Codeigniter检测表单post数据的方法

$name = $this->input->post(' name' ) ;
$email = $this- >input->post( ' email' ) ;
$subj ect = $this->input->post( ' subject' ) ;
$message = $this->input->post( ' message' ) ;
if(empty($name) OR empty($email) OR empty($subject) OR empty($message))
{
 show_404 ("Please go back and fill in all of the fields. " ) ;
}