From http://markvaneijk.com/caching-routes-using-filters-in-laravel-4 and amended to add configuration.

filters.php

<?php 
/*
|--------------------------------------------------------------------------
| Cache Filters
|--------------------------------------------------------------------------
|
| This filter can be attached to a route to easily add a simple caching
| layer.
|
| Use as a before and after filter. When fired after a request the cache
| will be updated if required, and when fired before a request the cache
| will be loaded if required.
|
| From: http://markvaneijk.com/caching-routes-using-filters-in-laravel-4
|
| Usage:
| Route::get('/', array
|     (
|       'before' => 'cache',
|       'after' => 'cache',
|       'uses' => 'HomeController@show'
|     )
| );
*/
Route::filter('cache', function($route, $request, $response = null)
    {
        if ( Config::get('cache.page_caching', false) === true )
        {
            $key = 'route-'.Str::slug(Request::url());
            if(is_null($response) && Cache::has($key))
            {
                return Cache::get($key);
            }
            elseif(!is_null($response) && !Cache::has($key))
            {
                Cache::put($key, $response->getContent(), 30);
            }
        }
    }
);