Re-enable Python scripts to access Quodlibet library

[davidSchlosser]

The proposed change

Allow stand-alone Python script access to the Quodlibet library as @lazka described in #1939 for Quodlibet 3.6

import os, sys
sys.path.insert(0, '/home/david/quodlibet')
import quodlibet
from quodlibet import library

quodlibet.init()
lib = library.init(os.path.join(quodlibet.get_user_dir(), "songs"))

With Quodlibet 4.6.1 this script fails with the following:

/home/david/quodlibet/quodlibet/qltk/__init__.py:21: PyGIWarning: PangoCairo was imported without specifying a version first. Use gi.require_version('PangoCairo', '1.0') before import to ensure that the right version gets loaded.
  from gi.repository import GLib, GObject, PangoCairo
Traceback (most recent call last):
  File "/home/david/PycharmProjects/qlbridge/access.py", line 8, in <module>
    quodlibet.init()
  File "/home/david/quodlibet/quodlibet/_init.py", line 55, in init
    init_cli(no_translations=no_translations, config_file=config_file)
  File "/home/david/quodlibet/quodlibet/_init.py", line 136, in init_cli
    _init_gettext(no_translations)
  File "/home/david/quodlibet/quodlibet/_init.py", line 76, in _init_gettext
    i18n.init(language)
  File "/home/david/quodlibet/quodlibet/util/i18n.py", line 282, in init
    assert "gi.repository.Gtk" not in sys.modules
AssertionError

Benefits of this change

I'll continue to use a script in newer Quodlibet versions to obtain & work with the song tag values extracted from the Quodlibet library, to support remote Quodlibet operation with simplified query creation from a mobile phone or tablet.

Any issues this might cause

I'm not sure if this is a documentation request for the Development Guide or FAQ, or a code change would be required.

[declension]

Sorry about the delay.

Probably best to do this within the Python console (plugin) within QL itself

[davidSchlosser]

My application operates from the command line so I don't see this could work. I have a work around using the QL query json command to effectively export the library, and processing the output, but unfortunately that doesn't perform well with a large library.

[declension]

Thanks, I understand a bit more now.

I guess the first thing to mention is that it's only really a curiosity of Python packaging that allows loading an application as a library (import quodlibet); note that it's not possible on newer packaging environments e.g. Snap / Flatpak (or Docker even). The upshot is that there's no drive to keep these kinds of integrations working as things change within the app itself.

So I'm not sure what your integration is but if you can use any of the supported methods then it might do better - or of course mutagen itself is a library and so will have guarantees.

If you prefer the hackier approach though:

• Try just moving the library import down:

import os, sys
sys.path.insert(0, '/home/david/quodlibet')
import quodlibet
quodlibet.init()

from quodlibet import library
lib = library.init(os.path.join(quodlibet.get_user_dir(), "songs"))

• To do anythign properly, make sure you have all the dependencies installed (poetry install will do this nicely) - you can't really just insert quodlibet itself into PYTHONPATH and necessarily have it all work.

[davidSchlosser]

Thanks for your suggestions. I won't get back to this for a while, but will check it out. Cheers!

[Moonbase59]

@davidSchlosser: Don’t know if this helps, but my little bash script ql-playlists uses the following code to find—in this case—the saved searches:

  # Get QL saved searches file location.
  # We query QL for that since there are so many possibilities.
  queriesfile=$(python3 -c "import os.path; from quodlibet import get_user_dir; print(os.path.join(get_user_dir(), 'lists', 'queries.saved'))")

  if [ $? -ne 0 ] || [ ! -r "${queriesfile}" ] ; then
    echo "$me: Couldn't read Quod Libet's saved searches file. Aborting." >&2
    exit 1
  fi

[declension]

Closing this for now, as plugins are the supported entry point.