Basic SilverStripe 3.0 Framework Bootstrap

app._config.routes.yml

---
Name: app
After: framework/routes#coreroutes
---
Director:
  rules:
    'dev': 'DevelopmentAdmin'
    'sitemap.xml': 'GoogleSitemap'
    '$Action' : 'BaseController'

app.code.controllers.BaseController.php

<?php

class BaseController extends Controller {

	public static $allowed_actions = array(
		'index'
	);


	/**
	 * Handle 404 errors gracefully as the normal 404 error pages are part
	 * of the CMS module
	 */
	public function handleAction($request) {
		try {
			$response = parent::handleAction($request);

			return $response;
		}
		catch(SS_HTTPResponse_Exception $e) {
			$response = $e->getResponse();
			$response->addHeader('Content-Type', 'text/html; charset=utf-8');
			$response->setBody($this->renderWith(array('Error', 'BaseController')));

			return $response;
		}
	}

	/**
	 * Return a HTTP error to the user
	 */
	public function httpError($errorCode = '404', $errorMessage = null) {
		$this->response->setStatusCode($errorCode);

		return $this->customise(new ArrayData(array(
			'Title' => 'Whoops!',
			'Content' => DBField::create_field('HTMLText', $errorMessage)
		)))->renderWith(array(
			'Error',
			'BaseController'
		));
	}

	/**
	 * Home action
	 *
	 * @return html
	 */
	public function index() {
		return $this->customise(new ArrayData(array(
			'Title' => 'Home',
		)))->renderWith(array(
			'Home'
		));
	}
}