Needless to say, everyone knows the role of Cache. I have interviewed some people these days and found that many people use frameworks too much and have forgotten the basics. When you ask some questions, they always say that the framework solves the problem, but they don’t understand how. This is the case, so I also remind everyone that you should pay attention to the accumulation of basic knowledge in daily life, so that you can deal with some problems with ease.
There are also some friends in the group who are very disdainful of basic knowledge. They always say that it is enough if you have the ability. Basic knowledge test Nothing comes out. I have always disagreed with this view.
This is just a general idea. Let’s get to the point and introduce a PHP Cache class:
Post the code: there is also a download address below , it is actually very simple, the important thing is to learn
Copy the code The code is as follows:
/**
* 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:
复制代码 代码如下:
$dir = !empty($_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
http://www.bkjia.com/PHPjc/321534.htmlwww.bkjia.comtruehttp://www.bkjia.com/PHPjc/321534.htmlTechArticleCache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...