TYPO3 12.4 API: RedisBackend

RedisBackend extends AbstractBackend implements TaggableBackendInterface

A caching backend which stores cache entries by using Redis with phpredis PHP module. Redis is a noSQL database with very good scaling characteristics in proportion to the amount of entries and data size.

Interfaces

TaggableBackendInterface: A contract for a cache backend which supports tagging.

Constants

DATETIME_EXPIRYTIME_UNLIMITED = '9999-12-31T23:59:59+0000'
FAKED_UNLIMITED_LIFETIME = 31536000: Faked unlimited lifetime = 31536000 (1 Year).
IDENTIFIER_DATA_PREFIX = 'identData:': Key prefix for identifier->data entries
IDENTIFIER_TAGS_PREFIX = 'identTags:': Key prefix for identifier->tags sets
TAG_IDENTIFIERS_PREFIX = 'tagIdents:': Key prefix for tag->identifiers sets
UNLIMITED_LIFETIME = 0

Properties

$cache : FrontendInterface: Reference to the cache which uses this backend
$cacheIdentifier : string
$compression : bool: Indicates whether data is compressed or not (requires php zlib)
$compressionLevel : int: -1 to 9, indicates zlib compression level: -1 = default level 6, 0 = no compression, 9 maximum compression
$connected : bool: Indicates whether the server is connected
$connectionTimeout : int: limit in seconds (default is 0 meaning unlimited)
$context : string: The current application context
$database : int: Number of selected database, defaults to 0
$defaultLifetime : int: Default lifetime of a cache entry in seconds
$hostname : string: Hostname / IP of the Redis server, defaults to 127.0.0.1.
$password : string: Password for redis authentication
$persistentConnection : bool: Persistent connection
$port : int: Port of the Redis server, defaults to 6379
$redis : Redis: Instance of the PHP redis class

Methods

__construct() : mixed: Construct this backend
collectGarbage() : mixed: With the current internal structure, only the identifier to data entries have a redis internal lifetime. If an entry expires, attached identifier to tags and tag to identifiers entries will be left over.
findIdentifiersByTag() : array<string|int, mixed>: Finds and returns all cache entry identifiers which are tagged by the specified tag.
flush() : mixed: Removes all cache entries of this cache.
flushByTag() : mixed: Removes all cache entries of this cache which are tagged with the specified tag.
flushByTags() : mixed: Backwards compatibility safeguard since re-introducing flushByTags as API.
get() : mixed: Loads data from the cache.
has() : bool: Checks if a cache entry with the specified identifier exists.
initializeObject() : mixed: Initializes the redis backend
remove() : bool: Removes all cache entries matching the specified identifier.
set() : mixed: Save data in the cache
setCache() : mixed: Sets a reference to the cache frontend which uses this backend
setCompression() : mixed: Enable data compression
setCompressionLevel() : mixed: Set data compression level.
setConnectionTimeout() : mixed: Set connection timeout.
setDatabase() : mixed: Setter for database number
setDefaultLifetime() : mixed: Sets the default lifetime for this cache backend
setHostname() : mixed: Setter for server hostname
setPassword() : mixed: Setter for authentication password
setPersistentConnection() : mixed: Setter for persistent connection
setPort() : mixed: Setter for server port
calculateExpiryTime() : DateTime: Calculates the expiry time by the given lifetime. If no lifetime is specified, the default lifetime is used.
canBeUsedInStringContext() : bool: Helper method to catch invalid identifiers and tags
removeIdentifierEntriesAndRelations() : mixed: Helper method for flushByTag() Gets list of identifiers and tags and removes all relations of those tags

DATETIME_EXPIRYTIME_UNLIMITED


    public
        mixed
    DATETIME_EXPIRYTIME_UNLIMITED
    = '9999-12-31T23:59:59+0000'

FAKED_UNLIMITED_LIFETIME

Faked unlimited lifetime = 31536000 (1 Year).


    public
        int
    FAKED_UNLIMITED_LIFETIME
    = 31536000

In redis an entry does not have a lifetime by default (it's not "volatile"). Entries can be made volatile either with EXPIRE after it has been SET, or with SETEX, which is a combined SET and EXPIRE command. But an entry can not be made "unvolatile" again. To set a volatile entry to not volatile again, it must be DELeted and SET without a following EXPIRE. To save these additional calls on every set(), we just make every entry volatile and treat a high number as "unlimited"

Faked unlimited lifetime

IDENTIFIER_DATA_PREFIX

Key prefix for identifier->data entries


    public
        string
    IDENTIFIER_DATA_PREFIX
    = 'identData:'

IDENTIFIER_TAGS_PREFIX

Key prefix for identifier->tags sets


    public
        string
    IDENTIFIER_TAGS_PREFIX
    = 'identTags:'

TAG_IDENTIFIERS_PREFIX

Key prefix for tag->identifiers sets


    public
        string
    TAG_IDENTIFIERS_PREFIX
    = 'tagIdents:'

UNLIMITED_LIFETIME


    public
        mixed
    UNLIMITED_LIFETIME
    = 0

$cache

Reference to the cache which uses this backend


    protected
        FrontendInterface
    $cache

$cacheIdentifier


    protected
        string
    $cacheIdentifier

$compression

Indicates whether data is compressed or not (requires php zlib)


    protected
        bool
    $compression
     = false

$compressionLevel

-1 to 9, indicates zlib compression level: -1 = default level 6, 0 = no compression, 9 maximum compression


    protected
        int
    $compressionLevel
     = -1

$connected

Indicates whether the server is connected


    protected
        bool
    $connected
     = false

$connectionTimeout

limit in seconds (default is 0 meaning unlimited)


    protected
        int
    $connectionTimeout
     = 0

$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.

$database

Number of selected database, defaults to 0


    protected
        int
    $database
     = 0

$defaultLifetime

Default lifetime of a cache entry in seconds


    protected
        int
    $defaultLifetime
     = 3600

$hostname

Hostname / IP of the Redis server, defaults to 127.0.0.1.


    protected
        string
    $hostname
     = '127.0.0.1'

$password

Password for redis authentication


    protected
        string
    $password
     = ''

$persistentConnection

Persistent connection


    protected
        bool
    $persistentConnection
     = false

$port

Port of the Redis server, defaults to 6379


    protected
        int
    $port
     = 6379

$redis

Instance of the PHP redis class


    protected
        Redis
    $redis

__construct()

Construct 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

collectGarbage()

With the current internal structure, only the identifier to data entries have a redis internal lifetime. If an entry expires, attached identifier to tags and tag to identifiers entries will be left over.


    public
                    collectGarbage() : mixed

This methods finds those entries and cleans them up.

Scales O(n*m) with number of cache entries (n) and number of tags (m)

findIdentifiersByTag()

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


    public
                    findIdentifiersByTag(string $tag) : array<string|int, mixed>

Scales O(1) with number of cache entries Scales O(n) with number of tag entries

Parameters

$tag : string: The tag to search for

Return values

array<string|int, mixed> —

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

flush()

Removes all cache entries of this cache.


    public
                    flush() : mixed

Scales O(1) with number of cache entries

flushByTag()

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


    public
                    flushByTag(string $tag) : mixed

Scales O(1) with number of cache entries Scales O(n^2) with number of tag entries

Parameters

$tag : string: Tag the entries must have

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()

Loads data from the cache.


    public
                    get(string $entryIdentifier) : mixed

Scales O(1) with number of cache entries

Parameters

$entryIdentifier : string: An identifier which describes the cache entry to load

Return values

mixed —

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

has()

Checks if a cache entry with the specified identifier exists.


    public
                    has(string $entryIdentifier) : bool

Scales O(1) with number of cache entries

Parameters

$entryIdentifier : string: Identifier specifying the cache entry

Return values

bool —

TRUE if such an entry exists, FALSE if not

initializeObject()

Initializes the redis backend


    public
                    initializeObject() : mixed

remove()

Removes all cache entries matching the specified identifier.


    public
                    remove(string $entryIdentifier) : bool

Scales O(1) with number of cache entries Scales O(n) with number of tags

Parameters

$entryIdentifier : string: Specifies the cache entry to remove

Return values

bool —

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

set()

Save data in the cache


    public
                    set(string $entryIdentifier, string $data[, array<string|int, mixed> $tags = [] ][, int $lifetime = null ]) : mixed

Scales O(1) with number of cache entries Scales O(n) with number of tags

Parameters

$entryIdentifier : string: Identifier for this specific cache entry
$data : string: Data to be stored
$tags : array<string|int, mixed> = []: Tags to associate with this cache entry
$lifetime : int = null: Lifetime of this cache entry in seconds. If NULL is specified, default lifetime is used. "0" means unlimited lifetime.

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()

Enable data compression


    public
                    setCompression(bool $compression) : mixed

Parameters

$compression : bool: TRUE to enable compression

setCompressionLevel()

Set data compression level.


    public
                    setCompressionLevel(int $compressionLevel) : mixed

If compression is enabled and this is not set, gzcompress default level will be used.

Parameters

$compressionLevel : int: -1 to 9: Compression level

setConnectionTimeout()

Set connection timeout.


    public
                    setConnectionTimeout(int $connectionTimeout) : mixed

This value in seconds is used as a maximum number of seconds to wait if a connection can be established.

Parameters

$connectionTimeout : int: limit in seconds, a value greater or equal than 0

setDatabase()

Setter for database number


    public
                    setDatabase(int $database) : mixed

Parameters

$database : int: Database

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.

setHostname()

Setter for server hostname


    public
                    setHostname(string $hostname) : mixed

Parameters

$hostname : string: Hostname

setPassword()

Setter for authentication password


    public
                    setPassword(string $password) : mixed

Parameters

$password : string: Password

setPersistentConnection()

Setter for persistent connection


    public
                    setPersistentConnection(bool $persistentConnection) : mixed

Parameters

$persistentConnection : bool

setPort()

Setter for server port


    public
                    setPort(int $port) : mixed

Parameters

$port : int: Port

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

canBeUsedInStringContext()

Helper method to catch invalid identifiers and tags


    protected
                    canBeUsedInStringContext(mixed $variable) : bool

Parameters

$variable : mixed: Variable to be checked

Return values

bool

removeIdentifierEntriesAndRelations()

Helper method for flushByTag() Gets list of identifiers and tags and removes all relations of those tags


    protected
                    removeIdentifierEntriesAndRelations(array<string|int, mixed> $identifiers, array<string|int, mixed> $tags) : mixed

Scales O(1) with number of cache entries Scales O(n^2) with number of tags

Parameters

$identifiers : array<string|int, mixed>: List of identifiers to remove
$tags : array<string|int, mixed>: List of tags to be handled

RedisBackend extends AbstractBackend implements TaggableBackendInterface

Tags

Table of Contents

Interfaces

Constants

Properties

Methods

Constants

DATETIME_EXPIRYTIME_UNLIMITED

FAKED_UNLIMITED_LIFETIME

Tags

IDENTIFIER_DATA_PREFIX

IDENTIFIER_TAGS_PREFIX

TAG_IDENTIFIERS_PREFIX

UNLIMITED_LIFETIME

Properties

$cache

$cacheIdentifier

$compression

$compressionLevel

$connected

$connectionTimeout

$context

$database

$defaultLifetime

$hostname

$password

$persistentConnection

$port

$redis

Methods

__construct()

Parameters

Tags

collectGarbage()

findIdentifiersByTag()

Parameters

Tags

Return values

flush()

flushByTag()

Parameters

Tags

flushByTags()

Parameters

get()

Parameters

Tags

Return values

has()

Parameters

Tags

Return values

initializeObject()

Tags

remove()

Parameters

Tags

Return values

set()

Parameters

Tags

setCache()

Parameters

setCompression()

Parameters

Tags

setCompressionLevel()

Parameters

Tags

setConnectionTimeout()

Parameters

Tags

setDatabase()

Parameters

Tags

setDefaultLifetime()

Parameters

Tags

setHostname()