diff --git a/ajax/events.php b/ajax/events.php
index 84554735..2dd411ed 100644
--- a/ajax/events.php
+++ b/ajax/events.php
@@ -42,6 +42,13 @@ if (OCP\User::isLoggedIn()) {
     header('HTTP/1.0 404 Not Found');
     exit();
   }
+  
+  // check if we're being asked for something we can provide
+  if ($_GET['calendar_id'] !== 'shared_events') {
+    header('HTTP/1.0 404 Not Found');
+    exit();
+  }
+  
   // get the data
   $linkItem = OCP\Share::getShareByToken(
     \OC::$session->get('public_link_token')
diff --git a/js/l10n.php b/js/l10n.php
index b270b04a..c81eaa0e 100644
--- a/js/l10n.php
+++ b/js/l10n.php
@@ -20,6 +20,7 @@ $l = OCP\Util::getL10N('calendar');
 // Get the event sources
 $eventSources = array();
 
+// only for a logged-in user
 if (OCP\User::isLoggedIn()) {
   $calendars = OC_Calendar_Calendar::allCalendars(OCP\User::getUser());
   foreach($calendars as $calendar) {
@@ -32,6 +33,7 @@ if (OCP\User::isLoggedIn()) {
   }
 }
 
+// this is needed also when displaying a link-shared calendar
 $events_baseURL = OCP\Util::linkTo('calendar', 'ajax/events.php');
 $eventSources[] = array('url' => $events_baseURL.'?calendar_id=shared_events',
 		'backgroundColor' => '#1D2D44',
@@ -39,7 +41,10 @@ $eventSources[] = array('url' => $events_baseURL.'?calendar_id=shared_events',
 		'textColor' => 'white',
 		'editable' => 'false');
 
-OCP\Util::emitHook('OC_Calendar', 'getSources', array('sources' => &$eventSources));
+// only for a logged-in user
+if (OCP\User::isLoggedIn()) {
+  OCP\Util::emitHook('OC_Calendar', 'getSources', array('sources' => &$eventSources));
+}
 
 $firstDay = null;
 $firstDayConfig = OCP\Config::getUserValue(OCP\USER::getUser(), 'calendar', 'firstday', 'mo');