我用了这句话。

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

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

你可以使用不带参数的http_build_url来获取当前页面的完整URL:

$url = http_build_url();

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

在网页上输出链接的简短版本

$url =  "//{$_SERVER['HTTP_HOST']}{$_SERVER['REQUEST_URI']}";

$escaped_url = htmlspecialchars( $url, ENT_QUOTES, 'UTF-8' );
echo '<a href="' . $escaped_url . '">' . $escaped_url . '</a>';

下面是关于//example.com/path/格式的问题和边缘情况的更多细节

完整版

function url_origin( $s, $use_forwarded_host = false )
{
    $ssl      = ( ! empty( $s['HTTPS'] ) && $s['HTTPS'] == 'on' );
    $sp       = strtolower( $s['SERVER_PROTOCOL'] );
    $protocol = substr( $sp, 0, strpos( $sp, '/' ) ) . ( ( $ssl ) ? 's' : '' );
    $port     = $s['SERVER_PORT'];
    $port     = ( ( ! $ssl && $port=='80' ) || ( $ssl && $port=='443' ) ) ? '' : ':'.$port;
    $host     = ( $use_forwarded_host && isset( $s['HTTP_X_FORWARDED_HOST'] ) ) ? $s['HTTP_X_FORWARDED_HOST'] : ( isset( $s['HTTP_HOST'] ) ? $s['HTTP_HOST'] : null );
    $host     = isset( $host ) ? $host : $s['SERVER_NAME'] . $port;
    return $protocol . '://' . $host;
}

function full_url( $s, $use_forwarded_host = false )
{
    return url_origin( $s, $use_forwarded_host ) . $s['REQUEST_URI'];
}

$absolute_url = full_url( $_SERVER );
echo $absolute_url;

这是一个经过大量修改的http://snipplr.com/view.php?codeview&id=2734(现在已经不存在了)

URL结构:

scheme：//username：password@domain：port/path？query_string#fragment_id

粗体部分将不包含在函数中

注:

This function does not include username:password from a full URL or the fragment (hash). It will not show the default port 80 for HTTP and port 443 for HTTPS. Only tested with http and https schemes. The #fragment_id is not sent to the server by the client (browser) and will not be added to the full URL. $_GET will only contain foo=bar2 for an URL like /example?foo=bar1&foo=bar2. Some CMS's and environments will rewrite $_SERVER['REQUEST_URI'] and return /example?foo=bar2 for an URL like /example?foo=bar1&foo=bar2, use $_SERVER['QUERY_STRING'] in this case. Keep in mind that an URI = URL + URN, but due to popular use, URL now means both URI and URL. You should remove HTTP_X_FORWARDED_HOST if you do not plan to use proxies or balancers. The spec says that the Host header must contain the port number unless it is the default number.

客户端(浏览器)控制变量:

$ _SERVER [' REQUEST_URI ']。任何不支持的字符在发送之前都由浏览器编码。 $_SERVER['HTTP_HOST']，根据PHP手册中的注释:http://php.net/manual/en/reserved.variables.php并不总是可用的 $_SERVER['HTTP_X_FORWARDED_HOST']由平衡器设置，在PHP手册中的$_SERVER变量列表中没有提到。

服务器控制变量:

$ _SERVER(“HTTPS”)。客户端选择使用此选项，但服务器返回的实际值为空或“on”。 $ _SERVER [' SERVER_PORT ']。服务器只接受允许的数字作为端口。 $ _SERVER [' SERVER_PROTOCOL ']。服务器只接受特定的协议。 $ _SERVER [' SERVER_NAME ']。它是在服务器配置中手动设置的，根据kralyk的说法，它不适用于IPv6。

相关:

PHP中的HTTP_HOST和SERVER_NAME之间的区别是什么? HTTP“主机”头参数中需要端口号吗? https://stackoverflow.com/a/28049503/175071

我用了这句话。

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