filter the eWAY invoice description for a Gravity Form post

gistfile1.php

<?php
/**
* filter the eWAY invoice description for a Gravity Form post
* @param string $desc the description before filtering
* @param array $form the Gravity Form object
* @return string
*/
function my_gfeway_invoice_desc($desc, $form) {
    // set by form ID
    switch ($form['id']) {
        case 1:
            $desc = 'Donate form';
            break;

        case 6:
            $desc = 'Recurring payment form';
            break;
    }

    // set by hidden field
    foreach($form['fields'] as $field) {
        if (RGFormsModel::get_input_type($field) == 'hidden' && $field['label'] == 'Invoice Description') {
            $desc = rgpost('input_' . $field['id']);
            break;
        }
    }

    return $desc;
}

add_filter('gfeway_invoice_desc', 'my_gfeway_invoice_desc', 10, 2);