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CMemCache

Package	system.caching
Inheritance	class CMemCache » CCache » CApplicationComponent » CComponent
Implements	ArrayAccess, ICache, IApplicationComponent
Since	1.0
Source Code	framework/caching/CMemCache.php

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 https://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

Hide inherited 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

Public Methods

Hide inherited methods

Method	Description	Defined By
__call()	Calls the named method which is not a class method.	CComponent
__get()	Returns a property value, an event handler list or a behavior based on its name.	CComponent
__isset()	Checks if a property value is null.	CComponent
__set()	Sets value of a component property.	CComponent
__unset()	Sets a component property to be null.	CComponent
add()	Stores a value identified by a key into cache if the cache does not contain this key.	CCache
asa()	Returns the named behavior object.	CComponent
attachBehavior()	Attaches a behavior to this component.	CComponent
attachBehaviors()	Attaches a list of behaviors to the component.	CComponent
attachEventHandler()	Attaches an event handler to an event.	CComponent
canGetProperty()	Determines whether a property can be read.	CComponent
canSetProperty()	Determines whether a property can be set.	CComponent
delete()	Deletes a value with the specified key from cache	CCache
detachBehavior()	Detaches a behavior from the component.	CComponent
detachBehaviors()	Detaches all behaviors from the component.	CComponent
detachEventHandler()	Detaches an existing event handler.	CComponent
disableBehavior()	Disables an attached behavior.	CComponent
disableBehaviors()	Disables all behaviors attached to this component.	CComponent
enableBehavior()	Enables an attached behavior.	CComponent
enableBehaviors()	Enables all behaviors attached to this component.	CComponent
evaluateExpression()	Evaluates a PHP expression or callback under the context of this component.	CComponent
flush()	Deletes all values from cache.	CCache
get()	Retrieves a value from cache with a specified key.	CCache
getEventHandlers()	Returns the list of attached event handlers for an event.	CComponent
getIsInitialized()	Checks if this application component has been initialized.	CApplicationComponent
getMemCache()	Returns the memcache instance (or memcached if useMemcached is true) used by this component.	CMemCache
getServers()	Returns list of memcache server configurations. Each element is a CMemCacheServerConfiguration.	CMemCache
hasEvent()	Determines whether an event is defined.	CComponent
hasEventHandler()	Checks whether the named event has attached handlers.	CComponent
hasProperty()	Determines whether a property is defined.	CComponent
init()	Initializes this application component.	CMemCache
mget()	Retrieves multiple values from cache with the specified keys.	CCache
offsetExists()	Returns whether there is a cache entry with a specified key.	CCache
offsetGet()	Retrieves the value from cache with a specified key.	CCache
offsetSet()	Stores the value identified by a key into cache.	CCache
offsetUnset()	Deletes the value with the specified key from cache	CCache
raiseEvent()	Raises an event.	CComponent
set()	Stores a value identified by a key into cache.	CCache
setServers()	Sets list of memcache server configurations. Each element must be an array with the following keys: host, port, persistent, weight, timeout, retryInterval, status.	CMemCache

Protected Methods

Hide inherited 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
normalizeDuration()	Normalizes duration value.	CMemCache
setValue()	Stores a value identified by a key in cache.	CMemCache

Property Details

memCache property read-only

public Memcache|Memcached getMemCache()

the memcache instance (or memcached if useMemcached is true) used by this component.

servers property

public array getServers()
public void setServers(array $config)

list of memcache server configurations. Each element is a CMemCacheServerConfiguration.

useMemcached property

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

addValue() method

protected boolean addValue(string $key, string $value, integer $duration)
$key	string	the key identifying the value to be cached
$value	string	the value to be cached
$duration	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#187 (show)


protected function addValue($key,$value,$duration)
{
    $expire = $this->normalizeDuration($duration);

    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.

deleteValue() method

protected boolean deleteValue(string $key)
$key	string	the key of the value to be deleted
{return}	boolean	if no error happens during deletion

Source Code: framework/caching/CMemCache.php#225 (show)


protected function deleteValue($key)
{
    return $this->_cache->delete($key, 0);
}

Deletes a value with the specified key from cache This is the implementation of the method declared in the parent class.

flushValues() method (available since v1.1.5)

protected boolean flushValues()
{return}	boolean	whether the flush operation was successful.

Source Code: framework/caching/CMemCache.php#236 (show)


protected function flushValues()
{
    return $this->_cache->flush();
}

Deletes all values from cache. This is the implementation of the method declared in the parent class.

getMemCache() method

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;
    }
}

getServers() method

public array getServers()
{return}	array	list of memcache server configurations. Each element is a CMemCacheServerConfiguration.

Source Code: framework/caching/CMemCache.php#125 (show)


public function getServers()
{
    return $this->_servers;
}

getValue() method

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.

Source Code: framework/caching/CMemCache.php#147 (show)


protected function getValue($key)
{
    return $this->_cache->get($key);
}

Retrieves a value from cache with a specified key. This is the implementation of the method declared in the parent class.

getValues() method

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

Source Code: framework/caching/CMemCache.php#157 (show)


protected function getValues($keys)
{
    return $this->useMemcached ? $this->_cache->getMulti($keys) : $this->_cache->get($keys);
}

Retrieves multiple values from cache with the specified keys.

init() method

public void init()

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.

normalizeDuration() method

protected int normalizeDuration(int $duration)
$duration	int
{return}	int

Source Code: framework/caching/CMemCache.php#206 (show)


    protected function normalizeDuration($duration)
    {
        if ($duration < 0) {
            return 0;
        }

        if ($duration < 2592001) {
            return $duration;
        }

        return $duration + time();
    }

Normalizes duration value. Ported code from yii2 after identifying issue with memcache falsely handling short term duration based on unix timestamps