徒然ぶろぐ

Etag, Last modified

$last_modified = UNIX_TIME;
$etag = md5($last_modified);
$http_if_none_match = $_SERVER['HTTP_IF_NONE_MATCH'];
$http_if_modified_since = strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']);
@header('Last-modified: ' . gmdate('D, d M Y H:i:s T', $last_modified));
@header('ETag: ' . $etag);

// 304
if ($http_if_modified_since == $last_modified || $etag == $http_if_none_match) {
    @header('HTTP/1.x 304');
    exit;
}