TempCache.php

<?php

namespace Cajogos;

/**
 * Class TempCache
 * @package Cajogos
 */
class TempCache
{
	const TIME_5_MIN = 300;
	const TIME_HALF_HOUR = 1800;
	const TIME_1_HOUR = 3600;
	const TIME_12_HOUR = 43200;
	const TIME_1_DAY = 86400;
	const TIME_1_WEEK = 604800;

	const CACHE_FOLDER = '/tmp/php-temp-cache/';

	/**
	 * @var bool
	 */
	private static $prepared = false;

	/**
	 * @param string $key
	 * @return mixed|null
	 */
	public static function get($key)
	{
		if (self::prepare())
		{
			$key = self::cache_key_convert($key);
			$file = $key . '.cache';
			$contents = self::load_cache_file($file);
			if ($contents === false)
			{
				return null;
			}
			$json_content = json_decode($contents);
			$expiry = $json_content->expiry;
			if (time() > $expiry)
			{
				self::delete_cache_file($file);
				return null;
			}
			$value = unserialize($json_content->value);
			return $value;
		}
		return null;
	}

	/**
	 * @param string $key
	 * @param string $value
	 * @param integer $expiry
	 * @return bool
	 */
	public static function put($key, $value, $expiry)
	{
		if (self::prepare())
		{
			$cache_key = $key;
			$key = self::cache_key_convert($key);
			$file = $key . '.cache';
			$expiry = time() + $expiry;
			$serialized = serialize($value);
			$store = array(
				'key' => $cache_key,
				'expiry' => $expiry,
				'value' => $serialized
			);
			$store = json_encode($store);
			return self::save_cache_file($file, $store);
		}
		return false;
	}

	/**
	 * @param string $key
	 * @return bool
	 */
	public static function remove($key)
	{
		if (self::prepare())
		{
			$key = self::cache_key_convert($key);
			$file = $key . '.cache';
			return self::delete_cache_file($file);
		}
		return false;
	}

	/**
	 * @param string $file
	 * @return bool|string
	 */
	private static function load_cache_file($file)
	{
		$file = self::CACHE_FOLDER . $file;
		if (file_exists($file))
		{
			return file_get_contents($file);
		}
		return false;
	}

	/**
	 * @param string $file
	 * @param string $data
	 * @return bool
	 */
	private static function save_cache_file($file, $data)
	{
		$file = self::CACHE_FOLDER . $file;
		return (!(file_put_contents($file, $data) === false));
	}

	/**
	 * @param string $file
	 * @return bool
	 */
	private static function delete_cache_file($file)
	{
		$file = self::CACHE_FOLDER . $file;
		return unlink($file);
	}

	/**
	 * @param string $key
	 * @return string
	 */
	private static function cache_key_convert($key)
	{
		$key = 'tmpcache_' . $key;
		return md5($key);
	}

	/**
	 * @return bool
	 */
	private static function prepare()
	{
		if (self::$prepared)
		{
			return true;
		}
		self::$prepared = true;
		if (file_exists(self::CACHE_FOLDER) === false)
		{
			return mkdir(self::CACHE_FOLDER);
		}
		return true;
	}
}