Comment 12 for bug 902762

I have checked further and found out that scp-dbus-service.py only uses authentication via asyncconn.py, never via asyncipp.py, asyncpk1.py, or authconn.py directly. So for all authentication access an auto-selection of IPP authentication (done by asyncipp.py and authconn.py) or PolicyKit authentication is done:

use_pk = ((host.startswith ('/') or host == 'localhost') and
                  os.getuid () != 0)

PoliciKit is chosen if the program is started by a non-root user and the CUPS host is local (either "localhost" or a socket). The PolicyKit authentication does not open any GTK windows.

Also note that the "import authconn" in asyncconn.py is bogus, there asyncconn.py does not use authconn.py directly.

The only use of the GTK module in asyncpk1.py are "gtk.gdk.threads_enter ()"/"gtk.gdk.threads_leave ()" pairs which should be made optional (only if gtk is present), removed, or replaced by something more general.

So one could do the following:

1. Make the KDE printer setup tool PolicyKit-only. For this let it error out (with an error dialog) when the user tries to start it as root and also ignore any remote CUPS servers set as default via client.conf and do not offer functionality to switch the CUPS server (If the default CUPS server is remote, try to access "localhost" or the local daemon via socket and if this does not work, error out with an error dialog). With all this, asyncconn will always select PolicyKit authentication.

2. Remove "import gtk" and "import authconn" in asyncconn.py

3. In ayncconn.py import only the one to be actually used of asyncipp and asyncpk1. If the import fails, let the creation of the Connection instance fail.

4. In asyncpk1.py bracket the "import gtk", "gtk.gdk.threads_enter ()", and "gtk.gdk.threads_leave ()" calls in "try: ... except: ...". In the "except:" blocks either do nothing or put any substitution for the "gtk.gdk.threads_enter ()"/"gtk.gdk.threads_leave ()" mechanism.

5. For the Ubuntu packaging move asyncconn.py and asyncpk1.py from the system-config-printer-gnome binary package into system-config-printer-common.

Scott, Tim, Jiri, WDYT about this solution?