<?php /** * StatusNet - the distributed open-source microblogging tool * Copyright (C) 2009, StatusNet, Inc. * * Plugin to implement cache interface for memcache * * 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> * @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 memcache 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> * @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 MemcachePlugin extends Plugin { static $cacheInitialized = false; private $_conn = null; public $servers = array('127.0.0.1;11211'); public $compressThreshold = 20480; public $compressMinSaving = 0.2; public $persistent = null; public $defaultExpiry = 86400; // 24h /** * Initialize the plugin * * Note that onStartCacheGet() may have been called before this! * * @return boolean flag value */ function onInitializePlugin() { if (self::$cacheInitialized) { $this->persistent = true; } else { // If we're a parent command-line process we need // to be able to close out the connection after // forking, so disable persistence. // // We'll turn it back on again the second time // through which will either be in a child process, // or a single-process script which is switching // configurations. $this->persistent = (php_sapi_name() == 'cli') ? false : true; } $this->_ensureConn(); self::$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, $this->flag(intval($flag)), $expiry); Event::handle('EndCacheSet', array($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) { if (empty($this->_conn)) { // nothing to do return true; } if ($this->persistent) { common_log(LOG_ERR, "Cannot close persistent memcached connection"); $success = false; } else { common_log(LOG_INFO, "Closing memcached connection"); $success = $this->_conn->close(); $this->_conn = null; } return false; } /** * 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)) { $this->_conn = new Memcache(); if (is_array($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, $this->persistent); } // Compress items stored in the cache if they're over threshold in size // (default 2KiB) and the compression would save more than min savings // ratio (default 0.2). // Allows the cache to store objects larger than 1MB (if they // compress to less than 1MB), and improves cache memory efficiency. $this->_conn->setCompressThreshold($this->compressThreshold, $this->compressMinSaving); } } /** * Translate general flags to Memcached-specific flags * @param int $flag * @return int */ protected function flag($flag) { $out = 0; if ($flag & Cache::COMPRESSED == Cache::COMPRESSED) { $out |= MEMCACHE_COMPRESSED; } return $out; } function onPluginVersion(&$versions) { $versions[] = array('name' => 'Memcache', 'version' => STATUSNET_VERSION, 'author' => 'Evan Prodromou, Craig Andrews', 'homepage' => 'http://status.net/wiki/Plugin:Memcache', 'rawdescription' => _m('Use <a href="http://memcached.org/">Memcached</a> to cache query results.')); return true; } }