File Source for Lite.php

<?php
/**
* Fast, light and safe Cache Class
*
* Cache_Lite is a fast, light and safe cache system. It's optimized
* for file containers. It is fast and safe (because it uses file
* locking and/or anti-corruption tests).
*
* There are some examples in the 'docs/examples' file
* Technical choices are described in the 'docs/technical' file
*
* A tutorial is available in english at this url :
* http://www.pearfr.org/index.php/en/article/cache_lite
* (big thanks to Pierre-Alain Joye for the translation)
*
* The same tutorial is also available in french at this url :
* http://www.pearfr.org/index.php/fr/article/cache_lite
*
* Memory Caching is from an original idea of
* Mike BENOIT <ipso@snappymail.ca>
*
* @package Cache_Lite
* @category Caching
* @version $Id: Lite.php,v 1.1 2005/07/22 01:57:12 eddieajau Exp $
* @author Fabien MARTY <fab@php.net>
*/
define('CACHE_LITE_ERROR_RETURN', 1);
define('CACHE_LITE_ERROR_DIE', 8);
class Cache_Lite
{
// --- Private properties ---
/**
* Directory where to put the cache files
* (make sure to add a trailing slash)
*
* @var string $_cacheDir
*/
var $_cacheDir = '/tmp/';
/**
* Enable / disable caching
*
* (can be very usefull for the debug of cached scripts)
*
* @var boolean $_caching
*/
var $_caching = true;
/**
* Cache lifetime (in seconds)
*
* @var int $_lifeTime
*/
var $_lifeTime = 3600;
/**
* Enable / disable fileLocking
*
* (can avoid cache corruption under bad circumstances)
*
* @var boolean $_fileLocking
*/
var $_fileLocking = true;
/**
* Timestamp of the last valid cache
*
* @var int $_refreshTime
*/
var $_refreshTime;
/**
* File name (with path)
*
* @var string $_file
*/
var $_file;
/**
* Enable / disable write control (the cache is read just after writing to detect corrupt entries)
*
* Enable write control will lightly slow the cache writing but not the cache reading
* Write control can detect some corrupt cache files but maybe it's not a perfect control
*
* @var boolean $_writeControl
*/
var $_writeControl = true;
/**
* Enable / disable read control
*
* If enabled, a control key is embeded in cache file and this key is compared with the one
* calculated after the reading.
*
* @var boolean $_writeControl
*/
var $_readControl = true;
/**
* Type of read control (only if read control is enabled)
*
* Available values are :
* 'md5' for a md5 hash control (best but slowest)
* 'crc32' for a crc32 hash control (lightly less safe but faster, better choice)
* 'strlen' for a length only test (fastest)
*
* @var boolean $_readControlType
*/
var $_readControlType = 'crc32';
/**
* Pear error mode (when raiseError is called)
*
* (see PEAR doc)
*
* @see setToDebug()
* @var int $_pearErrorMode
*/
var $_pearErrorMode = CACHE_LITE_ERROR_RETURN;
/**
* Current cache id
*
* @var string $_id
*/
var $_id;
/**
* Current cache group
*
* @var string $_group
*/
var $_group;
/**
* Enable / Disable "Memory Caching"
*
* NB : There is no lifetime for memory caching !
*
* @var boolean $_memoryCaching
*/
var $_memoryCaching = false;
/**
* Enable / Disable "Only Memory Caching"
* (be carefull, memory caching is "beta quality")
*
* @var boolean $_onlyMemoryCaching
*/
var $_onlyMemoryCaching = false;
/**
* Memory caching array
*
* @var array $_memoryCachingArray
*/
var $_memoryCachingArray = array();
/**
* Memory caching counter
*
* @var int $memoryCachingCounter
*/
var $_memoryCachingCounter = 0;
/**
* Memory caching limit
*
* @var int $memoryCachingLimit
*/
var $_memoryCachingLimit = 1000;
/**
* File Name protection
*
* if set to true, you can use any cache id or group name
* if set to false, it can be faster but cache ids and group names
* will be used directly in cache file names so be carefull with
* special characters...
*
* @var boolean $fileNameProtection
*/
var $_fileNameProtection = true;
/**
* Enable / disable automatic serialization
*
* it can be used to save directly datas which aren't strings
* (but it's slower)
*
* @var boolean $_serialize
*/
var $_automaticSerialization = false;
// --- Public methods ---
/**
* Constructor
*
* $options is an assoc. Available options are :
* $options = array(
* 'cacheDir' => directory where to put the cache files (string),
* 'caching' => enable / disable caching (boolean),
* 'lifeTime' => cache lifetime in seconds (int),
* 'fileLocking' => enable / disable fileLocking (boolean),
* 'writeControl' => enable / disable write control (boolean),
* 'readControl' => enable / disable read control (boolean),
* 'readControlType' => type of read control 'crc32', 'md5', 'strlen' (string),
* 'pearErrorMode' => pear error mode (when raiseError is called) (cf PEAR doc) (int),
* 'memoryCaching' => enable / disable memory caching (boolean),
* 'onlyMemoryCaching' => enable / disable only memory caching (boolean),
* 'memoryCachingLimit' => max nbr of records to store into memory caching (int),
* 'fileNameProtection' => enable / disable automatic file name protection (boolean),
* 'automaticSerialization' => enable / disable automatic serialization (boolean)
* );
*
* @param array $options options
* @access public
*/
function Cache_Lite($options = array(NULL))
{
$availableOptions = array('automaticSerialization', 'fileNameProtection', 'memoryCaching', 'onlyMemoryCaching', 'memoryCachingLimit', 'cacheDir', 'caching', 'lifeTime', 'fileLocking', 'writeControl', 'readControl', 'readControlType', 'pearErrorMode');
foreach($options as $key => $value) {
if(in_array($key, $availableOptions)) {
$property = '_'.$key;
$this->$property = $value;
}
}
$this->_refreshTime = time() - $this->_lifeTime;
}
/**
* Test if a cache is available and (if yes) return it
*
* @param string $id cache id
* @param string $group name of the cache group
* @param boolean $doNotTestCacheValidity if set to true, the cache validity won't be tested
* @return string data of the cache (or false if no cache available)
* @access public
*/
function get($id, $group = 'default', $doNotTestCacheValidity = false)
{
$this->_id = $id;
$this->_group = $group;
$data = false;
if ($this->_caching) {
$this->_setFileName($id, $group);
if ($this->_memoryCaching) {
if (isset($this->_memoryCachingArray[$this->_file])) {
if ($this->_automaticSerialization) {
return unserialize($this->_memoryCachingArray[$this->_file]);
} else {
return $this->_memoryCachingArray[$this->_file];
}
} else {
if ($this->_onlyMemoryCaching) {
return false;
}
}
}
if ($doNotTestCacheValidity) {
if (file_exists($this->_file)) {
$data = $this->_read();
}
} else {
if (@filemtime($this->_file) > $this->_refreshTime) {
$data = $this->_read();
}
}
if (($data) and ($this->_memoryCaching)) {
$this->_memoryCacheAdd($this->_file, $data);
}
if (($this->_automaticSerialization) and (is_string($data))) {
$data = unserialize($data);
}
return $data;
}
return false;
}
/**
* Save some data in a cache file
*
* @param string $data data to put in cache (can be another type than strings if automaticSerialization is on)
* @param string $id cache id
* @param string $group name of the cache group
* @return boolean true if no problem
* @access public
*/
function save($data, $id = NULL, $group = 'default')
{
if ($this->_caching) {
if ($this->_automaticSerialization) {
$data = serialize($data);
}
if (isset($id)) {
$this->_setFileName($id, $group);
}
if ($this->_memoryCaching) {
$this->_memoryCacheAdd($this->_file, $data);
if ($this->_onlyMemoryCaching) {
return true;
}
}
if ($this->_writeControl) {
if (!$this->_writeAndControl($data)) {
@touch($this->_file, time() - 2*abs($this->_lifeTime));
return false;
} else {
return true;
}
} else {
return $this->_write($data);
}
}
return false;
}
/**
* Remove a cache file
*
* @param string $id cache id
* @param string $group name of the cache group
* @return boolean true if no problem
* @access public
*/
function remove($id, $group = 'default')
{
$this->_setFileName($id, $group);
if (!@unlink($this->_file)) {
$this->raiseError('Cache_Lite : Unable to remove cache !', -3);
return false;
}
return true;
}
/**
* Clean the cache
*
* if no group is specified all cache files will be destroyed
* else only cache files of the specified group will be destroyed
*
* @param string $group name of the cache group
* @return boolean true if no problem
* @access public
*/
function clean($group = false)
{
if ($this->_fileNameProtection) {
$motif = ($group) ? 'cache_'.md5($group).'_' : 'cache_';
} else {
$motif = ($group) ? 'cache_'.$group.'_' : 'cache_';
}
if ($this->_memoryCaching) {
while (list($key, $value) = each($this->_memoryCaching)) {
if (strpos($key, $motif, 0)) {
unset($this->_memoryCaching[$key]);
$this->_memoryCachingCounter = $this->_memoryCachingCounter - 1;
}
}
if ($this->_onlyMemoryCaching) {
return true;
}
}
if (!($dh = opendir($this->_cacheDir))) {
$this->raiseError('Cache_Lite : Unable to open cache directory !', -4);
return false;
}
while ($file = readdir($dh)) {
if (($file != '.') && ($file != '..')) {
$file = $this->_cacheDir . $file;
if (is_file($file)) {
if (strpos($file, $motif, 0)) {
if (!@unlink($file)) {
$this->raiseError('Cache_Lite : Unable to remove cache !', -3);
return false;
}
}
}
}
}
return true;
}
/**
* Set to debug mode
*
* When an error is found, the script will stop and the message will be displayed
* (in debug mode only).
*
* @access public
*/
function setToDebug()
{
$this->_pearErrorMode = CACHE_LITE_ERROR_DIE;
}
/**
* Set a new life time
*
* @param int $newLifeTime new life time (in seconds)
* @access public
*/
function setLifeTime($newLifeTime)
{
$this->_lifeTime = $newLifeTime;
$this->_refreshTime = time() - $newLifeTime;
}
/**
*
* @access public
*/
function saveMemoryCachingState($id, $group = 'default')
{
if ($this->_caching) {
$array = array(
'counter' => $this->_memoryCachingCounter,
'array' => $this->_memoryCachingState
);
$data = serialize($array);
$this->save($data, $id, $group);
}
}
/**
*
* @access public
*/
function getMemoryCachingState($id, $group = 'default', $doNotTestCacheValidity = false)
{
if ($this->_caching) {
if ($data = $this->get($id, $group, $doNotTestCacheValidity)) {
$array = unserialize($data);
$this->_memoryCachingCounter = $array['counter'];
$this->_memoryCachingArray = $array['array'];
}
}
}
/**
* Return the cache last modification time
*
* BE CAREFUL : THIS METHOD IS FOR HACKING ONLY !
*
* @return int last modification time
*/
function lastModified() {
return filemtime($this->_file);
}
/**
* Trigger a PEAR error
*
* To improve performances, the PEAR.php file is included dynamically.
* The file is so included only when an error is triggered. So, in most
* cases, the file isn't included and perfs are much better.
*
* @param string $msg error message
* @param int $code error code
* @access public
*/
function raiseError($msg, $code)
{
include_once(mamboCore::get('mosConfig_absolute_path').'/includes/PEAR/PEAR.php');
PEAR::raiseError($msg, $code, $this->_pearErrorMode);
}
// --- Private methods ---
/**
*
* @access private
*/
function _memoryCacheAdd($id, $data)
{
$this->_memoryCachingArray[$this->_file] = $data;
if ($this->_memoryCachingCounter >= $this->_memoryCachingLimit) {
list($key, $value) = each($this->_memoryCachingArray);
unset($this->_memoryCachingArray[$key]);
} else {
$this->_memoryCachingCounter = $this->_memoryCachingCounter + 1;
}
}
/**
* Make a file name (with path)
*
* @param string $id cache id
* @param string $group name of the group
* @access private
*/
function _setFileName($id, $group)
{
if ($this->_fileNameProtection) {
$this->_file = ($this->_cacheDir.'cache_'.md5($group).'_'.md5($id));
} else {
$this->_file = $this->_cacheDir.'cache_'.$group.'_'.$id;
}
}
/**
* Read the cache file and return the content
*
* @return string content of the cache file
* @access private
*/
function _read()
{
$fp = @fopen($this->_file, "rb");
if ($this->_fileLocking) @flock($fp, LOCK_SH);
if ($fp) {
clearstatcache(); // because the filesize can be cached by PHP itself...
$length = @filesize($this->_file);
$mqr = get_magic_quotes_runtime();
set_magic_quotes_runtime(0);
if ($this->_readControl) {
$hashControl = @fread($fp, 32);
$length = $length - 32;
}
$data = @fread($fp, $length);
set_magic_quotes_runtime($mqr);
if ($this->_fileLocking) @flock($fp, LOCK_UN);
@fclose($fp);
if ($this->_readControl) {
$hashData = $this->_hash($data, $this->_readControlType);
if ($hashData != $hashControl) {
@touch($this->_file, time() - 2*abs($this->_lifeTime));
return false;
}
}
return $data;
}
$this->raiseError('Cache_Lite : Unable to read cache !', -2);
return false;
}
/**
* Write the given data in the cache file
*
* @param string $data data to put in cache
* @return boolean true if ok
* @access private
*/
function _write($data)
{
$fp = @fopen($this->_file, "wb");
if ($fp) {
if ($this->_fileLocking) @flock($fp, LOCK_EX);
if ($this->_readControl) {
@fwrite($fp, $this->_hash($data, $this->_readControlType), 32);
}
$len = strlen($data);
@fwrite($fp, $data, $len);
if ($this->_fileLocking) @flock($fp, LOCK_UN);
@fclose($fp);
return true;
}
$this->raiseError('Cache_Lite : Unable to write cache !', -1);
return false;
}
/**
* Write the given data in the cache file and control it just after to avoir corrupted cache entries
*
* @param string $data data to put in cache
* @return boolean true if the test is ok
* @access private
*/
function _writeAndControl($data)
{
$this->_write($data);
$dataRead = $this->_read($data);
return ($dataRead==$data);
}
/**
* Make a control key with the string containing datas
*
* @param string $data data
* @param string $controlType type of control 'md5', 'crc32' or 'strlen'
* @return string control key
* @access private
*/
function _hash($data, $controlType)
{
switch ($controlType) {
case 'md5':
return md5($data);
case 'crc32':
return sprintf('% 32d', crc32($data));
case 'strlen':
return sprintf('% 32d', strlen($data));
default:
$this->raiseError('Unknown controlType ! (available values are only \'md5\', \'crc32\', \'strlen\')', -5);
}
}
}
?>

Documentation generated on Mon, 05 May 2008 16:20:53 +0400 by phpDocumentor 1.4.0

Source for file Lite.php