Fix Scheme Problem & Rewrite Mode on Slim Frame Work 3

MyApp.php

<?php
/**
 * This only example usage of using slim as application
 *      By default Slim 3 only detect if environemnt https set not 'off'
 *      but on some case eg : cloudflare Flexible SSL / FULL SSL will be hide site behind
 *      the CloudFlare Secure Protocol.
 *      You could change anything namespace etc. to working with Slim 3 App
 * @see {https://support.cloudflare.com/hc/en-us/articles/203487280--How-do-I-fix-the-infinite-redirect-loop-error-after-enabling-Flexible-SSL-with-WordPress-}
 *      on some case cloud flare use Environment  (HTTP_X_FORWARDED_PROTO)
 *      to hide real site and serve on their secure protocol
 */
namespace MyApp;

use Slim\App;
use Slim\Http\Uri;
use Slim\Http\Environment;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

class MyApp
{
    /**
     * @var \Slim\App
     */
    protected $slim;
    
    /**
     * MyApp constructor
     */
    public function __construct()
    {
        // call Fix Protocol Environment
        $server_env = $this->fixHTTPSEnvironment();
        $this->slim = new App(
            [
                // even though this is a optional,
                // but better to set this (my opinion)
                'environment' => Environment::mock($server_env),
            ]
        );
        /**
         * Optional , if you have mod rewrite enable
         * and prevent duplicate URL, you could call
         * @method MyApp::registerMiddleWareFixRewrite()
         */
         $this->registerMiddleWareFixRewrite();
    }

    /**
     * Detecting & Fix Environment on some cases
     *     Default Environment uses $_SERVER to attach
     *     just to fix https
     * @return array
     */
    protected function fixHTTPSEnvironment()
    {
        if (!empty($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) !== 'off'
            // hide behind proxy / maybe cloudflare cdn
            || isset($_SERVER['HTTP_X_FORWARDED_PROTO']) && $_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https'
            || !empty($_SERVER['HTTP_FRONT_END_HTTPS']) && strtolower($_SERVER['HTTP_FRONT_END_HTTPS']) !== 'off'
        ) {
            // detect if non standard protocol
            if ($_SERVER['SERVER_PORT'] == 80
                && (isset($_SERVER['HTTP_X_FORWARDED_PROTO'])
                    || isset($_SERVER['HTTP_FRONT_END_HTTPS'])
                )
            ) {
                // add original standard port
                $_SERVER['SERVER_PORT_ORIGINAL'] = 80;
                $_SERVER['SERVER_PORT'] = 443;
            }
            // fixing HTTPS Environment
            $_SERVER['HTTPS'] = 'on';
        }

        return $_SERVER;
    }
    /**
     * Register Additional Middleware to make sure getting better on
     * mod_rewrite, prevent multiple /duplicate URL
     *
     * @return $this
     */
    protected function registerMiddleWareFixRewrite()
    {
        $this->slim->add(function (
            ServerRequestInterface $requestInterface,
            ResponseInterface $responseInterface,
            $next
        ) {
            /**
             * clone of environment toprevent override of environment setted
             *
             * @var Environment
             */
            $env = clone $this->environment;
            // use parent directory of script name
            $env['SCRIPT_NAME'] = dirname($env['SCRIPT_NAME']);
            $requestInterface =
                $this->request = // overwrite request for all resource
                    $requestInterface->withUri(Uri::createFromEnvironment($env));
            return $next($requestInterface, $responseInterface);
        });

        return $this;
    }
}