playlist: Add auto-update functionality and more tests

beetsplug/playlist.py

@@ -14,6 +14,7 @@
 
 import os
 import fnmatch
+import tempfile
 import beets
 
 
@@ -86,6 +87,99 @@ class PlaylistPlugin(beets.plugins.BeetsPlugin):
     def __init__(self):
         super(PlaylistPlugin, self).__init__()
         self.config.add({
+            'auto': False,
             'playlist_dir': '.',
             'relative_to': 'library',
         })
+
+        self.playlist_dir = self.config['playlist_dir'].as_filename()
+        self.changes = {}
+
+        if self.config['relative_to'].get() == 'library':
+            self.relative_to = beets.util.bytestring_path(
+                beets.config['directory'].as_filename())
+        elif self.config['relative_to'].get() != 'playlist':
+            self.relative_to = beets.util.bytestring_path(
+                self.config['relative_to'].as_filename())
+        else:
+            self.relative_to = None
+
+        if self.config['auto']:
+            self.register_listener('item_moved', self.item_moved)
+            self.register_listener('item_removed', self.item_removed)
+            self.register_listener('cli_exit', self.cli_exit)
+
+    def item_moved(self, item, source, destination):
+        self.changes[source] = destination
+
+    def item_removed(self, item):
+        if not os.path.exists(beets.util.syspath(item.path)):
+            self.changes[item.path] = None
+
+    def cli_exit(self, lib):
+        for playlist in self.find_playlists():
+            self._log.info('Updating playlist: {0}'.format(playlist))
+            base_dir = beets.util.bytestring_path(
+                self.relative_to if self.relative_to
+                else os.path.dirname(playlist)
+            )
+
+            try:
+                self.update_playlist(playlist, base_dir)
+            except beets.util.FilesystemError:
+                self._log.error('Failed to update playlist: {0}'.format(
+                    beets.util.displayable_path(playlist)))
+
+    def find_playlists(self):
+        """Find M3U playlists in the playlist directory."""
+        try:
+            dir_contents = os.listdir(beets.util.syspath(self.playlist_dir))
+        except OSError:
+            self._log.warning('Unable to open playlist directory {0}'.format(
+                beets.util.displayable_path(self.playlist_dir)))
+            return
+
+        for filename in dir_contents:
+            if fnmatch.fnmatch(filename, '*.[mM]3[uU]'):
+                yield os.path.join(self.playlist_dir, filename)
+
+    def update_playlist(self, filename, base_dir):
+        """Find M3U playlists in the specified directory."""
+        changes = 0
+        deletions = 0
+
+        with tempfile.NamedTemporaryFile(mode='w+b', delete=False) as tempfp:
+            new_playlist = tempfp.name
+            with open(filename, mode='rb') as fp:
+                for line in fp:
+                    original_path = line.rstrip(b'\r\n')
+
+                    # Ensure that path from playlist is absolute
+                    is_relative = not os.path.isabs(line)
+                    if is_relative:
+                        lookup = os.path.join(base_dir, original_path)
+                    else:
+                        lookup = original_path
+
+                    try:
+                        new_path = self.changes[beets.util.normpath(lookup)]
+                    except KeyError:
+                        tempfp.write(line)
+                    else:
+                        if new_path is None:
+                            # Item has been deleted
+                            deletions += 1
+                            continue
+
+                        changes += 1
+                        if is_relative:
+                            new_path = os.path.relpath(new_path, base_dir)
+
+                        tempfp.write(line.replace(original_path, new_path))
+
+        if changes or deletions:
+            self._log.info(
+                'Updated playlist {0} ({1} changes, {2} deletions)'.format(
+                    filename, changes, deletions))
+            beets.util.copy(new_playlist, filename, replace=True)
+        beets.util.remove(new_playlist)

docs/plugins/playlist.rst

@@ -8,6 +8,7 @@ To use it, enable the ``playlist`` plugin in your configuration
 Then configure your playlists like this::
 
     playlist:
+        auto: no
         relative_to: ~/Music
         playlist_dir: ~/.mpd/playlists
 
@@ -22,13 +23,21 @@ name::
 
     $ beet ls playlist:anotherplaylist
 
+The plugin can also update playlists in the playlist directory automatically
+every time an item is moved or deleted. This can be controlled by the ``auto``
+configuration option.
+
 Configuration
 -------------
 
 To configure the plugin, make a ``smartplaylist:`` section in your
 configuration file. In addition to the ``playlists`` described above, the
 other configuration options are:
 
+- **auto**: If this is set to ``yes``, then anytime an item in the library is
+  moved or removed, the plugin will update all playlists in the
+  ``playlist_dir`` directory that contain that item to reflect the change.
+  Default: ``no``
 - **playlist_dir**: Where to read playlist files from.
   Default: The current working directory (i.e., ``'.'``).
 - **relative_to**: Interpret paths in the playlist files relative to a base