[PLUGINS] Updated and reviewed the Memcached plugin

plugins/Memcached/MemcachedPlugin.php

@@ -1,13 +1,15 @@
 <?php
+
 /**
- * StatusNet - the distributed open-source microblogging tool
+ * GNU social - a federating social network
- * Copyright (C) 2009, StatusNet, Inc.
  *
- * Plugin to implement cache interface for memcached
+ * A plugin to use memcached for the interface with memcache
  *
- * PHP version 5
+ * 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.
  *
- * This program is free software: you can redistribute it and/or modify
+ * LICENCE: 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.
@@ -21,48 +23,29 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  * @category  Cache
- * @package   StatusNet
+ * @package   GNUsocial
  * @author    Evan Prodromou <evan@status.net>
  * @author    Craig Andrews <candrews@integralblue.com>
+ * @author    Miguel Dantas <biodantas@gmail.com>
  * @copyright 2009 StatusNet, Inc.
- * @copyright 2009 Free Software Foundation, Inc http://www.fsf.org
+ * @copyright 2009, 2019 Free Software Foundation, Inc http://www.fsf.org
  * @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')) {
+defined('GNUSOCIAL') || die();
-    // 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>
- * @author    Craig Andrews <candrews@integralblue.com>
- * @copyright 2009 StatusNet, Inc.
- * @copyright 2009 Free Software Foundation, Inc http://www.fsf.org
- * @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
 {
-    const PLUGIN_VERSION = '2.0.0';
+    const PLUGIN_VERSION = '2.1.0';
 
     static $cacheInitialized = false;
 
-    private $_conn  = null;
+    public $servers = ['127.0.0.1'];
-    public $servers = array('127.0.0.1;11211');
-
     public $defaultExpiry = 86400; // 24h
 
+    private $_conn  = null;
+
     /**
      * Initialize the plugin
      *
@@ -72,8 +55,12 @@ class MemcachedPlugin extends Plugin
      */
     function onInitializePlugin()
     {
+        try {
             $this->_ensureConn();
             self::$cacheInitialized = true;
+        } catch (MemcachedException $e) {
+            common_log(LOG_ERR, 'Memcached encountered exception ' . get_class($e) . ': ' . $e->getMessage());
+        }
         return true;
     }
 
@@ -89,10 +76,20 @@ class MemcachedPlugin extends Plugin
      */
     function onStartCacheGet(&$key, &$value)
     {
+        try {
             $this->_ensureConn();
             $value = $this->_conn->get($key);
+        } catch (MemcachedException $e) {
+            common_log(LOG_ERR, 'Memcached encountered exception ' . get_class($e) . ': ' . $e->getMessage());
+            return true;
+        }
+        if ($value === false) {
+            // If not found, let other plugins handle it
+            return $this->_conn->getResultCode() === Memcached::RES_NOTFOUND;
+        } else {
             return false;
         }
+    }
 
     /**
      * Associate a value with a key
@@ -107,12 +104,17 @@ class MemcachedPlugin extends Plugin
      */
     function onStartCacheSet(&$key, &$value, &$flag, &$expiry, &$success)
     {
-        $this->_ensureConn();
         if ($expiry === null) {
             $expiry = $this->defaultExpiry;
         }
+        try {
+            $this->_ensureConn();
             $success = $this->_conn->set($key, $value, $expiry);
-        return false;
+        } catch (MemcachedException $e) {
+            common_log(LOG_ERR, 'Memcached encountered exception ' . get_class($e) . ': ' . $e->getMessage());
+            return true;
+        }
+        return !$success;
     }
 
     /**
@@ -127,10 +129,20 @@ class MemcachedPlugin extends Plugin
      */
     function onStartCacheIncrement(&$key, &$step, &$value)
     {
+        try {
             $this->_ensureConn();
             $value = $this->_conn->increment($key, $step);
+        } catch (MemcachedException $e) {
+            common_log(LOG_ERR, 'Memcached encountered exception ' . get_class($e) . ': ' . $e->getMessage());
+            return true;
+        }
+        if ($value === false) {
+            // If not found, let other plugins handle it
+            return $this->_conn->getResultCode() === Memcached::RES_NOTFOUND;
+        } else {
             return false;
         }
+    }
 
     /**
      * Delete a value associated with a key
@@ -142,14 +154,23 @@ class MemcachedPlugin extends Plugin
      */
     function onStartCacheDelete(&$key, &$success)
     {
+        try {
             $this->_ensureConn();
             $success = $this->_conn->delete($key);
-        return false;
+        } catch (MemcachedException $e) {
+            common_log(LOG_ERR, 'Memcached encountered exception ' . get_class($e) . ': ' . $e->getMessage());
+            return true;
+        }
+        return !$success;
     }
 
     function onStartCacheReconnect(&$success)
     {
-        // nothing to do
+        try {
+            $this->_ensureConn();
+        } catch (MemcachedException $e) {
+            common_log(LOG_ERR, 'Memcached encountered exception ' . get_class($e) . ': ' . $e->getMessage());
+        }
         return true;
     }
 
@@ -170,13 +191,13 @@ class MemcachedPlugin extends Plugin
                 if (is_array($this->servers)) {
                     $servers = $this->servers;
                 } else {
-                $servers = array($this->servers);
+                    $servers = [$this->servers];
                 }
                 foreach ($servers as $server) {
-                if (strpos($server, ';') !== false) {
+                    if (is_array($server) && count($server) === 2) {
-                    list($host, $port) = explode(';', $server);
+                        list($host, $port) = $server;
                     } else {
-                    $host = $server;
+                        $host = is_array($server) ? $server[0] : $server;
                         $port = 11211;
                     }
 

plugins/Memcached/README

@@ -2,20 +2,37 @@ The Memcached plugin implements cache interface for memcached.
 
 See: http://memcached.org/
 
+The difference between the former `MemcachePlugin` and `MemcachedPlugin` is that they use,
+respectively, `memcache` and `memcached` as the underlying php libraries. These are similar
+libraries, made by different authors with slightly different cacpabilities, therefore `memcached`
+was selected.
+
 Installation
 ============
-add "addPlugin('Memcached');"
+
-to the bottom of your config.php
+Tell your `config.php` to use this plugin (replace `tcp://localhost:6379` with the address/port
+of your Memcache backend server):
+
+`addPlugin('Memcached');`
+
+Note that this typically requires configuring the `memcached` extension for `php`, which is
+typically available as a binary package from your system's package manager. In Debian based systems
+and on Arch based systems, this is likely available under the `php-memcached` package. Note the
+final `d`. On Arch, uncomment the line in `/etc/php/conf.d/memcached.ini` and restart your webserver
+and/or php-fpm or similar.
 
 Settings
 ========
-servers: Array of memcached servers addresses
+
+servers: Array of memcached servers addresses. Each server address should be either a string with
+address or an array where the first element is a string with the address an optional second element
+with the port.
+
 defaultExpiry: How long before cache expires (in seconds)
 
 Example
 =======
-addPlugin('Memcached', array(
-    'servers' => array('127.0.0.1;11211'),
-    'defaultExpiry' => 86400 // 24h
-));
 
+addPlugin('Memcached', [ 'servers' => ['127.0.0.1', 11211],
+                         'defaultExpiry' => 86400 // 24h
+                       ]);