fix: use custom 404 page

lib/Middleware/JoinMiddleware.php

@@ -6,8 +6,8 @@ use OCA\BigBlueButton\Controller\JoinController;
 use OCA\BigBlueButton\NoPermissionException;
 use OCA\BigBlueButton\NoPermissionResponse;
 use OCA\BigBlueButton\NotFoundException;
+use OCA\BigBlueButton\NotFoundResponse;
 use OCP\AppFramework\Middleware;
-use OCP\AppFramework\Http\NotFoundResponse;
 use OCP\IRequest;
 
 class JoinMiddleware extends Middleware {

lib/NotFoundResponse.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace OCA\BigBlueButton;
+
+use OCP\Template;
+use OCP\AppFramework\Http\Response;
+use OCP\AppFramework\Http\ContentSecurityPolicy;
+
+class NotFoundResponse extends Response {
+	public function __construct() {
+		parent::__construct();
+
+		$this->setContentSecurityPolicy(new ContentSecurityPolicy());
+		$this->setStatus(404);
+	}
+
+	public function render() {
+		$template = new Template('bbb', '404', 'guest');
+		return $template->fetchPage();
+	}
+}

templates/404.php

@@ -0,0 +1,13 @@
+<?php
+/** @var array $_ */
+/** @var \OCP\IL10N $l */
+/** @var \OCP\Defaults $theme */
+?>
+<div class="body-login-container update">
+	<div class="icon-big icon-search icon-white"></div>
+	<h2><?php p($l->t('Room not found')); ?></h2>
+	<p class="infogroup"><?php p($l->t('The room could not be found. Maybe it was deleted?')); ?></p>
+	<p><a class="button primary" href="<?php p(\OC::$server->getURLGenerator()->linkTo('', 'index.php')) ?>">
+		<?php p($l->t('Back to %s', [$theme->getName()])); ?>
+	</a></p>
+</div>