Abstract Class yii\caching\Cache
| Inheritance | yii\caching\Cache » yii\base\Component » yii\base\Object |
|---|---|
| Implements | ArrayAccess, yii\base\Configurable |
| Subclasses | yii\caching\ApcCache, yii\caching\ArrayCache, yii\caching\DbCache, yii\caching\DummyCache, yii\caching\FileCache, yii\caching\MemCache, yii\caching\WinCache, yii\caching\XCache, yii\caching\ZendDataCache, yii\mongodb\Cache, yii\redis\Cache |
| Available since version | 2.0 |
| Source Code | https://github.com/yiisoft/yii2/blob/master/framework/caching/Cache.php |
Cache is the base class for cache classes supporting different cache storage implementations.
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 Cache implements the ArrayAccess interface, it can be used like an array. For example,
$cache['foo'] = 'some data';
echo $cache['foo'];Derived classes should implement the following methods which do the actual cache storage operations:
- getValue(): retrieve the value with a key (if any) from cache
- setValue(): store the value with a key into cache
- addValue(): store the value only if the cache does not have this key before
- deleteValue(): delete the value with the specified key from cache
- flushValues(): delete all values from cache
Public Properties
| Property | Type | Description | Defined By |
|---|---|---|---|
| $behaviors | yii\base\Behavior[] | List of behaviors attached to this component | yii\base\Component |
| $keyPrefix | string | A string prefixed to every cache key so that it is unique globally in the whole cache storage. | yii\caching\Cache |
| $serializer | array|boolean | The functions used to serialize and unserialize cached data. | yii\caching\Cache |
Public Methods
| Method | Description | Defined By |
|---|---|---|
| __call() | Calls the named method which is not a class method. | yii\base\Object |
| __clone() | This method is called after the object is created by cloning an existing one. | yii\base\Component |
| __construct() | Constructor. | yii\base\Object |
| __get() | Returns the value of an object property. | yii\base\Object |
| __isset() | Checks if a property is set, i.e. defined and not null. | yii\base\Object |
| __set() | Sets value of an object property. | yii\base\Object |
| __unset() | Sets an object property to null. | yii\base\Object |
| 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() | Builds a normalized cache key from a given key. | yii\caching\Cache |
| canGetProperty() | Returns a value indicating whether a property can be read. | yii\base\Object |
| canSetProperty() | Returns a value indicating whether a property can be set. | yii\base\Object |
| className() | Returns the fully qualified name of this class. | yii\base\Object |
| 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\caching\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 |
| 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\Object |
| hasProperty() | Returns a value indicating whether a property is defined. | yii\base\Object |
| init() | Initializes the object. | yii\base\Object |
| 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 |
| 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
| Method | Description | Defined By |
|---|---|---|
| addValue() | Stores a value identified by a key into cache if the cache does not contain this key. | yii\caching\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\caching\Cache |
| flushValues() | Deletes all values from cache. | yii\caching\Cache |
| getValue() | Retrieves a value from cache with a specified key. | yii\caching\Cache |
| getValues() | Retrieves multiple values from cache with the specified keys. | yii\caching\Cache |
| setValue() | Stores a value identified by a key in cache. | yii\caching\Cache |
| setValues() | Stores multiple key-value pairs in cache. | yii\caching\Cache |
Property Details
A string prefixed to every cache key so that it is unique globally in the whole cache storage. It is recommended that you set a unique cache key prefix for each application if the same cache storage is being used by different applications.
To ensure interoperability, only alphanumeric characters should be used.
The functions used to serialize and unserialize cached data. Defaults to null, meaning
using the default PHP serialize() and unserialize() functions. If you want to use some more efficient
serializer (e.g. igbinary), you may configure this property with
a two-element array. The first element specifies the serialization function, and the second the deserialization
function. If this property is set false, data will be directly sent to and retrieved from the underlying
cache component without any serialization or deserialization. You should not turn off serialization if
you are using cache dependency, because it relies on data serialization.
Method Details
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.
| boolean add( $key, $value, $duration = 0, $dependency = null ) | ||
| $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 | integer | The number of seconds in which the cached value will expire. 0 means never expire. |
| $dependency | yii\caching\Dependency | 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. |
| return | boolean | Whether the value is successfully stored into cache |
|---|---|---|
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.
| boolean addValue( $key, $value, $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 |
|---|---|---|
Adds multiple key-value pairs to cache.
The default implementation calls addValue() multiple times add values one by one. If the underlying cache storage supports multi-add, this method should be overridden to exploit that feature.
| array addValues( $data, $duration ) | ||
| $data | array | Array where key corresponds to cache key while value is the value stored |
| $duration | integer | The number of seconds in which the cached values will expire. 0 means never expire. |
| return | array | Array of failed keys |
|---|---|---|
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.
| string buildKey( $key ) | ||
| $key | mixed | The key to be normalized |
| return | string | The generated cache key |
|---|---|---|
Deletes a value with the specified key from cache
| boolean delete( $key ) | ||
| $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. |
| return | boolean | If no error happens during deletion |
|---|---|---|
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.
| boolean deleteValue( $key ) | ||
| $key | string | The key of the value to be deleted |
| return | boolean | If no error happens during deletion |
|---|---|---|
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.
| 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. |
|---|---|---|
Deletes all values from cache.
Be careful of performing this operation if the cache is shared among multiple applications.
| boolean flush( ) | ||
| return | boolean | Whether the flush operation was successful. |
|---|---|---|
Deletes all values from cache.
Child classes may implement this method to realize the flush operation.
| boolean flushValues( ) | ||
| return | boolean | Whether the flush operation was successful. |
|---|---|---|
Retrieves a value from cache with a specified key.
| mixed get( $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 | 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. |
|---|---|---|
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.
| string|boolean getValue( $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 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.
| array getValues( $keys ) | ||
| $keys | array | A list of keys identifying the cached values |
| return | array | A list of cached values indexed by the keys |
|---|---|---|
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.
| boolean madd( $items, $duration = 0, $dependency = null ) | ||
| $items | array | The items to be cached, as key-value pairs. |
| $duration | integer | Default number of seconds in which the cached values will expire. 0 means never expire. |
| $dependency | yii\caching\Dependency | 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. |
| return | boolean | Whether the items are successfully stored into cache |
|---|---|---|
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.
| array mget( $keys ) | ||
| $keys | string[] | List of string keys identifying the cached values |
| return | 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. |
|---|---|---|
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.
| boolean mset( $items, $duration = 0, $dependency = null ) | ||
| $items | array | The items to be cached, as key-value pairs. |
| $duration | integer | Default number of seconds in which the cached values will expire. 0 means never expire. |
| $dependency | yii\caching\Dependency | 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. |
| return | boolean | Whether the items are successfully stored into cache |
|---|---|---|
Returns whether there is a cache entry with a specified key.
This method is required by the interface ArrayAccess.
| boolean offsetExists( $key ) | ||
| $key | string | A key identifying the cached value |
Retrieves the value from cache with a specified key.
This method is required by the interface ArrayAccess.
| mixed offsetGet( $key ) | ||
| $key | string | A key identifying the cached value |
| return | mixed | The value stored in cache, false if the value is not in the cache or expired. |
|---|---|---|
Stores the value identified by a key into cache.
If the cache already contains such a key, the existing value will be replaced with the new ones. To add expiration and dependencies, use the set() method. This method is required by the interface ArrayAccess.
| void offsetSet( $key, $value ) | ||
| $key | string | The key identifying the value to be cached |
| $value | mixed | The value to be cached |
Deletes the value with the specified key from cache This method is required by the interface ArrayAccess.
| void offsetUnset( $key ) | ||
| $key | string | The key of the value to be deleted |
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.
| boolean set( $key, $value, $duration = 0, $dependency = null ) | ||
| $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 | integer | The number of seconds in which the cached value will expire. 0 means never expire. |
| $dependency | yii\caching\Dependency | 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. |
| return | boolean | Whether the value is successfully stored into cache |
|---|---|---|
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.
| boolean setValue( $key, $value, $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 |
|---|---|---|
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.
| array setValues( $data, $duration ) | ||
| $data | array | Array where key corresponds to cache key while value is the value stored |
| $duration | integer | The number of seconds in which the cached values will expire. 0 means never expire. |
| return | array | Array of failed keys |
|---|---|---|