The primary use of this hook would be for creating an alternate storage system for attachments. Using this hook, you can delete the file from your alternate storage.

Call time:

In include/posting/action_attachments.php, right after a file attachment is deleted from the database.

Hook input:

Two part array where the first element is the message array and the second element is a file array that contains the name, size, and file_id of the deleted file.

Hook output:

Same as input.

Example code:

function phorum_mod_foo_reopen_after_detach($data)
{
    global $PHORUM;

    // Remove the attachment from the log of messages with
    // attachments
    unset($PHORUM["mod_foo"]["messages_with_attachments"][$data[0]["message_id"]][$data[1]["file_id"]]);

    // If there are now no attachments on the current
    // message, remove the message from the log
    if (empty($PHORUM["mod_foo"]["messages_with_attachments"][$data[0]["message_id"]]))
        unset($PHORUM["mod_foo"]["messages_with_attachments"][$data[0]["message_id"]]);
    phorum_db_update_settings(array("mod_foo" => $PHORUM["mod_foo"]));

    return $data;
}