From cd91718107f1760396befa75abcfadb348276946 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julius=20H=C3=A4rtl?= <jus@bitgrid.net>
Date: Fri, 14 Oct 2022 07:42:25 +0200
Subject: [PATCH] Use proper error pages instead of always redirecting
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Julius Härtl <jus@bitgrid.net>
---
 core/Controller/ErrorController.php | 44 +++++++++++++++++++++++++++++
 core/routes.php                     |  2 ++
 core/templates/404.php              |  4 +--
 lib/base.php                        | 32 +++++++++++++++------
 4 files changed, 71 insertions(+), 11 deletions(-)
 create mode 100644 core/Controller/ErrorController.php

diff --git a/core/Controller/ErrorController.php b/core/Controller/ErrorController.php
new file mode 100644
index 0000000000000..b0e1d9dad867c
--- /dev/null
+++ b/core/Controller/ErrorController.php
@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright Copyright (c) 2022 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ *
+ * @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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OC\Core\Controller;
+
+use OCP\AppFramework\Http\TemplateResponse;
+
+class ErrorController extends \OCP\AppFramework\Controller {
+	/**
+	 * @PublicPage
+	 * @NoCSRFRequired
+	 */
+	public function error404(): TemplateResponse {
+		return new TemplateResponse(
+			'core',
+			'404',
+			[],
+			'error'
+		);
+	}
+}
diff --git a/core/routes.php b/core/routes.php
index 820db44bf90a4..6ead401d96458 100644
--- a/core/routes.php
+++ b/core/routes.php
@@ -95,6 +95,8 @@
 		['name' => 'WebAuthn#startAuthentication', 'url' => 'login/webauthn/start', 'verb' => 'POST'],
 		['name' => 'WebAuthn#finishAuthentication', 'url' => 'login/webauthn/finish', 'verb' => 'POST'],
 
+		['name' => 'Error#error404', 'url' => 'error/404'],
+
 		// Well known requests https://tools.ietf.org/html/rfc5785
 		['name' => 'WellKnown#handle', 'url' => '.well-known/{service}'],
 	],
diff --git a/core/templates/404.php b/core/templates/404.php
index 64595c9a092a3..fcfc7cc1ef8bb 100644
--- a/core/templates/404.php
+++ b/core/templates/404.php
@@ -17,8 +17,8 @@
 <?php else: ?>
 	<div class="body-login-container update">
 		<div class="icon-big icon-search"></div>
-		<h2><?php p($l->t('File not found')); ?></h2>
-		<p class="infogroup"><?php p($l->t('The document could not be found on the server. Maybe the share was deleted or has expired?')); ?></p>
+		<h2><?php p($l->t('Page not found')); ?></h2>
+		<p class="infogroup"><?php p($l->t('The page could not be found on the server.')); ?></p>
 		<p><a class="button primary" href="<?php p(\OC::$server->getURLGenerator()->linkTo('', 'index.php')) ?>">
 			<?php p($l->t('Back to %s', [$theme->getName()])); ?>
 		</a></p>
diff --git a/lib/base.php b/lib/base.php
index 0ae7aefbcc354..62b159e480351 100644
--- a/lib/base.php
+++ b/lib/base.php
@@ -72,6 +72,7 @@
 use OC\Files\Filesystem;
 use OC\Share20\Hooks;
 use OCP\User\Events\UserChangedEvent;
+use function OCP\Log\logger;
 
 require_once 'public/Constants.php';
 
@@ -1069,15 +1070,28 @@ public static function handleRequest() {
 			return;
 		}
 
-		// Someone is logged in
-		if (\OC::$server->getUserSession()->isLoggedIn()) {
-			OC_App::loadApps();
-			OC_User::setupBackends();
-			OC_Util::setupFS();
-			header('Location: ' . \OC::$server->getURLGenerator()->linkToDefaultPageUrl());
-		} else {
-			// Not handled and not logged in
-			header('Location: ' . \OC::$server->getURLGenerator()->linkToRouteAbsolute('core.login.showLoginForm'));
+		// Redirect to the default app or login only as an entry point
+		if ($requestPath === '') {
+			// Someone is logged in
+			if (\OC::$server->getUserSession()->isLoggedIn()) {
+				header('Location: ' . \OC::$server->getURLGenerator()->linkToDefaultPageUrl());
+			} else {
+				// Not handled and not logged in
+				header('Location: ' . \OC::$server->getURLGenerator()->linkToRouteAbsolute('core.login.showLoginForm'));
+			}
+			return;
+		}
+
+		try {
+			return OC::$server->get(\OC\Route\Router::class)->match('/error/404');
+		} catch (\Exception $e) {
+			logger('core')->emergency($e->getMessage(), ['exception' => $e]);
+			$l = \OC::$server->getL10N('lib');
+			OC_Template::printErrorPage(
+				$l->t('404'),
+				$l->t('We can\'t find the page you\'re looking for.'),
+				404
+			);
 		}
 	}