PHP file cache class usage example analysis_PHP tutorial

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/**

* 简单的文件缓存类

*

*/

class XZCache{

// default cache time one hour

var $cache_time = 3600;

// default cache dir

var $cache_dir = './cache';

public function __construct($cache_dir=null, $cache_time=null){

$this->cache_dir = isset($cache_dir) ? $cache_dir : $this->cache_dir;

$this->cache_time = isset($cache_time) ? $cache_time : $this->cache_time;

}

public function saveCache ($key, $value){

if (is_dir($this->cache_dir)){

$cache_file = $this->cache_dir . '/xzcache_' . md5($key);

$timedif = @(time() - filemtime($cache_file));

if ($timedif >= $this->cache_time) {

// cached file is too old, create new

$serialized = serialize($value);

if ($f = @fopen($cache_file, 'w')) {

fwrite ($f, $serialized, strlen($serialized));

fclose($f);

}

}

$result = 1;

}else{

echo "Error:dir is not exist.";

$result = 0;

}

return $result;

}

/**

* @return array

* 0 no cache

* 1 cached

* 2 overdue

*/

public function getCache ($key) {

$cache_file = $this->cache_dir . '/xzcache_' . md5($key);

if (is_dir($this->cache_dir) && is_file($cache_file)) {

$timedif = @(time() - filemtime($cache_file));

if ($timedif >= $this->cache_time) {

$result['cached'] = 2;

}else{

// cached file is fresh enough, return cached array

$result['value'] = unserialize(file_get_contents($cache_file));

$result['cached'] = 1;

}

}else {

echo "Error:no cache";

$result['cached'] = 0;

}

return $result;

}

} //end of class

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$cache = new XZCache();

$key = 'global';

$value = $GLOBALS;

$cache->saveCache($key, $value);

$result = $cache->getCache($key);

var_dump($result);