ServiceProviderDB.php

<?php
// Service Provider
$app->register(new Via\Content\ContentServiceProvider());

// Route
$app->get('/{id}', function($id) use ($app) {
	return $app['content.id_checker']->check($id);
});

// and in .... ContentServiceProvider
public function register(Application $app)
{
  $app['content.id_checker'] = $app->share(function () use ($app) {
  	return new IdChecker($app['db']);
  });
};

// IdChecker() instantiates...method check($id)
public function check($id)
{
  // Check against $db and return boolean.
}