【下载文档:  将PHP的session数据存储到数据库中的代码实例.txt 】

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将PHP的session数据存储到数据库中的代码实例
一个开发环境有多个网站，需要使用不同的session，解决方案很多。不过这次也高大上一把，用数据库存，方便以后扩展。
PostgreSQL版
首先是数据库的部分
--drop table php_session
create unlogged table php_session
(
sess_id varchar(32) primary key,
modify_time timestamp with time zone not null,
sess_data varchar(3000) default ''
);
create index concurrently idx_php_session_modify_time on php_session(modify_time);
--set_session(id, data)
create or replace function set_session(varchar, varchar) returns void as $set_session$
with upsert as (
update php_session
set modify_time = current_timestamp, sess_data = $2
where sess_id = $1
returning 1
)
insert into php_session (sess_id, modify_time, sess_data)
select $1, current_timestamp, $2
where not exists (
select 1 from upsert
);
$set_session$ language sql;
--get_session(id)
create or replace function get_session(varchar) returns varchar as $get_session$
select sess_data from php_session where sess_id = $1
$get_session$ language sql;
--del_session
create or replace function del_session(varchar) returns void as $del_session$
delete from php_session where sess_id = $1
$del_session$ language sql;
--gc_session
create or replace function gc_session() returns void as $del_session$
delete from php_session where modify_time < current_timestamp - interval '30 days'
$del_session$ language sql;
然后是PHP的部分
session_set_save_handler(
function ($savePath, $sessionName) {//open
return true;
},
function () {//close
return true;
},
function ($id) {//read
$sql = "select get_session($1)";
$stmt = pg_query_params(SESSION_CONN, $sql, array($id));
$result = pg_fetch_row($stmt);
return $result[0];
},
function ($id, $data) {//write
$sql = "select set_session($1, $2)";
pg_query_params(SESSION_CONN, $sql, array($id, $data));
return true;
},
function ($id) {//destroy
$sql = "select del_session($1)";
pg_query_params(SESSION_CONN, $sql, array($id, $data));
return true;
},
function ($maxlifetime) {//gc
//php needn't control the global session gc
return true;
}
);
register_shutdown_function('session_write_close');
?>
然后只要在session_start之前调用这个就可以了
至于SESSION_CONN，那是我定义的一个常量，表示一个指向session数据库的链接而已。
MySQL版
再总结一个针对MySQL的集成更多基础功能的例子：
表结构：
CREATE TABLE IF NOT EXISTS `sessioninfo` (
`sid` varchar(255) NOT NULL,
`value` text NOT NULL,
`expiration` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`sid`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
session信息存储到数据库的类：
class MySessionHandler implements SessionHandlerInterface {
/**
* @access private
* @var object 数据库连接
*/
private $_dbLink;
/**
* @access private
* @var string 保存session的表名
*/
Private $_sessionTable;
/**
* @access private
* @var string session名
*/
private $_sessionName;
/**
* @const 过期时间
*/
const SESSION_EXPIRE = 10;
public function __construct($dbLink, $sessionTable) {
if(!is_object($dbLink)) {
return false;
}
$this->_dbLink = $dbLink;
$this->_sessionTable = $sessionTable;
}
/**
* 打开
* @access public
* @param string $session_save_path 保存session的路径
* @param string $session_name session名
* @return integer
*/
public function open($session_save_path, $session_name) {
$this->_sessionName = $session_name;
return 0;
}
/**
* 关闭
* @access public
* @return integer
*/
public function close() {
return 0;
}
/**
* 关闭session
* @access public
* @param string $session_id session ID
* @return string
*/
public function read($session_id) {
$query = "SELECT value FROM {$this->_sessionTable} WHERE sid = {$session_id} AND UNIX_TIMESTAMP(expiration) + " . self::SESSION_EXPIRE . " > UNIX_TIMESTAMP(NOW())";
$result = $this->_dbLink->query($query);
if(!isset($value) || empty($value)) {
$value = "";
return $value;
}
$this->_dbLink->query("UPDATE {$this->_sessionTable} SET expiration = CURRENT_TIMESTAMP() WHERE sid = {$session_id}");
$value = $result->fetch_array();
$result->free();
return $value['value'];
}
/**
* 写入session
* @access public
* @param string $session_id session ID
* @param string $session_data session data
* @return integer
*/
public function write($session_id, $session_data) {
$query = "SELECT value FROM {$this->_sessionTable} WHERE sid = '{$session_id}' AND UNIX_TIMESTAMP(expiration) + " . self::SESSION_EXPIRE . " > UNIX_TIMESTAMP(NOW())";
$result = $this->_dbLink->query($query);
$result = $result->fetch_array();
if(!empty($result)) {
$result = $this->_dbLink->query("UPDATE {$this->_sessionTable} SET value = {$session_data} WHERE sid = {$session_id}");
}
else{
$result = $this->_dbLink->query("INSERT INTO {$this->_sessionTable} (sid, value) VALUES ('{$session_id}', '{$session_data}')");
}
if($result){
return 0;
}
else{
return 1;
}
}
/**
* 销魂session
* @access public
* @param string $session_id session ID
* @return integer
*/
public function destroy($session_id) {
$result = $this->_dbLink->query("DELETE FROM {$this->_sessionTable} WHERE sid = '{$session_id}'");
if($result){
return 0;
}
else{
return 1;
}
}
/**
* 垃圾回收
* @access public
* @param string $maxlifetime session 最长生存时间
* @return integer
*/
public function gc($maxlifetime) {
$result = $this->_dbLink->query("DELETE FROM {$this->_sessionTable} WHERE UNIX_TIMESTAMP(expiration) < UNIX_TIMESTAMP(NOW()) - " . self::SESSION_EXPIRE);
if($result){
return 0;
}
else{
return 1;
}
}
}
$dbLink = new mysqli("localhost", "root", "root", "test");
$sessionTable = "sessioninfo";
$handler = new MySessionHandler($dbLink, $sessionTable);
session_set_save_handler($handler);
session_start();
$_SESSION['name'] = "test";
echo $_SESSION["name"];
//session_destroy();