|
<?php
// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006-2012 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------
// $Id: CacheDb.class.php 2734 2012-02-14 06:55:15Z liu21st $
/**
+-----------------------------------------------
* 数据库类型缓存驱动类
CREATE TABLE think_cache (
cachekey varchar(255) NOT NULL,
expire int(11) NOT NULL,
data blob,
datacrc int(32),
UNIQUE KEY `cachekey` (`cachekey`)
);
+-----------------------------------------------
*/
class CacheDb extends Cache {
/**
+----------------------------------------------------------
* 缓存数据库对象 采用数据库方式有效
+----------------------------------------------------------
* @var string
* @access protected
+----------------------------------------------------------
*/
private $db ;
/**
+----------------------------------------------------------
* 架构函数
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
*/
public function __construct($options='') {
if(empty($options)){
$options= array (
'db' => C('DB_NAME'),
'table' => C('DATA_CACHE_TABLE'),
'expire' => C('DATA_CACHE_TIME'),
'length' => 0,
);
}
$this->options = $options;
import('Db');
$this->db = DB::getInstance();
$this->connected = is_resource($this->db);
}
/**
+----------------------------------------------------------
* 是否连接
+----------------------------------------------------------
* @access private
+----------------------------------------------------------
* @return boolen
+----------------------------------------------------------
*/
private function isConnected() {
return $this->connected;
}
/**
+----------------------------------------------------------
* 读取缓存
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @param string $name 缓存变量名
+----------------------------------------------------------
* @return mixed
+----------------------------------------------------------
*/
public function get($name) {
$name = addslashes($name);
N('cache_read',1);
$result = $this->db->query('SELECT `data`,`datacrc` FROM `'.$this->options['table'].'` WHERE `cachekey`=\''.$name.'\' AND (`expire` =0 OR `expire`>'.time().') LIMIT 0,1');
if(false !== $result ) {
$result = $result[0];
if(C('DATA_CACHE_CHECK')) {//开启数据校验
if($result['datacrc'] != md5($result['data'])) {//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 $expire 有效时间（秒）
+----------------------------------------------------------
* @return boolen
+----------------------------------------------------------
*/
public function set($name, $value,$expire=null) {
$data = serialize($value);
$name = addslashes($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'];
}
$expire = ($expire==0)?0: (time()+$expire) ;//缓存有效期为0表示永久缓存
$result = $this->db->query('select `cachekey` from `'.$this->options['table'].'` where `cachekey`=\''.$name.'\' limit 0,1');
if(!empty($result) ) {
//更新记录
$result = $this->db->execute('UPDATE '.$this->options['table'].' SET data=\''.$data.'\' ,datacrc=\''.$crc.'\',expire='.$expire.' WHERE `cachekey`=\''.$name.'\'');
}else {
//新增记录
$result = $this->db->execute('INSERT INTO '.$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 $name 缓存变量名
+----------------------------------------------------------
* @return boolen
+----------------------------------------------------------
*/
public function rm($name) {
$name = addslashes($name);
return $this->db->execute('DELETE FROM `'.$this->options['table'].'` WHERE `cachekey`=\''.$name.'\'');
}
/**
+----------------------------------------------------------
* 清除缓存
+----------------------------------------------------------
* @access public
+----------------------------------------------------------
* @return boolen
+----------------------------------------------------------
*/
public function clear() {
return $this->db->execute('TRUNCATE TABLE `'.$this->options['table'].'`');
}
}
|
