Code example for storing PHP session data in the database_php example

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

<&#63;php

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');

&#63;>

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();

Statement of this Website

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn