How to get the complete URL address of the current page using PHP

function get_full_url(){
    $protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
    $url = $protocol.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
    return $url;
 }

//获取域名或主机地址  
echo $_SERVER[&#39;HTTP_HOST&#39;]."<br>"; #localhost
 
//获取网页地址 
echo $_SERVER[&#39;PHP_SELF&#39;]."<br>"; #/blog/testurl.php
 
//获取网址参数 
echo $_SERVER["QUERY_STRING"]."<br>"; #id=5
 
//获取完整的url
echo &#39;http://&#39;.$_SERVER[&#39;HTTP_HOST&#39;].$_SERVER[&#39;REQUEST_URI&#39;];
echo &#39;http://&#39;.$_SERVER[&#39;HTTP_HOST&#39;].$_SERVER[&#39;PHP_SELF&#39;].&#39;?&#39;.$_SERVER[&#39;QUERY_STRING&#39;];
#http://localhost/blog/testurl.php?id=5
 
//包含端口号的完整url
echo &#39;http://&#39;.$_SERVER[&#39;SERVER_NAME&#39;].&#39;:&#39;.$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"]; 
#http://localhost:80/blog/testurl.php?id=5
 
//只取路径
$url=&#39;http://&#39;.$_SERVER[&#39;SERVER_NAME&#39;].$_SERVER["REQUEST_URI"]; 
echo dirname($url);