NullBackend extends AbstractBackend implements PhpCapableBackendInterface, TaggableBackendInterface
A caching backend which forgets everything immediately
Table of Contents
Interfaces
- PhpCapableBackendInterface
- A contract for a cache backend which is capable of storing, retrieving and including PHP source code.
- TaggableBackendInterface
- A contract for a cache backend which supports tagging.
Constants
- DATETIME_EXPIRYTIME_UNLIMITED = '9999-12-31T23:59:59+0000'
- UNLIMITED_LIFETIME = 0
Properties
- $cache : FrontendInterface
- Reference to the cache which uses this backend
- $cacheIdentifier : string
- $context : string
- The current application context
- $defaultLifetime : int
- Default lifetime of a cache entry in seconds
Methods
- __construct() : mixed
- Constructs this backend
- collectGarbage() : mixed
- Does nothing
- findIdentifiersByTag() : array<string|int, mixed>
- Returns an empty array
- flush() : mixed
- Does nothing
- flushByTag() : mixed
- Does nothing
- flushByTags() : mixed
- Backwards compatibility safeguard since re-introducing flushByTags as API.
- get() : bool
- Returns False
- has() : bool
- Returns False
- remove() : bool
- Does nothing
- require() : bool
- Does nothing
- requireOnce() : bool
- Does nothing
- set() : mixed
- Acts as if it would save data
- setCache() : mixed
- Sets a reference to the cache frontend which uses this backend
- setCompression() : mixed
- Acts as if it would enable data compression
- setDefaultLifetime() : mixed
- Sets the default lifetime for this cache backend
- calculateExpiryTime() : DateTime
- Calculates the expiry time by the given lifetime. If no lifetime is specified, the default lifetime is used.
Constants
DATETIME_EXPIRYTIME_UNLIMITED
public
mixed
DATETIME_EXPIRYTIME_UNLIMITED
= '9999-12-31T23:59:59+0000'
UNLIMITED_LIFETIME
public
mixed
UNLIMITED_LIFETIME
= 0
Properties
$cache
Reference to the cache which uses this backend
protected
FrontendInterface
$cache
$cacheIdentifier
protected
string
$cacheIdentifier
$context
The current application context
protected
string
$context
This variable is currently unused and set to "production" always. It is only kept to keep backwards compatibility.
$defaultLifetime
Default lifetime of a cache entry in seconds
protected
int
$defaultLifetime
= 3600
Methods
__construct()
Constructs this backend
public
__construct(string $context[, array<string|int, mixed> $options = [] ]) : mixed
Parameters
- $context : string
-
Unused, for backward compatibility only
- $options : array<string|int, mixed> = []
-
Configuration options - depends on the actual backend
Tags
collectGarbage()
Does nothing
public
collectGarbage() : mixed
findIdentifiersByTag()
Returns an empty array
public
findIdentifiersByTag(mixed $tag) : array<string|int, mixed>
Parameters
- $tag : mixed
-
The tag to search for
Return values
array<string|int, mixed> —An array with identifiers of all matching entries. An empty array if no entries matched
flush()
Does nothing
public
flush() : mixed
flushByTag()
Does nothing
public
flushByTag(string $tag) : mixed
Parameters
- $tag : string
-
ignored
flushByTags()
Backwards compatibility safeguard since re-introducing flushByTags as API.
public
flushByTags(array<string|int, string> $tags) : mixed
See https://review.typo3.org/#/c/50537/ comments for patch set 14.
The method is here even though it is only required for TaggableBackendInterface. We add it here to ensure third party cache backends do not fail but instead delegate to a less efficient linear flushing behavior.
Parameters
- $tags : array<string|int, string>
get()
Returns False
public
get(string $entryIdentifier) : bool
Parameters
- $entryIdentifier : string
-
ignored
Return values
bool —FALSE
has()
Returns False
public
has(string $entryIdentifier) : bool
Parameters
- $entryIdentifier : string
-
ignored
Return values
bool —FALSE
remove()
Does nothing
public
remove(string $entryIdentifier) : bool
Parameters
- $entryIdentifier : string
-
ignored
Return values
bool —FALSE
require()
Does nothing
public
require(string $identifier) : bool
Parameters
- $identifier : string
-
An identifier which describes the cache entry to load
Return values
boolrequireOnce()
Does nothing
public
requireOnce(string $identifier) : bool
Parameters
- $identifier : string
-
An identifier which describes the cache entry to load
Return values
boolset()
Acts as if it would save data
public
set(string $entryIdentifier, string $data[, array<string|int, mixed> $tags = [] ][, int $lifetime = null ]) : mixed
Parameters
- $entryIdentifier : string
-
ignored
- $data : string
-
ignored
- $tags : array<string|int, mixed> = []
-
ignored
- $lifetime : int = null
-
ignored
setCache()
Sets a reference to the cache frontend which uses this backend
public
setCache(FrontendInterface $cache) : mixed
Parameters
- $cache : FrontendInterface
-
The frontend for this backend
setCompression()
Acts as if it would enable data compression
public
setCompression(bool $compression) : mixed
Parameters
- $compression : bool
-
ignored
setDefaultLifetime()
Sets the default lifetime for this cache backend
public
setDefaultLifetime(int $defaultLifetime) : mixed
Parameters
- $defaultLifetime : int
-
Default lifetime of this cache backend in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited lifetime.
Tags
calculateExpiryTime()
Calculates the expiry time by the given lifetime. If no lifetime is specified, the default lifetime is used.
protected
calculateExpiryTime([int $lifetime = null ]) : DateTime
Parameters
- $lifetime : int = null
-
The lifetime in seconds
Return values
DateTime —The expiry time