batcache::generate_keys PHP Method

    function generate_keys()
    {
        // ksort($this->keys); // uncomment this when traffic is slow
        $this->key = md5(serialize($this->keys));
        $this->req_key = $this->key . '_reqs';
    }

header('Vary: Cookie', false);
// Things that define a unique page.
if (isset($_SERVER['QUERY_STRING'])) {
    parse_str($_SERVER['QUERY_STRING'], $batcache->query);
}
$batcache->keys = array('host' => $_SERVER['HTTP_HOST'], 'method' => $_SERVER['REQUEST_METHOD'], 'path' => ($batcache->pos = strpos($_SERVER['REQUEST_URI'], '?')) ? substr($_SERVER['REQUEST_URI'], 0, $batcache->pos) : $_SERVER['REQUEST_URI'], 'query' => $batcache->query, 'extra' => $batcache->unique);
if ($batcache->is_ssl()) {
    $batcache->keys['ssl'] = true;
}
// Recreate the permalink from the URL
$batcache->permalink = 'http://' . $batcache->keys['host'] . $batcache->keys['path'] . (isset($batcache->keys['query']['p']) ? "?p=" . $batcache->keys['query']['p'] : '');
$batcache->url_key = md5($batcache->permalink);
$batcache->url_version = (int) wp_cache_get("{$batcache->url_key}_version", $batcache->group);
$batcache->configure_groups();
$batcache->do_variants();
$batcache->generate_keys();
// Get the batcache
$batcache->cache = wp_cache_get($batcache->key, $batcache->group);
// Are we only caching frequently-requested pages?
if ($batcache->seconds < 1 || $batcache->times < 2) {
    $batcache->do = true;
} else {
    // No batcache item found, or ready to sample traffic again at the end of the batcache life?
    if (!is_array($batcache->cache) || time() >= $batcache->cache['time'] + $batcache->max_age - $batcache->seconds) {
        wp_cache_add($batcache->req_key, 0, $batcache->group);
        $batcache->requests = wp_cache_incr($batcache->req_key, 1, $batcache->group);
        if ($batcache->requests >= $batcache->times) {
            $batcache->do = true;
        } else {
            $batcache->do = false;
        }