documentation I can't use waitForReadyRead() function because I use Windows platform.
Note: This function may fail randomly on Windows. Consider using the
event loop and the readyRead() signal if your software will run on
Windows. http://doc.qt.io/qt-5/qabstractsocket.html#waitForReadyRead
I have only one decision now:
pseudo code:
QString MainQTFunc() {
create new thread;
while (!thread.isStopped()) {
sleep(x);
}
return QString variable from thread to GWT client;
}
New Thread {
run() {
make a TcpRequest to the device...
}
boolean isStopped() {
if(we got the response!!!) {
return true;
}
}
}
Does it the best solution to do so? I can't understand how to send simply QString variable after I get the result. Is it really impossible to the powerful QT?
Now I have(without any threads):
// The function should to return QString to the GWT client
QString MainWindow::TcpConnect(QByteArray data) {
_pSocket = new QTcpSocket( this );
connect( _pSocket, SIGNAL(readyRead()), SLOT(readTcpData()) );
connect( _pSocket, SIGNAL(connected()), SLOT(connected()) );
connect( _pSocket, SIGNAL(disconnected()), SLOT(disconnected()) );
dataGlobal = data;
_pSocket->connectToHost("IP", port);
//waiting here for all responses and sendinig the last response
return responseHexGlobal;
}
void MainWindow::connected() {
qDebug() << "connected. " << QDateTime::currentDateTime();
_pSocket->write( dataGlobal );
}
void MainWindow::disconnected() {
qDebug() << "disconnected. " << QDateTime::currentDateTime();
}
void MainWindow::readTcpData()
{
QByteArray data = _pSocket->readAll();
QByteArray as_hex_string = data.toHex();
QString response = QString(as_hex_string);
if(some condition here...) {
responseHexGlobal = response;
_pSocket->disconnectFromHost();
}
}

Answer 1

It's the best solution I've found. It works, but I don't like it
QString JSPrinter::connectTcp(QByteArray data) {
QTimer timer;
timer.setSingleShot(true);
QEventLoop loop;
_pSocket = new QTcpSocket( this ); // <-- needs to be a member variable: QTcpSocket * _pSocket;
connect( _pSocket, SIGNAL(readyRead()), SLOT(readTcpData()) );
connect( _pSocket, SIGNAL(connected()), SLOT(connected()) );
connect( _pSocket, SIGNAL(disconnected()), SLOT(disconnected()) );
connect( &timer, SIGNAL(timeout()), &loop, SLOT(quit()) );
loop.connect( this, SIGNAL(exitLoop()), SLOT(quit()) );
dataGlobal = data;
_pSocket->connectToHost(ip_, port_);
timer.start(75000);
loop.exec();
if(timer.isActive())
logger()->info("ok");
else
logger()->info("timeout");
return responseHexGlobal;
}
void JSPrinter::connected() {
qDebug() << "connected. " << QDateTime::currentDateTime();
_pSocket->write( dataGlobal );
}
void JSPrinter::disconnected() {
qDebug() << "disconnected. " << QDateTime::currentDateTime();
}
void JSPrinter::readTcpData() {
QByteArray data = _pSocket->readAll();
QByteArray as_hex_string = data.toHex();
std::string stdString(as_hex_string.constData(), as_hex_string.length());
qDebug() << "readTcpData response " << QDateTime::currentDateTime() << QString::fromStdString(stdString);
// doing something...
if(condition) {
responseHexGlobal = received;
qDebug() << "responseHexGlobal " << responseHexGlobal;
emit exitLoop();
_pSocket->disconnectFromHost();
} else {
emit exitLoop();
_pSocket->disconnectFromHost();
return;
}
}