mpd: Faster playlist listing

docs/changelog.rst

@@ -119,6 +119,14 @@ MPD frontend
 - Implement protocol extensions to output Album URIs and Album Images when
   outputting track data to clients. (PR: :issue:`1230`)
 
+- The MPD commands ``lsinfo`` and ``listplaylists`` are now implemented using
+  the :meth:`~mopidy.core.PlaylistsProvider.as_list` method, which retrieves a
+  lot less data and is thus much faster than the deprecated
+  :meth:`~mopidy.core.PlaylistsProvider.get_playlists`. The drawback is that
+  the ``Last-Modified`` timestamp is not available through this method, and the
+  timestamps in the MPD command responses are now always set to the current
+  time.
+
 Stream backend
 --------------
 

mopidy/mpd/protocol/stored_playlists.py

@@ -75,29 +75,29 @@ def listplaylists(context):
     - ncmpcpp 0.5.10 segfaults if we return 'playlist: ' on a line, so we must
       ignore playlists without names, which isn't very useful anyway.
     """
+    last_modified = _get_last_modified()
     result = []
-    for playlist in context.core.playlists.get_playlists().get():
+    for playlist_ref in context.core.playlists.as_list().get():
-        if not playlist.name:
+        if not playlist_ref.name:
             continue
-        name = context.lookup_playlist_name_from_uri(playlist.uri)
+        name = context.lookup_playlist_name_from_uri(playlist_ref.uri)
         result.append(('playlist', name))
-        result.append(('Last-Modified', _get_last_modified(playlist)))
+        result.append(('Last-Modified', last_modified))
     return result
 
 
 # TODO: move to translators?
-def _get_last_modified(playlist):
+def _get_last_modified(last_modified=None):
     """Formats last modified timestamp of a playlist for MPD.
 
     Time in UTC with second precision, formatted in the ISO 8601 format, with
     the "Z" time zone marker for UTC. For example, "1970-01-01T00:00:00Z".
     """
-    if playlist.last_modified is None:
+    if last_modified is None:
         # If unknown, assume the playlist is modified
         dt = datetime.datetime.utcnow()
     else:
-        dt = datetime.datetime.utcfromtimestamp(
+        dt = datetime.datetime.utcfromtimestamp(last_modified / 1000.0)
-            playlist.last_modified / 1000.0)
     dt = dt.replace(microsecond=0)
     return '%sZ' % dt.isoformat()
 

tests/mpd/protocol/test_music_db.py

@@ -2,8 +2,10 @@ from __future__ import absolute_import, unicode_literals
 
 import unittest
 
+import mock
+
 from mopidy.models import Album, Artist, Playlist, Ref, SearchResult, Track
-from mopidy.mpd.protocol import music_db
+from mopidy.mpd.protocol import music_db, stored_playlists
 
 from tests.mpd import protocol
 
@@ -299,33 +301,37 @@ class MusicDatabaseHandlerTest(protocol.BaseTestCase):
         self.send_request('listfiles')
         self.assertEqualResponse('ACK [0@0] {listfiles} Not implemented')
 
-    def test_lsinfo_without_path_returns_same_as_for_root(self):
+    @mock.patch.object(stored_playlists, '_get_last_modified')
-        last_modified = 1390942873222
+    def test_lsinfo_without_path_returns_same_as_for_root(
+            self, last_modified_mock):
+        last_modified_mock.return_value = '2015-08-05T22:51:06Z'
         self.backend.playlists.set_dummy_playlists([
-            Playlist(name='a', uri='dummy:/a', last_modified=last_modified)])
+            Playlist(name='a', uri='dummy:/a')])
 
         response1 = self.send_request('lsinfo')
         response2 = self.send_request('lsinfo "/"')
         self.assertEqual(response1, response2)
 
-    def test_lsinfo_with_empty_path_returns_same_as_for_root(self):
+    @mock.patch.object(stored_playlists, '_get_last_modified')
-        last_modified = 1390942873222
+    def test_lsinfo_with_empty_path_returns_same_as_for_root(
+            self, last_modified_mock):
+        last_modified_mock.return_value = '2015-08-05T22:51:06Z'
         self.backend.playlists.set_dummy_playlists([
-            Playlist(name='a', uri='dummy:/a', last_modified=last_modified)])
+            Playlist(name='a', uri='dummy:/a')])
 
         response1 = self.send_request('lsinfo ""')
         response2 = self.send_request('lsinfo "/"')
         self.assertEqual(response1, response2)
 
-    def test_lsinfo_for_root_includes_playlists(self):
+    @mock.patch.object(stored_playlists, '_get_last_modified')
-        last_modified = 1390942873222
+    def test_lsinfo_for_root_includes_playlists(self, last_modified_mock):
+        last_modified_mock.return_value = '2015-08-05T22:51:06Z'
         self.backend.playlists.set_dummy_playlists([
-            Playlist(name='a', uri='dummy:/a', last_modified=last_modified)])
+            Playlist(name='a', uri='dummy:/a')])
 
         self.send_request('lsinfo "/"')
         self.assertInResponse('playlist: a')
-        # Date without milliseconds and with time zone information
+        self.assertInResponse('Last-Modified: 2015-08-05T22:51:06Z')
-        self.assertInResponse('Last-Modified: 2014-01-28T21:01:13Z')
         self.assertInResponse('OK')
 
     def test_lsinfo_for_root_includes_dirs_for_each_lib_with_content(self):
@@ -337,7 +343,10 @@ class MusicDatabaseHandlerTest(protocol.BaseTestCase):
         self.assertInResponse('directory: dummy')
         self.assertInResponse('OK')
 
-    def test_lsinfo_for_dir_with_and_without_leading_slash_is_the_same(self):
+    @mock.patch.object(stored_playlists, '_get_last_modified')
+    def test_lsinfo_for_dir_with_and_without_leading_slash_is_the_same(
+            self, last_modified_mock):
+        last_modified_mock.return_value = '2015-08-05T22:51:06Z'
         self.backend.library.dummy_browse_result = {
             'dummy:/': [Ref.track(uri='dummy:/a', name='a'),
                         Ref.directory(uri='dummy:/foo', name='foo')]}
@@ -346,7 +355,10 @@ class MusicDatabaseHandlerTest(protocol.BaseTestCase):
         response2 = self.send_request('lsinfo "/dummy"')
         self.assertEqual(response1, response2)
 
-    def test_lsinfo_for_dir_with_and_without_trailing_slash_is_the_same(self):
+    @mock.patch.object(stored_playlists, '_get_last_modified')
+    def test_lsinfo_for_dir_with_and_without_trailing_slash_is_the_same(
+            self, last_modified_mock):
+        last_modified_mock.return_value = '2015-08-05T22:51:06Z'
         self.backend.library.dummy_browse_result = {
             'dummy:/': [Ref.track(uri='dummy:/a', name='a'),
                         Ref.directory(uri='dummy:/foo', name='foo')]}
@@ -404,12 +416,11 @@ class MusicDatabaseHandlerTest(protocol.BaseTestCase):
         self.assertInResponse('OK')
 
     def test_lsinfo_for_root_returns_browse_result_before_playlists(self):
-        last_modified = 1390942873222
         self.backend.library.dummy_browse_result = {
             'dummy:/': [Ref.track(uri='dummy:/a', name='a'),
                         Ref.directory(uri='dummy:/foo', name='foo')]}
         self.backend.playlists.set_dummy_playlists([
-            Playlist(name='a', uri='dummy:/a', last_modified=last_modified)])
+            Playlist(name='a', uri='dummy:/a')])
 
         response = self.send_request('lsinfo "/"')
         self.assertLess(response.index('directory: dummy'),

tests/mpd/protocol/test_stored_playlists.py

@@ -1,6 +1,9 @@
 from __future__ import absolute_import, unicode_literals
 
+import mock
+
 from mopidy.models import Playlist, Track
+from mopidy.mpd.protocol import stored_playlists
 
 from tests.mpd import protocol
 
@@ -76,15 +79,16 @@ class PlaylistsHandlerTest(protocol.BaseTestCase):
         self.assertNotInResponse('Pos: 0')
         self.assertInResponse('OK')
 
-    def test_listplaylists(self):
+    @mock.patch.object(stored_playlists, '_get_last_modified')
-        last_modified = 1390942873222
+    def test_listplaylists(self, last_modified_mock):
+        last_modified_mock.return_value = '2015-08-05T22:51:06Z'
         self.backend.playlists.set_dummy_playlists([
-            Playlist(name='a', uri='dummy:a', last_modified=last_modified)])
+            Playlist(name='a', uri='dummy:a')])
 
         self.send_request('listplaylists')
         self.assertInResponse('playlist: a')
         # Date without milliseconds and with time zone information
-        self.assertInResponse('Last-Modified: 2014-01-28T21:01:13Z')
+        self.assertInResponse('Last-Modified: 2015-08-05T22:51:06Z')
         self.assertInResponse('OK')
 
     def test_listplaylists_duplicate(self):