Hi All!

I'm trying to build a plugin that will notify all users that comment on any post, I attempt to do this by creating a new metadata called commenters, commenters will be an array of GUIDs of users who hv added a comment and then notify them all using the notify_user() function.

The concept worked but however whenever a new user joins the comment stream, older users start getting DOUBLE notifications i.e there GUIDs are inserted twice, below is code for my modified actions/comments/add.php

<?php
/**
* Elgg add comment action
*
* @package Elgg
* @author Curverider <curverider.co.uk>
* @link http://elgg.org/
*/

// Make sure we're logged in; forward to the front page if not
gatekeeper();

// Get input
$entity_guid = (int) get_input('entity_guid');
$comment_text = get_input('generic_comment');

// make sure comment is not empty
if (empty($comment_text)) {
register_error(elgg_echo("generic_comment:blank"));
forward($_SERVER['HTTP_REFERER']);
}

// Let's see if we can get an entity with the specified GUID
$entity = get_entity($entity_guid);
if (!$entity) {
register_error(elgg_echo("generic_comment:notfound"));
forward($_SERVER['HTTP_REFERER']);
}

$user = get_loggedin_user();

$annotation = create_annotation($entity->guid,
'generic_comment',
$comment_text,
"",
$user->guid,
$entity->access_id);

// tell user annotation posted
if (!$annotation) {
register_error(elgg_echo("generic_comment:failure"));
forward($_SERVER['HTTP_REFERER']);
}

//Notify everybody!
//create metadata to do that!
if (!$entity->commenters || !is_array($entity->commenters)){
if ($entity->owner_guid != $user->guid) {
$commenters = array();
//add owner_guid
$commenters[] = $entity->owner_guid;
//add poster's guid
$commenters[] = $user->guid;
$entity->commenters = $commenters;
}

}else{
//check if guid is inside, else add it!
if (!in_array($user->guid,$entity->commenters)){
$commenters = array();
$commenters = $entity->commenters;
$commenters[] = $user->guid;
//clean up first
//remove_metadata($entity->guid, commenters);
$entity->commenters = $commenters;
}
}

notify_user($entity->commenters,
$user->guid,
elgg_echo('generic_comment:email:subject'),
sprintf(
elgg_echo('generic_comment:email:body'),
$entity->title,
$user->name,
$comment_text,
$entity->getURL(),
$user->name,
$user->getURL()
)
);
system_message(elgg_echo("generic_comment:posted"));
//add to river
add_to_river('annotation/annotate','comment',$user->guid,$entity->guid, "", 0, $annotation);

// Forward to the entity page
forward($entity->getURL());

I'm planning to release it as a full plugin and would appreciate any help.