CMemCache
CMemCache implements a cache application component based on
memcached.
CMemCache can be configured with a list of memcache servers by settings its
servers property. By default, CMemCache assumes there is a memcache server running on localhost at port 11211.
See
CCache manual for common cache operations that are supported by CMemCache.
Note, there is no security measure to protected data in memcache. All data in memcache can be accessed by any process running in the system.
To use CMemCache as the cache application component, configure the application as follows,
array(
'components'=>array(
'cache'=>array(
'class'=>'CMemCache',
'servers'=>array(
array(
'host'=>'server1',
'port'=>11211,
'weight'=>60,
),
array(
'host'=>'server2',
'port'=>11211,
'weight'=>40,
),
),
),
),
)
In the above, two memcache servers are used: server1 and server2. You can configure more properties of every server, including: host, port, persistent, weight, timeout, retryInterval, status. See
http://www.php.net/manual/en/function.memcache-addserver.php for more details.
CMemCache can also be used with
memcached. To do so, set
useMemcached to be true.
Public Properties
Property |
Type |
Description |
Defined By |
behaviors | array | the behaviors that should be attached to this component. | CApplicationComponent |
hashKey | boolean | whether to md5-hash the cache key for normalization purposes. | CCache |
isInitialized | boolean | Checks if this application component has been initialized. | CApplicationComponent |
keyPrefix | string | a string prefixed to every cache key so that it is unique. | CCache |
memCache | Memcache|Memcached | the memcache instance (or memcached if useMemcached is true) used by this component. | CMemCache |
serializer | array|boolean | the functions used to serialize and unserialize cached data. | CCache |
servers | array | list of memcache server configurations. | CMemCache |
useMemcached | boolean | whether to use memcached or memcache as the underlying caching extension. | CMemCache |
Protected Methods
Method |
Description |
Defined By |
addValue() | Stores a value identified by a key into cache if the cache does not contain this key. | CMemCache |
deleteValue() | Deletes a value with the specified key from cache | CMemCache |
flushValues() | Deletes all values from cache. | CMemCache |
generateUniqueKey() | | CCache |
getValue() | Retrieves a value from cache with a specified key. | CMemCache |
getValues() | Retrieves multiple values from cache with the specified keys. | CMemCache |
setValue() | Stores a value identified by a key in cache. | CMemCache |
Property Details
public Memcache|Memcached getMemCache()
the memcache instance (or memcached if useMemcached is true) used by this component.
public array getServers()
public void setServers(array $config)
list of memcache server configurations. Each element is a CMemCacheServerConfiguration.
public boolean $useMemcached;
whether to use memcached or memcache as the underlying caching extension. If true memcached will be used. If false memcache. will be used. Defaults to false.
Method Details
protected boolean addValue(string $key, string $value, integer $expire) |
$key | string | the key identifying the value to be cached |
$value | string | the value to be cached |
$expire | integer | the number of seconds in which the cached value will expire. 0 means never expire. |
{return} | boolean | true if the value is successfully stored into cache, false otherwise |
Source Code: framework/caching/CMemCache.php#190 (
show)
protected function addValue($key,$value,$expire)
{
if($expire>0)
$expire+=time();
else
$expire=0;
return $this->useMemcached ? $this->_cache->add($key,$value,$expire) : $this->_cache->add($key,$value,0,$expire);
}
Stores a value identified by a key into cache if the cache does not contain this key. This is the implementation of the method declared in the parent class.
protected boolean deleteValue(string $key) |
$key | string | the key of the value to be deleted |
{return} | boolean | if no error happens during deletion |
Deletes a value with the specified key from cache This is the implementation of the method declared in the parent class.
protected boolean flushValues() |
{return} | boolean | whether the flush operation was successful. |
Deletes all values from cache. This is the implementation of the method declared in the parent class.
public Memcache|Memcached getMemCache() |
{return} | Memcache|Memcached | the memcache instance (or memcached if useMemcached is true) used by this component. |
Source Code: framework/caching/CMemCache.php#108 (
show)
public function getMemCache()
{
if($this->_cache!==null)
return $this->_cache;
else
{
$extension=$this->useMemcached ? 'memcached' : 'memcache';
if(!extension_loaded($extension))
throw new CException(Yii::t('yii',"CMemCache requires PHP {extension} extension to be loaded.",
array('{extension}'=>$extension)));
return $this->_cache=$this->useMemcached ? new Memcached : new Memcache;
}
}
protected string|boolean getValue(string $key) |
$key | string | a unique key identifying the cached value |
{return} | string|boolean | the value stored in cache, false if the value is not in the cache or expired. |
Retrieves a value from cache with a specified key. This is the implementation of the method declared in the parent class.
protected array getValues(array $keys) |
$keys | array | a list of keys identifying the cached values |
{return} | array | a list of cached values indexed by the keys |
Retrieves multiple values from cache with the specified keys.
Source Code: framework/caching/CMemCache.php#85 (
show)
public function init()
{
parent::init();
$servers=$this->getServers();
$cache=$this->getMemCache();
if(count($servers))
{
foreach($servers as $server)
{
if($this->useMemcached)
$cache->addServer($server->host,$server->port,$server->weight);
else
$cache->addServer($server->host,$server->port,$server->persistent,$server->weight,$server->timeout,$server->retryInterval,$server->status);
}
}
else
$cache->addServer('localhost',11211);
}
Initializes this application component. This method is required by the IApplicationComponent interface. It creates the memcache instance and adds memcache servers.
public void setServers(array $config) |
$config | array | list of memcache server configurations. Each element must be an array with the following keys: host, port, persistent, weight, timeout, retryInterval, status. |
protected boolean setValue(string $key, string $value, integer $expire) |
$key | string | the key identifying the value to be cached |
$value | string | the value to be cached |
$expire | integer | the number of seconds in which the cached value will expire. 0 means never expire. |
{return} | boolean | true if the value is successfully stored into cache, false otherwise |
Source Code: framework/caching/CMemCache.php#171 (
show)
protected function setValue($key,$value,$expire)
{
if($expire>0)
$expire+=time();
else
$expire=0;
return $this->useMemcached ? $this->_cache->set($key,$value,$expire) : $this->_cache->set($key,$value,0,$expire);
}
Stores a value identified by a key in cache. This is the implementation of the method declared in the parent class.