来自phpguru得Php Cache类源码

cache的作用不用说大家都知道咯,这些天也面试了一些人,发现很多人框架用多了,基础都忘记了,你问一些事情,他总是说框架解决了,而根本不明白是怎么回事,所以也提醒大家应该注意平时基础知识的积累,之后对一些问题才能游刃有余.

群里也有些朋友对基础知识很不屑,总说有能力就可以了,基础知识考不出来什么.对于这样的观点,我一直不苟同.
这个只是一点感概罢了. 下面看正题,介绍一个php的cache类:

贴一下代码吧:下面也有下载地址，其实很简单，重要的是学习

<?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
{
/**
* whether caching is enabled
* @var bool
*/
public static $enabled = true;
/**
* place to store the cache files
* @var string
*/
protected static $store = '/dev/shm/';
/**
* prefix to use on cache files
* @var string
*/
protected static $prefix = 'cache_';
/**
* stores data
*
* @param string $group group to store data under
* @param string $id unique id of this data
* @param int $ttl how long to cache for (in seconds)
*/
protected static function write($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);
}
}
/**
* reads data
*
* @param string $group group to store data under
* @param string $id unique id of this data
*/
protected static function read($group, $id)
{
$filename = self::getfilename($group, $id);
return file_get_contents($filename);
}
/**
* determines if an entry is cached
*
* @param string $group group to store data under
* @param string $id unique id of this data
*/
protected static function iscached($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}";
}
/**
* sets the filename prefix to use
*
* @param string $prefix filename prefix to use
*/
public static function setprefix($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;
}
}
/**
* output cache extension of base caching class
*/
class outputcache extends cache
{
/**
* group of currently being recorded data
* @var string
*/
private static $group;
/**
* id of currently being recorded data
* @var string
*/
private static $id;
/**
* ttl of currently being recorded data
* @var int
*/
private static $ttl;
/**
* starts caching off. returns true if cached, and dumps
* the output. false if not cached and start output buffering.
*
* @param string $group group to store data under
* @param string $id unique id of this data
* @param int $ttl how long to cache for (in seconds)
* @return bool true if cached, false if not
*/
public static function start($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;
}
}
/**
* ends caching. writes data to disk.
*/
public static function end()
{
$data = ob_get_contents();
ob_end_flush();
self::write(self::$group, self::$id, self::$ttl, $data);
}
}
/**
* data cache extension of base caching class
*/
class datacache extends cache
{
/**
* retrieves data from the cache
*
* @param string $group group this data belongs to
* @param string $id unique id of the data
* @return mixed either the resulting data, or null
*/
public static function get($group, $id)
{
if (self::iscached($group, $id)) {
return unserialize(self::read($group, $id));
}
return null;
}
/**
* stores data in the cache
*
* @param string $group group this data belongs to
* @param string $id unique id of the data
* @param int $ttl how long to cache for (in seconds)
* @param mixed $data the data to store
*/
public static function put($group, $id, $ttl, $data)
{
self::write($group, $id, $ttl, serialize($data));
}
}
?>

使用方法：

$dir = !empty($_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);
}
}

源码打包下载