beets/beetsplug/lastgenre/client.py
2026-03-17 07:49:05 +01:00

146 lines
5 KiB
Python

# This file is part of beets.
# Copyright 2016, Adrian Sampson.
# Copyright 2026, J0J0 Todos.
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
"""Last.fm API client for genre lookups."""
from __future__ import annotations
import traceback
from typing import TYPE_CHECKING, Any
import pylast
from beets import plugins
if TYPE_CHECKING:
from collections.abc import Callable
from beets.logging import BeetsLogger
GenreCache = dict[str, list[str]]
"""Cache mapping entity keys to their genre lists.
Keys are formatted as 'entity.arg1-arg2-...' (e.g., 'album.artist-title').
Values are lists of lowercase genre strings."""
LASTFM = pylast.LastFMNetwork(api_key=plugins.LASTFM_KEY)
PYLAST_EXCEPTIONS = (
pylast.WSError,
pylast.MalformedResponseError,
pylast.NetworkError,
)
class LastFmClient:
"""Client for fetching genres from Last.fm."""
def __init__(self, log: BeetsLogger, min_weight: int):
"""Initialize the client.
The min_weight parameter filters tags by their minimum weight.
"""
self._log = log
self._min_weight = min_weight
self._genre_cache: GenreCache = {}
def fetch_genre(
self, lastfm_obj: pylast.Album | pylast.Artist | pylast.Track
) -> list[str]:
"""Return genres for a pylast entity. Returns an empty list if
no suitable genres are found.
"""
return self._tags_for(lastfm_obj, self._min_weight)
def _tags_for(
self,
obj: pylast.Album | pylast.Artist | pylast.Track,
min_weight: int | None = None,
) -> list[str]:
"""Core genre identification routine.
Given a pylast entity (album or track), return a list of
tag names for that entity. Return an empty list if the entity is
not found or another error occurs.
If `min_weight` is specified, tags are filtered by weight.
"""
# Work around an inconsistency in pylast where
# Album.get_top_tags() does not return TopItem instances.
# https://github.com/pylast/pylast/issues/86
obj_to_query: Any = obj
if isinstance(obj, pylast.Album):
obj_to_query = super(pylast.Album, obj)
try:
res: Any = obj_to_query.get_top_tags()
except PYLAST_EXCEPTIONS as exc:
self._log.debug("last.fm error: {}", exc)
return []
except Exception as exc:
# Isolate bugs in pylast.
self._log.debug("{}", traceback.format_exc())
self._log.error("error in pylast library: {}", exc)
return []
# Filter by weight (optionally).
if min_weight:
res = [el for el in res if (int(el.weight or 0)) >= min_weight]
# Get strings from tags.
tags: list[str] = [el.item.get_name().lower() for el in res]
return tags
def _last_lookup(
self, entity: str, method: Callable[..., Any], *args: str
) -> list[str]:
"""Get genres based on the named entity using the callable `method`
whose arguments are given in the sequence `args`. The genre lookup
is cached based on the entity name and the arguments.
Before the lookup, each argument has the "-" Unicode character replaced
with its rough ASCII equivalents in order to return better results from
the Last.fm database.
"""
# Shortcut if we're missing metadata.
if any(not s for s in args):
return []
key = f"{entity}.{'-'.join(str(a) for a in args)}"
if key not in self._genre_cache:
args_replaced = [a.replace("\u2010", "-") for a in args]
self._genre_cache[key] = self.fetch_genre(method(*args_replaced))
genre = self._genre_cache[key]
self._log.extra_debug("last.fm (unfiltered) {} tags: {}", entity, genre)
return genre
def fetch_album_genre(self, albumartist: str, albumtitle: str) -> list[str]:
"""Return genres from Last.fm for the album by albumartist."""
return self._last_lookup(
"album", LASTFM.get_album, albumartist, albumtitle
)
def fetch_artist_genre(self, artist: str) -> list[str]:
"""Return genres from Last.fm for the artist."""
return self._last_lookup("artist", LASTFM.get_artist, artist)
def fetch_track_genre(self, trackartist: str, tracktitle: str) -> list[str]:
"""Return genres from Last.fm for the track by artist."""
return self._last_lookup(
"track", LASTFM.get_track, trackartist, tracktitle
)