How to create an alerthandler for a custom content type?

Hi Guys,

Edit: sorry title should be how to create a alerthandler for a custom content type?

I hope there are some experience members online who can help me.
I'm working on a upload center (file sharing) mod but I've been stuck all day trying to implement the alert system for likes.
I created a new content type and an AlertHandler for my mod. The like/unlike is working but when I like a custom content type it only display in the alert system if a post with the same ID excist on the forum, if there's no post with the same ID it will still say there's a new alert since it's inserted in the database correctly but it's not displaying it.

When I look at the query on the alerts page it does contain all the id numbers including the id's it doesn't show so I think somewhere there's a function that checks if the content excist and it's checking in the xf_post table.

Here's the code of my LikeHandler

class ULC_AlertHandler_File extends XenForo_AlertHandler_DiscussionMessage
	public function getContentByIds(array $contentIds, $model, $userId, array $viewingUser)
		// this
		return $model->getModelFromCache('ULC_Model_Files')->getFilesByIds($contentIds);

	public function canViewAlert(array $alert, $content, array $viewingUser)
		return true;
Here's the code from ULC_Model_File which is called for function getFilesByIds
	public function getFilesByIds(array $fileIds, array $fetchOptions = array())
		if (!$fileIds)
			return array();

		return $this->fetchAllKeyed('
			SELECT attachment.attachment_id, data.filename
			FROM xf_attachment AS attachment
			INNER JOIN xf_attachment_data AS data
				ON (data.data_id = attachment.data_id)
			WHERE attachment.attachment_id IN (' . $this->_getDb()->quote($fileIds) . ')
		', 'file_id');
demo link:



Well-known member
Did you create a new LikeHandler for attachments? It sounds like your Alert works, but it is based off of posts, so when no postid matches there is nothing to display.