我最喜欢的查找当前URL的跨平台方法是:

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

Use:

$base_dir = __DIR__; // Absolute path to your installation, ex: /var/www/mywebsite
$doc_root = preg_replace("!{$_SERVER['SCRIPT_NAME']}$!", '', $_SERVER['SCRIPT_FILENAME']); # ex: /var/www
$base_url = preg_replace("!^{$doc_root}!", '', $base_dir); # ex: '' or '/mywebsite'
$base_url = str_replace('\\', '/', $base_url);//On Windows
$base_url = str_replace($doc_root, '', $base_url);//On Windows
$protocol = empty($_SERVER['HTTPS']) ? 'http' : 'https';
$port = $_SERVER['SERVER_PORT'];
$disp_port = ($protocol == 'http' && $port == 80 || $protocol == 'https' && $port == 443) ? '' : ":$port";
$domain = $_SERVER['SERVER_NAME'];
$full_url = "$protocol://{$domain}{$disp_port}{$base_url}"; # Ex: 'http://example.com', 'https://example.com/mywebsite', etc. 

来源:PHP文档根，路径和URL检测

你可以使用HTTP_ORIGIN，如下面的代码片段所示:

if ( ! array_key_exists( 'HTTP_ORIGIN', $_SERVER ) ) {
    $this->referer = $_SERVER['SERVER_NAME'];
} else {
    $this->referer = $_SERVER['HTTP_ORIGIN'];
}

使用这一行程序来查找父文件夹URL(如果您无法访问pecl_http附带的http_build_url()):

$url = (isset($_SERVER['HTTPS']) ? 'https://' : 'http://').$_SERVER['SERVER_NAME'].str_replace($_SERVER['DOCUMENT_ROOT'], '', dirname(dirname(__FILE__)));

非常简单的用法:

function current_url() {
    $current_url  = ( $_SERVER["HTTPS"] != 'on' ) ? 'http://'.$_SERVER["SERVER_NAME"] :  'https://'.$_SERVER["SERVER_NAME"];
    $current_url .= ( $_SERVER["SERVER_PORT"] != 80 ) ? ":".$_SERVER["SERVER_PORT"] : "";
    $current_url .= $_SERVER["REQUEST_URI"];

    return $current_url;
}

我用了这句话。

$base = "http://$_SERVER[SERVER_NAME]:$_SERVER[SERVER_PORT]$my_web_base_path";
$url = $base . "/" . dirname(dirname(__FILE__));