Sending messages from a client to server using network on the same machine

SGaist

Are you using the Fortune client and server examples as a base ?
If so, please take a look at the server side implementation, QDataStream is used there to write the data in a QByteArray that is then written in the socket. The transaction handling happens on the receiving end.

qcoderpro

@SGaist

Are you using the Fortune client and server examples as a base ?

Partly.

QDataStream is used there to write the data in a QByteArray that is then written in the socket.

I didn't know QString wouldn't work, but anyway, it's now changed to:

void Client::sendMessage(const QString& message)
{
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_5_10);
    out << message;
}

But still no change in the result! :|

The transaction handling happens on the receiving end.

Yes, it's implemented in the setMessage() slot.

jsulm

@qcoderpro said in Sending messages from a client to server using network on the same machine:

But still no change in the result!

Because sendMessage does not send anything.
It only writes the message into a QByteArray.
You also need to send that QByteArray through the socket.

qcoderpro

@jsulm
Yeah, right, so I added this line at the end of the slot:
tcpSocket->write(block);
But I think there's an earlier problem. No connection arrives. I set a debug in the onNewConnection() slot in the server app but nothing is printed although I put the IP and port in the client and click on the "Send Address" button! :|

jsulm

@qcoderpro Then you should debug on the client side

qcoderpro

@jsulm

The client's sendAddress slot sends the IP and port number as a string and int respectively, based on this version. So that connection is expected to be received in the server's NewConnection() slot, but it doesn't, I don't know why! :|

jsulm

@qcoderpro said in Sending messages from a client to server using network on the same machine:

sendAddress slot sends the IP and port number

It does not send anything, it just calls connectToHost. Did you check what happens on client side? Is https://doc.qt.io/qt-5/qabstractsocket.html#connected emitted? Is https://doc.qt.io/qt-5/qabstractsocket.html#errorOccurred signal emitted?

qcoderpro

@jsulm

I set this in the client's sendAddress slot:

connect(tcpSocket, &QAbstractSocket::connected, []() {
       qDebug() << "Connected to the host";
   });

And it prints that message on Application Output window. So the connection is assumed to be established correctly without errors. Right?

qcoderpro

No further contribution? :(

Bob64

@qcoderpro I'd suggest that you go back to the fortune example and debug what is happening on the client and server side until you have a good understanding. I found it very useful when I was figuring out how Qt did sockets.

Do you have any background with sockets at all? If not, I wonder if it would be worth having a play around with something like Python first to firm up the ideas. The official Python docs on sockets are very good.

qcoderpro

@Bob64
The fortune client/server apps are different from (at least) that point of view that the server sends messages to the client by a button on the client. It's way different from mine.
Well, these two QML apps are considerably simple but I don't know why we (helpers and me) can't work it out and get them to work! :(