diff options
Diffstat (limited to 'lib/prado/framework/Caching/TSqliteCache.php')
| -rw-r--r-- | lib/prado/framework/Caching/TSqliteCache.php | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/lib/prado/framework/Caching/TSqliteCache.php b/lib/prado/framework/Caching/TSqliteCache.php new file mode 100644 index 0000000..8451a9e --- /dev/null +++ b/lib/prado/framework/Caching/TSqliteCache.php @@ -0,0 +1,222 @@ +<?php +/** + * TSqliteCache class file + * + * @author Qiang Xue <qiang.xue@gmail.com> + * @link https://github.com/pradosoft/prado + * @copyright Copyright © 2005-2015 The PRADO Group + * @license https://github.com/pradosoft/prado/blob/master/COPYRIGHT + * @package System.Caching + */ + +/** + * TSqliteCache class + * + * TSqliteCache implements a cache application module based on SQLite database. + * + * THIS CLASS IS DEPRECATED since it relies on the sqlite PHP extension, that is + * no longer loaded by default since PHP 5.1. You are discouraged from using it: + * use {@link TDbCache} instead. + * + * Since PRADO v3.1.0, a new DB-based cache module called {@link TDbCache} + * is provided. If you have PDO extension installed, you may consider using + * the new cache module instead as it allows you to use different database + * to store the cached data. + * + * The database file is specified by the {@link setDbFile DbFile} property. + * If not set, the database file will be created under the system state path. + * If the specified database file does not exist, it will be created automatically. + * Make sure the directory containing the specified DB file and the file itself is + * writable by the Web server process. + * + * 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 TSqliteCache. + * Also note, cache is shared by all user sessions of an application. + * + * Some usage examples of TSqliteCache are as follows, + * <code> + * $cache=new TSqliteCache; // TSqliteCache may also be loaded as a Prado application module + * $cache->setDbFile($dbFilePath); + * $cache->init(null); + * $cache->add('object',$object); + * $object2=$cache->get('object'); + * </code> + * + * If loaded, TSqliteCache will register itself with {@link TApplication} as the + * cache module. It can be accessed via {@link TApplication::getCache()}. + * + * TSqliteCache may be configured in application configuration file as follows + * <code> + * <module id="cache" class="System.Caching.TSqliteCache" DbFile="Application.Data.site" /> + * </code> + * where {@link getDbFile DbFile} is a property specifying the location of the + * SQLite DB file (in the namespace format). + * + * @author Qiang Xue <qiang.xue@gmail.com> + * @package System.Caching + * @since 3.0 + */ +class TSqliteCache extends TCache +{ + /** + * name of the table storing cache data + */ + const CACHE_TABLE='cache'; + /** + * extension of the db file name + */ + const DB_FILE_EXT='.db'; + + /** + * @var boolean if the module has been initialized + */ + private $_initialized=false; + /** + * @var SQLiteDatabase the sqlite database instance + */ + private $_db=null; + /** + * @var string the database file name + */ + private $_file=null; + + /** + * Destructor. + * Disconnect the db connection. + */ + public function __destruct() + { + $this->_db=null; + } + + /** + * Initializes this module. + * This method is required by the IModule interface. It checks if the DbFile + * property is set, and creates a SQLiteDatabase instance for it. + * The database or the cache table does not exist, they will be created. + * Expired values are also deleted. + * @param TXmlElement configuration for this module, can be null + * @throws TConfigurationException if sqlite extension is not installed, + * DbFile is set invalid, or any error happens during creating database or cache table. + */ + public function init($config) + { + if(!function_exists('sqlite_open')) + throw new TConfigurationException('sqlitecache_extension_required'); + if($this->_file===null) + $this->_file=$this->getApplication()->getRuntimePath().'/sqlite.cache'; + $error=''; + if(($this->_db=new SQLiteDatabase($this->_file,0666,$error))===false) + throw new TConfigurationException('sqlitecache_connection_failed',$error); + if(@$this->_db->query('DELETE FROM '.self::CACHE_TABLE.' WHERE expire<>0 AND expire<'.time())===false) + { + if($this->_db->query('CREATE TABLE '.self::CACHE_TABLE.' (key CHAR(128) PRIMARY KEY, value BLOB, expire INT)')===false) + throw new TConfigurationException('sqlitecache_table_creation_failed',sqlite_error_string(sqlite_last_error())); + } + $this->_initialized=true; + parent::init($config); + } + + /** + * @return string database file path (in namespace form) + */ + public function getDbFile() + { + return $this->_file; + } + + /** + * @param string database file path (in namespace form) + * @throws TInvalidOperationException if the module is already initialized + * @throws TConfigurationException if the file is not in proper namespace format + */ + public function setDbFile($value) + { + if($this->_initialized) + throw new TInvalidOperationException('sqlitecache_dbfile_unchangeable'); + else if(($this->_file=Prado::getPathOfNamespace($value,self::DB_FILE_EXT))===null) + throw new TConfigurationException('sqlitecache_dbfile_invalid',$value); + } + + /** + * Retrieves a value from cache with a specified key. + * This is the implementation of the method declared in the parent class. + * @param string a unique key identifying the cached value + * @return string the value stored in cache, false if the value is not in the cache or expired. + */ + protected function getValue($key) + { + $sql='SELECT value FROM '.self::CACHE_TABLE.' WHERE key=\''.$key.'\' AND (expire=0 OR expire>'.time().') LIMIT 1'; + if(($ret=$this->_db->query($sql))!=false && ($row=$ret->fetch(SQLITE_ASSOC))!==false) + return unserialize($row['value']); + else + return false; + } + + /** + * Stores a value identified by a key in cache. + * This is the implementation of the method declared in the parent class. + * + * @param string the key identifying the value to be cached + * @param string the value to be cached + * @param integer the number of seconds in which the cached value will expire. 0 means never expire. + * @return boolean true if the value is successfully stored into cache, false otherwise + */ + protected function setValue($key,$value,$expire) + { + $expire=($expire<=0)?0:time()+$expire; + $sql='REPLACE INTO '.self::CACHE_TABLE.' VALUES(\''.$key.'\',\''.sqlite_escape_string(serialize($value)).'\','.$expire.')'; + return $this->_db->query($sql)!==false; + } + + /** + * Stores a value identified by a key into cache if the cache does not contain this key. + * This is the implementation of the method declared in the parent class. + * + * @param string the key identifying the value to be cached + * @param string the value to be cached + * @param integer the number of seconds in which the cached value will expire. 0 means never expire. + * @return boolean true if the value is successfully stored into cache, false otherwise + */ + protected function addValue($key,$value,$expire) + { + $expire=($expire<=0)?0:time()+$expire; + $sql='INSERT INTO '.self::CACHE_TABLE.' VALUES(\''.$key.'\',\''.sqlite_escape_string(serialize($value)).'\','.$expire.')'; + return @$this->_db->query($sql)!==false; + } + + /** + * Deletes a value with the specified key from cache + * This is the implementation of the method declared in the parent class. + * @param string the key of the value to be deleted + * @return boolean if no error happens during deletion + */ + protected function deleteValue($key) + { + $sql='DELETE FROM '.self::CACHE_TABLE.' WHERE key=\''.$key.'\''; + return $this->_db->query($sql)!==false; + } + + /** + * Deletes all values from cache. + * Be careful of performing this operation if the cache is shared by multiple applications. + */ + public function flush() + { + return $this->_db->query('DELETE FROM '.self::CACHE_TABLE)!==false; + } +} + |