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
复制代码 代码如下:
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($filename);
return false;
}
protected static function getFilename($group, $id)
{
$id = md5($id);
return self::$store . self::$prefix . "{$group}_{$id}";
}
public static function setPrefix($prefix)
{
self::$prefix = $prefix;
}
public static function setStore($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));
}
}
?>
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
