Fix program crash when AudioFeatures is missing

Fixes #32. AudioFeatures object query is now wrapped in a try/except
block to account for the scenario where the object doesn't exist.

spotifyvis/utils.py

@@ -127,7 +127,7 @@ def save_audio_features(headers, track_id, track):
     
     response = requests.get("https://api.spotify.com/v1/audio-features/{}".format(track_id), headers = headers).json()
     if 'error' in response:
-        return {}
+        return
 
     # Data that we don't need
     useless_keys = [ 

spotifyvis/views.py

@@ -204,8 +204,11 @@ def get_audio_feature_data(request, audio_feature, client_secret):
         'data_points': [],
     }
     for track in user_tracks:
-        audio_feature_obj = AudioFeatures.objects.get(track=track)
-        response_payload['data_points'].append(getattr(audio_feature_obj, audio_feature))
+        try:
+            audio_feature_obj = AudioFeatures.objects.get(track=track)
+            response_payload['data_points'].append(getattr(audio_feature_obj, audio_feature))
+        except AudioFeatures.DoesNotExist:
+            continue
     return JsonResponse(response_payload)
 
 #  }}} get_audio_feature_data #