<?php
/**
 * Function to get the client ip address
 *
 * @return string The Ip address
 */
function getIp(): string {
    if (! empty($_SERVER['HTTP_CLIENT_IP'])) {
        return $_SERVER['HTTP_CLIENT_IP'];
    }

    if (! empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
        return $_SERVER['HTTP_X_FORWARDED_FOR'];
    }

    return $_SERVER['REMOTE_ADDR'] ?? '?';
}

更小的

/**
 * Function to get the client ip address
 *
 * @return string The Ip address
 */
function getIp(): string {
    return $_SERVER['HTTP_CLIENT_IP'] ?? $_SERVER['HTTP_X_FORWARDED_FOR'] ?? $_SERVER['REMOTE_ADDR'] ?? '';
}

这可以通过使用名为$_SERVER的GLOBAL变量来简单地完成。

$_SERVER是一个属性名为REMOTE_ADDR的数组。

就像这样分配它:

$userIp = $_SERVER['REMOTE_ADDR'];

或者直接使用它像echo $_SERVER['REMOTE_ADDR']; 或者echo ($_SERVER['REMOTE_ADDR']);

这是我使用的方法，它验证IPv4输入:

// Get user IP address
if ( isset($_SERVER['HTTP_CLIENT_IP']) && ! empty($_SERVER['HTTP_CLIENT_IP'])) {
    $ip = $_SERVER['HTTP_CLIENT_IP'];
} elseif ( isset($_SERVER['HTTP_X_FORWARDED_FOR']) && ! empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
    $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
} else {
    $ip = (isset($_SERVER['REMOTE_ADDR'])) ? $_SERVER['REMOTE_ADDR'] : '0.0.0.0';
}

$ip = filter_var($ip, FILTER_VALIDATE_IP);
$ip = ($ip === false) ? '0.0.0.0' : $ip;

其中之一:

    $ip = $_SERVER['REMOTE_ADDR'];
    $ip = $_SERVER['HTTP_CLIENT_IP'];
    $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
    $ip = $_SERVER['HTTP_X_FORWARDED'];
    $ip = $_SERVER['HTTP_FORWARDED_FOR'];
    $ip = $_SERVER['HTTP_FORWARDED'];

如果您不喜欢使用If -else/switch语句，那么下面的解决方案适合您。

function get_client_ip()
{
    $fields = array(
        'HTTP_CF_CONNECTING_IP',
        'HTTP_X_SUCURI_CLIENTIP',
        'HTTP_CLIENT_IP',
        'HTTP_X_FORWARDED_FOR',
        'HTTP_X_FORWARDED',
        'HTTP_FORWARDED_FOR',
        'HTTP_FORWARDED',
        'REMOTE_ADDR',
        // more custom fields
    );

    foreach ($fields as $ip_field) {
        if (!empty($_SERVER[$ip_field])) {
            return $_SERVER[$ip_field];
        }
    }

    return null;
}

<?php
/**
 * Function to get the client ip address
 *
 * @return string The Ip address
 */
function getIp(): string {
    if (! empty($_SERVER['HTTP_CLIENT_IP'])) {
        return $_SERVER['HTTP_CLIENT_IP'];
    }

    if (! empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
        return $_SERVER['HTTP_X_FORWARDED_FOR'];
    }

    return $_SERVER['REMOTE_ADDR'] ?? '?';
}

更小的

/**
 * Function to get the client ip address
 *
 * @return string The Ip address
 */
function getIp(): string {
    return $_SERVER['HTTP_CLIENT_IP'] ?? $_SERVER['HTTP_X_FORWARDED_FOR'] ?? $_SERVER['REMOTE_ADDR'] ?? '';
}