Frozennode\Administrator\Http\Middleware\ValidateAdmin::handle PHP Method

    public function handle($request, Closure $next)
    {
        $configFactory = app('admin_config_factory');
        //get the admin check closure that should be supplied in the config
        $permission = config('administrator.permission');
        //if this is a simple false value, send the user to the login redirect
        if (!($response = $permission())) {
            $loginUrl = url(config('administrator.login_path', 'user/login'));
            $redirectKey = config('administrator.login_redirect_key', 'redirect');
            $redirectUri = $request->url();
            return redirect()->guest($loginUrl)->with($redirectKey, $redirectUri);
        } elseif (is_a($response, 'Illuminate\\Http\\JsonResponse') || is_a($response, 'Illuminate\\Http\\Response')) {
            return $response;
        } elseif (is_a($response, 'Illuminate\\Http\\RedirectResponse')) {
            $redirectKey = config('administrator.login_redirect_key', 'redirect');
            $redirectUri = $request->url();
            return $response->with($redirectKey, $redirectUri);
        }
        return $next($request);
    }