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<?php
// +----------------------------------------------------------------------+
// | PEAR :: Cache |
// +----------------------------------------------------------------------+
// | Copyright (c) 1997-2003 The PHP Group |
// +----------------------------------------------------------------------+
// | This source file is subject to version 2.0 of the PHP license, |
// | that is bundled with this package in the file LICENSE, and is |
// | available at through the world-wide-web at |
// | http://www.php.net/license/2_02.txt. |
// | If you did not receive a copy of the PHP license and are unable to |
// | obtain it through the world-wide-web, please send a note to |
// | license@php.net so we can mail you a copy immediately. |
// +----------------------------------------------------------------------+
// | Authors: Ulf Wendel <ulf.wendel@phpdoc.de> |
// | Sebastian Bergmann <sb@sebastian-bergmann.de> |
// +----------------------------------------------------------------------+
//
// $Id: phplib.php,v 1.3 2003/01/04 11:54:46 mj Exp $
require_once 'Cache/Container.php';
/**
* Stores cache data into a database table using PHPLibs DB abstraction.
*
* WARNING: Other systems might or might not support certain datatypes of
* the tables shown. As far as I know there's no large binary
* type in SQL-92 or SQL-99. Postgres seems to lack any
* BLOB or TEXT type, for MS-SQL you could use IMAGE, don't know
* about other databases. Please add sugestions for other databases to
* the inline docs.
*
* The field 'changed' is used by the garbage collection. Depending on
* your databasesystem you might have to subclass fetch() and garbageCollection().
*
* For _MySQL_ you need this DB table:
*
* CREATE TABLE cache (
* id CHAR(32) NOT NULL DEFAULT '',
* cachegroup VARCHAR(127) NOT NULL DEFAULT '',
* cachedata BLOB NOT NULL DEFAULT '',
* userdata VARCHAR(255) NOT NULL DEFAUL '',
* expires INT(9) NOT NULL DEFAULT 0,
*
* changed TIMESTAMP(14) NOT NULL,
*
* INDEX (expires),
* PRIMARY KEY (id, cachegroup)
* )
*
*
* @author Ulf Wendel <ulf.wendel@phpdoc.de>, Sebastian Bergmann <sb@sebastian-bergmann.de>
* @version $Id: phplib.php,v 1.3 2003/01/04 11:54:46 mj Exp $
* @package Cache
* @see save()
*/
class Cache_Container_phplib extends Cache_Container {
/**
* Name of the DB table to store caching data
*
* @see Cache_Container_file::$filename_prefix
*/
var $cache_table = 'cache';
/**
* PHPLib object
*
* @var object PEAR_DB
*/
var $db;
/**
* Name of the PHPLib DB class to use
*
* @var string
* @see $db_path, $local_path
*/
var $db_class = '';
/**
* Filename of your local.inc
*
* If empty, 'local.inc' is assumed.
*
* @var string
*/
var $local_file = '';
/**
* Include path for you local.inc
*
* HINT: If your're not using PHPLib's prepend.php you must
* take care that all classes (files) references by you
* local.inc are included automatically. So you might
* want to write a new local2.inc that only referrs to
* the database class (file) you're using and includes all required files.
*
* @var string path to your local.inc - make sure to add a trailing slash
* @see $local_file
*/
var $local_path = '';
/**
* Creates an instance of a phplib db class to use it for storage.
*
* @param mixed If empty the object tries to used the
* preconfigured class variables. If given it
* must be an array with:
* db_class => name of the DB class to use
* optional:
* db_file => filename of the DB class
* db_path => path to the DB class
* local_file => kind of local.inc
* local_patk => path to the local.inc
* see $local_path for some hints.s
* @see $local_path
*/
function Cache_Container_phplib($options = '') {
if (is_array($options))
$this->setOptions($options, array_merge($this->allowed_options, array('db_class', 'db_file', 'db_path', 'local_file', 'local_path')));
if (!$this->db_class)
return new Cache_Error('No database class specified.', __FILE__, __LINE__);
// include the required files
if ($this->db_file)
include_once($this->db_path . $this->db_file);
if ($this->local_file)
include_once($this->local_path . $this->local_file);
// create a db object
$this->db = new $this->db_class;
} // end constructor
function fetch($id, $group) {
$query = sprintf("SELECT expires, cachedata, userdata FROM %s WHERE id = '%s' AND cachegroup = '%s'",
$this->cache_table,
$id,
$group
);
$this->db->query($query);
if (!$this->db->Next_Record())
return array(NULL, NULL, NULL);
// last used required by the garbage collection
// WARNING: might be MySQL specific
$query = sprintf("UPDATE %s SET changed = (NOW() + 0) WHERE id = '%s' AND cachegroup = '%s'",
$this->cache_table,
$id,
$group
);
$this->db->query($query);
return array($this->db->f('expires'), $this->decode($this->db->f('cachedata')), $this->db->f('userdata'));
} // end func fetch
/**
* Stores a dataset.
*
* WARNING: we use the SQL command REPLACE INTO this might be
* MySQL specific. As MySQL is very popular the method should
* work fine for 95% of you.
*/
function save($id, $data, $expires, $group) {
$this->flushPreload($id, $group);
$query = sprintf("REPLACE INTO %s (cachedata, expires, id, cachegroup) VALUES ('%s', %d, '%s', '%s')",
$this->cache_table,
addslashes($this->encode($data)),
$this->getExpiresAbsolute($expires) ,
$id,
$group
);
$this->db->query($query);
return (boolean)$this->db->affected_rows();
} // end func save
function remove($id, $group) {
$this->flushPreload($id, $group);
$this->db->query(
sprintf("DELETE FROM %s WHERE id = '%s' AND cachegroup = '%s'",
$this->cache_table,
$id,
$group
)
);
return (boolean)$this->db->affected_rows();
} // end func remove
function flush($group) {
$this->flushPreload();
if ($group) {
$this->db->query(sprintf("DELETE FROM %s WHERE cachegroup = '%s'", $this->cache_table, $group));
} else {
$this->db->query(sprintf("DELETE FROM %s", $this->cache_table));
}
return $this->db->affected_rows();
} // end func flush
function idExists($id, $group) {
$this->db->query(
sprintf("SELECT id FROM %s WHERE ID = '%s' AND cachegroup = '%s'",
$this->cache_table,
$id,
$group
)
);
return (boolean)$this->db->nf();
} // end func isExists
function garbageCollection($maxlifetime) {
$this->flushPreload();
$this->db->query(
sprintf("DELETE FROM %s WHERE (expires <= %d AND expires > 0) OR changed <= (NOW() - %d)",
$this->cache_table,
time(),
$maxlifetime
)
);
//check for total size of cache
$query = sprintf('select sum(length(cachedata)) as CacheSize from %s',
$this->cache_table
);
$this->db->query($query);
$this->db->Next_Record();
$cachesize = $this->db->f('CacheSize');
//if cache is to big.
if ($cachesize > $this->highwater)
{
//find the lowwater mark.
$query = sprintf('select length(cachedata) as size, changed from %s order by changed DESC',
$this->cache_table
);
$this->db->query($query);
$keep_size=0;
while ($keep_size < $this->lowwater && $this->db->Next_Record() )
{
$keep_size += $this->db->f('size');
}
//delete all entries, which were changed before the "lowwwater mark"
$query = sprintf('delete from %s where changed <= '.$this->db->f('changed'),
$this->cache_table
);
$this->db->query($query);
}
} // end func garbageCollection
}
?>
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