CacheInterface

API reference › yii › caching › CacheInterface

interface	yii\caching\CacheInterface
Extends	ArrayAccess
Source	framework/caching/CacheInterface.php

Implemented by 1 type

• Cache

CacheInterface is the base interface for cache.

A data item can be stored in the cache by calling set() and be retrieved back later (in the same or different request) by get(). In both operations, a key identifying the data item is required. An expiration time and/or a dependency can also be specified when calling set(). If the data item expires or the dependency changes at the time of calling get(), the cache will return no data.

A typical usage pattern of cache is like the following:

$key = 'demo';
$data = $cache->get($key);
if ($data === false) {
    // ...generate $data here...
    $cache->set($key, $data, $duration, $dependency);
}

Because CacheInterface extends the ArrayAccess interface, it can be used like an array. For example,

$cache['foo'] = 'some data';
echo $cache['foo'];

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

Methods

Method	Description	Defined by
add() abstract	Stores a value identified by a key into cache if the cache does not contain this key.	CacheInterface
buildKey() abstract	Builds a normalized cache key from a given key.	CacheInterface
delete() abstract	Deletes a value with the specified key from cache.	CacheInterface
exists() abstract	Checks whether a specified key exists in the cache.	CacheInterface
flush() abstract	Deletes all values from cache.	CacheInterface
get() abstract	Retrieves a value from cache with a specified key.	CacheInterface
getOrSet() abstract	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.	CacheInterface
multiAdd() abstract	Stores multiple items in cache. Each item contains a value identified by a key.	CacheInterface
multiGet() abstract	Retrieves multiple values from cache with the specified keys.	CacheInterface
multiSet() abstract	Stores multiple items in cache. Each item contains a value identified by a key.	CacheInterface
set() abstract	Stores a value identified by a key into cache.	CacheInterface

Method details

add()

abstract public function add(mixed $key, mixed $value, int $duration = 0, yii\caching\Dependency|null $dependency = null): bool

Stores a value identified by a key into cache if the cache does not contain this key.

Nothing will be done if the cache already contains the key.

Parameters

Parameter	Type	Description
$key	mixed	A key identifying the value to be cached. This can be a simple string or a complex data structure consisting of factors representing the key.
$value	mixed	The value to be cached
$duration	int	The number of seconds in which the cached value will expire. 0 means never expire.
$dependency	Dependency|null	Dependency of the cached item. If the dependency changes, the corresponding value in the cache will be invalidated when it is fetched via get(). This parameter is ignored if serializer is false.

Returns

bool: Whether the value is successfully stored into cache

buildKey()

abstract public function buildKey(mixed $key): string

Builds a normalized cache key from a given key.

If the given key is a string containing alphanumeric characters only and no more than 32 characters, then the key will be returned back prefixed with keyPrefix. Otherwise, a normalized key is generated by serializing the given key, applying MD5 hashing, and prefixing with keyPrefix.

Parameters

Parameter	Type	Description
$key	mixed	The key to be normalized

Returns

string: The generated cache key

delete()

abstract public function delete(mixed $key): bool

Deletes a value with the specified key from cache.

Parameters

Parameter	Type	Description
$key	mixed	A key identifying the value to be deleted from cache. This can be a simple string or a complex data structure consisting of factors representing the key.

Returns

bool: If no error happens during deletion

exists()

abstract public function exists(mixed $key): bool

Checks whether a specified key exists in the cache.

This can be faster than getting the value from the cache if the data is big. In case a cache does not support this feature natively, this method will try to simulate it but has no performance improvement over getting it. Note that this method does not check whether the dependency associated with the cached data, if there is any, has changed. So a call to get() may return false while exists returns true.

Parameters

Parameter	Type	Description
$key	mixed	A key identifying the cached value. This can be a simple string or a complex data structure consisting of factors representing the key.

Returns

bool: True if a value exists in cache, false if the value is not in the cache or expired.

flush()

abstract public function flush(): bool

Deletes all values from cache.

Be careful of performing this operation if the cache is shared among multiple applications.

Returns

bool: Whether the flush operation was successful.

get()

abstract public function get(mixed $key): mixed

Retrieves a value from cache with a specified key.

Parameters

Parameter	Type	Description
$key	mixed	A key identifying the cached value. This can be a simple string or a complex data structure consisting of factors representing the key.

Returns

mixed: The value stored in cache, false if the value is not in the cache, expired, or the dependency associated with the cached data has changed.

getOrSet()

abstract public function getOrSet(mixed $key, callable(): yii\caching\TResult|Closure(): yii\caching\TResult $callable, int|null $duration = null, yii\caching\Dependency|null $dependency = null): yii\caching\TResult

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.

Usage example:

public function getTopProducts($count = 10) {
    $cache = $this->cache; // Could be Yii::$app->cache
    return $cache->getOrSet(['top-n-products', 'n' => $count], function ($cache) use ($count) {
        return Products::find()->mostPopular()->limit($count)->all();
    }, 1000);
}

Parameters

Parameter	Type	Description
$key	mixed	A key identifying the value to be cached. This can be a simple string or a complex data structure consisting of factors representing the key.
$callable	callable(): yii\caching\TResult|Closure(): yii\caching\TResult	The callable or closure that will be used to generate a value to be cached. In case $callable returns false, the value will not be cached.
$duration	int|null	Default duration in seconds before the cache will expire. If not set, defaultDuration value will be used.
$dependency	Dependency|null	Dependency of the cached item. If the dependency changes, the corresponding value in the cache will be invalidated when it is fetched via get(). This parameter is ignored if serializer is false.

Returns

yii\caching\TResult: Result of $callable execution

multiAdd()

abstract public function multiAdd(array $items, int $duration = 0, yii\caching\Dependency|null $dependency = null): array

Stores multiple items in cache. Each item contains a value identified by a key.

If the cache already contains such a key, the existing value and expiration time will be preserved.

Parameters

Parameter	Type	Description
$items	array	The items to be cached, as key-value pairs.
$duration	int	Default number of seconds in which the cached values will expire. 0 means never expire.
$dependency	Dependency|null	Dependency of the cached items. If the dependency changes, the corresponding values in the cache will be invalidated when it is fetched via get(). This parameter is ignored if serializer is false.

Returns

array: Array of failed keys

multiGet()

abstract public function multiGet(string[] $keys): array

Retrieves multiple values from cache with the specified keys.

Some caches (such as memcache, apc) allow retrieving multiple cached values at the same time, which may improve the performance. In case a cache does not support this feature natively, this method will try to simulate it.

Parameters

Parameter	Type	Description
$keys	string[]	List of string keys identifying the cached values

Returns

array: List of cached values corresponding to the specified keys. The array is returned in terms of (key, value) pairs. If a value is not cached or expired, the corresponding array value will be false.

multiSet()

abstract public function multiSet(array $items, int|null $duration = null, yii\caching\Dependency|null $dependency = null): array

Stores multiple items in cache. Each item contains a value identified by a key.

If the cache already contains such a key, the existing value and expiration time will be replaced with the new ones, respectively.

Parameters

Parameter	Type	Description
$items	array	The items to be cached, as key-value pairs.
$duration	int|null	Default duration in seconds before the cache will expire. If not set, default defaultDuration value is used.
$dependency	Dependency|null	Dependency of the cached items. If the dependency changes, the corresponding values in the cache will be invalidated when it is fetched via get(). This parameter is ignored if serializer is false.

Returns

array: Array of failed keys

set()

abstract public function set(mixed $key, mixed $value, int|null $duration = null, yii\caching\Dependency|null $dependency = null): bool

Stores a value identified by a key into cache.

If the cache already contains such a key, the existing value and expiration time will be replaced with the new ones, respectively.

Parameters

Parameter	Type	Description
$key	mixed	A key identifying the value to be cached. This can be a simple string or a complex data structure consisting of factors representing the key.
$value	mixed	The value to be cached
$duration	int|null	Default duration in seconds before the cache will expire. If not set, default defaultDuration value is used.
$dependency	Dependency|null	Dependency of the cached item. If the dependency changes, the corresponding value in the cache will be invalidated when it is fetched via get(). This parameter is ignored if serializer is false.

Returns

bool: Whether the value is successfully stored into cache