How to integrate python Socket.IO with Qt

Question

import sys
import socketio
from PyQt5.QtCore import QThread
from PyQt5.QtWidgets import QApplication


class ServerConnection(QThread):

    def __init__(self):
        QThread.__init__(self)
        self.sio = socketio.AsyncClient(reconnection=True, reconnection_attempts=3,
                   reconnection_delay=5, reconnection_delay_max=5, logger=True)

    'thread run function'
    def run(self) -> None:
        self.sio.connect(url="...",socketio_path="/...", transports="websocket")
        self.sio.on('connect', self.connect, namespace=None)
        self.sio.on('socket_connected', self.socket_connected, namespace=None)
        self.sio.on('connect_error', self.connect_error, namespace=None)
        self.sio.on('/client_Unlock', self.client_unlock_ack, namespace=None)

    # @sio.on('/client_unlock')
    'custom event from server, on receiving, this socketio thread needs to inform main GUI'
    async def client_unlock_ack(self, data):
            print("")
            'from here i want to call pyqt GUI main class function'

    # @sio.event
    'connection established status'
    def connect(self):
        print('Server Connection established!')

    # @sio.on("socket_connected")
    'socket connection status check'
    async def socket_connected(self, message):
        print("Socket Connected!", message)

    # @sio.event
    def connect_error(self, data):
        print('Connection error!', data)

    # @sio.on('disconnect' or 'socket_disconnected')
    def disconnect(self):
        print('Disconnected!')

'main function call'
def main():
    app = QApplication(sys.argv)
    con = ServerConnection()
    con.start()
    sys.exit(app.exec())


if __name__ == "__main__":
    main()

'GUI class is a QMainWindow application which processes further other functionalities of my application. Socketio thread connection is triggered from GUI main thread. Basically, GUI main started->Socketio thread called from GUI thread-> once we receive socketio client-unlock event inside socketio thread class-> from client_unlock_ack, i need to trigger a signal to GUI main thread to call a member function'. Please guide.

Answer 1

It is not necessary to use threads since you can use libraries such as asyncqt so that Qt works together with asyncio avoiding adding unnecessary complexity with QThreads

import asyncio
import sys
from functools import cached_property

from PyQt5.QtCore import pyqtSignal, QObject, Qt
from PyQt5.QtWidgets import QApplication, QLabel, QMainWindow
from asyncqt import QEventLoop

import socketio


class Client(QObject):
    connected = pyqtSignal()
    disconnected = pyqtSignal()
    error_ocurred = pyqtSignal(object, name="errorOcurred")
    data_changed = pyqtSignal(str, name="dataChanged")

    def __init__(self, parent=None):
        super().__init__(parent)

        self.sio.on("connect", self._handle_connect, namespace=None)
        self.sio.on("connect_error", self._handle_connect_error, namespace=None)
        self.sio.on("disconnect", self._handle_disconnect, namespace=None)
        self.sio.on("/client_Unlock", self.client_unlock_ack, namespace=None)

    @cached_property
    def sio(self):
        return socketio.AsyncClient(
            reconnection=True,
            reconnection_attempts=3,
            reconnection_delay=5,
            reconnection_delay_max=5,
            logger=True,
        )

    async def start(self):
        await self.sio.connect(url="...",socketio_path="/...", transports="websocket")

    def _handle_connect(self):
        self.connected.emit()

    def _handle_disconnect(self):
        self.disconnect.emit()

    def _handle_connect_error(self, data):
        self.error_ocurred.emit(data)

    def client_unlock_ack(self, data):
        self.data_changed.emit(data)


class View(QMainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.label = QLabel(alignment=Qt.AlignCenter)
        self.setCentralWidget(self.label)
        self.resize(640, 480)

    def update_data(self, message):
        self.label.setText(message)


def main():
    app = QApplication(sys.argv)
    loop = QEventLoop(app)
    asyncio.set_event_loop(loop)

    view = View()
    view.show()

    client = Client()
    client.data_changed.connect(view.update_data)

    with loop:
        asyncio.ensure_future(client.start(), loop=loop)
        loop.run_forever()


if __name__ == "__main__":
    main()