Session expired: report details about session timestamps

extension/Source/core/Constants.php

@@ -321,6 +321,7 @@ const ERROR_MISSING_SESSIONNAME = 2400;
 const ERROR_QFQ_SESSION_MISSING = 2401;
 const ERROR_SESSION_BROKEN_SCRIPT_PATH = 2402;
 const ERROR_MISSING_COOKIE = 2403;
+const ERROR_SESSION_EXPIRED = 2404;
 
 const ERROR_HTML2PDF_MISSING_CONFIG = 2500;
 const ERROR_HTML2PDF_WKHTML_NOT_EXECUTABLE = 2501;

extension/Source/core/store/Session.php

@@ -157,7 +157,8 @@ class Session {
         $feUserSession = Session::get(SESSION_FE_USER);
         $feUserGroup = false;
 
-        self::$lastActivity = false; // Session Timeout only exists for logged in FE users - the default is no user logged in, so set to false to switch of session expiration.
+        // Session Timeout only exists for logged in FE users - the default is no user logged in, so set to false to switch of session expiration.
+        self::$lastActivity = false;
 
         if (isset($GLOBALS["TSFE"])) {
             // if no one is logged in: 0
@@ -316,7 +317,9 @@ class Session {
         }
 
         if (time() - self::$lastActivity > $timeout) {
-            throw new UserFormException("Your session is expired. Please logout and login again.");
+            throw new UserFormException(json_encode(
+                [ERROR_MESSAGE_TO_USER => 'Your session is expired. Please logout and login again.',
+                    ERROR_MESSAGE_SUPPORT => "lastActivity:" . self::$lastActivity . ' Timeout:' . $timeout]), ERROR_SESSION_EXPIRED);
         }
     }