Redirections des anciennes URL

$id = isset($_GET['id']) ? intval($_GET['id']) : 0;

if (preg_match('~.*sujet-*~', $_SERVER['REQUEST_URI']))
{
    $query = array(
        'SELECT'    => 't.subject AS subject',
        'FROM'        => 'topics AS t',
        'JOINS'        => array(
            array(
                'INNER JOIN'    => 'forums AS f',
                'ON'            => 'f.id=t.forum_id'
            ),
            array(
                'LEFT JOIN'        => 'forum_perms AS fp',
                'ON'            => '(fp.forum_id=f.id AND fp.group_id='.$forum_user['g_id'].')'
            )
        ),
        'WHERE'        => '(fp.read_forum IS NULL OR fp.read_forum=1) AND t.id='.$id.' AND t.moved_to IS NULL'
    );
    $page = 'sujet';
}


$result = $forum_db->query_build($query) or error(__FILE__, __LINE__);
if (!$forum_db->num_rows($result))
    message($lang_common['Bad request']);

list($subject) = $forum_db->fetch_row($result);

if ($page == 'sujet')
    $redirect_url = str_replace('&', '&', forum_link($forum_url['topic'], array($id, sef_friendly($subject))));

header('HTTP/1.1 301 Moved Permanently');    
header('Location: '.$redirect_url);