Rdio: Potential new class

We use similar convenience methods to the ones in this class at Rdio.
I'm suggesting we reincoprate them into	  PyEchonest for other developers.

examples/rdio_playlist_test.py

@@ -0,0 +1,20 @@
+#!/usr/bin/python 
+import sys
+
+from pyechonest.artist import Artist
+from pyechonest.playlist import Playlist
+from pyechonest.rdio import RdioCatalog
+
+def process(artist_name):
+    rdio = RdioCatalog('US')
+    a = Artist(artist_name)
+    p = Playlist(type="artist-radio", artist=a, buckets=[rdio.bucket_identifier(), 'tracks'])
+    songs = p.get_next_songs(5)
+    for s in songs:
+        print "Found rdio track id: %s" % rdio.get_track_id(s)
+
+def main():
+    process(sys.argv[1])
+
+if __name__ == "__main__":
+    main()

pyechonest/__init__.py

@@ -6,4 +6,4 @@
 Created by Tyler Williams on 2009-06-25.
 """
 
-__all__ = ['config', 'util', 'proxies', 'artist', 'catalog', 'song', 'track', 'playlist']
+__all__ = ['config', 'util', 'proxies', 'artist', 'catalog', 'song', 'track', 'playlist', 'rdio']

pyechonest/rdio.py

@@ -0,0 +1,99 @@
+#!/usr/bin/env python
+# encoding: utf-8
+
+"""
+Created by Rob Ferguson on May 5, 2013
+
+This file contains convenience methods for working with the Rdio API
+"""
+import logging
+
+from pyechonest.song import Song
+from pyechonest.util import EchoNestException
+
+class EchoNestAPICodes:
+  Unknown_Error = -1
+  Success = 0
+  Invalid_API_Key = 1
+  Insufficient_Rights = 2
+  Rate_Limit_Exceeded = 3
+  Missing_Parameter = 4
+  Invalid_Parameter = 5
+
+class RdioCatalog(object):
+  """
+  A convenience class to make calls to The Echo Nest API with Rdio Results
+  """
+  def __init__(self, region):
+    """
+    @param self.region: The Rdio catalog to call against, e.g. rdio-US (restrict to the US) or rdio-WW (all rdio catalogs)
+    @return: A convenience class to make API calls to The Echo Nest with results from the Rdio Catalog.
+    """
+    self.region = region
+
+  def rdio_identifier(self):
+    """
+    @return: Identification for the Rdio Catalog in 'self.region' country
+    """
+    return "rdio-%s" % self.region
+
+  def artist_identifier(self, rdio_artist_key):
+    """
+    @param rdio_artist_key: Rdio artist key e.g. r91318 (Radiohead)
+
+    @return: Format to identify an artist with an Rdio Key e.g. rdio-US:artist:r91318
+    """
+    return "%s:artist:%s" % (self.rdio_identifier(), artist_key)
+
+  def bucket_identifier(self):
+    """
+    @return: Convenience to specify the Rdio id space.
+    """
+    return "id:%s" % self.rdio_identifier()
+
+  def track_identifier(self, rdio_track_key):
+    """
+    @return: Format to identify a track with an Rdio Key e.g. rdio-US:track:t2062705 (Airbag)
+    """
+    return "%s:track:%s" % (self.region, rdio_track_key)
+
+  def get_artist_id(self, echo_artist_object):
+    """
+    @param echo_artist_object: pyechonest Artist object
+    @return: An Rdio artist key key from an EchoNest Artist.
+    """
+    try:
+      # Call API
+      identifier, category, id = echo_artist_object.get_foreign_id(self.rdio_identifier()).split(':')
+
+      if not identifier == self.rdio_identifier() or not category == "artist":
+        logging.error("Expected %s got %s, category %s" % (self.region, identifier, category))
+
+      return id
+    except EchoNestException as e:
+      if e == EchoNestAPICodes.Invalid_Parameter:
+        logging.exception("Echonest failed artist lookup: %s", echoartist)
+        return None
+      raise EchoNestException(e)
+    except AttributeError:
+      # Should not happen, but does in practice.
+      return None
+
+  def get_track_key(self, echonest_song_object):
+    """
+    @param echonest_song_object:  A PyEchonest Song object.
+    @return: An Rdio track key
+    """
+    try:
+      playback_dict = echonest_song_object.get_tracks(self.rdio_identifier())[0]
+      identifier, category, id = playback_dict['foreign_id'].split(':')
+
+      if not identifier == self.rdio_identifier() or not category == "track":
+        logging.error("Expected %s got %s, category %s" % (self.region, identifier, category))
+        return None
+      return id
+
+    except IndexError:
+      logging.info("EchoNest track did not map to an Rdio track: %s" % echonest_song_object)
+      return None
+