diff options
Diffstat (limited to 'engine/classes/ElggMemcache.php')
| -rw-r--r-- | engine/classes/ElggMemcache.php | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/engine/classes/ElggMemcache.php b/engine/classes/ElggMemcache.php new file mode 100644 index 000000000..d9539b9cb --- /dev/null +++ b/engine/classes/ElggMemcache.php @@ -0,0 +1,201 @@ +<?php +/** + * Memcache wrapper class. + * + * @package Elgg.Core + * @subpackage Memcache + */ +class ElggMemcache extends ElggSharedMemoryCache { + /** + * Minimum version of memcached needed to run + * + */ + private static $MINSERVERVERSION = '1.1.12'; + + /** + * Memcache object + */ + private $memcache; + + /** + * Expiry of saved items (default timeout after a day to prevent anything getting too stale) + */ + private $expires = 86400; + + /** + * The version of memcache running + */ + private $version = 0; + + /** + * Connect to memcache. + * + * @param string $namespace The namespace for this cache to write to - + * note, namespaces of the same name are shared! + */ + function __construct($namespace = 'default') { + global $CONFIG; + + $this->setNamespace($namespace); + + // Do we have memcache? + if (!class_exists('Memcache')) { + throw new ConfigurationException('PHP memcache module not installed, you must install php5-memcache'); + } + + // Create memcache object + $this->memcache = new Memcache; + + // Now add servers + if (!$CONFIG->memcache_servers) { + throw new ConfigurationException('No memcache servers defined, please populate the $CONFIG->memcache_servers variable'); + } + + if (is_callable(array($this->memcache, 'addServer'))) { + foreach ($CONFIG->memcache_servers as $server) { + if (is_array($server)) { + $this->memcache->addServer( + $server[0], + isset($server[1]) ? $server[1] : 11211, + isset($server[2]) ? $server[2] : FALSE, + isset($server[3]) ? $server[3] : 1, + isset($server[4]) ? $server[4] : 1, + isset($server[5]) ? $server[5] : 15, + isset($server[6]) ? $server[6] : TRUE + ); + + } else { + $this->memcache->addServer($server, 11211); + } + } + } else { + // don't use elgg_echo() here because most of the config hasn't been loaded yet + // and it caches the language, which is hard coded in $CONFIG->language as en. + // overriding it with real values later has no effect because it's already cached. + elgg_log("This version of the PHP memcache API doesn't support multiple servers.", 'ERROR'); + + $server = $CONFIG->memcache_servers[0]; + if (is_array($server)) { + $this->memcache->connect($server[0], $server[1]); + } else { + $this->memcache->addServer($server, 11211); + } + } + + // Get version + $this->version = $this->memcache->getVersion(); + if (version_compare($this->version, ElggMemcache::$MINSERVERVERSION, '<')) { + $msg = vsprintf('Memcache needs at least version %s to run, you are running %s', + array(ElggMemcache::$MINSERVERVERSION, + $this->version + )); + + throw new ConfigurationException($msg); + } + + // Set some defaults + if (isset($CONFIG->memcache_expires)) { + $this->expires = $CONFIG->memcache_expires; + } + } + + /** + * Set the default expiry. + * + * @param int $expires The lifetime as a unix timestamp or time from now. Defaults forever. + * + * @return void + */ + public function setDefaultExpiry($expires = 0) { + $this->expires = $expires; + } + + /** + * Combine a key with the namespace. + * Memcache can only accept <250 char key. If the given key is too long it is shortened. + * + * @param string $key The key + * + * @return string The new key. + */ + private function makeMemcacheKey($key) { + $prefix = $this->getNamespace() . ":"; + + if (strlen($prefix . $key) > 250) { + $key = md5($key); + } + + return $prefix . $key; + } + + /** + * Saves a name and value to the cache + * + * @param string $key Name + * @param string $data Value + * @param integer $expires Expires (in seconds) + * + * @return bool + */ + public function save($key, $data, $expires = null) { + $key = $this->makeMemcacheKey($key); + + if ($expires === null) { + $expires = $this->expires; + } + + $result = $this->memcache->set($key, $data, null, $expires); + if ($result === false) { + elgg_log("MEMCACHE: FAILED TO SAVE $key", 'ERROR'); + } + + return $result; + } + + /** + * Retrieves data. + * + * @param string $key Name of data to retrieve + * @param int $offset Offset + * @param int $limit Limit + * + * @return mixed + */ + public function load($key, $offset = 0, $limit = null) { + $key = $this->makeMemcacheKey($key); + + $result = $this->memcache->get($key); + if ($result === false) { + elgg_log("MEMCACHE: FAILED TO LOAD $key", 'ERROR'); + } + + return $result; + } + + /** + * Delete data + * + * @param string $key Name of data + * + * @return bool + */ + public function delete($key) { + $key = $this->makeMemcacheKey($key); + + return $this->memcache->delete($key, 0); + } + + /** + * Clears the entire cache? + * + * @todo write or remove. + * + * @return true + */ + public function clear() { + // DISABLE clearing for now - you must use delete on a specific key. + return true; + + // @todo Namespaces as in #532 + } +} |