发一个自己写的PHP文件缓存函数


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/**
+----------------------------------------------------------
* PHP文件缓存函数
* @author LiuYuanjun <http://www.liuyuanjun.com>
+----------------------------------------------------------
* @param string $key 缓存KEY 设为null则清空所有缓存
* @param mixed $data 缓存内容 设为null则删除KEY为$key的缓存
* @param int $time 缓存时间 秒数，如果大于当前时间戳则按照时间戳来处理，为0则永不过期
+----------------------------------------------------------
* @return mixed
+----------------------------------------------------------
*/
function file_cache($key, $data='', $time=0) {
    $cacheDir = ROOTPATH . 'Cache' . DS; //这里设置缓存目录
    $timestamp = time();
    if ($key === null) { //clear all
        $dirFiles = scandir($cacheDir);
        foreach ($dirFiles as $dirFile) {
            if ($dirFile != '.' && $dirFile != '..')
                @unlink($cacheDir . $dirFile);
        }
    }
    $cachePath = $cacheDir . '~' . $key . '.php';
    if ($data === '') { //get cache
        if (!is_file($cachePath))
            return false;
        $cacheData = @require $cachePath;
        if ($cacheData[0] > 0 && $cacheData[0] < $timestamp) {
            @unlink($cachePath);
            return false;
        } else {
            return @unserialize($cacheData[1]);
        }
    }
    if ($data === null)
        @unlink($cachePath); //delete cache
    $time = intval($time);
    $deadline = $time == 0 ? 0 : ($time>$timestamp?$time:($timestamp+$time));
    $storeData = '<?php return array(' . $deadline . ',\'' . serialize($data) . '\'); ?>';
    @file_put_contents($cachePath, $storeData);
}