main.py

from PyQt5.QtWidgets import QApplication
from PyQt5.QtWebEngineWidgets import QWebEngineView
from PyQt5.QtWebChannel import QWebChannel

from PyQt5.QtCore import QObject, pyqtSlot, QUrl, QVariant

import os

class CallHandler(QObject):


    # @pyqtProperty(int)
    # def data(self):
    #     return 2
    
    # @data.setter
    # def data(self, value):
    #     self.data = value

    @pyqtSlot(QVariant, result=QVariant)
    def test1(self, args):
      print('i got')
      print(args)
      return 'OK'

    @pyqtSlot(result=QVariant)
    def test(self):
        print('call received')
        return QVariant({"abc": "def", "ab": 22})

class WebView(QWebEngineView):

    def __init__(self):
        super(WebView, self).__init__()

        self.channel = QWebChannel()
        self.handler = CallHandler()
        self.channel.registerObject('handler', self.handler)
        self.page().setWebChannel(self.channel)

        file_path = os.path.abspath(os.path.join(os.path.dirname(__file__), "index.html"))
        local_url = QUrl.fromLocalFile(file_path)

        self.load(local_url)


if __name__ == "__main__":
  app = QApplication([])
  view = WebView()
  view.show()
  app.exec_()