gnu-social/plugins/MemcachedPlugin.php

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<?php
/**
* StatusNet - the distributed open-source microblogging tool
* Copyright (C) 2009, StatusNet, Inc.
*
* Plugin to implement cache interface for memcached
*
* PHP version 5
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* @category Cache
* @package StatusNet
* @author Evan Prodromou <evan@status.net>, Craig Andrews <candrews@integralblue.com>
* @copyright 2009 StatusNet, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
* @link http://status.net/
*/
if (!defined('STATUSNET')) {
// This check helps protect against security problems;
// your code file can't be executed directly from the web.
exit(1);
}
/**
* A plugin to use memcached for the cache interface
*
* This used to be encoded as config-variable options in the core code;
* it's now broken out to a separate plugin. The same interface can be
* implemented by other plugins.
*
* @category Cache
* @package StatusNet
* @author Evan Prodromou <evan@status.net>, Craig Andrews <candrews@integralblue.com>
* @copyright 2009 StatusNet, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
* @link http://status.net/
*/
class MemcachedPlugin extends Plugin
{
static $cacheInitialized = false;
private $_conn = null;
public $servers = array('127.0.0.1;11211');
public $defaultExpiry = 86400; // 24h
/**
* Initialize the plugin
*
* Note that onStartCacheGet() may have been called before this!
*
* @return boolean flag value
*/
function onInitializePlugin()
{
$this->_ensureConn();
self::$cacheInitialized = true;
return true;
}
/**
* Get a value associated with a key
*
* The value should have been set previously.
*
* @param string &$key in; Lookup key
* @param mixed &$value out; value associated with key
*
* @return boolean hook success
*/
function onStartCacheGet(&$key, &$value)
{
$this->_ensureConn();
$value = $this->_conn->get($key);
Event::handle('EndCacheGet', array($key, &$value));
return false;
}
/**
* Associate a value with a key
*
* @param string &$key in; Key to use for lookups
* @param mixed &$value in; Value to associate
* @param integer &$flag in; Flag empty or Cache::COMPRESSED
* @param integer &$expiry in; Expiry (passed through to Memcache)
* @param boolean &$success out; Whether the set was successful
*
* @return boolean hook success
*/
function onStartCacheSet(&$key, &$value, &$flag, &$expiry, &$success)
{
$this->_ensureConn();
if ($expiry === null) {
$expiry = $this->defaultExpiry;
}
$success = $this->_conn->set($key, $value, $expiry);
Event::handle('EndCacheSet', array($key, $value, $flag,
$expiry));
return false;
}
/**
* Atomically increment an existing numeric key value.
* Existing expiration time will not be changed.
*
* @param string &$key in; Key to use for lookups
* @param int &$step in; Amount to increment (default 1)
* @param mixed &$value out; Incremented value, or false if key not set.
*
* @return boolean hook success
*/
function onStartCacheIncrement(&$key, &$step, &$value)
{
$this->_ensureConn();
$value = $this->_conn->increment($key, $step);
Event::handle('EndCacheIncrement', array($key, $step, $value));
return false;
}
/**
* Delete a value associated with a key
*
* @param string &$key in; Key to lookup
* @param boolean &$success out; whether it worked
*
* @return boolean hook success
*/
function onStartCacheDelete(&$key, &$success)
{
$this->_ensureConn();
$success = $this->_conn->delete($key);
Event::handle('EndCacheDelete', array($key));
return false;
}
function onStartCacheReconnect(&$success)
{
// nothing to do
return true;
}
/**
* Ensure that a connection exists
*
* Checks the instance $_conn variable and connects
* if it is empty.
*
* @return void
*/
private function _ensureConn()
{
if (empty($this->_conn)) {
$this->_conn = new Memcached(common_config('site', 'nickname'));
if (!count($this->_conn->getServerList())) {
if (is_array($this->servers)) {
$servers = $this->servers;
} else {
$servers = array($this->servers);
}
foreach ($servers as $server) {
if (strpos($server, ';') !== false) {
list($host, $port) = explode(';', $server);
} else {
$host = $server;
$port = 11211;
}
$this->_conn->addServer($host, $port);
}
// Compress items stored in the cache.
// Allows the cache to store objects larger than 1MB (if they
// compress to less than 1MB), and improves cache memory efficiency.
$this->_conn->setOption(Memcached::OPT_COMPRESSION, true);
}
}
}
/**
* Translate general flags to Memcached-specific flags
* @param int $flag
* @return int
*/
protected function flag($flag)
{
//no flags are presently supported
return $flag;
}
function onPluginVersion(&$versions)
{
$versions[] = array('name' => 'Memcached',
'version' => STATUSNET_VERSION,
'author' => 'Evan Prodromou, Craig Andrews',
'homepage' => 'http://status.net/wiki/Plugin:Memcached',
'rawdescription' =>
_m('Use <a href="http://memcached.org/">Memcached</a> to cache query results.'));
return true;
}
}