CI_Input::server()

server($index[, $xss_clean = NULL])

This method is identical to the post(), get() and cookie() methods, only it fetches server data ($_SERVER):

$this->input->server('some_data');

To return an array of multiple $_SERVER values, pass all the required keys as an array.

$this->input->server(array('SERVER_PROTOCOL', 'REQUEST_URI'));