private function _check_cache()
{
// cache is found and readable, check if we can still use it based
// on its last modified timestamp
$last_modified = @filemtime($this->cache_file);
if ($last_modified + $this->cache_time <= $this->now && 'yes' == $this->options['enable_cache_auto_gen']) {
// cached sitemap file has expired, and cache auto-regenerate
// is enabled, remove the cached sitemap file and return to the main
// handle to re-generate a new sitemap file.
@unlink($this->cache_file);
return false;
}
$lastmod = bwp_gxs_format_header_time($last_modified);
$expires = bwp_gxs_format_header_time($last_modified + $this->cache_time);
$etag = md5($expires . $this->cache_file);
// build cached sitemap's headers for later use
$this->cache_headers = array('lastmod' => $lastmod, 'expires' => $expires, 'etag' => $etag);
if ($this->_check_http_cache($lastmod, $etag)) {
return '304';
}
return '200';
}
private static function _format_header_time($time)
{
return bwp_gxs_format_header_time($time);
}
