我使用了下面的代码，它对我来说工作得很好，对于HTTP和HTTPS这两种情况。

function curPageURL() {
  if(isset($_SERVER["HTTPS"]) && !empty($_SERVER["HTTPS"]) && ($_SERVER["HTTPS"] != 'on' )) {
        $url = 'https://'.$_SERVER["SERVER_NAME"];//https url
  }  else {
    $url =  'http://'.$_SERVER["SERVER_NAME"];//http url
  }
  if(( $_SERVER["SERVER_PORT"] != 80 )) {
     $url .= $_SERVER["SERVER_PORT"];
  }
  $url .= $_SERVER["REQUEST_URI"];
  return $url;
}

echo curPageURL();

Demo

下面是更安全版本的接受答案的基础，使用PHP的filter_input函数，这也弥补了$_SERVER['REQUEST_URI']的潜在缺失:

$protocol_https = filter_input(INPUT_SERVER, 'HTTPS', FILTER_SANITIZE_STRING);
$host = filter_input(INPUT_SERVER, 'HTTP_HOST', FILTER_SANITIZE_URL);
$request_uri = filter_input(INPUT_SERVER, 'REQUEST_URI', FILTER_SANITIZE_URL);
if(strlen($request_uri) == 0)
{
    $request_uri = filter_input(INPUT_SERVER, 'SCRIPT_NAME', FILTER_SANITIZE_URL);
    $query_string = filter_input(INPUT_SERVER, 'QUERY_STRING', FILTER_SANITIZE_URL);
    if($query_string)
    {
        $request_uri .= '?' . $query_string;
    }
}
$full_url = ($protocol_https ? 'https' : 'http') . '://' . $host . $request_uri;

你可以使用一些不同的过滤器来调整它到你的喜欢。

清晰的代码，工作在所有的web服务器(Apache, nginx, IIS，…)

$url = (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' ? 'https' : 'http') . '://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];

HTTP_HOST和REQUEST_URI必须加引号，否则会在PHP 7.2中抛出错误

使用:

$actual_link = 'https://'.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];

如果你想同时支持HTTP和HTTPS:

$actual_link = (isset($_SERVER['HTTPS']) ? 'https' : 'http').'://'.$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];

我觉得这个方法不错，试试吧

if($_SERVER['HTTP_HOST'] == "localhost"){
    define('SITEURL', 'http://' . $_SERVER['HTTP_HOST']);
    define('SITEPATH', $_SERVER['DOCUMENT_ROOT']);
    define('CSS', $_SERVER['DOCUMENT_ROOT'] . '/css/');
    define('IMAGES', $_SERVER['DOCUMENT_ROOT'] . '/images/');
}
else{
    define('SITEURL', 'http://' . $_SERVER['HTTP_HOST']);
    define('SITEPATH', $_SERVER['DOCUMENT_ROOT']);
    define('TEMPLATE', $_SERVER['DOCUMENT_ROOT'] . '/incs/template/');
    define('CSS', $_SERVER['DOCUMENT_ROOT'] . '/css/');
    define('IMAGES', $_SERVER['DOCUMENT_ROOT'] . '/images/');
}

我用这个函数来处理URL:

 <?php
     function curPageURL()
     {
         $pageURL = 'http';
         if ($_SERVER["HTTPS"] == "on") {$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;
     }
 ?>