streaming: Add scanner lookup of stream metadata.

This adds support for looking up metada for all any any protocols the streaming
backend will support. This should also ensure that file:// files get metadata.

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
-        # Note that we would only want the stream metadata at this stage,
-        # not the currently playing track's.
-        return [Track(uri=uri, name=uri)]
+
+        try:
+            data = self._scanner.scan(uri)
+            track = scan.audio_data_to_track(data)
+        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