CDN rewrite in Page_Controller

Page.php

<?php
	
class Page_Controller extends ContentController
{

	private static $cdn_domain = 'cdn.mysite.com';
	private static $cdn_rewrite = false;
	
	public function handleRequest(SS_HTTPRequest $request, DataModel $model = null)
	{
		$response = parent::handleRequest($request, $model);

		if (!Director::isDev() && $body = $response->getBody()) {
			$body = self::replaceCDN($body);

			$response->setBody($body);
		}

		return $response;
	}


	static function replaceCDN($body)
	{
		if (!Config::inst()->get('Page_Controller', 'cdn_rewrite')) {
			return;
		}
		if (!$body) {
			return;
		}
		if (Versioned::current_stage() == 'dev') {
			return;
		}

		$cdn = Config::inst()->get('Page_Controller','cdn_domain');


		$body = str_replace('src="/assets/', 'src="' . $cdn . '/assets/', $body);
		$body = str_replace('src=\"/assets/', 'src=\"' . $cdn . '/assets/', $body);
		$body = str_replace('href="/assets/', 'href="' . $cdn . '/assets/', $body);
		$body = str_replace(Director::absoluteBaseURL() . 'assets/', $cdn . '/assets/', $body);

		return $body;
	}
}

Now refactored as a module: https://github.com/wernerkrauss/silverstripe-cdnrewrite