Added Memcached plugin (using pecl/memcached versus pecl/memcache)

1 files changed, 223 insertions, 0 deletions

diff --git a/plugins/MemcachedPlugin.php b/plugins/MemcachedPlugin.php
new file mode 100644
index 000000000..707e6db9a
--- /dev/null
+++ b/plugins/MemcachedPlugin.php
@@ -0,0 +1,223 @@
+<?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;
+    }
+}
+