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PHP Class Prado\Caching\TDbCache

TDbCache implements a cache application module by storing cached data in a database. TDbCache relies on {@link http://www.php.net/manual/en/ref.pdo.php PDO} to retrieve data from databases. In order to use TDbCache, you need to enable the PDO extension as well as the corresponding PDO DB driver. For example, to use SQLite database to store cached data, you need both php_pdo and php_pdo_sqlite extensions. By default, TDbCache creates and uses an SQLite database under the application runtime directory. You may change this default setting by specifying the following properties: - {@link setConnectionID ConnectionID} or - {@link setConnectionString ConnectionString}, {@link setUsername Username} and {@link setPassword Pasword}. The cached data is stored in a table in the specified database. By default, the name of the table is called 'pradocache'. If the table does not exist in the database, it will be automatically created with the following structure: CREATE TABLE pradocache (itemkey CHAR(128), value BLOB, expire INT) CREATE INDEX IX_itemkey ON pradocache (itemkey) CREATE INDEX IX_expire ON pradocache (expire) Note, some DBMS might not support BLOB type. In this case, replace 'BLOB' with a suitable binary data type (e.g. LONGBLOB in MySQL, BYTEA in PostgreSQL.) Important: Make sure that the indices are non-unique! If you want to change the cache table name, or if you want to create the table by yourself, you may set {@link setCacheTableName CacheTableName} and {@link setAutoCreateCacheTable AutoCreateCacheTableName} properties. {@link setFlushInterval FlushInterval} control how often expired items will be removed from cache. If you prefer to remove expired items manualy e.g. via cronjob you can disable automatic deletion by setting FlushInterval to '0'. The following basic cache operations are implemented: - {@link get} : retrieve the value with a key (if any) from cache - {@link set} : store the value with a key into cache - {@link add} : store the value only if cache does not have this key - {@link delete} : delete the value with the specified key from cache - {@link flush} : delete all values from cache Each value is associated with an expiration time. The {@link get} operation ensures that any expired value will not be returned. The expiration time by the number of seconds. A expiration time 0 represents never expire. By definition, cache does not ensure the existence of a value even if it never expires. Cache is not meant to be an persistent storage. Do not use the same database file for multiple applications using TDbCache. Also note, cache is shared by all user sessions of an application. Some usage examples of TDbCache are as follows, $cache=new TDbCache; // TDbCache may also be loaded as a Prado application module $cache->init(null); $cache->add('object',$object); $object2=$cache->get('object'); If loaded, TDbCache will register itself with {@link TApplication} as the cache module. It can be accessed via {@link TApplication::getCache()}. TDbCache may be configured in application configuration file as follows Show file Open project: pradosoft/prado

Public Methods

Method	Description
__destruct ( )	Destructor.
doFlushCacheExpired ( ) : void	Event listener for TApplication.OnSaveState
doInitializeCache ( ) : void	Event listener for TApplication.OnLoadStateComplete
flush ( )	Deletes all values from cache.
flushCacheExpired ( $force = false ) : void	Flush expired values from cache depending on {@link setFlushInterval FlushInterval}
getAutoCreateCacheTable ( ) : boolean
getCacheTableName ( ) : string
getConnectionID ( ) : string
getConnectionString ( ) : string
getDbConnection ( ) : TDbConnection
getFlushInterval ( ) : integer
getPassword ( ) : string
getUsername ( ) : string
init ( $config )	Initializes this module.
setAutoCreateCacheTable ( $value )
setCacheTableName ( $value )	Sets the name of the DB table to store cache content.
setConnectionID ( $value )	Sets the ID of a TDataSourceConfig module.
setConnectionString ( $value )
setFlushInterval ( $value )	Sets interval expired items will be removed from cache
setPassword ( $value )
setUsername ( $value )

Protected Methods

Method	Description
addValue ( $key, $value, $expire ) : boolean	Stores a value identified by a key into cache if the cache does not contain this key.
createDbConnection ( ) : TDbConnection	Creates the DB connection.
deleteValue ( $key ) : boolean	Deletes a value with the specified key from cache This is the implementation of the method declared in the parent class.
getValue ( $key ) : string	Retrieves a value from cache with a specified key.
initializeCache ( $force = false ) : void	Initialize TDbCache
setValue ( $key, $value, $expire ) : boolean	Stores a value identified by a key in cache.

Method Details