win32com: How to pass a reference object into a COM server class

[Alfalfa]

I'm trying to implement a cross-platform python interface for a third-party API (Antidote), so that it can communicate with a PyQt application.

Firstly, for Linux here's the working D-Bus interface; https://gitlab.com/-/snippets/2151173
Simply put, we create a DBus server (class AdaptateurAntidote) which relay all calls to another class (ImplementationAntidote), which in turn communicates with the GUI widgets.

Then, below is a tentative for the COM interface (notice that the method differ between the two API);

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#!/usr/bin/python3 import pythoncom import sys import winreg import win32com.client import win32com.server.register import win32com.server.util from win32com.server import localserver from pathlib import Path from PyQt5 import QtCore, QtWidgets     class MainWindow(QtWidgets.QMainWindow):     def __init__(self, app):         super().__init__()         self.body = QtWidgets.QTextEdit("Texte à corrigée.")         self.setCentralWidget(self.body)         self.antidote = ImplementationAntidote(self, self.body)       def closeEvent(self, event):         super().closeEvent(event)         sys.exit(0)  # Kills the hanging server in QThread     class ImplementationAntidote(QtCore.QObject):     def __init__(self, parent: QtCore.QObject, body: QtWidgets.QTextEdit):         super().__init__()         self.parent = parent         self.body = body         # self._register()           self._launch()         self.worker = ServerThread()         self.serverThread = QtCore.QThread()         self.serverThread.started.connect(self.worker.run)         self.worker.moveToThread(self.serverThread)         self.serverThread.start()           # this should renew a timer until local com server and antidote are both ready  # ##         QtCore.QTimer.singleShot(1000, self._connect)       @staticmethod     def readRegistry(path: str, name: str):         key = winreg.OpenKey(winreg.HKEY_LOCAL_MACHINE, path, 0, winreg.KEY_READ)         value, regtype = winreg.QueryValueEx(key, name)         winreg.CloseKey(key)         return value       def _connect(self):         version = self.readRegistry(r"Software\Druide informatique inc.\Antidote", "VersionAPI")         version = min([2.0, float(version)])         self.server = win32com.client.Dispatch("Correcteur.Antidote")         self.antidote = win32com.client.Dispatch("Antidote.ApiOle")         self.antidote.LanceOutilDispatch2(self.server, "C", "", str(version))  # Server, outil, langue, version API       def _launch(self):         antidoteFolder = self.readRegistry(r"Software\Druide informatique inc.\Antidote", "DossierAntidote")         antidotePath = Path(antidoteFolder) / "Antidote.exe"         QtCore.QProcess.startDetached(str(antidotePath), ["-activex"])       def _register(self):         win32com.server.register.UseCommandLine(AdapteurAntidote)     class EventHandler:     pass     class ServerThread(QtCore.QObject):     def __init__(self):         super().__init__()       def run(self):         pythoncom.CoInitialize()         localserver.serve(["{D390AE78-D6A2-47CF-B462-E4F2DC9C70F5}"])  # ## Hangs on quit         pythoncom.CoUninitialize()  # ## Never called     class AdapteurAntidote:     _reg_clsctx_ = pythoncom.CLSCTX_LOCAL_SERVER     _reg_clsid_ = "{D390AE78-D6A2-47CF-B462-E4F2DC9C70F5}"  # pythoncom.CreateGuid()     _reg_progid_ = "Correcteur.Antidote"     _reg_verprogid_ = "Correcteur.Antidote.1"     _reg_class_spec_ = "AntidoteCOM.AdapteurAntidote"     _public_methods_ = ["ActiveApplication", "ActiveDocument", "DonneDebutSelection", "DonneFinSelection",                         "DonneIdDocumentCourant", "DonneIdZoneDeTexte", "DonneIdZoneDeTexteCourante", "DonneIntervalle",                         "DonneLongueurZoneDeTexte", "DonneNbZonesDeTexte", "DonnePolice", "DonneTitreDocCourant",                         "RemplaceIntervalle", "SelectionneIntervalle"]       def DonneIdDocumentCourant(self):         print("DonneIdDocumentCourant")       def DonneIdZoneDeTexte(self):         print("DonneIdZoneDeTexte")       def DonneIdZoneDeTexteCourante(self):         print("DonneIdZoneDeTexteCourante")       def DonneIntervalle(self):         print("DonneIntervalle")       def DonneLongueurZoneDeTexte(self):         print("DonneLongueurZoneDeTexte")       def DonneNbZonesDeTexte(self):         print("DonneNbZonesDeTexte")       def DonnePolice(self):         print("DonnePolice")       def DonneTitreDocCourant(self):         print("DonneTitreDocCourant")       def RemplaceIntervalle(self):         print("RemplaceIntervalle")       def ActiveDocument(self):         print("ActiveDocument")         # self.parent.activeDocument()       def ActiveApplication(self):         print("ActiveApplication")         # self.parent.activeDocument()       def DonneDebutSelection(self) -> int:         print("DonneDebutSelection")         # return self.parent.donneDebutSelection()       def DonneFinSelection(self) -> int:         print("DonneFinSelection")         # return self.parent.donneFinSelection()       def SelectionneIntervalle(self, debut: int, fin: int):         print("SelectionneIntervalle")         # self.parent.selectionneIntervalle(debut, fin)     if __name__ == '__main__':     app = QtWidgets.QApplication([])     gui = MainWindow(app)     gui.show()     app.exec()

Similarly a COM server is created (AdaptateurAntidote), which receives calls from Antidote's API. However, due to the nature of COM objects, the adapter class is never instantiated, and won't accept the ImplementationAntidote as its parent attribute.

For instance, if "parent" is declared in _public_attrs_, this;

1	self.server.parent = self

Results in;

Error:
TypeError: must be real number, not ImplementationAntidote.

If "parent" is not declared;

Error:
AttributeError: 'Correcteur.Antidote.parent' can not be set.

Settings a global variable or setting a "parent" attribute into AdaptateurAntidote also does not work, as it always return its default value (None).

Finally, instead of using Dispatch(), I've tried;

1	self.server = win32com.client.DispatchWithEvents("Correcteur.Antidote", EventHandler)

So I could split the COM objects properties in a class, and handle the events in another. However, this gives;

Error:
TypeError: This COM object can not automate the makepy process - please run makepy manually for this object

Documentation is scarce and I'm stuck !

[Larz60+]

Always show complete unaltered error messages (tracebacks), they contain extremely valuable information on what leads up to an error.

[Alfalfa]

"Parent" declared in _public_attrs_

Error:
Traceback (most recent call last):
  File "Z:\.antidote_\AntidoteCOM.py", line 53, in _connect
    self.server.parent = self  # This
  File "C:\Users\user\AppData\Local\Programs\Python\Python38\lib\site-packages\win32com\client\dynamic.py", line 559, in __setattr__
    self._oleobj_.Invoke(entry.dispid, 0, invoke_type, 0, value)
TypeError: must be real number, not ImplementationAntidote

"Parent" undeclared in _public_attrs_

Error:
Traceback (most recent call last):
  File "Z:\.antidote_\AntidoteCOM.py", line 53, in _connect
    self.server.parent = self  # This
  File "C:\Users\user\AppData\Local\Programs\Python\Python38\lib\site-packages\win32com\client\dynamic.py", line 565, in __setattr__
    raise AttributeError("Property '%s.%s' can not be set." % (self._username_,attr))
AttributeError: Property 'Correcteur.Antidote.parent' can not be set.

Replacing Dispatch() with DispatchWithEvents

Error:
Traceback (most recent call last):
  File "C:\Users\user\AppData\Local\Programs\Python\Python38\lib\site-packages\win32com\client\__init__.py", line 256, in DispatchWithEvents
    ti = disp._oleobj_.GetTypeInfo()
pywintypes.com_error: (-2147352567, 'Exception occurred.', None, None)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "Z:\.antidote_\AntidoteCOM.py", line 52, in _connect
    self.server = win32com.client.DispatchWithEvents("Correcteur.Antidote", EventHandler)
  File "C:\Users\user\AppData\Local\Programs\Python\Python38\lib\site-packages\win32com\client\__init__.py", line 264, in DispatchWithEvents
    raise TypeError("This COM object can not automate the makepy process - please run makepy manually for this object")
TypeError: This COM object can not automate the makepy process - please run makepy manually for this object

[Alfalfa]

From the documentation, it really seems that DispatchWithEvents() is the way to go in order to relays the events to a regular Python class. However, as shown in the error above it fails on this line (win32com.client::DispatchWithEvents);

1	ti = disp._oleobj_.GetTypeInfo()

I noticed that when running localserve.serve() in a separate console, the server returns as DispatchWithEvents() is called. No errors are thrown on the server side, but I assume there is something wrong or missing in the class definition of AdaptateurAntidote. I tried changing its policy to dynamic, but that did not help.

If someone could provide a minimal example of a custom server working along with DispatchWithEvents(), that would be very helpful. All the examples I could find use third-party servers such as those provided by Microsoft.