Last-Modified: 2019年5月10日16:06:36
前言
小型web服务, session数据基本是保存在本地(更多是本地磁盘文件), 但是当部署多台服务, 且需要共享session, 确保每个服务都能共享到同一份session数据.
redis 数据存储在内存中, 性能好, 配合持久化可确保数据完整.
设计方案
1. 通过php自身session配置实现
# 使用 redis 作为存储方案session.save_handler = redissession.save_path = "tcp://127.0.0.1:6379"# 若设置了连接密码, 则使用如下session.save_path = "tcp://127.0.0.1:6379?auth=密码"测试代码
<?phpini_set("session.save_handler", "redis");ini_set("session.save_path", "tcp://127.0.0.1:6379");session_start();echo "<pre>";$_SESSION['usertest'.rand(1,5)]=1;var_dump($_SESSION);echo "</pre>";输出 ↓
array(2) { ["usertest1"]=> int(88) ["usertest3"]=> int(1)}usertest1|i:1;usertest3|i:1;评价
- 优点: 实现简单, 无需修改php代码
- 缺点: 配置不支持多样化, 只能应用于简单场景
2. 设置用户自定义会话存储函数
通过 session_set_save_handler() 函数设置用户自定义会话函数.
session_set_save_handler ( callable $open , callable $close , callable $read , callable $write , callable $destroy , callable $gc [, callable $create_sid [, callable $validate_sid [, callable $update_timestamp ]]] ) : bool # >= php5.4session_set_save_handler ( object $sessionhandler [, bool $register_shutdown = TRUE ] ) : bool在配置完会话存储函数后, 再执行 session_start() 即可.
具体代码略, 以下提供一份 Memcached 的(来自Symfony框架代码):
<?php/* * This file is part of the Symfony package. * * (c) Fabien Potencier <fabien@symfony.com> * * For the full copyright and license information, please view the LICENSE * file that was distributed with this source code. */namespace Symfony\Component\HttpFoundation\Session\Storage\Handler;/** * MemcacheSessionHandler. * * @author Drak <drak@zikula.org> */class MemcacheSessionHandler implements \SessionHandlerInterface{ /** * @var \Memcache Memcache driver. */ private $memcache; /** * @var int Time to live in seconds */ private $ttl; /** * @var string Key prefix for shared environments. */ private $prefix; /** * Constructor. * * List of available options: * * prefix: The prefix to use for the memcache keys in order to avoid collision * * expiretime: The time to live in seconds * * @param \Memcache $memcache A \Memcache instance * @param array $options An associative array of Memcache options * * @throws \InvalidArgumentException When unsupported options are passed */ public function __construct(\Memcache $memcache, array $options = array()) { if ($diff = array_diff(array_keys($options), array('prefix', 'expiretime'))) { throw new \InvalidArgumentException(sprintf( 'The following options are not supported "%s"', implode(', ', $diff) )); } $this->memcache = $memcache; $this->ttl = isset($options['expiretime']) ? (int) $options['expiretime'] : 86400; $this->prefix = isset($options['prefix']) ? $options['prefix'] : 'sf2s'; } /** * {@inheritdoc} */ public function open($savePath, $sessionName) { return true; } /** * {@inheritdoc} */ public function close() { return $this->memcache->close(); } /** * {@inheritdoc} */ public function read($sessionId) { return $this->memcache->get($this->prefix.$sessionId) ?: ''; } /** * {@inheritdoc} */ public function write($sessionId, $data) { return $this->memcache->set($this->prefix.$sessionId, $data, 0, time() + $this->ttl); } /** * {@inheritdoc} */ public function destroy($sessionId) { return $this->memcache->delete($this->prefix.$sessionId); } /** * {@inheritdoc} */ public function gc($maxlifetime) { // not required here because memcache will auto expire the records anyhow. return true; } /** * Return a Memcache instance * * @return \Memcache */ protected function getMemcache() { return $this->memcache; }}