opensupports/server/models/ERRORS.php

<?php
class ERRORS {
    const INVALID_CREDENTIALS = 'User or password is not defined';
    const SESSION_EXISTS = 'User is already logged in';
    const SHORT_TITLE = 'Title is too short';
    const LONG_TITLE = 'Title is very long';
    const SHORT_CONTENT = 'Content is too short';
    const LONG_CONTENT = 'Content is very long';
}