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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
<div class="codetitle"><a style="CURSOR: pointer" data="40368" class="copybut" id="copybut40368" onclick="doCopy('code40368')"> 代码如下:<div class="codebody" id="code40368">
<?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')) {
$data = time();
DataCache::Put('group',10,$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,$id);
if (self::$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,$ttl)
{
if (self::isCached($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,$data)
{
self::write($group,serialize($data));
}
}
?>
使用方法：
<div class="codetitle"><a style="CURSOR: pointer" data="32082" class="copybut" id="copybut32082" onclick="doCopy('code32082')"> 代码如下:<div class="codebody" id="code32082">
$dir = !empty($_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 （编辑：李大同）
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