Search moodle.org's
Developer Documentation

See Release Notes

  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.

The library file for the session cache store. This file is part of the session cache store, it contains the API for interacting with an instance of the store. This is used as a default cache store within the Cache API. It should never be deleted.

Copyright: 2012 Sam Hemelryk
License: http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
File Size: 595 lines (18 kb)
Included or required:0 times
Referenced: 0 times
Includes or requires: 0 files

Defines 2 classes

session_data_store:: (3 methods):
  register_store_id()
  flush_store_by_id()
  flush_store()

cachestore_session:: (28 methods):
  __construct()
  get_supported_features()
  supports_multiple_identifiers()
  get_supported_modes()
  are_requirements_met()
  is_supported_mode()
  initialise()
  is_initialised()
  get()
  get_many()
  set()
  set_many()
  has()
  has_all()
  has_any()
  delete()
  delete_many()
  purge()
  reduce_for_maxsize()
  can_add_instance()
  instance_deleted()
  initialise_test_instance()
  unit_test_configuration()
  my_name()
  check_ttl()
  find_all()
  find_by_prefix()
  store_supports_native_ttl()


Class: session_data_store  - X-Ref

The session data store class.

register_store_id($id)   X-Ref
Returns a static store by reference... REFERENCE SUPER IMPORTANT.

param: string $id
return: array

flush_store_by_id($id)   X-Ref
Flushes the data belong to the given store id.

param: string $id

flush_store()   X-Ref
Flushes the store of all data.


Class: cachestore_session  - X-Ref

The Session store class.

__construct($name, array $configuration = array()   X-Ref
Constructs the store instance.

Noting that this function is not an initialisation. It is used to prepare the store for use.
The store will be initialised when required and will be provided with a cache_definition at that time.

param: string $name
param: array $configuration

get_supported_features(array $configuration = array()   X-Ref
Returns the supported features as a combined int.

param: array $configuration
return: int

supports_multiple_identifiers()   X-Ref
Returns false as this store does not support multiple identifiers.
(This optional function is a performance optimisation; it must be
consistent with the value from get_supported_features.)

return: bool False

get_supported_modes(array $configuration = array()   X-Ref
Returns the supported modes as a combined int.

param: array $configuration
return: int

are_requirements_met()   X-Ref
Returns true if the store requirements are met.

return: bool

is_supported_mode($mode)   X-Ref
Returns true if the given mode is supported by this store.

param: int $mode One of cache_store::MODE_*
return: bool

initialise(cache_definition $definition)   X-Ref
Initialises the cache.

Once this has been done the cache is all set to be used.

param: cache_definition $definition

is_initialised()   X-Ref
Returns true once this instance has been initialised.

return: bool

get($key)   X-Ref
Retrieves an item from the cache store given its key.

param: string $key The key to retrieve
return: mixed The data that was associated with the key, or false if the key did not exist.

get_many($keys)   X-Ref
Retrieves several items from the cache store in a single transaction.

If not all of the items are available in the cache then the data value for those that are missing will be set to false.

param: array $keys The array of keys to retrieve
return: array An array of items from the cache. There will be an item for each key, those that were not in the store will

set($key, $data, $testmaxsize = true)   X-Ref
Sets an item in the cache given its key and data value.

param: string $key The key to use.
param: mixed $data The data to set.
param: bool $testmaxsize If set to true then we test the maxsize arg and reduce if required. If this is set to false you will
return: bool True if the operation was a success false otherwise.

set_many(array $keyvaluearray)   X-Ref
Sets many items in the cache in a single transaction.

param: array $keyvaluearray An array of key value pairs. Each item in the array will be an associative array with two
return: int The number of items successfully set. It is up to the developer to check this matches the number of items

has($key)   X-Ref
Checks if the store has a record for the given key and returns true if so.

param: string $key
return: bool

has_all(array $keys)   X-Ref
Returns true if the store contains records for all of the given keys.

param: array $keys
return: bool

has_any(array $keys)   X-Ref
Returns true if the store contains records for any of the given keys.

param: array $keys
return: bool

delete($key)   X-Ref
Deletes an item from the cache store.

param: string $key The key to delete.
return: bool Returns true if the operation was a success, false otherwise.

delete_many(array $keys)   X-Ref
Deletes several keys from the cache in a single action.

param: array $keys The keys to delete
return: int The number of items successfully deleted.

purge()   X-Ref
Purges the cache deleting all items within it.

return: boolean True on success. False otherwise.

reduce_for_maxsize()   X-Ref
Reduces the size of the array if maxsize has been hit.

This function reduces the size of the store reducing it by 10% of its maxsize.
It removes the oldest items in the store when doing this.
The reason it does this an doesn't use a least recently used system is purely the overhead such a system
requires. The current approach is focused on speed, MUC already adds enough overhead to static/session caches
and avoiding more is of benefit.

return: int

can_add_instance()   X-Ref
Returns true if the user can add an instance of the store plugin.

return: bool

instance_deleted()   X-Ref
Performs any necessary clean up when the store instance is being deleted.


initialise_test_instance(cache_definition $definition)   X-Ref
Generates an instance of the cache store that can be used for testing.

param: cache_definition $definition
return: cachestore_session

unit_test_configuration()   X-Ref
Generates the appropriate configuration required for unit testing.

return: array Array of unit test configuration data to be used by initialise().

my_name()   X-Ref
Returns the name of this instance.

return: string

check_ttl()   X-Ref
Removes expired elements.

return: int number of removed elements

find_all()   X-Ref
Finds all of the keys being stored in the cache store instance.

return: array

find_by_prefix($prefix)   X-Ref
Finds all of the keys whose keys start with the given prefix.

param: string $prefix
return: array An array of keys.

store_supports_native_ttl()   X-Ref
This store supports native TTL handling.

return: bool