core-bundle/src/Resources/contao/library/Contao/Automator.php
public function purgePageCache()
	{
		$strCacheDir = StringUtil::stripRootDir(System::getContainer()->getParameter('kernel.cache_dir'));

		$objFolder = new Folder($strCacheDir . '/http_cache');
		$objFolder->purge();

		// Add a log entry
		$this->log('Purged the page cache', __METHOD__, TL_CRON);
	}
public function purgePageCache()
	{
		$strCacheDir = StringUtil::stripRootDir(System::getContainer()->getParameter('kernel.cache_dir'));

		$objFolder = new Folder($strCacheDir . '/http_cache');
		$objFolder->purge();

		// Add a log entry
		$this->log('Purged the page cache', __METHOD__, TL_CRON);
	}
Purge the page cache

@todo Replace this with a more sophisticated invalidation routine