Added middleware to modify the path when running from a sub-directory

app/Bootstrap/AppManager.php

@@ -2,6 +2,7 @@
 
 namespace App\Bootstrap;
 
+use App\Middleware;
 use App\Providers;
 use DI\Bridge\Slim\Bridge;
 use DI\Container;
@@ -19,6 +20,11 @@ class AppManager
         Providers\TwigProvider::class,
     ];
 
+    /** @const Constant description */
+    protected const MIDDLEWARES = [
+        Middleware\StripBasePathMiddleware::class,
+    ];
+
     /** @var Container The applicaiton container */
     protected $container;
 
@@ -48,8 +54,10 @@ class AppManager
     public function __invoke(): App
     {
         $this->registerProviders();
+        $app = Bridge::create($this->container);
+        $this->registerMiddlewares($app);
 
-        return Bridge::create($this->container);
+        return $app;
     }
 
     /**
@@ -67,4 +75,20 @@ class AppManager
             );
         });
     }
+
+    /**
+     * Register application middleware.
+     *
+     * @param \Slim\App $app
+     *
+     * @return void
+     */
+    protected function registerMiddlewares(App $app): void
+    {
+        Collection::make(self::MIDDLEWARES)->merge(
+            $this->config->get('app.middlewares', [])
+        )->each(function (string $middleware) use ($app) {
+            $app->add($middleware);
+        });
+    }
 }

app/Middleware/StripBasePathMiddleware.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace App\Middleware;
+
+use DI\Container;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Slim\Psr7\Response;
+
+class StripBasePathMiddleware
+{
+    /**
+     * Create a new CanonicalizePathMiddleware object.
+     *
+     * @param \DI\Container $container
+     */
+    public function __construct(Container $container)
+    {
+        $this->container = $container;
+    }
+
+    /**
+     * Canonicalize the received path variable.
+     *
+     * @param \Slim\Psr7\Request  $request
+     * @param \Slim\Psr7\Response $response
+     * @param callable            $next
+     *
+     * @return void
+     */
+    public function __invoke(
+        ServerRequestInterface $request,
+        RequestHandlerInterface $handler
+    ): Response {
+        $path = $request->getUri()->getPath();
+
+        $request = $request->withUri(
+            $request->getUri()->withPath($this->stripBasePath($path))
+        );
+
+        return $handler->handle($request);
+    }
+
+    /**
+     * Strip the base URL path from a path string.
+     *
+     * @param string $path
+     *
+     * @return string
+     */
+    protected function stripBasePath(string $path): string
+    {
+        $pattern = sprintf('/^%s/', preg_quote(dirname($_SERVER['SCRIPT_NAME']), '/'));
+
+        return preg_replace($pattern, '', $path);
+    }
+}

app/config/app.php

@@ -65,4 +65,13 @@ return [
     'providers' => [
         // ...
     ],
+
+    /**
+     * Additional middlewares to be registered.
+     *
+     * Default value: []
+     */
+    'middlewares' => [
+        // ...
+    ],
 ];

tests/Support/HelpersTest.php

@@ -4,6 +4,7 @@ namespace Tests\Support;
 
 use App\Support\Helpers;
 use PHPUnit\Framework\TestCase;
+use RuntimeException;
 
 class HelpersTest extends TestCase
 {
@@ -47,4 +48,25 @@ class HelpersTest extends TestCase
 
         $this->assertEquals('Test charlie; please ignore', $env);
     }
+
+    public function test_it_can_get_a_relative_path_from_one_path_to_another(): void
+    {
+        $relativePath = Helpers::realativePath('foo/bar', 'foo/bar/baz/qux');
+
+        $this->assertEquals('baz/qux', $relativePath);
+    }
+
+    public function test_it_cat_get_a_relative_path_to_itself(): void
+    {
+        $relativePath = Helpers::realativePath('foo/bar/baz', 'foo/bar/baz');
+
+        $this->assertEquals('', $relativePath);
+    }
+
+    public function test_it_can_get_a_relative_path_between_two_unrelated_paths(): void
+    {
+        $path = $this->expectException(RuntimeException::class);
+
+        Helpers::realativePath('foo/bar', 'baz/qux');
+    }
 }