cache the media collection between page loads

apps/media/ajax/api.php

@@ -56,6 +56,7 @@ OC_MEDIA_COLLECTION::$uid=OC_User::getUser();
 if($arguments['action']){
 	switch($arguments['action']){
 		case 'delete':
+			unset($_SESSION['collection']);
 			$path=$arguments['path'];
 			OC_MEDIA_COLLECTION::deleteSongByPath($path);
 			$paths=explode(PATH_SEPARATOR,OC_Preferences::getValue(OC_User::getUser(),'media','paths',''));
@@ -64,17 +65,21 @@ if($arguments['action']){
 				OC_Preferences::setValue(OC_User::getUser(),'media','paths',implode(PATH_SEPARATOR,$paths));
 			}
 		case 'get_collection':
-			$artists=OC_MEDIA_COLLECTION::getArtists();
-			foreach($artists as &$artist){
-				$artist['albums']=OC_MEDIA_COLLECTION::getAlbums($artist['artist_id']);
-				foreach($artist['albums'] as &$album){
-					$album['songs']=OC_MEDIA_COLLECTION::getSongs($artist['artist_id'],$album['album_id']);
+			if(!isset($_SESSION['collection'])){
+				$artists=OC_MEDIA_COLLECTION::getArtists();
+				foreach($artists as &$artist){
+					$artist['albums']=OC_MEDIA_COLLECTION::getAlbums($artist['artist_id']);
+					foreach($artist['albums'] as &$album){
+						$album['songs']=OC_MEDIA_COLLECTION::getSongs($artist['artist_id'],$album['album_id']);
+					}
 				}
+
+				$_SESSION['collection']=json_encode($artists);
 			}
-			
-			echo json_encode($artists);
+			echo $_SESSION['collection'];
 			break;
 		case 'scan':
+			unset($_SESSION['collection']);
 			OC_DB::beginTransaction();
 			set_time_limit(0); //recursive scan can take a while
 			$path=$arguments['path'];
@@ -90,6 +95,7 @@ if($arguments['action']){
 			flush();
 			break;
 		case 'scanFile':
+			unset($_SESSION['collection']);
 			echo (OC_MEDIA_SCANNER::scanFile($arguments['path']))?'true':'false';
 			break;
 		case 'get_artists':