railpage/railpagecore

<?php

/**
 * Cache templates using Memcache
 * @since Version 3.8.7
 * @package Railpage
 * @author Michael Greenhill
 * 
 * Code lifted from http://www.smarty.net/docs/en/caching.custom.tpl
 *
 * See Railpage bug/issue http://redmine.railpage.org/redmine/issues/141
 */


namespace Railpage;
use Smarty_CacheResource_KeyValueStore;
use Memcached as PhpMemcached;

/**
 * CacheResource
 *
 * CacheResource Implementation based on the KeyValueStore API to use
 * memcache as the storage resource for Smarty's output caching.
 *
 * Note that memcache has a limitation of 256 characters per cache-key.
 * To avoid complications all cache-keys are translated to a sha1 hash.
 *
 * @package CacheResource-examples
 * @author Rodney Rehm
 */

class Template_Cache_Memcached extends Smarty_CacheResource_KeyValueStore {
    
    /**
     * Cache instance
     * @var Cache
     */
    protected $Cache = null;
    
    public function __construct()
    {
        //$this->Cache = AppCore::getMemcached(); 
        
        $host = defined("RP_MEMCACHE_HOST") ? RP_MEMCACHE_HOST : "cache.railpage.com.au";
        $port = defined("RP_MEMCACHE_PORT") ? RP_MEMCACHE_PORT : 11211;
        
        $this->Cache = new PhpMemcached;
        $this->Cache->addServer($host, $port);
        
        $Smarty = AppCore::GetSmarty();
        $Smarty->caching_type = "memcached";
        
    }
    
    /**
     * Read values for a set of keys from cache
     *
     * @param array $keys list of keys to fetch
     * @return array list of values with the given keys used as indexes
     * @return boolean true on success, false on failure
     */
    protected function read(array $keys)
    {
        #echo "reading template from cache";
        #printArray($keys);
        $_keys = $lookup = array();
        foreach ($keys as $k) {
            $_k = sha1($k);
            $_keys[] = $_k;
            $lookup[$_k] = $k;
        }
        $_res = array();
        $res = $this->Cache->getMulti($_keys, null, PhpMemcached::GET_PRESERVE_ORDER);
        foreach ($res as $k => $v) {
            $_res[$lookup[$k]] = $v;
        }
        return $_res;
    }
    
    /**
     * Save values for a set of keys to cache
     *
     * @param array $keys list of values to save
     * @param int $expire expiration time
     * @return boolean true on success, false on failure
     */
    protected function write(array $keys, $expire=null)
    {   
        #echo "writing template to cache";
        #printArray($keys);
        foreach ($keys as $k => $v) {
            $k = sha1($k);
            $rs = $this->Cache->set($k, $v, 0, $expire);
        }
        
        #$this->Cache->setMulti($keys, $expire); 
        
        return true;
    }

    /**
     * Remove values from cache
     *
     * @param array $keys list of keys to delete
     * @return boolean true on success, false on failure
     */
    protected function delete(array $keys)
    {
        
        #$this->Cache->deleteMulti($keys); 
        
        #echo "deleting template from cache";
        #printArray($keys);
        foreach ($keys as $k) {
            $k = sha1($k);
            $this->Cache->delete($k);
        }
        return true;
    }

    /**
     * Remove *all* values from cache
     *
     * @return boolean true on success, false on failure
     */
    protected function purge()
    {
        return false; #return $this->Memcached->flush();
    }
}