PHP开发中如何获取页面URL函数

/* 获得当前页面URL开始 */
function curPageURL() {
    $pageURL = 'http';
    if ($_SERVER["HTTPS"] == "on") {    // 如果是SSL加密则加上“s”
        $pageURL .= "s";
    }
    $pageURL .= "://";
    if ($_SERVER["SERVER_PORT"] != "80") {
        $pageURL .= $_SERVER["SERVER_NAME"].":".$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"];
    } else {
        $pageURL .= $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"];
    }
    return $pageURL;
}
/* 获得当前页面URL结束 */

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