Controller.php

<?php
/**
 * Matomo - free/libre analytics platform
 *
 * @link https://matomo.org
 * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
 */

namespace Piwik\Plugins\WeatherReports;

use Piwik\Common;
use Piwik\IP;

class Controller extends \Piwik\Plugin\Controller
{
    /**
     * Public endpoint that returns the visitor's IP as Matomo resolves it
     * (honouring proxy_client_headers / proxy_host_headers in config.ini.php).
     *
     * URL: /index.php?module=WeatherReports&action=getUserIp
     *
     * Intended as a self-hosted replacement for third-party IP lookups
     * (ipapi.co etc.) when WeatherAPI's q=auto:ip cannot be used — for
     * example behind a CDN where the client IP needs Matomo's proxy
     * configuration to be resolved correctly.
     */
    public function getUserIp()
    {
        Common::sendHeader('Content-Type: application/json; charset=utf-8');
        Common::sendHeader('Cache-Control: no-store');

        return json_encode(['ip' => IP::getIpFromHeader()]);
    }
}