KVCache.php

<?php
namespace app\helpers;

/**
 * A simple k/v cache manager based on file system.
 *
 * @author Allex Wang ([email protected])
 *
 * GistID: b3793353690a89452c7f
 * GistURL: https://gist.github.com/allex/b3793353690a89452c7f
 */
class KVCache {
    private static $_instance;

    private $cacheDir = null;

    private function __construct() {
        $dir = rtrim(sys_get_temp_dir(), '/') . DIRECTORY_SEPARATOR . 'php_kvcache' . DIRECTORY_SEPARATOR . ftok(__FILE__, 't');
        if (!file_exists($dir) && !mkdir($dir, 0700, true)) {
            throw new \Exception("Create cache dir fails: $dir");
        }
        $this->cacheDir = $dir;
    }

    public static function getInstance() {
        if (!(self::$_instance instanceof self)) {
            self::$_instance = new self();
        }
        return self::$_instance;
    }

    public function set($k, $v) {
        if (!$this->has($k)) {
            return file_put_contents($this->cacheDir . '/' . $k, $v);
        }
        return FALSE;
    }

    public function get($k) {
        if ($this->has($k)) {
            return file_get_contents($this->cacheDir . '/' . $k);
        }
        return NULL;
    }

    public function has($k) {
        return file_exists($this->cacheDir . '/' . $k);
    }
}