api, getArticle: check for article_id being present

classes/api.php

@@ -307,6 +307,8 @@ class API extends Handler {
 
 		$article_id = join(",", array_filter(explode(",", $this->dbh->escape_string($_REQUEST["article_id"])), is_numeric));
 
+		if ($article_id) {
+
 			$query = "SELECT id,title,link,content,cached_content,feed_id,comments,int_id,
 				marked,unread,published,score,
 				".SUBSTRING_FOR_DATE."(updated,1,16) as updated,
@@ -354,7 +356,9 @@ class API extends Handler {
 			}
 
 			$this->wrap(self::STATUS_OK, $articles);
-
+		} else {
+			$this->wrap(self::STATUS_ERR, array("error" => 'INCORRECT_USAGE'));
+		}
 	}
 
 	function getConfig() {