TYPO3\CMS\Core\Cache\Backend\ApcuBackend Class Reference

Inheritance diagram for TYPO3\CMS\Core\Cache\Backend\ApcuBackend:

Public Member Functions
	__construct ($context, array $options=[])
	setCache (FrontendInterface $cache)
	set ($entryIdentifier, $data, array $tags=[], $lifetime=null)
mixed	get ($entryIdentifier)
bool	has ($entryIdentifier)
bool	remove ($entryIdentifier)
array	findIdentifiersByTag ($tag)
	flush ()
	flushByTag ($tag)
	collectGarbage ()
‪Public Member Functions inherited from ‪TYPO3\CMS\Core\Cache\Backend\AbstractBackend
	setDefaultLifetime ($defaultLifetime)
	flushByTags (array $tags)
‪Public Member Functions inherited from ‪TYPO3\CMS\Core\Cache\Backend\TaggableBackendInterface
	flushByTags (array $tags)

Private Member Functions
	addIdentifierToTags (string $entryIdentifier, array $tags)
	removeIdentifierFromAllTags (string $entryIdentifier)
	findTagsByIdentifier (string $identifier)

Private Attributes
string	$identifierPrefix = ''

Additional Inherited Members
‪Public Attributes inherited from ‪TYPO3\CMS\Core\Cache\Backend\AbstractBackend
const	DATETIME_EXPIRYTIME_UNLIMITED = '9999-12-31T23:59:59+0000'
const	UNLIMITED_LIFETIME = 0
‪Protected Member Functions inherited from ‪TYPO3\CMS\Core\Cache\Backend\AbstractBackend
DateTime	calculateExpiryTime ($lifetime=null)
‪Protected Attributes inherited from ‪TYPO3\CMS\Core\Cache\Backend\AbstractBackend
FrontendInterface	$cache
string	$cacheIdentifier
string	$context
int	$defaultLifetime = 3600

Detailed Description

A caching backend which stores cache entries by using APCu.

The APCu backend is not very good with tagging and scales O(2n) with the number of tags. Do not use this backend if the data to be cached has many tags!

This backend uses the following types of keys:

• ‪tag_xxx xxx is tag name, value is array of associated identifiers identifier. This is "forward" tag index. It is mainly used for obtaining content by tag (get identifier by tag -> get content by identifier)
• ‪ident_xxx xxx is identifier, value is array of associated tags. This is "reverse" tag index. It provides quick access for all tags associated with this identifier and used when removing the identifier

Each key is prepended with a prefix. The prefix makes sure keys from the different installations do not conflict. By default, prefix consists from two parts separated by underscore character and ends in yet another underscore character:

• ‪"TYPO3"
• ‪Hash of path to TYPO3 and user running TYPO3

Definition at line 44 of file ApcuBackend.php.

Constructor & Destructor Documentation

__construct()

TYPO3\CMS\Core\Cache\Backend\ApcuBackend::__construct	(		$context,
		array	$options = []
	)

Constructs this backend

Parameters

string	$context	‪Unused, for backward compatibility only
array	$options	‪Configuration options - unused here

Exceptions

Exception

Reimplemented from TYPO3\CMS\Core\Cache\Backend\AbstractBackend.

Definition at line 58 of file ApcuBackend.php.

References TYPO3\CMS\Core\Cache\Backend\AbstractBackend\$context.

Member Function Documentation

addIdentifierToTags()

TYPO3\CMS\Core\Cache\Backend\ApcuBackend::addIdentifierToTags ( string  $entryIdentifier, array  $tags  )

private

Associates the identifier with the given tags

Definition at line 188 of file ApcuBackend.php.

References TYPO3\CMS\Core\Cache\Backend\ApcuBackend\findIdentifiersByTag(), and TYPO3\CMS\Core\Cache\Backend\ApcuBackend\findTagsByIdentifier().

Referenced by TYPO3\CMS\Core\Cache\Backend\ApcuBackend\set().

collectGarbage()

TYPO3\CMS\Core\Cache\Backend\ApcuBackend::collectGarbage

(

)

Does garbage collection

Implements TYPO3\CMS\Core\Cache\Backend\BackendInterface.

Definition at line 253 of file ApcuBackend.php.

findIdentifiersByTag()

array TYPO3\CMS\Core\Cache\Backend\ApcuBackend::findIdentifiersByTag

(

$tag

)

Finds and returns all cache entry identifiers which are tagged by the specified tag.

Parameters

string

$tag

‪The tag to search for

Returns

‪array An array with identifiers of all matching entries. An empty array if no entries matched

Implements TYPO3\CMS\Core\Cache\Backend\TaggableBackendInterface.

Definition at line 149 of file ApcuBackend.php.

Referenced by TYPO3\CMS\Core\Cache\Backend\ApcuBackend\addIdentifierToTags(), TYPO3\CMS\Core\Cache\Backend\ApcuBackend\flushByTag(), and TYPO3\CMS\Core\Cache\Backend\ApcuBackend\removeIdentifierFromAllTags().

findTagsByIdentifier()

TYPO3\CMS\Core\Cache\Backend\ApcuBackend::findTagsByIdentifier ( string  $identifier )

private

Finds all tags for the given identifier. This function uses reverse tag index to search for tags.

Definition at line 246 of file ApcuBackend.php.

References TYPO3\CMS\Webhooks\Message\$identifier.

Referenced by TYPO3\CMS\Core\Cache\Backend\ApcuBackend\addIdentifierToTags(), and TYPO3\CMS\Core\Cache\Backend\ApcuBackend\removeIdentifierFromAllTags().

flush()

TYPO3\CMS\Core\Cache\Backend\ApcuBackend::flush

(

)

Removes all cache entries of this cache.

Exceptions

Exception

Implements TYPO3\CMS\Core\Cache\Backend\BackendInterface.

Definition at line 164 of file ApcuBackend.php.

flushByTag()

TYPO3\CMS\Core\Cache\Backend\ApcuBackend::flushByTag

(

$tag

)

Removes all cache entries of this cache which are tagged by the specified tag.

Parameters

string

$tag

‪The tag the entries must have

Implements TYPO3\CMS\Core\Cache\Backend\TaggableBackendInterface.

Definition at line 177 of file ApcuBackend.php.

References TYPO3\CMS\Webhooks\Message\$identifier, and TYPO3\CMS\Core\Cache\Backend\ApcuBackend\findIdentifiersByTag().

get()

mixed TYPO3\CMS\Core\Cache\Backend\ApcuBackend::get

(

$entryIdentifier

)

Loads data from the cache.

Parameters

string

$entryIdentifier

‪An identifier which describes the cache entry to load

Returns

‪mixed The cache entry's content as a string or FALSE if the cache entry could not be loaded

Implements TYPO3\CMS\Core\Cache\Backend\BackendInterface.

Definition at line 108 of file ApcuBackend.php.

has()

bool TYPO3\CMS\Core\Cache\Backend\ApcuBackend::has

(

$entryIdentifier

)

Checks if a cache entry with the specified identifier exists.

Parameters

string

$entryIdentifier

‪An identifier specifying the cache entry

Returns

‪bool TRUE if such an entry exists, FALSE if not

Implements TYPO3\CMS\Core\Cache\Backend\BackendInterface.

Definition at line 121 of file ApcuBackend.php.

remove()

bool TYPO3\CMS\Core\Cache\Backend\ApcuBackend::remove

(

$entryIdentifier

)

Removes all cache entries matching the specified identifier. Usually this only affects one entry but if - for what reason ever - old entries for the identifier still exist, they are removed as well.

Parameters

string

$entryIdentifier

‪Specifies the cache entry to remove

Returns

‪bool TRUE if (at least) an entry could be removed or FALSE if no entry was found

Implements TYPO3\CMS\Core\Cache\Backend\BackendInterface.

Definition at line 136 of file ApcuBackend.php.

References TYPO3\CMS\Core\Cache\Backend\ApcuBackend\removeIdentifierFromAllTags().

removeIdentifierFromAllTags()

TYPO3\CMS\Core\Cache\Backend\ApcuBackend::removeIdentifierFromAllTags ( string  $entryIdentifier )

private

Removes association of the identifier with the given tags

Definition at line 217 of file ApcuBackend.php.

References TYPO3\CMS\Core\Cache\Backend\ApcuBackend\findIdentifiersByTag(), and TYPO3\CMS\Core\Cache\Backend\ApcuBackend\findTagsByIdentifier().

Referenced by TYPO3\CMS\Core\Cache\Backend\ApcuBackend\remove(), and TYPO3\CMS\Core\Cache\Backend\ApcuBackend\set().

set()

TYPO3\CMS\Core\Cache\Backend\ApcuBackend::set	(		$entryIdentifier,
			$data,
		array	$tags = [],
			$lifetime = null
	)

Saves data in the cache.

Parameters

string	$entryIdentifier	‪An identifier for this specific cache entry
mixed	$data	‪The data to be stored
array	$tags	‪Tags to associate with this cache entry
int	$lifetime	‪Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited lifetime.

Exceptions

Exception

‪if no cache frontend has been set.

Implements TYPO3\CMS\Core\Cache\Backend\BackendInterface.

Definition at line 87 of file ApcuBackend.php.

References TYPO3\CMS\Core\Cache\Backend\AbstractBackend\$defaultLifetime, TYPO3\CMS\Core\Cache\Backend\ApcuBackend\addIdentifierToTags(), and TYPO3\CMS\Core\Cache\Backend\ApcuBackend\removeIdentifierFromAllTags().

setCache()

TYPO3\CMS\Core\Cache\Backend\ApcuBackend::setCache

(

FrontendInterface

$cache

)

Initializes the identifier prefix when setting the cache.

Reimplemented from TYPO3\CMS\Core\Cache\Backend\AbstractBackend.

Definition at line 72 of file ApcuBackend.php.

References TYPO3\CMS\Core\Cache\Backend\AbstractBackend\$cache, TYPO3\CMS\Core\Cache\Frontend\FrontendInterface\getIdentifier(), and TYPO3\CMS\Core\Core\Environment\getProjectPath().

Member Data Documentation

$identifierPrefix

string TYPO3\CMS\Core\Cache\Backend\ApcuBackend::$identifierPrefix = ''

private

A prefix to separate stored data from other data possible stored in the APC.

Definition at line 49 of file ApcuBackend.php.