# Class yii\redis\Cache

Inheritance | yii\redis\Cache » yii\caching\Cache » yii\base\Component » yii\base\BaseObject
Implements | yii\base\Configurable, yii\caching\CacheInterface
Available since version | 2.0
Source Code | https://github.com/yiisoft/yii2-redis/blob/master/Cache.php

Redis Cache implements a cache application component based on redis key-value store.

Redis Cache requires redis version 2.6.12 or higher to work properly.

It needs to be configured with a redis yii\redis\Connection. By default it will use the `redis` application component.

> Note: It is recommended to use separate database for cache and do not share it with other components. If you need to share database, you should set $shareDatabase to `true` and make sure that $keyPrefix has unique value which will allow to distinguish between cache keys and other data in database.

See yii\caching\Cache manual for common cache operations that redis Cache supports.

Unlike the yii\caching\Cache, redis Cache allows the expire parameter of set(), add(), mset() and madd() to be a floating point number, so you may specify the time in milliseconds (e.g. 0.1 will be 100 milliseconds).

To use redis Cache as the cache application component, configure the application as follows,

    [
        'components' => [
            'cache' => [
                'class' => 'yii\redis\Cache',
                'redis' => [
                    'hostname' => 'localhost',
                    'port' => 6379,
                    'database' => 0,
                ]
            ],
        ],
    ]

Or if you have configured the redis yii\redis\Connection as an application component, the following is sufficient:

    [
        'components' => [
            'cache' => [
                'class' => 'yii\redis\Cache',
                // 'redis' => 'redis' // id of the connection application component
            ],
        ],
    ]

If you have multiple redis replicas (e.g. AWS ElasticCache Redis) you can configure the cache to send read operations to the replicas. If no replicas are configured, all operations will be performed on the master connection configured via the $redis property.

    [
        'components' => [
            'cache' => [
                'class' => 'yii\redis\Cache',
                'enableReplicas' => true,
                'replicas' => [
                    // config for replica redis connections, (default class will be yii\redis\Connection if not provided)
                    // you can optionally put in master as hostname as well, as all GET operation will use replicas
                    'redis',//id of Redis [[Connection]] Component
                    ['hostname' => 'redis-slave-002.xyz.0001.apse1.cache.amazonaws.com'],
                    ['hostname' => 'redis-slave-003.xyz.0001.apse1.cache.amazonaws.com'],
                ],
            ],
        ],
    ]

If you're using redis in cluster mode and want to use `MGET` and `MSET` effectively, you will need to supply a hash tag to allocate cache keys to the same hash slot.

    \Yii::$app->cache->multiSet([
        'posts{user1}' => 123,
        'settings{user1}' => [
            'showNickname' => false,
            'sortBy' => 'created_at',
        ],
        'unreadMessages{user1}' => 5,
    ]);

## Public Properties

Hide inherited properties

Property | Type | Description | Defined By
--- | --- | --- | ---
$behaviors | yii\base\Behavior[] | List of behaviors attached to this component. This property is read-only. | yii\base\Component
$defaultDuration | integer | Default duration in seconds before a cache entry will expire. | yii\caching\Cache
$enableReplicas | boolean | Whether to enable read / get from redis replicas. | yii\redis\Cache
$forceClusterMode | boolean|null | Force cluster mode, don't check on every request. | yii\redis\Cache
$isCluster | boolean | Whether redis is running in cluster mode or not. This property is read-only. | yii\redis\Cache
$keyPrefix | string | A string prefixed to every cache key so that it is unique globally in the whole cache storage. | yii\caching\Cache
$redis | yii\redis\Connection|string|array | The Redis yii\redis\Connection object or the application component ID of the Redis yii\redis\Connection. | yii\redis\Cache
$replicas | array | The Redis yii\redis\Connection configurations for redis replicas. | yii\redis\Cache
$serializer | null|array|false | The functions used to serialize and unserialize cached data. | yii\caching\Cache
$shareDatabase | boolean | Whether redis database is shared and can contain other data than cache. | yii\redis\Cache

## Public Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
__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
__construct() | Constructor. | yii\base\BaseObject
__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. | yii\caching\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() |  | yii\redis\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() | Returns the fully qualified name of this class. | yii\base\BaseObject
delete() | Deletes a value with the specified key from cache. | yii\caching\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. | yii\redis\Cache
flush() | Deletes all values from cache. | yii\caching\Cache
get() | Retrieves a value from cache with a specified key. | yii\caching\Cache
getBehavior() | Returns the named behavior object. | yii\base\Component
getBehaviors() | Returns all behaviors attached to this component. | yii\base\Component
getIsCluster() | Returns `true` if the redis extension is forced to run in cluster mode through config or the redis command `CLUSTER INFO` executes successfully, `false` otherwise. | yii\redis\Cache
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. | yii\caching\Cache
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 the redis Cache component. | yii\redis\Cache
madd() | Stores multiple items in cache. Each item contains a value identified by a key. | yii\caching\Cache
mget() | Retrieves multiple values from cache with the specified keys. | yii\caching\Cache
mset() | Stores multiple items in cache. Each item contains a value identified by a key. | yii\caching\Cache
multiAdd() | Stores multiple items in cache. Each item contains a value identified by a key. | yii\caching\Cache
multiGet() | Retrieves multiple values from cache with the specified keys. | yii\caching\Cache
multiSet() | Stores multiple items in cache. Each item contains a value identified by a key. | yii\caching\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. | yii\caching\Cache
offsetGet() | Retrieves the value from cache with a specified key. | yii\caching\Cache
offsetSet() | Stores the value identified by a key into cache. | yii\caching\Cache
offsetUnset() | Deletes the value with the specified key from cache This method is required by the interface ArrayAccess. | yii\caching\Cache
on() | Attaches an event handler to an event. | yii\base\Component
set() | Stores a value identified by a key into cache. | yii\caching\Cache
trigger() | Triggers an event. | yii\base\Component

## 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. | yii\redis\Cache
addValues() | Adds multiple key-value pairs to cache. | yii\caching\Cache
deleteValue() | Deletes a value with the specified key from cache This method should be implemented by child classes to delete the data from actual cache storage. | yii\redis\Cache
flushValues() | Deletes all values from cache. | yii\redis\Cache
getReplica() | It will return the current Replica Redis yii\redis\Connection, and fall back to default $redis yii\redis\Connection defined in this instance. Only used in getValue() and getValues(). | yii\redis\Cache
getValue() | Retrieves a value from cache with a specified key. | yii\redis\Cache
getValues() | Retrieves multiple values from cache with the specified keys. | yii\redis\Cache
setValue() | Stores a value identified by a key in cache. | yii\redis\Cache
setValues() | Stores multiple key-value pairs in cache. | yii\redis\Cache

## Property Details

$enableReplicas public property (available since version 2.0.8)

Whether to enable read / get from redis replicas.

See also $replicas.

public boolean $enableReplicas = false
$forceClusterMode public property (available since version 2.0.11)

Force cluster mode, don't check on every request. If this is null, cluster mode will be checked once per request whenever the cache is accessed. To disable the check, set to true if cluster mode should be enabled, or false if it should be disabled.

public boolean|null $forceClusterMode = null
$isCluster public property

Whether redis is running in cluster mode or not. This property is read-only.

public boolean $isCluster = null
$redis public property

The Redis yii\redis\Connection object or the application component ID of the Redis yii\redis\Connection. This can also be an array that is used to create a redis yii\redis\Connection instance in case you do not want do configure redis connection as an application component. After the Cache object is created, if you want to change this property, you should only assign it with a Redis yii\redis\Connection object.

public yii\redis\Connection|string|array $redis = 'redis'
$replicas public property (available since version 2.0.8)

The Redis yii\redis\Connection configurations for redis replicas. Each entry is a class configuration, which will be used to instantiate a replica connection. The default class is yii\redis\Connection. You should at least provide a hostname.

Configuration example:

    'replicas' => [
        'redis',
        ['hostname' => 'redis-slave-002.xyz.0001.apse1.cache.amazonaws.com'],
        ['hostname' => 'redis-slave-003.xyz.0001.apse1.cache.amazonaws.com'],
    ],

See also $enableReplicas.

public array $replicas = []
$shareDatabase public property (available since version 2.0.12)

Whether redis database is shared and can contain other data than cache. Setting this to `true` will change flush() behavior - instead of using `FLUSHDB` command, component will iterate through all keys in database and remove only these with matching $keyPrefix. Note that this will no longer be an atomic operation and it is much less efficient than `FLUSHDB` command. It is recommended to use separate database for cache and leave this value as `false`.

public boolean $shareDatabase = false

## Method Details

addValue() protected method

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

This method should be implemented by child classes to store the data in specific cache storage.

protected boolean addValue ( $key, $value, $expire )
$key | string | The key identifying the value to be cached
$value | mixed | The value to be cached. Most often it's a string. If you have disabled $serializer, it could be something else.
$expire |  |
return | boolean | True if the value is successfully stored into cache, false otherwise

buildKey() public method

public void buildKey ( $key )
$key |  |

deleteValue() protected method

Deletes a value with the specified key from cache This method should be implemented by child classes to delete the data from actual cache storage.

protected boolean deleteValue ( $key )
$key | string | The key of the value to be deleted
return | boolean | If no error happens during deletion

exists() public method

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. 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.

public boolean exists ( $key )
$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.
return | boolean | True if a value exists in cache, false if the value is not in the cache or expired.

flushValues() protected method

Deletes all values from cache.

Child classes may implement this method to realize the flush operation.

protected boolean flushValues ( )
return | boolean | Whether the flush operation was successful.

getIsCluster() public method (available since version 2.0.11)

Returns `true` if the redis extension is forced to run in cluster mode through config or the redis command `CLUSTER INFO` executes successfully, `false` otherwise.

Setting $forceClusterMode to either `true` or `false` is preferred.

public boolean getIsCluster ( )
return | boolean | Whether redis is running in cluster mode or not

getReplica() protected method (available since version 2.0.8)

It will return the current Replica Redis yii\redis\Connection, and fall back to default $redis yii\redis\Connection defined in this instance. Only used in getValue() and getValues().

protected array|string|yii\redis\Connection getReplica ( )
throws | yii\base\InvalidConfigException |

getValue() protected method

Retrieves a value from cache with a specified key.

This method should be implemented by child classes to retrieve the data from specific cache storage.

protected mixed|false getValue ( $key )
$key | string | A unique key identifying the cached value
return | mixed|false | The value stored in cache, false if the value is not in the cache or expired. Most often value is a string. If you have disabled $serializer, it could be something else.

getValues() protected method

Retrieves multiple values from cache with the specified keys.

The default implementation calls getValue() multiple times to retrieve the cached values one by one. If the underlying cache storage supports multiget, this method should be overridden to exploit that feature.

protected array getValues ( $keys )
$keys | array | A list of keys identifying the cached values
return | array | A list of cached values indexed by the keys

init() public method

Initializes the redis Cache component.

This method will initialize the $redis property to make sure it refers to a valid redis connection.

public void init ( )
throws | yii\base\InvalidConfigException | if $redis is invalid.

setValue() protected method

Stores a value identified by a key in cache.

This method should be implemented by child classes to store the data in specific cache storage.

protected boolean setValue ( $key, $value, $expire )
$key | string | The key identifying the value to be cached
$value | mixed | The value to be cached. Most often it's a string. If you have disabled $serializer, it could be something else.
$expire |  |
return | boolean | True if the value is successfully stored into cache, false otherwise

setValues() protected method

Stores multiple key-value pairs in cache.

The default implementation calls setValue() multiple times store values one by one. If the underlying cache storage supports multi-set, this method should be overridden to exploit that feature.

protected array setValues ( $data, $expire )
$data | array | Array where key corresponds to cache key while value is the value stored
$expire |  |
return | array | Array of failed keys