Merge pull request #603 from adamcik/feature/lookup-stream-metadata

Add metadata lookup to streaming backend.

docs/changelog.rst

@@ -25,6 +25,10 @@ a temporary regression of :issue:`527`.
 - Added support for deprecated config values in order to allow for
   graceful removal of :confval:`local/tag_cache_file`.
 
+**Streaming backend**
+
+- Live lookup of URI metadata has been added. (Fixes :issue:`540`)
+
 **Internal changes**
 
 - Events from the audio actor, backends, and core actor are now emitted

docs/ext/stream.rst

@@ -42,6 +42,10 @@ Configuration values
     Whitelist of URI schemas to allow streaming from. Values should be
     separated by either comma or newline.
 
+.. confval:: stream/timeout
+
+    Number of milliseconds before giving up looking up stream metadata.
+
 
 Usage
 =====

mopidy/audio/scan.py

@@ -83,15 +83,14 @@ class Scanner(object):
         """Polls for messages to collect data."""
         start = time.time()
         timeout_s = self._timeout_ms / float(1000)
-        poll_timeout_ns = 1000
         data = {}
 
         while time.time() - start < timeout_s:
-            message = self._bus.poll(gst.MESSAGE_ANY, poll_timeout_ns)
+            if not self._bus.have_pending():
+                continue
+            message = self._bus.pop()
 
-            if message is None:
+            if message.type == gst.MESSAGE_ERROR:
-                pass  # polling the bus timed out.
-            elif message.type == gst.MESSAGE_ERROR:
                 raise exceptions.ScannerError(message.parse_error()[0])
             elif message.type == gst.MESSAGE_EOS:
                 return data
@@ -133,7 +132,7 @@ def audio_data_to_track(data):
 
     def _retrieve(source_key, target_key, target):
         if source_key in data:
-            target[target_key] = data[source_key]
+            target.setdefault(target_key, data[source_key])
 
     _retrieve(gst.TAG_ALBUM, 'name', album_kwargs)
     _retrieve(gst.TAG_TRACK_COUNT, 'num_tracks', album_kwargs)
@@ -156,6 +155,11 @@ def audio_data_to_track(data):
     _retrieve(
         'musicbrainz-albumartistid', 'musicbrainz_id', albumartist_kwargs)
 
+    # For streams, will not override if a better value has already been set.
+    _retrieve(gst.TAG_ORGANIZATION, 'name', track_kwargs)
+    _retrieve(gst.TAG_LOCATION, 'comment', track_kwargs)
+    _retrieve(gst.TAG_COPYRIGHT, 'comment', track_kwargs)
+
     if gst.TAG_DATE in data and data[gst.TAG_DATE]:
         date = data[gst.TAG_DATE]
         try:
@@ -168,9 +172,13 @@ def audio_data_to_track(data):
     if albumartist_kwargs:
         album_kwargs['artists'] = [Artist(**albumartist_kwargs)]
 
+    if data['mtime']:
+        track_kwargs['last_modified'] = int(data['mtime'])
+
+    if data[gst.TAG_DURATION]:
+        track_kwargs['length'] = data[gst.TAG_DURATION] // gst.MSECOND
+
     track_kwargs['uri'] = data['uri']
-    track_kwargs['last_modified'] = int(data['mtime'])
-    track_kwargs['length'] = data[gst.TAG_DURATION] // gst.MSECOND
     track_kwargs['album'] = Album(**album_kwargs)
 
     if ('name' in artist_kwargs

mopidy/backends/stream/__init__.py

@@ -19,6 +19,8 @@ class Extension(ext.Extension):
     def get_config_schema(self):
         schema = super(Extension, self).get_config_schema()
         schema['protocols'] = config.List()
+        schema['timeout'] = config.Integer(
+            minimum=1000, maximum=1000 * 60 * 60)
         return schema
 
     def validate_environment(self):

mopidy/backends/stream/actor.py

@@ -5,7 +5,8 @@ import urlparse
 
 import pykka
 
-from mopidy import audio as audio_lib
+from mopidy import audio as audio_lib, exceptions
+from mopidy.audio import scan
 from mopidy.backends import base
 from mopidy.models import Track
 
@@ -16,7 +17,8 @@ class StreamBackend(pykka.ThreadingActor, base.Backend):
     def __init__(self, config, audio):
         super(StreamBackend, self).__init__()
 
-        self.library = StreamLibraryProvider(backend=self)
+        self.library = StreamLibraryProvider(
+            backend=self, timeout=config['stream']['timeout'])
         self.playback = base.BasePlaybackProvider(audio=audio, backend=self)
         self.playlists = None
 
@@ -24,14 +26,20 @@ class StreamBackend(pykka.ThreadingActor, base.Backend):
             config['stream']['protocols'])
 
 
-# TODO: Should we consider letting lookup know how to expand common playlist
-# formats (m3u, pls, etc) for http(s) URIs?
 class StreamLibraryProvider(base.BaseLibraryProvider):
+    def __init__(self, backend, timeout):
+        super(StreamLibraryProvider, self).__init__(backend)
+        self._scanner = scan.Scanner(min_duration=None, timeout=timeout)
+
     def lookup(self, uri):
         if urlparse.urlsplit(uri).scheme not in self.backend.uri_schemes:
             return []
-        # TODO: actually lookup the stream metadata by getting tags in same
+
-        # way as we do for updating the local library with mopidy.scanner
+        try:
-        # Note that we would only want the stream metadata at this stage,
+            data = self._scanner.scan(uri)
-        # not the currently playing track's.
+            track = scan.audio_data_to_track(data)
-        return [Track(uri=uri, name=uri)]
+        except exceptions.ScannerError as e:
+            logger.warning('Problem looking up %s: %s', uri, e)
+            track = Track(uri=uri, name=uri)
+
+        return [track]

mopidy/backends/stream/ext.conf

@@ -8,3 +8,4 @@ protocols =
     rtmp
     rtmps
     rtsp
+timeout = 5000