File transfer through sockets

[anda_skoa]

Thank you very much for your example. It helps me a lot to introduce me to QT code and TCP data transfer too. (I'm a student)

I tried your code for a basic project at school : transfer a movie from a server to a client and play it on the client side.
I just have to made some modification to your code in order to make it work properly.

1. I had to write a waitForReadyRead in the client side because it doesn't do anything when the SIGNAL(readyRead()) happens

No. The client example code was even driven, no need to call any waitForXYZ. Whenever something happens on the socket, e.g. data received, a signal will be emitted and the client code reacts to that. In the example code it reads the available data and appends it to the file.

Your modification effetively blocks the ClientReadData() method until all data has been transferred, totally blocking the thread that executes it, needlessly introducing the need for a thread in order not to block the main thread.

There is no need for threading here at all, it just complicates the two programs and makes them harder to debug.

Cheers,
_

[Quenix]

No. The client example code was even driven, no need to call any waitForXYZ. Whenever something happens on the socket, e.g. data received, a signal will be emitted and the client code reacts to that. In the example code it reads the available data and appends it to the file.

Thank you very much for your answer.

What should I use instead of a client->waitForSomething because without this, nothing happens in the client side after the initial TCP Handshake when the server started to write in the socket.

Your modification effetively blocks the ClientReadData() method until all data has been transferred, totally blocking the thread that executes it, needlessly introducing the need for a thread in order not to block the main thread.

There is no need for threading here at all, it just complicates the two programs and makes them harder to debug.

The only way I see to do it better is to introduce a new threads, but that's because I'm a beginner ;-)
How could it be written in a better way ?

Thank you,

--
Serge

[anda_skoa]

Check that you have started the main thread's event loop, i.e. called exec() on the application object.

Cheers,
_

[Quenix]

Check that you have started the main thread's event loop, i.e. called exec() on the application object.

I tried the code in a QT application with GUI and I create the Class Client object with a button.clicked(). When I click on the button, I thought that the QApplication::exec() happens in the main.cpp before I pressed on the button. So, normally, the main thread's event loop is supposed to be started before I click anywhere on the mainwindow .?

Thank you very much for the time you take to answer all my newbe question :-)

--
Serge

[anda_skoa]

Yes, if you have a working GUI then the eventloop should be running.

Hard to tell without a minimal program using the concrete code.
All signal/slots setup correctly?

Cheers,
_

[Quenix]

All signal/slots setup correctly?

This is exactly the code you can see upper.
For the rest, there's just 1 button in the client side and I used "Go to slot..." in qtdesigner to create the SIGNAL/SLOT connection.

thanks,
Serge

[anda_skoa]

Well, since you claim this is all the code and the code does not contain any signal/slot connects, you are obviously missing those.

Cheers,
_