Db.class.php
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<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2014 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------
namespace Think\Cache\Driver;
use Think\Cache;
/**
* 数据库方式缓存驱动
* CREATE TABLE think_cache (
* cachekey varchar(255) NOT NULL,
* expire int(11) NOT NULL,
* data blob,
* datacrc int(32),
* UNIQUE KEY `cachekey` (`cachekey`)
* );
*/
class Db extends Cache
{
/**
* 架构函数
* @param array $options 缓存参数
* @access public
*/
public function __construct($options = array())
{
if (empty($options)) {
$options = array(
'table' => C('DATA_CACHE_TABLE'),
);
}
$this->options = $options;
$this->options['prefix'] = isset($options['prefix']) ? $options['prefix'] : C('DATA_CACHE_PREFIX');
$this->options['length'] = isset($options['length']) ? $options['length'] : 0;
$this->options['expire'] = isset($options['expire']) ? $options['expire'] : C('DATA_CACHE_TIME');
$this->handler = \Think\Db::getInstance();
}
/**
* 读取缓存
* @access public
* @param string $name 缓存变量名
* @return mixed
*/
public function get($name)
{
$name = $this->options['prefix'] . addslashes($name);
N('cache_read', 1);
$result = $this->handler->query('SELECT `data`,`datacrc` FROM `' . $this->options['table'] . '` WHERE `cachekey`=\'' . $name . '\' AND (`expire` =0 OR `expire`>' . time() . ') LIMIT 0,1');
if (false !== $result) {
$result = $result[0];
if (C('DATA_CACHE_CHECK')) {
//开启数据校验
if (md5($result['data']) != $result['datacrc']) { //校验错误
return false;
}
}
$content = $result['data'];
if (C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {
//启用数据压缩
$content = gzuncompress($content);
}
$content = unserialize($content);
return $content;
} else {
return false;
}
}
/**
* 写入缓存
* @access public
* @param string $name 缓存变量名
* @param mixed $value 存储数据
* @param integer $expire 有效时间（秒）
* @return boolean
*/
public function set($name, $value, $expire = null)
{
$data = serialize($value);
$name = $this->options['prefix'] . addslashes($name);
N('cache_write', 1);
if (C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {
//数据压缩
$data = gzcompress($data, 3);
}
if (C('DATA_CACHE_CHECK')) {
//开启数据校验
$crc = md5($data);
} else {
$crc = '';
}
if (is_null($expire)) {
$expire = $this->options['expire'];
}
$expire = (0 == $expire) ? 0 : (time() + $expire); //缓存有效期为0表示永久缓存
$result = $this->handler->query('select `cachekey` from `' . $this->options['table'] . '` where `cachekey`=\'' . $name . '\' limit 0,1');
if (!empty($result)) {
//更新记录
$result = $this->handler->execute('UPDATE ' . $this->options['table'] . ' SET data=\'' . $data . '\' ,datacrc=\'' . $crc . '\',expire=' . $expire . ' WHERE `cachekey`=\'' . $name . '\'');
} else {
//新增记录
$result = $this->handler->execute('INSERT INTO ' . $this->options['table'] . ' (`cachekey`,`data`,`datacrc`,`expire`) VALUES (\'' . $name . '\',\'' . $data . '\',\'' . $crc . '\',' . $expire . ')');
}
if ($result) {
if ($this->options['length'] > 0) {
// 记录缓存队列
$this->queue($name);
}
return true;
} else {
return false;
}
}
/**
* 删除缓存
* @access public
* @param string $name 缓存变量名
* @return boolean
*/
public function rm($name)
{
$name = $this->options['prefix'] . addslashes($name);
return $this->handler->execute('DELETE FROM `' . $this->options['table'] . '` WHERE `cachekey`=\'' . $name . '\'');
}
/**
* 清除缓存
* @access public
* @return boolean
*/
public function clear()
{
return $this->handler->execute('TRUNCATE TABLE `' . $this->options['table'] . '`');
}
}