Route Guard (security feature)?

[longtimedeveloper]

Hi Chris,

I can't find the concept of a Route Guards.

Does Go Router support route guards similar to AutoRoute Route Guards

Best regards,

Karl

[csells]

Check out redirection: https://gorouter.dev/redirection

[longtimedeveloper]

Thank you!!!

[danielmahon]

Here is a compose function if you want to combine multiple guards, which will let you "fall through" multiple guards until you hit one that returns a redirect or returns null by default. FYI probably isn't perfect.

You want to pass next() instead of null so it will continue through the chain

typedef Next<K> = K? Function();
typedef Middleware<T, K> = K? Function(T state, Next<K> next);
K? Function(T) _compose<T, K>(List<Middleware<T, K>> middlewares) {
  return (T state) {
    var lastIndex = -1;
    K? dispatch(int index) {
      if (index <= lastIndex) {
        throw Exception('next() called multiple times');
      }
      lastIndex = index;
      if (index < middlewares.length) {
        return middlewares[index](state, () => dispatch(index + 1));
      }
      return null;
    }

    return dispatch(0);
  };
}

usage

  String? privateGuard(GoRouterState state, Next<String> next) {
    return ref.read(authProvider).maybeWhen(
          orElse: () => LoginScreen.path,
          loggedIn: () => next(),
        );
  }

String? adminRoleGuard(GoRouterState state, Next<String> next) {
    return ref.read(roleProvider).maybeWhen(
          orElse: () => LoginScreen.path,
          isAdmin: () => next(),
        );
  }
//...
    // Private routes
    GoRoute(
      path: HomeScreen.path,
      redirect: _compose([privateGuard]),
      pageBuilder: (context, state) => NoTransitionPage(
        key: state.pageKey,
        child: const HomeScreen(),
      ),
    ),
    GoRoute(
      path: SettingsScreen.path,
      redirect: _compose([privateGuard,adminRoleGuard]),
      pageBuilder: (context, state) => NoTransitionPage(
        key: state.pageKey,
        child: const SettingsScreen(),
      ),
    ),
//...

[longtimedeveloper]

Thank you for an in-depth example. Best regards, Karl