function staticContentHeader($mod_timestamp, $etag_base = '', $expires = -1)
{
if (!empty($mod_timestamp)) {
$etag = md5($_SERVER["REQUEST_URI"] . $mod_timestamp . $etag_base);
header('Pragma:');
header('Etag: "' . $etag . '"');
header('Cache-Control:');
if ($expires == -1) {
header('Expires:');
} else {
header('Expires: ' . gmdate('D, d M Y H:i:s', time() + intval($expires)) . ' GMT');
}
header('Last-Modified: ' . gmdate('D, d M Y H:i:s', $mod_timestamp) . ' GMT');
if (!empty($_SERVER['HTTP_IF_MODIFIED_SINCE']) && $mod_timestamp == NBFrameHTTPOutput::_str2Time($_SERVER['HTTP_IF_MODIFIED_SINCE']) || !empty($_SERVER['HTTP_IF_NONE_MATCH']) && $etag == $_SERVER['HTTP_IF_NONE_MATCH']) {
header('HTTP/1.1 304 Not Modified');
exit;
}
}
}
