qmqtt QDatastream between Qt and PyQt back and forth

[RahibeMeryem]

Hi,

I can send Qdatastream (Qstring + Png) to python with qmqtt thwough broker and succesfully decode them in python with below code:

data_ is coming from paho mqt client

            data_ = model_worker_queue.get()
            

            out = qt.QDataStream(data_, qt.QIODevice.ReadOnly)
            out.setVersion(qt.QDataStream.Qt_5_10)
            png = out.readBytes()
            text = out.readQString()

All is good:

But I couldn find a way to send back Qdatastream message to the Qt C++ through paho mqt client.

I create Qbytearray but client asking bytes

how can I pack image + text in python and send through mqt to Qt C++ and decode there ?

struggled half day and forgetting now what I now :)

Best

[SGaist]

Hi,

What version of PyQt are you using ?
What version of Python ?

[RahibeMeryem]

PyQt5
python 3.6

[Pablo J. Rogina]

@RahibeMeryem maybe this answer from stackoverflow helps you (Python app publishing a jpg file)

Just to be sure, you have 2 Python applications right? One subscriber (from the code you posted) receiving the image from Qt C++, and another Python app (perhaps the same but acting) as publisher which will read a jpg file and send data to Qt C++ subscriber

[RahibeMeryem]

two app : c++ and python:

I manage this way to send python to c++:

    result_name = x[0]
    name = bytearray()
    name.extend(map(ord, result_name))

    result_image = QImage(x[1])
    bytearray__ = QByteArray()

    bio = QBuffer(bytearray__)
    bio.open(QIODevice.WriteOnly)
    result_image.save(bio, "PNG")

    block = QByteArray()
    xout = QDataStream(block, QIODevice.WriteOnly)
    xout.setVersion(qt.QDataStream.Qt_5_10)
    xout << QByteArray(result_name.encode('utf-8')) << bytearray__
    xox = (b'')
    xox = block.data()

    res = publisher.publish("result/light", xox , 2, retain=True)

[RahibeMeryem]

Now I have re-connecting issue.

when my c++ qmqtt client disconnected , I cant re-connect . its hanging on the state 1.

What is the proper way to reconnect ?