[PyQt] QTcpSocket connections

[Jorge Tornero]

Hello again, and thanks for your answer:

Well I tried what you suggested (I guess) but got no luck. I know that I am
able to send the data but can't receive anything... seems that readAll or
read....() don't work at all

I've drop some lines on pastebin

http://pastebin.com/mpYC0pPt

with an tiny application where the problem is shown

I hope someone can put some light on this... Thank you very much


2013/7/22 Phil Thompson <phil at riverbankcomputing.com>

> On Mon, 22 Jul 2013 16:31:55 +0200, Jorge Tornero - Listas
> <jtorlistas at gmail.com> wrote:
> > Hello everybody,
> >
> > I'm trying to share a digital scale through the network, making it able
> > to receive tare/send weight commands.
> > The scale is connected to a remote computer (a raspberry pi, by the way)
>
> > with a serial converter an the raspi is executing remserial, thus makin
> > avalilable the serial port to the network through port 23000.
> >
> > Because I am making my application with PyQt4, I have chosen to use
> > QTcpSocket to do the communications between the computers. It is pretty
> > easy and I am able to get what i want (sending command and receiving
> > weights) just by:
> >
> > soc=QtNetwork.QTcpSocket()
> >
> >
> > soc.connectToHost('174.33.22.11',23000)
> >
> > soc.writeData('01ST@')
> > print soc.readAll()
> > soc.disconnectFromHost()
> >
> >
> > And of course I get the weight and I am able to repeat the cycle
> > connect-poll-receive-disonnect
> >
> > The problem is whe I put that into a function like:
> >
> > def captura():
> >
> >    soc=QtNetwork.QTcpSocket(app)
> >    comandoCaptura=chr(6)+'01S@'+chr(13)
> >    soc.connectToHost('172.23.2.25',23000)
> >    soc.writeData(comandoCaptura)
> >    a=soc.readAll()
> >    print a
> >    soc.disconnectFromHost()
> >    return a
> >
> >
> > Ther is no wai to make it works. I guess is a basic python issue, but
> > can anyone help?
>
> QTcpSocket is asynchronous, so you need an event loop. After calling
> connectToHost() you shouldn't try to read or write until the connected()
> signal has been emitted.
>
> Phil
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.riverbankcomputing.com/pipermail/pyqt/attachments/20130723/b7e1bf5e/attachment.html>