friendica/src/Module/HTTPException/PageNotFound.php

<?php
/**
 * @copyright Copyright (C) 2010-2021, the Friendica project
 *
 * @license GNU AGPL version 3 or any later version
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

namespace Friendica\Module\HTTPException;

use Friendica\BaseModule;
use Friendica\DI;
use Friendica\Network\HTTPException;

class PageNotFound extends BaseModule
{
	protected function content(array $request = []): string
	{
		throw new HTTPException\NotFoundException(DI::l10n()->t('Page not found.'));
	}

	public function run(array $post = [], array $request = []): string
	{
		/* The URL provided does not resolve to a valid module.
		 *
		 * On Dreamhost sites, quite often things go wrong for no apparent reason and they send us to '/internal_error.html'.
		 * We don't like doing this, but as it occasionally accounts for 10-20% or more of all site traffic -
		 * we are going to trap this and redirect back to the requested page. As long as you don't have a critical error on your page
		 * this will often succeed and eventually do the right thing.
		 *
		 * Otherwise we are going to emit a 404 not found.
		 */
		$queryString = $this->server['QUERY_STRING'];
		// Stupid browser tried to pre-fetch our Javascript img template. Don't log the event or return anything - just quietly exit.
		if (!empty($queryString) && preg_match('/{[0-9]}/', $queryString) !== 0) {
			exit();
		}

		if (!empty($queryString) && ($queryString === 'q=internal_error.html') && isset($dreamhost_error_hack)) {
			$this->logger->info('index.php: dreamhost_error_hack invoked.', ['Original URI' => $this->server['REQUEST_URI']]);
			$this->baseUrl->redirect($this->server['REQUEST_URI']);
		}

		$this->logger->debug('index.php: page not found.', [
			'request_uri' => $this->server['REQUEST_URI'],
			'address'     => $this->server['REMOTE_ADDR'],
			'query'       => $this->server['QUERY_STRING']
		]);

		return parent::run($post, $request); // TODO: Change the autogenerated stub
	}
}