Actively expire login sesssions and notify user

packages/node_modules/@node-red/editor-api/lib/auth/tokens.js

@@ -25,27 +25,39 @@ function generateToken(length) {
 
 
 var storage;
-
 var sessionExpiryTime
-
 var sessions = {};
-
 var loadedSessions = null;
-
 var apiAccessTokens;
+var sessionExpiryListeners = [];
+var expiryTimeout;
 
 function expireSessions() {
+    if (expiryTimeout) {
+        clearTimeout(expiryTimeout);
+        expiryTimeout = null;
+    }
+    var nextExpiry = Number.MAX_SAFE_INTEGER;
     var now = Date.now();
     var modified = false;
     for (var t in sessions) {
         if (sessions.hasOwnProperty(t)) {
             var session = sessions[t];
             if (!session.hasOwnProperty("expires") || session.expires < now) {
+                sessionExpiryListeners.forEach(listener => { listener(session) })
                 delete sessions[t];
                 modified = true;
+            } else {
+                if (session.expires < nextExpiry) {
+                    nextExpiry = session.expires;
+                }
             }
         }
     }
+    if (nextExpiry < Number.MAX_SAFE_INTEGER) {
+        // Allow 5 seconds grace
+        expiryTimeout = setTimeout(expireSessions,(nextExpiry - Date.now()) + 5000)
+    }
     if (modified) {
         return storage.saveSessions(sessions);
     } else {
@@ -65,6 +77,9 @@ function loadSessions() {
 module.exports = {
     init: function(adminAuthSettings, _storage) {
         storage = _storage;
+
+        sessionExpiryListeners = [];
+
         sessionExpiryTime = adminAuthSettings.sessionExpiryTime || 604800; // 1 week in seconds
         // At this point, storage will not have been initialised, so defer loading
         // the sessions until there's a request for them.
@@ -112,6 +127,11 @@ module.exports = {
                 expires: accessTokenExpiresAt
             };
             sessions[accessToken] = session;
+
+            if (!expiryTimeout) {
+                expiryTimeout = setTimeout(expireSessions,(accessTokenExpiresAt - Date.now()) + 5000)
+            }
+
             return storage.saveSessions(sessions).then(function() {
                 return {
                     accessToken: accessToken,
@@ -125,5 +145,8 @@ module.exports = {
             delete sessions[token];
             return storage.saveSessions(sessions);
         });
+    },
+    onSessionExpiry: function(callback) {
+        sessionExpiryListeners.push(callback);
     }
 }