Check if site run over https

is_https.php

<?php
/**
 * Check if site run over https
 *
 * @author Marco Cesarato <cesarato.developer@gmail.com>
 * @return boolean
 */
if (!function_exists('is_https')){
    function is_https(){
        if (isset($_SERVER['HTTP_HOST'])){
            if(((!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') || $_SERVER['SERVER_PORT'] == 443)
            || !empty($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https' || !empty($_SERVER['HTTP_X_FORWARDED_SSL']) && $_SERVER['HTTP_X_FORWARDED_SSL'] == 'on'){
                return true;
            }
            return false;
        }
        return false;
    }
}