MemCache

API reference › yii › caching › MemCache

class	yii\caching\MemCache
Extends	Cache » yii\base\Component » yii\base\BaseObject
Implements	CacheInterface, yii\base\Configurable
Since	2.0
Source	framework/caching/MemCache.php

MemCache implements a cache application component based on memcache and memcached.

MemCache supports both memcache and memcached. By setting $useMemcached to be true or false, one can let MemCache to use either memcached or memcache, respectively.

MemCache can be configured with a list of memcache servers by settings its $servers property. By default, MemCache assumes there is a memcache server running on localhost at port 11211.

See Cache for common cache operations that MemCache supports.

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 MemCache as the cache application component, configure the application as follows,

[
    'components' => [
        'cache' => [
            'class' => 'yii\caching\MemCache',
            'servers' => [
                [
                    'host' => 'server1',
                    'port' => 11211,
                    'weight' => 60,
                ],
                [
                    'host' => 'server2',
                    'port' => 11211,
                    'weight' => 40,
                ],
            ],
        ],
    ],
]

In the above, two memcache servers are used: server1 and server2. You can configure more properties of each server, such as persistent, weight, timeout. Please see MemCacheServer for available options.

For more details and usage information on Cache, see the guide article on caching.

Properties

Property	Type	Description	Defined by
$behaviors read-only	array<yii\base\Behavior<static>>	List of behaviors attached to this component.	yii\base\Component
$defaultDuration	int	Default duration in seconds before a cache entry will expire. Default: 0. Available since 2.0.11.	Cache
$keyPrefix	string	A string prefixed to every cache key so that it is unique globally in the whole cache storage. Default: null.	Cache
$memcache read-only	Memcache|Memcached	The memcache (or memcached) object used by this cache component.	MemCache
$options	array	Options for Memcached. Default: null.	MemCache
$password	string	Memcached sasl password. Default: null.	MemCache
$persistentId	string	An ID that identifies a Memcached instance. Default: null.	MemCache
$serializer	array|null|false	The functions used to serialize and unserialize cached data. Default: null.	Cache
$servers	array	List of memcache or memcached server configurations.	MemCache
$useMemcached	bool	Whether to use memcached or memcache as the underlying caching extension. Default: false.	MemCache
$username	string	Memcached sasl username. Default: null.	MemCache

Methods

Method	Description	Defined by
__construct()	Constructor.	yii\base\BaseObject
__call()	Calls the named method which is not a class method.	yii\base\Component
__clone()	This method is called after the object is created by cloning an existing one.	yii\base\Component
__get()	Returns the value of a component property.	yii\base\Component
__isset()	Checks if a property is set, i.e. defined and not null.	yii\base\Component
__set()	Sets the value of a component property.	yii\base\Component
__unset()	Sets a component property to be null.	yii\base\Component
add()	Stores a value identified by a key into cache if the cache does not contain this key.	Cache
attachBehavior()	Attaches a behavior to this component.	yii\base\Component
attachBehaviors()	Attaches a list of behaviors to the component.	yii\base\Component
behaviors()	Returns a list of behaviors that this component should behave as.	yii\base\Component
buildKey()	Builds a normalized cache key from a given key.	Cache
canGetProperty()	Returns a value indicating whether a property can be read.	yii\base\Component
canSetProperty()	Returns a value indicating whether a property can be set.	yii\base\Component
className() static	Returns the fully qualified name of this class.	yii\base\BaseObject
delete()	Deletes a value with the specified key from cache.	Cache
detachBehavior()	Detaches a behavior from the component.	yii\base\Component
detachBehaviors()	Detaches all behaviors from the component.	yii\base\Component
ensureBehaviors()	Makes sure that the behaviors declared in behaviors() are attached to this component.	yii\base\Component
exists()	Checks whether a specified key exists in the cache.	Cache
flush()	Deletes all values from cache.	Cache
get()	Retrieves a value from cache with a specified key.	Cache
getBehavior()	Returns the named behavior object.	yii\base\Component
getBehaviors()	Returns all behaviors attached to this component.	yii\base\Component
getMemcache()	Returns the underlying memcache (or memcached) object.	MemCache
getOrSet()	Method combines both set() and get() methods to retrieve value identified by a $key, or to store the result of $callable execution if there is no cache available for the $key.	Cache
getServers()	Returns the memcache or memcached server configurations.	MemCache
hasEventHandlers()	Returns a value indicating whether there is any handler attached to the named event.	yii\base\Component
hasMethod()	Returns a value indicating whether a method is defined.	yii\base\Component
hasProperty()	Returns a value indicating whether a property is defined for this component.	yii\base\Component
init()	Initializes this application component.	MemCache
multiAdd()	Stores multiple items in cache. Each item contains a value identified by a key.	Cache
multiGet()	Retrieves multiple values from cache with the specified keys.	Cache
multiSet()	Stores multiple items in cache. Each item contains a value identified by a key.	Cache
off()	Detaches an existing event handler from this component.	yii\base\Component
offsetExists()	Returns whether there is a cache entry with a specified key.	Cache
offsetGet()	Retrieves the value from cache with a specified key.	Cache
offsetSet()	Stores the value identified by a key into cache.	Cache
offsetUnset()	Deletes the value with the specified key from cache This method is required by the interface ArrayAccess.	Cache
on()	Attaches an event handler to an event.	yii\base\Component
set()	Stores a value identified by a key into cache.	Cache
setServers()		MemCache
trigger()	Triggers an event.	yii\base\Component
addMemcachedServers() protected	Add servers to the server pool of the cache specified Used for memcached PECL extension.	MemCache
addMemcacheServers() protected	Add servers to the server pool of the cache specified Used for memcache PECL extension.	MemCache
addServers() protected	Add servers to the server pool of the cache specified.	MemCache
addValue() protected	Stores a value identified by a key into cache if the cache does not contain this key.	MemCache
addValues() protected	Adds multiple key-value pairs to cache.	Cache
deleteValue() protected	Deletes a value with the specified key from cache This is the implementation of the method declared in the parent class.	MemCache
flushValues() protected	Deletes all values from cache.	MemCache
getValue() protected	Retrieves a value from cache with a specified key.	MemCache
getValues() protected	Retrieves multiple values from cache with the specified keys.	MemCache
normalizeDuration() protected	Normalizes duration value	MemCache
setValue() protected	Stores a value identified by a key in cache.	MemCache
setValues() protected	Stores multiple key-value pairs in cache.	MemCache

Property details

$options

public array $options = null

Options for Memcached.

This property is used only when $useMemcached is true.

$password

public string $password = null

Memcached sasl password.

This property is used only when $useMemcached is true.

$persistentId

public string $persistentId = null

An ID that identifies a Memcached instance.

This property is used only when $useMemcached is true. By default the Memcached instances are destroyed at the end of the request. To create an instance that persists between requests, you may specify a unique ID for the instance. All instances created with the same ID will share the same connection.

$servers

public array $servers

List of memcache or memcached server configurations.

Each element must be an array with the following keys: host, port, persistent, weight, timeout, retryInterval, status.

$useMemcached

public bool $useMemcached = false

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.

$username

public string $username = null

Memcached sasl username.

This property is used only when $useMemcached is true.

Method details

getMemcache()

public function getMemcache(): Memcache|Memcached

Returns the underlying memcache (or memcached) object.

Returns

Memcache|Memcached: The memcache (or memcached) object used by this cache component.

Throws

• yii\base\InvalidConfigException: if memcache or memcached extension is not loaded

getServers()

public function getServers(): yii\caching\MemCacheServer[]

Returns the memcache or memcached server configurations.

Returns

MemCacheServer[]: List of memcache server configurations.

init()

public function init(): mixed

Initializes this application component.

It creates the memcache instance and adds memcache servers.

Returns

mixed

setServers()

public function setServers(array $config): mixed

Parameters

Parameter	Type	Description
$config	array	List of memcache or memcached server configurations. Each element must be an array with the following keys: host, port, persistent, weight, timeout, retryInterval, status.

Returns

mixed

See also

• https://www.php.net/manual/en/memcache.addserver.php
• https://www.php.net/manual/en/memcached.addserver.php

addMemcachedServers()

protected function addMemcachedServers(Memcached $cache, yii\caching\MemCacheServer[] $servers): mixed

Add servers to the server pool of the cache specified Used for memcached PECL extension.

Parameters

Parameter	Type	Description
$cache	Memcached
$servers	MemCacheServer[]

Returns

mixed

addMemcacheServers()

protected function addMemcacheServers(Memcache $cache, yii\caching\MemCacheServer[] $servers): mixed

Add servers to the server pool of the cache specified Used for memcache PECL extension.

Parameters

Parameter	Type	Description
$cache	Memcache
$servers	MemCacheServer[]

Returns

mixed

addServers()

protected function addServers(Memcache|Memcached $cache, yii\caching\MemCacheServer[] $servers): mixed

Add servers to the server pool of the cache specified.

Parameters

Parameter	Type	Description
$cache	Memcache|Memcached
$servers	MemCacheServer[]

Returns

mixed

Throws

• yii\base\InvalidConfigException

addValue()

protected function addValue(string $key, mixed $value, int $duration): bool

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.

Parameters

Parameter	Type	Description
$key	string	The key identifying the value to be cached
$value	mixed	The value to be cached
$duration	int	The number of seconds in which the cached value will expire. 0 means never expire.

Returns

bool: True if the value is successfully stored into cache, false otherwise

See also

• Memcache::set()

deleteValue()

protected function deleteValue(string $key): bool

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

Parameters

Parameter	Type	Description
$key	string	The key of the value to be deleted

Returns

bool: If no error happens during deletion

flushValues()

protected function flushValues(): bool

Deletes all values from cache.

This is the implementation of the method declared in the parent class.

Returns

bool: Whether the flush operation was successful.

getValue()

protected function getValue(string $key): mixed|false

Retrieves a value from cache with a specified key.

This is the implementation of the method declared in the parent class.

Parameters

Parameter	Type	Description
$key	string	A unique key identifying the cached value

Returns

mixed|false: The value stored in cache, false if the value is not in the cache or expired.

getValues()

protected function getValues(array $keys): array

Retrieves multiple values from cache with the specified keys.

Parameters

Parameter	Type	Description
$keys	array	A list of keys identifying the cached values

Returns

array: A list of cached values indexed by the keys

normalizeDuration()

protected function normalizeDuration(int $duration): int

Normalizes duration value

Parameters

Parameter	Type	Description
$duration	int

Returns

int

Since

2.0.31

See also

• https://github.com/yiisoft/yii2/issues/17710
• https://www.php.net/manual/en/memcache.set.php
• https://www.php.net/manual/en/memcached.expiration.php

setValue()

protected function setValue(string $key, mixed $value, int $duration): bool

Stores a value identified by a key in cache.

This is the implementation of the method declared in the parent class.

Parameters

Parameter	Type	Description
$key	string	The key identifying the value to be cached
$value	mixed	The value to be cached.
$duration	int	The number of seconds in which the cached value will expire. 0 means never expire.

Returns

bool: True if the value is successfully stored into cache, false otherwise

See also

• Memcache::set()

setValues()

protected function setValues(array $data, int $duration): array

Stores multiple key-value pairs in cache.

Parameters

Parameter	Type	Description
$data	array	Array where key corresponds to cache key while value is the value stored
$duration	int	The number of seconds in which the cached values will expire. 0 means never expire.

Returns

array: Array of failed keys.