Triggers before comment is created.

<?php
function my_component_init(){
		ossn_register_callback('comment', 'before:created', 'my_component_cb');
}
function my_component_cb($callback, $type, $params){
		// $params['type'] (entity, object, post).
		// $params['entity] Entity instance, in case of entity, $params['object'] OssnObject instance in case of object, $params['post'] in case of OssnWall instance. 
}
ossn_register_callback('ossn', 'init', 'my_component_init');