Codeigniter Memcached

Question

我不知道为什么memcached不能正常工作。

已启用的PHP详细信息：

memcache support | enabled
Active persistent connections | 0
Version | 2.2.6
Revision | $Revision: 303962 $

等等。

装载驱动器

$this->load->driver('cache',array('adapter'=>'mecached'));

错误响应：

get() on a non-object in /system/libraries/Cache/drivers/Cache_memcached.php on line 50

当我尝试使用这段代码

var_dump(var_dump($this->cache->memcached->is_supported()));

答复:bool(假)

我也会查看这个论坛的主题。

http://codeigniter.com/forums/viewthread/180005/#855216

看来memcache仍然不起作用。

Answer 1

看来你有一个老版本的Codeigniter。您的服务器已经启用了模缓存扩展，但是代码点火器的缓存驱动程序正在等待安装梅卡奇。"Johnbellone“在大约一年前增加了对Memcached扩展的支持。详细信息这里。

Answer 2

在windows下运行Memcache时，只需在system/libraries/Cache/drivers/Cache_memcached.php中将Memcached更改为Memcache即可。

这将使Memcache工作，但它不会使项过期，因为Memcache使用4rd参数作为TTL，Memcached使用第三个参数作为TTL，CI只接受3个参数。

要克服这一问题(并使其同时适用于Memcache和Memcached)，您需要对system/libraries/Cache/drivers/Cache_memcached.php.进行以下更改

1)声明一个新属性private $_is_memcache = FALSE;

2)将函数save()更改如下：

public function save($id, $data, $ttl = 60)
{
    if($this->_is_memcache) {
        return $this->_memcached->add($id, array($data, time(), $ttl), FALSE, $ttl);
    } else {
        return $this->_memcached->add($id, array($data, time(), $ttl), $ttl);
    }
}

3)在函数_setup_memcached()中，将$this->_memcached = new Memcached();行替换为：

if(class_exists("Memcached")) {
    $this->_memcached = new Memcached();
} else {
    $this->_memcached = new Memcache();
    $this->_is_memcache = TRUE;
}

4)在函数is_supported ()中，将if ( ! extension_loaded('memcached'))行替换为：

if ( !extension_loaded('memcached') && !extension_loaded('memcache'))

完全类

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package     CodeIgniter
 * @author      ExpressionEngine Dev Team
 * @copyright   Copyright (c) 2006 - 2011 EllisLab, Inc.
 * @license     http://codeigniter.com/user_guide/license.html
 * @link        http://codeigniter.com
 * @since       Version 2.0
 * @filesource  
 */

// ------------------------------------------------------------------------

/**
 * CodeIgniter Memcached Caching Class 
 *
 * @package     CodeIgniter
 * @subpackage  Libraries
 * @category    Core
 * @author      ExpressionEngine Dev Team
 * @link        
 */

class CI_Cache_memcached extends CI_Driver {

    private $_memcached;            // Holds the memcached object
    private $_is_memcache = FALSE;  // Identifies wether it's Memcache instead of Memcached

    protected $_memcache_conf   = array(
                    'default' => array(
                        'default_host'      => '127.0.0.1',
                        'default_port'      => 11211,
                        'default_weight'    => 1
                    )
                );

    // ------------------------------------------------------------------------ 

    /**
     * Fetch from cache
     *
     * @param   mixed       unique key id
     * @return  mixed       data on success/false on failure
     */ 
    public function get($id)
    {   
        $data = $this->_memcached->get($id);

        return (is_array($data)) ? $data[0] : FALSE;
    }

    // ------------------------------------------------------------------------

    /**
     * Save
     *
     * @param   string      unique identifier
     * @param   mixed       data being cached
     * @param   int         time to live
     * @return  boolean     true on success, false on failure
     */
    public function save($id, $data, $ttl = 60)
    {
        if($this->_is_memcache) {
            return $this->_memcached->add($id, array($data, time(), $ttl), FALSE, $ttl);
        } else {
            return $this->_memcached->add($id, array($data, time(), $ttl), $ttl);
        }
    }

    // ------------------------------------------------------------------------

    /**
     * Delete from Cache
     *
     * @param   mixed       key to be deleted.
     * @return  boolean     true on success, false on failure
     */
    public function delete($id)
    {
        return $this->_memcached->delete($id);
    }

    // ------------------------------------------------------------------------

    /**
     * Clean the Cache
     *
     * @return  boolean     false on failure/true on success
     */
    public function clean()
    {
        return $this->_memcached->flush();
    }

    // ------------------------------------------------------------------------

    /**
     * Cache Info
     *
     * @param   null        type not supported in memcached
     * @return  mixed       array on success, false on failure
     */
    public function cache_info($type = NULL)
    {
        return $this->_memcached->getStats();
    }

    // ------------------------------------------------------------------------

    /**
     * Get Cache Metadata
     *
     * @param   mixed       key to get cache metadata on
     * @return  mixed       FALSE on failure, array on success.
     */
    public function get_metadata($id)
    {
        $stored = $this->_memcached->get($id);

        if (count($stored) !== 3)
        {
            return FALSE;
        }

        list($data, $time, $ttl) = $stored;

        return array(
            'expire'    => $time + $ttl,
            'mtime'     => $time,
            'data'      => $data
        );
    }

    // ------------------------------------------------------------------------

    /**
     * Setup memcached.
     */
    private function _setup_memcached()
    {
        // Try to load memcached server info from the config file.
        $CI =& get_instance();
        if ($CI->config->load('memcached', TRUE, TRUE))
        {
            if (is_array($CI->config->config['memcached']))
            {
                $this->_memcache_conf = NULL;

                foreach ($CI->config->config['memcached'] as $name => $conf)
                {
                    $this->_memcache_conf[$name] = $conf;
                }               
            }           
        }

        if(class_exists("Memcached")) {
            $this->_memcached = new Memcached();
        } else {
            $this->_memcached = new Memcache();
            $this->_is_memcache = TRUE;
        }

        foreach ($this->_memcache_conf as $name => $cache_server)
        {
            if ( ! array_key_exists('hostname', $cache_server))
            {
                $cache_server['hostname'] = $this->_default_options['default_host'];
            }

            if ( ! array_key_exists('port', $cache_server))
            {
                $cache_server['port'] = $this->_default_options['default_port'];
            }

            if ( ! array_key_exists('weight', $cache_server))
            {
                $cache_server['weight'] = $this->_default_options['default_weight'];
            }

            $this->_memcached->addServer(
                    $cache_server['hostname'], $cache_server['port'], $cache_server['weight']
            );
        }
    }

    // ------------------------------------------------------------------------


    /**
     * Is supported
     *
     * Returns FALSE if memcached is not supported on the system.
     * If it is, we setup the memcached object & return TRUE
     */
    public function is_supported()
    {
        if ( !extension_loaded('memcached') && !extension_loaded('memcache'))
        {
            log_message('error', 'The Memcached Extension must be loaded to use Memcached Cache.');

            return FALSE;
        }

        $this->_setup_memcached();
        return TRUE;
    }

    // ------------------------------------------------------------------------

}
// End Class

/* End of file Cache_memcached.php */
/* Location: ./system/libraries/Cache/drivers/Cache_memcached.php */