PHP session handlers

[twn39]

PHP session handlers,扩展原生$_SESSION全局变量，对老对代码或遗留代码的扩展性很有用。

[twn39]

Memcached

<?php
namespace App\Handlers;
/**
 * MemcachedSessionHandler.
 *
 * Memcached based session storage handler based on the Memcached class
 * provided by the PHP memcached extension.
 *
 * @see http://php.net/memcached
 *
 * @author Drak <drak@zikula.org>
 */
class MemcachedSessionHandler implements \SessionHandlerInterface
{
    /**
     * @var \Memcached Memcached driver
     */
    private $memcached;

    /**
     * @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 memcached keys in order to avoid collision
     *  * expiretime: The time to live in seconds
     *
     * @param \Memcached $memcached A \Memcached instance
     * @param array      $options   An associative array of Memcached options
     *
     * @throws \InvalidArgumentException When unsupported options are passed
     */
    public function __construct(\Memcached $memcached, array $options = array())
    {
        $this->memcached = $memcached;

        if ($diff = array_diff(array_keys($options), array('prefix', 'expiretime'))) {
            throw new \InvalidArgumentException(sprintf(
                'The following options are not supported "%s"', implode(', ', $diff)
            ));
        }

        $this->ttl = isset($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 true;
    }

    /**
     * {@inheritdoc}
     */
    public function read($sessionId)
    {
        return $this->memcached->get($this->prefix.$sessionId) ?: '';
    }

    /**
     * {@inheritdoc}
     */
    public function write($sessionId, $data)
    {
        return $this->memcached->set($this->prefix.$sessionId, $data, time() + $this->ttl);
    }

    /**
     * {@inheritdoc}
     */
    public function destroy($sessionId)
    {
        return $this->memcached->delete($this->prefix.$sessionId);
    }

    /**
     * {@inheritdoc}
     */
    public function gc($maxlifetime)
    {
        // not required here because memcached will auto expire the records anyhow.
        return true;
    }

    /**
     * Return a Memcached instance.
     *
     * @return \Memcached
     */
    protected function getMemcached()
    {
        return $this->memcached;
    }
}

注： Memcache 有命中率的概念，流量大了，会有个别没法命中取不到而被无故踢下线，session不建议使用memcache存储

[twn39]

Redis

<?php

/*
 * This file is part of the Predis package.
 *
 * (c) Daniele Alessandri <suppakilla@gmail.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace App\Handlers;

use Predis\ClientInterface;

/**
 * Session handler class that relies on Predis\Client to store PHP's sessions
 * data into one or multiple Redis servers.
 *
 * This class is mostly intended for PHP 5.4 but it can be used under PHP 5.3
 * provided that a polyfill for `SessionHandlerInterface` is defined by either
 * you or an external package such as `symfony/http-foundation`.
 *
 * @author Daniele Alessandri <suppakilla@gmail.com>
 */
class Handler implements \SessionHandlerInterface
{
    protected $redis;
    protected $ttl;
    private $prefix;

    /**
     * @param ClientInterface $client  Fully initialized client instance.
     * @param array           $options Session handler options.
     */
    public function __construct(ClientInterface $client, array $options = array())
    {
        $this->redis = $client;

        if ($diff = array_diff(array_keys($options), array('prefix', 'expiretime'))) {
            throw new \InvalidArgumentException(sprintf(
                'The following options are not supported "%s"', implode(', ', $diff)
            ));
        }

        $this->ttl = isset($options['expiretime']) ? (int) $options['expiretime'] : 86400;
        $this->prefix = isset($options['prefix']) ? $options['prefix'] : 'sf2s';
    }

    /**
     * {@inheritdoc}
     */
    public function open($save_path, $session_id)
    {
        // NOOP
        return true;
    }

    /**
     * {@inheritdoc}
     */
    public function close()
    {
        // NOOP
        return true;
    }

    /**
     * {@inheritdoc}
     */
    public function gc($maxlifetime)
    {
        // NOOP
        return true;
    }

    /**
     * {@inheritdoc}
     */
    public function read($session_id)
    {
        return $this->redis->get($this->prefix.$session_id) ?: '';
    }
    /**
     * {@inheritdoc}
     */
    public function write($session_id, $session_data)
    {
        $this->redis->setex($this->prefix.$session_id, $this->ttl, $session_data);

        return true;
    }

    /**
     * {@inheritdoc}
     */
    public function destroy($session_id)
    {
        $this->redis->del($this->prefix.$session_id);

        return true;
    }

    /**
     * Returns the underlying client instance.
     *
     * @return ClientInterface
     */
    public function getClient()
    {
        return $this->redis;
    }

    /**
     * Returns the session max lifetime value.
     *
     * @return int
     */
    public function getMaxLifeTime()
    {
        return $this->ttl;
    }
}