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-rw-r--r--engine/classes/ElggMemcache.php201
1 files changed, 201 insertions, 0 deletions
diff --git a/engine/classes/ElggMemcache.php b/engine/classes/ElggMemcache.php
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+<?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
+ }
+}