Source code for Php Cache class from phpguru

Cache of needless to say, everyone knows, also interviewed some people these days, found a lot of people with more framework, foundation, had forgotten you ask something, he always said framework settled, and don't know what's going on, so also remind everyone should pay attention to the accumulation of basic knowledge, at ordinary times before for some problems.

Some friends in the group also despise the basic knowledge, and always say that it is ok to have the ability, the basic knowledge can not test out anything. For this view, I have always disagreed.
This is just a bit of a metaphor. Here's the main idea: PHP's Cache class:

Post the code: there is also a download address, in fact, it is very simple, the important thing is to learn

<?php 
/** 
* o------------------------------------------------------------------------------o 
* | This package is licensed under the Phpguru license. A quick summary is | 
* | that for commercial use, there is a small one-time licensing fee to pay. For | 
* | registered charities and educational institutes there is a reduced license | 
* | fee available. You can read more at: | 
* | | 
* | http://www.phpguru.org/static/license.html | 
* o------------------------------------------------------------------------------o 
*/ 
/** 
* Caching Libraries for PHP5 
* 
* Handles data and output caching. Defaults to /dev/shm 
* (shared memory). All methods are static. 
* 
* Eg: (output caching) 
* 
* if (!OutputCache::Start('group', 'unique id', 600)) { 
* 
* // ... Output 
* 
* OutputCache::End(); 
* } 
* 
* Eg: (data caching) 
* 
* if (!$data = DataCache::Get('group', 'unique id')) { 
* 
* $data = time(); 
* 
* DataCache::Put('group', 'unique id', 10, $data); 
* } 
* 
* echo $data; 
*/ 
class Cache 
{ 
 
public static $enabled = true; 
 
protected static $store = '/dev/shm/'; 
 
protected static $prefix = 'cache_'; 
 
protected static function write($group, $id, $ttl, $data) 
{ 
$filename = self::getFilename($group, $id); 
if ($fp = @fopen($filename, 'xb')) { 
if (flock($fp, LOCK_EX)) { 
fwrite($fp, $data); 
} 
fclose($fp); 
// Set filemtime 
touch($filename, time() + $ttl); 
} 
} 
 
protected static function read($group, $id) 
{ 
$filename = self::getFilename($group, $id); 
return file_get_contents($filename); 
} 
 
protected static function isCached($group, $id) 
{ 
$filename = self::getFilename($group, $id); 
if (self::$enabled && file_exists($filename) && filemtime($filename) > time()) { 
return true; 
} 
@unlink($filename); 
return false; 
} 
/** 
* Builds a filename/path from group, id and 
* store. 
* 
* @param string $group Group to store data under 
* @param string $id Unique ID of this data 
*/ 
protected static function getFilename($group, $id) 
{ 
$id = md5($id); 
return self::$store . self::$prefix . "{$group}_{$id}"; 
} 
 
public static function setPrefix($prefix) 
{ 
self::$prefix = $prefix; 
} 
/** 
* Sets the store for cache files. Defaults to 
* /dev/shm. Must have trailing slash. 
* 
* @param string $store The dir to store the cache data in 
*/ 
public static function setStore($store) 
{ 
self::$store = $store; 
} 
} 
 
class OutputCache extends Cache 
{ 
 
private static $group; 
 
private static $id; 
 
private static $ttl; 
 
public static function Start($group, $id, $ttl) 
{ 
if (self::isCached($group, $id)) { 
echo self::read($group, $id); 
return true; 
} else { 
ob_start(); 
self::$group = $group; 
self::$id = $id; 
self::$ttl = $ttl; 
return false; 
} 
} 
 
public static function End() 
{ 
$data = ob_get_contents(); 
ob_end_flush(); 
self::write(self::$group, self::$id, self::$ttl, $data); 
} 
} 
 
class DataCache extends Cache 
{ 
 
public static function Get($group, $id) 
{ 
if (self::isCached($group, $id)) { 
return unserialize(self::read($group, $id)); 
} 
return null; 
} 
 
public static function Put($group, $id, $ttl, $data) 
{ 
self::write($group, $id, $ttl, serialize($data)); 
} 
} 
?>

Usage:

$dir = !empty($_SERVER['argv'][1]) ? $_SERVER['argv'][1] : '.'; 
$dh = opendir($dir); 
while ($filename = readdir($dh)) { 
if ($filename == '.' OR $filename == '..') { 
continue; 
} 
if (filemtime($dir . DIRECTORY_SEPARATOR . $filename) < time()) { 
unlink($dir . DIRECTORY_SEPARATOR . $filename); 
} 
}

(link: http://xiazai.jb51.net/201004/yuanma/php_Cache.rar)