public function base_url($uri = '', $protocol = NULL)
{
$base_url = $this->slash_item('base_url');
if (isset($protocol)) {
// For protocol-relative links
if ($protocol === '') {
$base_url = substr($base_url, strpos($base_url, '//'));
} else {
$base_url = $protocol . substr($base_url, strpos($base_url, '://'));
}
}
return $base_url . ltrim($this->_uri_string($uri), '/');
}