php判斷服務器l是否爲https

/**
    動態獲取當前請求的url
/*
<?php

$protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTPS'] !='off' || $_SERVER['SERVER_PORT'] == 443) ?'https':'http';
$url = $protocol.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
echo $url;