php__silex__book/src/controllers-blog.php

<?php

/**
 * @file
 * Demo typical entity listing routes with their modifiers.
 */

use demo\Controllers\BlogController;
use Silex\Application;
use Silex\ControllerCollection;

$blogCollection = function (Application $app): ControllerCollection {
  $MAGIC = 'xyzzy';

  // This is a factory service, producing a new instance every time.
  $blog = $app['controllers_factory'];

  $blog->get('/',             BlogController::class       . '::index')
    ->bind('blog_list');
  $blog->get('/{id}',         BlogController::class       . '::index2')
    ->assert('id', $MAGIC)
    // Serve '(mount)/xyzzy' when asked for '(mount)'.
    ->value('id', $MAGIC)
    ->bind('blog_mount');

  $blog->get('/json',         BlogController::class       . '::json');
  $blog->get('/json-view',    BlogController::class       . '::jsonView');
  $blog->get('/{id}',         BlogController::class       . '::fifiAction')
    ->assert('id', '\d+')
    // See Symfony expression language.
    ->when("request.headers.get('User-Agent') matches '/firefox/i'");
  $blog->get('/{id}',         BlogController::class       . '::show')
    ->assert('id', '\d+')
    // Serve '(mount)/1' when asked for '(mount)/'.
    ->value('id', 1)
    ->bind('blog_post');

  return $blog;
};

return $blogCollection($app);