Add getSong endpoint and complete CarPlay audio streaming server

src/routes/subsonic.js

@@ -682,6 +682,24 @@ router.get('/getPlaylist.view', authenticateSubsonic, async (req, res) => {
   }
 });
 
+// Get song
+router.get('/getSong.view', authenticateSubsonic, async (req, res) => {
+  try {
+    const { id } = req.query;
+    const track = await get('SELECT * FROM tracks WHERE id = ?', [id]);
+    
+    if (!track) {
+      return sendSubsonicError(res, 70, 'Song not found');
+    }
+
+    const songXml = buildSongXml(track, req);
+    sendSubsonicResponse(res, `<song>${songXml}</song>`);
+  } catch (error) {
+    console.error('Error in getSong:', error);
+    sendSubsonicError(res, 0, error.message);
+  }
+});
+
 // Search
 router.get('/search3.view', authenticateSubsonic, async (req, res) => {
   try {