Add getReleaseMetadata and modify _getMetadata

_getMetadata got changed so that it works with a release
without specifying a discid
getReleaseData is used in mblookup

[Fixes whipper-team#251]
Signed-off-by: ABCbum <[email protected]>

whipper/common/mbngs.py

@@ -161,7 +161,7 @@ def _getWorks(recording):
     return works
 
 
-def _getMetadata(release, discid, country=None):
+def _getMetadata(release, discid=None, country=None):
     """
     :type  release: dict
     :param release: a release dict as returned in the value for key release
@@ -220,7 +220,7 @@ def _getMetadata(release, discid, country=None):
     # only show discs from medium-list->disc-list with matching discid
     for medium in release['medium-list']:
         for disc in medium['disc-list']:
-            if disc['id'] == discid:
+            if discid is None or disc['id'] == discid:
                 title = release['title']
                 discMD.releaseTitle = title
                 if 'disambiguation' in release:
@@ -274,6 +274,19 @@ def _getMetadata(release, discid, country=None):
 # see http://bugs.musicbrainz.org/browser/python-musicbrainz2/trunk/examples/
 #     ripper.py
 
+def getReleaseMetadata(release_id):
+    import musicbrainzngs
+
+    musicbrainzngs.set_useragent("whipper", whipper.__version__,
+                                 "https://github.com/whipper-team/whipper")
+    release = musicbrainzngs.get_release_by_id(
+            release_id, includes=["artists", "artist-credits",
+                                  "recordings", "discids",
+                                  "labels", "recording-level-rels",
+                                  "work-rels", "release-groups"])
+    releaseDetail = release['release']
+    return _getMetadata(releaseDetail)
+
 
 def musicbrainz(discid, country=None, record=False):
     """