Cache_Memcache
› Kohana_Cache_Memcache
› Cache
› Kohana_Cache

Class Contents

Class declared in MODPATH/cache/classes/cache/memcache.php on line 3.

Properties

Methods

protected function __construct(array $config)
{
	// Check for the memcache extention
	if ( ! extension_loaded('memcache'))
	{
		throw new Kohana_Cache_Exception('Memcache PHP extention not loaded');
	}

	parent::__construct($config);

	// Setup Memcache
	$this->_memcache = new Memcache;

	// Load servers from configuration
	$servers = Arr::get($this->_config, 'servers', NULL);

	if ( ! $servers)
	{
		// Throw an exception if no server found
		throw new Kohana_Cache_Exception('No Memcache servers defined in configuration');
	}

	// Setup default server configuration
	$this->_default_config = array(
			'host'             => 'localhost',
			'port'             => 11211,
			'persistent'       => FALSE,
			'weight'           => 1,
			'timeout'          => 1,
			'retry_interval'   => 15,
			'status'           => TRUE,
			'instant_death'	   => TRUE,
			'failure_callback' => array($this, '_failed_request'),
	);

	// Add the memcache servers to the pool
	foreach ($servers as $server)
	{
		// Merge the defined config with defaults
		$server += $this->_default_config;

		if ( ! $this->_memcache->addServer($server['host'], $server['port'], $server['persistent'], $server['weight'], $server['timeout'], $server['retry_interval'], $server['status'], $server['failure_callback']))
		{
			throw new Kohana_Cache_Exception('Memcache could not connect to host \':host\' using port \':port\'', array(':host' => $server['host'], ':port' => $server['port']));
		}
	}

	// Setup the flags
	$this->_flags = Arr::get($this->_config, 'compression', FALSE) ? MEMCACHE_COMPRESSED : FALSE;
}

public function _failed_request($hostname, $port)
{
	if ( ! $this->_config['instant_death'])
		return; 

	// Setup non-existent host
	$host = FALSE;

	// Get host settings from configuration
	foreach ($this->_config['servers'] as $server)
	{
		// Merge the defaults, since they won't always be set
		$server += $this->_default_config;
		// We're looking at the failed server
		if ($hostname == $server['host'] and $port == $server['port'])
		{
			// Server to disable, since it failed
			$host = $server;
			continue;
		}
	}

	if ( ! $host)
		return;
	else
	{
		return $this->_memcache->setServerParams(
			$host['host'],
			$host['port'],
			$host['timeout'],
			$host['retry_interval'],
			FALSE, // Server is offline
			array($this, '_failed_request'
			));
	}
}

public function delete($id, $timeout = 0)
{
	// Delete the id
	return $this->_memcache->delete($this->_sanitize_id($id), $timeout);
}

public function delete_all()
{
	$result = $this->_memcache->flush();

	// We must sleep after flushing, or overwriting will not work!
	// @see http://php.net/manual/en/function.memcache-flush.php#81420
	sleep(1);

	return $result;
}

public function get($id, $default = NULL)
{
	// Get the value from Memcache
	$value = $this->_memcache->get($this->_sanitize_id($id));

	// If the value wasn't found, normalise it
	if ($value === FALSE)
	{
		$value = (NULL === $default) ? NULL : $default;
	}

	// Return the value
	return $value;
}

public function set($id, $data, $lifetime = 3600)
{
	// If the lifetime is greater than the ceiling
	if ($lifetime > Cache_Memcache::CACHE_CEILING)
	{
		// Set the lifetime to maximum cache time
		$lifetime = Cache_Memcache::CACHE_CEILING + time();
	}
	// Else if the lifetime is greater than zero
	elseif ($lifetime > 0)
	{
		$lifetime += time();
	}
	// Else
	else
	{
		// Normalise the lifetime
		$lifetime = 0;
	}

	// Set the data to memcache
	return $this->_memcache->set($this->_sanitize_id($id), $data, $this->_flags, $lifetime);
}

public function __clone()
{
	throw new Kohana_Cache_Exception('Cloning of Kohana_Cache objects is forbidden');
}

protected function _sanitize_id($id)
{
	// Change slashes and spaces to underscores
	return str_replace(array('/', '\\', ' '), '_', $id);
}

public static function instance($group = NULL)
{
	// If there is no group supplied
	if ($group === NULL)
	{
		// Use the default setting
		$group = Cache::$default;
	}

	if (isset(Cache::$instances[$group]))
	{
		// Return the current group if initiated already
		return Cache::$instances[$group];
	}

	$config = Kohana::config('cache');

	if ( ! $config->offsetExists($group))
	{
		throw new Kohana_Cache_Exception('Failed to load Kohana Cache group: :group', array(':group' => $group));
	}

	$config = $config->get($group);

	// Create a new cache type instance
	$cache_class = 'Cache_'.ucfirst($config['driver']);
	Cache::$instances[$group] = new $cache_class($config);

	// Return the instance
	return Cache::$instances[$group];
}