A URL base path detector for Slim 4

2.1.0 2021-07-17 10:03 UTC

This package is auto-updated.

Last update: 2022-11-16 13:00:12 UTC


A URL base path detector for Slim 4.

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  • Support for Apache and the PHP built-in webserver
  • Tested
  • No dependencies
  • Very fast

Supported servers

  • Apache webserver with mod_rewrite and .htaccess
  • PHP build-in webserver


  • PHP 7.2+ or 8.0+


composer require selective/basepath

The recommended directory structure:

  • public/ Web server files, the DocumentRoot
    • .htaccess Apache redirect rules for the front controller
    • index.php The front controller
  • .htaccess Internal redirect to the public/ directory

The following steps are necessary for your Slim 4 application:

For Apache we have to "redirect" the web traffic to the front controller in public/index.php.

Create a file: public/.htaccess with this content:

# Redirect to front controller
RewriteEngine On
# RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php [QSA,L]

We also need a rule to "redirect" the sub-directories to the front-controller in public/index.php.

Create a second .htaccess file above the public/ directory with this content:

RewriteEngine on
RewriteRule ^$ public/ [L]
RewriteRule (.*) public/$1 [L]


Slim 4 integration

Add the BasePathMiddleware after addRoutingMiddleware() to set the basePath before the routing is started.

Example: public/index.php


use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;
use Selective\BasePath\BasePathMiddleware;
use Slim\Factory\AppFactory;

require_once __DIR__ . '/../vendor/autoload.php';

$app = AppFactory::create();

// Add Slim routing middleware

// Set the base path to run the app in a subdirectory.
// This path is used in urlFor().
$app->add(new BasePathMiddleware($app));

$app->addErrorMiddleware(true, true, true);

// Define app routes
$app->get('/', function (Request $request, Response $response) {
    $response->getBody()->write('Hello, World!');
    return $response;

// Run app

Apache usage

  • Start the apache webserver
  • Open your website, e.g. http://localhost or http://localhost/{my-sub-directory} and you should see the message Hello, World!.

PHP built-in webserver usage

  • Open the console and change into the project public/ directory. Then run:
php -S localhost:8000

If you don't start the webserver from the project public/ directory, you have start it with a specific document root directory:

php -S localhost:8000 -t public
  • Open http://localhost:8000 and you should see the message Hello, World!.

Good URLs

The public/ directory is only the DocumentRoot of your webserver, but it's never part of your base path and the official url.

Good URLs:


Bad URLs:


Retrieving the base path

$basePath = \Slim\Routing\RouteContext::fromRequest($request)->getBasePath();

Creating a relative url with the base path

$routeParser = \Slim\Routing\RouteContext::fromRequest($request)->getRouteParser();
$url = $routeParser->urlFor('root');

Rendering the base path into a Twig layout template

This example requires slim/twig-view

<!DOCTYPE html>
    <meta charset="utf-8">
    <base href="{{ base_path() }}/"/>
{% block content %}{% endblock %}



The MIT License (MIT). Please see License File for more information.