lastgenre plugin (#139)

beetsplug/lastgenre.py

@@ -0,0 +1,74 @@
+# This file is part of beets.
+# Copyright 2011, Adrian Sampson.
+#
+# 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.
+
+"""Gets genres for imported music based on Last.fm tags.
+"""
+
+import logging
+import pylast
+
+from beets.plugins import BeetsPlugin
+
+log = logging.getLogger('beets')
+LASTFM = pylast.LastFMNetwork(api_key='2dc3914abf35f0d9c92d97d8f8e42b43')
+WEIGHT_THRESH = 50
+
+def _tags_for(obj):
+    """Given a pylast entity (album or track), returns a list of
+    tag names for that entity. Returns an empty list if the entity is
+    not found or another error occurs.
+    """
+    try:
+        res = obj.get_top_tags()
+    except pylast.WSError, exc:
+        log.debug(u'last.fm error: %s' % unicode(exc))
+        return []
+
+    tags = []
+    for el in res:
+        if isinstance(el, pylast.TopItem):
+            el = el.item
+        tags.append(el.get_name())
+    log.debug(u'last.fm tags: %s' % unicode(tags))
+    return tags
+
+def _tags_to_genre(tags):
+    """Given a tag list, returns a genre. Returns None if no tag is
+    suitable. This should be smarter, but at the moment it just takes
+    the top tag and puts it in Title Case.
+    """
+    if not tags:
+        return None
+    return tags[0].title()
+
+class LastGenrePlugin(BeetsPlugin):
+    pass
+
+@LastGenrePlugin.listen('album_imported')
+def album_imported(lib, album):
+    tags = _tags_for(LASTFM.get_album(album.albumartist, album.album))
+    genre = _tags_to_genre(tags)
+    if genre:
+        log.debug(u'adding last.fm album genre: %s' % genre)
+        album.genre = genre
+        lib.save()
+
+@LastGenrePlugin.listen('item_imported')
+def item_imported(lib, item):
+    tags = _tags_for(LASTFM.get_track(item.artist, item.title))
+    genre = _tags_to_genre(tags)
+    if genre:
+        log.debug(u'adding last.fm item genre: %s' % genre)
+        item.genre = genre
+        lib.save()

docs/changelog.rst

@@ -1,6 +1,12 @@
 Changelog
 =========
 
+1.0b11 (In Development)
+-----------------------
+
+* The new :doc:`/plugins/lastgenre` automatically assigns genres to imported
+  albums and items based on Last.fm tags.
+
 1.0b10 (September 22, 2011)
 ---------------------------
 

docs/plugins/index.rst

@@ -41,6 +41,7 @@ disabled by default, but you can turn them on as described above:
    mpdupdate
    embedart
    web
+   lastgenre
 
 .. _other-plugins:
 

docs/plugins/lastgenre.rst

@@ -0,0 +1,30 @@
+LastGenre Plugin
+================
+
+The MusicBrainz database `does not contain genre information`_. Therefore, when
+importing and autotagging music, beets does not assign a genre.  The
+``lastgenre`` plugin fetches *tags* from `Last.fm`_ and assigns them as genres
+to your albums and items. The plugin is included with beets as of version
+1.0b11.
+
+.. _does not contain genre information:
+    http://musicbrainz.org/doc/General_FAQ#Why_does_MusicBrainz_not_support_genre_information.3F
+.. _Last.fm: http://last.fm/
+
+The plugin requires `pylast`_, which you can install using `pip`_ by typing::
+
+    pip install pylast
+
+After you have pylast installed, enable the plugin by putting ``lastgenre`` on
+your ``plugins`` line in :doc:`/reference/config`, like so::
+
+    [beets]
+    plugins: lastgenre
+
+For the time being, the genre-selection algorithm is pretty dumb: the most
+popular tag is treated as the genre. This could be enhanced by using a "white
+list" of known genre names. (This would be a great project for someone looking
+to contribute to the beets project!)
+
+.. _pip: http://www.pip-installer.org/
+.. _pylast: http://code.google.com/p/pylast/