I'm trying to see if it's possible to use DBus from within an extension and how.

I'm making progress with some things, but I am blocked with others.

in the code below, I manage to execute some commands both at the application and at the window level, but cannot manage to get inkscape to save the current document somewhere. This would be useful for other type of things, such as daemonizing this process and have it happen every x seconds without blocking (more about this at some point).

Is there a way to use Inkscape to transparently save a document? and how do I pass arguments to dbus functions that seem to want more complex things?

import inkex
import dbus
import sys
import os
import warnings
import time
import builtins

import gi
import json
gi.require_version("Gio", "2.0")
gi.require_version("GLib", "2.0")
from gi.repository import Gio, GLib

from inkex import etree

class Logger():
    def el_to_str(self, element):
        """Convert an Inkex BaseElement or etree element to a string."""
        if isinstance(element, etree._Element):
            return etree.tostring(element, pretty_print=True).decode()
        return str(element)
    def log(self, *args, **kwargs):
        try:
            with open('/dev/tty', 'w') as tty:
                # Convert BaseElement or etree._Element instances to XML strings
                converted_args = [
                    self.el_to_str(arg) if isinstance(arg, inkex.elements._base.BaseElement) else arg
                    for arg in args
                ]
                print(*converted_args, file=tty, **kwargs)
        except Exception as e:
            print(e, file=sys.stderr)

class DBUSTestExtension(inkex.EffectExtension, Logger):
    def __init__(self):
        super().__init__()
        self.log("{} running in {}".format(self.__class__.__name__,  __file__ ))
        with warnings.catch_warnings():
            warnings.simplefilter('ignore', category=ImportWarning)
            _oldprint = builtins.print
            builtins.print = lambda *args, **kwargsx: None
            # def print(s): pass

            import gi
            gi.require_version("Gio", "2.0")
            from gi.repository import Gio, GLib

            globals()['GLib'] = GLib

            try:
               bus = Gio.bus_get_sync(Gio.BusType.SESSION, None)
            except BaseException:
               exit()

            proxy = Gio.DBusProxy.new_sync(bus,
                                           Gio.DBusProxyFlags.NONE,
                                           None,
                                          'org.freedesktop.DBus',
                                          '/org/freedesktop/DBus',
                                          'org.freedesktop.DBus',
                                           None)

            names_list = proxy.call_sync('ListNames', None, Gio.DBusCallFlags.NO_AUTO_START, 500, None)
            names = names_list.unpack()[0]

            for name in names:
               if ('org.inkscape.Inkscape' in name): break

            app_group_name = "/org/inkscape/Inkscape"
            win_group_name = app_group_name + "/window/1"
            doc_group_name = app_group_name + "/document/1"

            self.log(win_group_name)
            self.log(doc_group_name)
            
            application_group = Gio.DBusActionGroup.get( bus, name, app_group_name)
            window_group = Gio.DBusActionGroup.get(bus, name, win_group_name)
            document_group = Gio.DBusActionGroup.get(bus, name, doc_group_name)

        self.bus = bus
        self.application_group = application_group
        self.window_group = window_group
        self.document_group = document_group
        builtins.print = _oldprint
        
    def effect(self):
        self.log("{} running in {}".format(self.__class__.__name__,  __file__ ))
        # self.log(self.application_group)

        self.log("-" * 96)
        # --------------------------------------------------------------
        # these all work
        # --------------------------------------------------------------
        self.application_group.activate_action('select-all', GLib.Variant.new_string("all"))
        self.application_group.activate_action('copy')
        self.application_group.activate_action('object-rotate-90-cw')
        self.window_group.activate_action('paste') # this works

        # --------------------------------------------------------------
        # none of these work: they do nothing and generate an error
        # (org.inkscape.Inkscape:60441): GLib-GIO-CRITICAL **: 10:20:28.339: g_simple_action_activate: assertion 'simple->parameter_type == NULL ? parameter == NULL : (parameter != NULL && g_variant_is_of_type (parameter, simple->parameter_type))' failed

        # --------------------------------------------------------------
        self.window_group.activate_action('document-save-as', GLib.Variant.new_string("/home/simone/dbus_foobar.svg"))
        self.window_group.activate_action('document-save-as', GLib.Variant('a{sv}', {'filename': GLib.Variant('s', "/home/simone/output.svg")}))

        
        self.log(self.window_group)
        self.log("-" * 96)

if __name__ == '__main__':
    DBUSTestExtension().run()

It follows the same pattern as on the command line.

export-filename

export-do

It's that simple.

However, it's import to understand that this is the current state of the gui document.

If you are combining dbus commands with standard extension code, until the extension returns the svg back to the gui, export cannot 'see' it.

Thanks @inklinea for your answer!

I did get it to work like this:

self.application_group.activate_action('export-filename', GLib.Variant.new_string("/home/gropius/dbus_foobar.svg"))

self.application_group.activate_action('export-do')

however - for the sake of knowledge - do you know why this:
 

self.window_group.activate_action('document-save-as', GLib.Variant.new_string("/home/simone/dbus_foobar.svg"))

does not work?

It's not the window group when this:
 

self.window_group.activate_action('paste')

works - so what is it?