如何序列化视图响应？

Question

I'm currently working on this (unfortunately no one responded):

https://stackoverflow.com/questions/31057493/laravel-caching-while-using-ajax

I've changed the code for CacheFilter.php to this:

public function fetch(Route $route, Request $request) {
    $key = $this->makeCacheKey($request);

    if( Cache::has($key) ) return Cache::get($key);
}

public function put(Route $route, Request $request, Response $response) {
    $key = $this->makeCacheKey($request);

    if( !Cache::has($key) ) Cache::put($key, $response->getOriginalContent(), 60);
}

protected function makeCacheKey(Request $request) {
    $ajaxRequest = json_encode($request->ajax());

    if($ajaxRequest == 'true') {
        return 'ajax_route_' . Str::slug($request->url());
    }
    else {
        return 'route_' . Str::slug($request->url());
    }
}

I'm getting the error:

Serialization of 'Closure' is not allowed

from the following line of code:

if( !Cache::has($key) ) Cache::put($key, $response->getOriginalContent(), 60);

How can I serialize the view response to make this work?