How to send QMap over socket?

[YouKnowMe]

Hello everybody,

I have a QMap object:

QMap<QString, int> map; 

and I would like to send it over TCP socket. Is there a way to do that somehow?

[VRonin]

QDataStream stream(socket);
stream << map;

[fcarney]

@VRonin said in How to send QMap over socket?:

stream << map;

Did not expect that. Apparently a lot of Qt objects have serialization operators defined for them. Mind blown! Really, really, really cool!

[arsinte_andrei]

to send as QByteArray

QByteArray atpCommandCentre::messageToQByteArray(const QMap<QString, int> data)  {
	qDebug() <<this << "messageToQByteArray" << data;
	QByteArray ar;
	QDataStream out(&ar,QIODevice::WriteOnly); //Serializing
	out << data; // write the data

	return ar;
}

On Server or where you have to read it back to QMap

QMap<QString, int> atpCommandCentre::messageFromQByteArray(QByteArray data) {
	qDebug() <<this << "messageFromQByteArray" << data;
	QMap<QString, int> myTmpMessage;
	QDataStream in(&data, QIODevice::ReadOnly); //Deserializing
	in >> myTmpMessage;

	return myTmpMessage;
}

Hope that help you

[arsinte_andrei]

Anyway, I do think that this post can be safely marked as Solved now, in order for others to know that it has been solved.

[YouKnowMe]

@arsinte_andrei when I qDebug "out" variable, it says: QVariant(Invalid)... is that ok? I have some problems receiving the data, so I'm trying to find out whats wrong step by step.

[VRonin]

@YouKnowMe said in How to send QMap over socket?:

when I qDebug "out" variable, it says: QVariant(Invalid)

What is out?

if the one socket sends:

QDataStream stream(socket);
stream << map;

the receiving end should be something like:

// slot connected to QTcpSocket::readyRead
QDataStream socketStream(socket);
QMap<QString, int> data;
for (;;) {
socketStream.startTransaction();
socketStream >> data;
if (socketStream.commitTransaction()) 
qDebug() << "Received " << data;
else
break;
}

See ChatClient::onReadyRead of this example for an explanation of what that code is doing

[arsinte_andrei]

@YouKnowMe
so... first of all, how do you use my functions??
it should be something like that
pseudo code

QMap<QString, int> myMap
myMap.insert("one", 1);
myMap.insert("two", 2);
myMap.insert("three", 3);

QByteArray myMessageToSend = messageToQBuyteArray(myMap);
qDebug() << myMessageToSend; // this has to work - this is the bytes that you are sending

anyway, if what you try is not working please post a bit of code to understand better what are you trying to do