Upload Contorller related to media model

gistfile1.php

<?php defined('SYSPATH') or die('No direct script access.');

class Controller_Upload extends Controller {

  protected $path;
	
	public function before()
	{
                // Set the proper headers to allow caching
		$this->response->headers('Pragma',  'no-cache');
                $this->response->headers('Cache-Control',  'no-store, no-cache, must-revalidate');

                if ( isset($_SERVER['HTTP_ACCEPT']) AND (strpos($_SERVER['HTTP_ACCEPT'], 'application/json') !== false))
                {
                        $this->response->headers('Content-type',  'application/json');
                }

                //$this->response->headers('Content-type',  'application/json');
                $this->response->headers('Content-Disposition: inline', 'filename="files.json"');
                $this->response->headers('Vary',  'Accept');
        
                $this->response->headers('X-Content-Type-Options',  'nosniff');
                $this->response->headers('Access-Control-Allow-Methods',  'OPTIONS, HEAD, GET, POST, PUT, DELETE');
                $this->response->headers('Access-Control-Allow-Headers',  'X-File-Name, X-File-Type, X-File-Size');
                $this->response->headers('Access-Control-Allow-Origin',  '*');

                // Ajax request only!
		if ( !$this->request->is_ajax() AND ! isset($_POST['script']) )
		{
			throw new HTTP_Exception_404('Accessing an ajax request <small>:type</small> externally',
                                                    array( ':type' => $this->request->uri() ));
		}

                $this->_upload_request($this->request->method());
		//ACL::Required('view uploaded files');
		parent::before();
	}

        public function action_list()
        {
                $mid = (int) $this->request->param('id', 0);
                $model = $this->request->param('model', 'post');
                
		$files = Model::factory('Media')->find_all($mid, $model);

		$this->response->body( JSON::encode($files) );
	}
        
        public function action_post()
        {
                $mid = (int) $this->request->param('id', 0);
                $model = $this->request->param('model', 'post');
        
                $files = Model::factory('Media')->set('model', $model)->set('mid', $mid)->save( $_FILES );

                $this->response->body( JSON::encode($files) );
        }

        public function action_delete()
        {
                $id = (int) $this->request->param('id', 0);
                $files = Model::factory('Media')->delete( $id );

                $this->response->body( JSON::encode($files) );
        }

        private function _upload_request($method)
        {
                switch ($method)
                {
                        case 'OPTIONS':
                        break;
                        case 'HEAD':
                        case 'GET':
                                $this->request->action('list');
                        break;
                        case 'POST':
                                if (isset($_REQUEST['_method']) && $_REQUEST['_method'] === 'DELETE')
                                {
                                        $this->request->action('delete');
                                }
                                else
                                {
                                        $this->request->action('post');
                                }
                        break;
                        case 'DELETE':
                                $this->request->action('delete');
                        break;
                        default:
                                throw new HTTP_Exception_405('HTTP/1.1 405 Method Not Allowed');
                }  
        }
}