feat: Added callbacks onTokenExpiring and onTokenExpired

packages/oidc_core/lib/src/managers/user_manager_base.dart

@@ -784,15 +784,6 @@ abstract class OidcUserManagerBase {
     if (user == null) {
       tokenEventsManager.unload();
     } else {
-      if (!discoveryDocument.grantTypesSupportedOrDefault
-          .contains(OidcConstants_GrantType.refreshToken)) {
-        //Server doesn't support refresh_token grant.
-        return;
-      }
-      if (user.token.refreshToken == null) {
-        // Can't refresh the access token anyway.
-        return;
-      }
       if (user.token.expiresIn == null) {
         // Can't know how much time is left.
         return;
@@ -803,6 +794,8 @@ abstract class OidcUserManagerBase {
 
   @protected
   Future<void> handleTokenExpiring(OidcToken event) async {
+    settings.onTokenExpiring?.call(event);
+
     final refreshToken = event.refreshToken;
     if (refreshToken == null) {
       return;
@@ -843,6 +836,8 @@ abstract class OidcUserManagerBase {
 
   @protected
   void handleTokenExpired(OidcToken event) {
+    settings.onTokenExpired?.call(event);
+
     if (!settings.supportOfflineAuth) {
       forgetUser();
     }

packages/oidc_core/lib/src/models/settings/user_manager_settings.dart

@@ -3,6 +3,8 @@ import 'package:oidc_core/oidc_core.dart';
 /// The callback used to determine the `expiring` duration.
 typedef OidcRefreshBeforeCallback = Duration? Function(OidcToken token);
 
+typedef OidcTokenCallback = void Function(OidcToken token);
+
 /// The default refreshBefore function, which refreshes 1 minute before the token expires.
 Duration? defaultRefreshBefore(OidcToken token) {
   return const Duration(minutes: 1);
@@ -35,6 +37,8 @@ class OidcUserManagerSettings {
     this.sessionManagementSettings = const OidcSessionManagementSettings(),
     this.getIdToken,
     this.supportOfflineAuth = false,
+    this.onTokenExpiring,
+    this.onTokenExpired,
   });
 
   /// The default scopes
@@ -127,6 +131,12 @@ class OidcUserManagerSettings {
 
   /// platform-specific options.
   final OidcPlatformSpecificOptions? options;
+
+  /// Callback that is called before the token expires.
+  final OidcTokenCallback? onTokenExpiring;
+
+  /// Callback that is called after the token expired.
+  final OidcTokenCallback? onTokenExpired;
 }
 
 ///