Add {machine_id} to notification options

data/interfaces/default/settings.html

@@ -1242,6 +1242,10 @@ available_notification_agents = sorted(notifiers.available_notification_agents()
                                     <td><strong>{user_id}</strong></td>
                                     <td>The unique identifier for the user.</td>
                                 </tr>
+                                <tr>
+                                    <td><strong>{machine_id}</strong></td>
+                                    <td>The unique identifier for the player.</td>
+                                </tr>
                             </tbody>
                         </table>
                         <table class="notification-params">

plexpy/notification_handler.py

@@ -512,6 +512,7 @@ def build_notify_text(session=None, timeline=None, state=None):
                         'transcode_audio_channels': session.get('transcode_audio_channels',''),
                         'session_key': session.get('session_key',''),
                         'user_id': session.get('user_id',''),
+                        'machine_id': session.get('machine_id',''),
                         # Metadata parameters
                         'media_type': metadata['media_type'],
                         'title': full_title,