diff --git a/src/WebSockets/WebSocketHandler.php b/src/WebSockets/WebSocketHandler.php
index a2a917f..7b0eaf1 100644
--- a/src/WebSockets/WebSocketHandler.php
+++ b/src/WebSockets/WebSocketHandler.php
@@ -25,7 +25,7 @@ class WebSocketHandler implements MessageComponentInterface
         $this->channelManager = $channelManager;
     }
 
-    function onOpen(ConnectionInterface $connection)
+    public function onOpen(ConnectionInterface $connection)
     {
         $this
             ->generateSocketId($connection)