object-cache.php

<?php
/*
Plugin Name: Memcached
Description: Memcached backend for the WP Object Cache.
Version: 2.1
Plugin URI: http://wordpress.org/extend/plugins/memcached/
Author: Ryan Boren, Denis de Bernardy, Matt Martz
Install this file to wp-content/object-cache.php
Alterations done by: Thorsten Ott (tott)
- For debugging purposes the following debug parameters can be used
	- ?memcache=skip would skip memcache and fallback to regular cache class
	- ?memcache=wipe-page-cache would delete each key before trying to get it.
- Set WP_CACHE_KEY_SALT to DB_NAME by default to ensure that multiple installs on one server won't overlap
- You can define the memcache parameters used for skip/wipe adding
	define( 'WP_CACHE_SECRET_KEY_SKIP', '<your-secret-skip-parameter>' );
	define( 'WP_CACHE_SECRET_KEY_WIPE', '<your-secret-wipe-parameter>' );
  to your wp-config.php (functions.php would be to late).
- Added a simple admin bar menu
*/

// Users with setups where multiple installs share a common wp-config.php or $table_prefix
// can use this to guarantee uniqueness for the keys generated by this object cache
if ( !defined( 'WP_CACHE_KEY_SALT' ) )
	define( 'WP_CACHE_KEY_SALT', ( defined( 'DB_NAME' ) ? DB_NAME : '' ) ); // use DB_NAME by default to ensure that multiple installs on the same server won't overlap.

if ( !defined( 'WP_CACHE_SECRET_KEY_SKIP' ) )
	define( 'WP_CACHE_SECRET_KEY_SKIP', 'skip' );
if ( !defined( 'WP_CACHE_SECRET_KEY_WIPE' ) )
	define( 'WP_CACHE_SECRET_KEY_WIPE', 'wipe-page-cache' );


// Allow a memcache bypass based on $_REQUEST parameters
function wp_start_default_object_cache() {
	global $blog_id;
	$first_init = false;
	if ( ! function_exists( 'wp_cache_init' ) ) {
		wp_using_ext_object_cache( false );
		$first_init = true;
	}

	if ( ! wp_using_ext_object_cache() )
		require_once ABSPATH . WPINC . '/cache.php';

	// If cache supports reset, reset instead of init if already initialized.
	// Reset signals to the cache that global IDs have changed and it may need to update keys
	// and cleanup caches.
	if ( ! $first_init && function_exists( 'wp_cache_switch_to_blog' ) )
		wp_cache_switch_to_blog( $blog_id );
	elseif ( function_exists( 'wp_cache_init' ) )
		wp_cache_init();

	if ( function_exists( 'wp_cache_add_global_groups' ) ) {
		wp_cache_add_global_groups( array( 'users', 'userlogins', 'usermeta', 'user_meta', 'site-transient', 'site-options', 'site-lookup', 'blog-lookup', 'blog-details', 'rss', 'global-posts', 'blog-id-cache' ) );
		wp_cache_add_non_persistent_groups( array( 'comment', 'counts', 'plugins' ) );
	}
}

if ( function_exists( 'add_action' ) ) {
	add_action( 'admin_bar_menu', 'wp_cache_action_admin_bar_menu', 9999 );
}
function wp_cache_action_admin_bar_menu() {
	global $wp_admin_bar, $wp_object_cache;
	if ( !is_site_admin() )
		return;

	$wp_admin_bar->add_menu( array(
		'id' => 'mc',
		'title' => 'MemCache',
		'href' => false
		) );
	$wp_admin_bar->add_menu( array(
		'id' => 'mcskip',
		'parent' => 'mc',
		'title' => 'skip',
		'href' => add_query_arg( array( 'memcache' => WP_CACHE_SECRET_KEY_SKIP ) )
		) );
	$wp_admin_bar->add_menu( array(
		'id' => 'mcwipe',
		'parent' => 'mc',
		'title' => 'wipe',
		'href' => add_query_arg( array( 'memcache' => WP_CACHE_SECRET_KEY_WIPE ) )
		) );
	$wp_admin_bar->add_menu( array(
		'id' => 'mcdefault',
		'parent' => 'mc',
		'title' => 'default',
		'href' => remove_query_arg( array( 'memcache' ) )
		) );
	if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
		if ( is_callable( array( $wp_object_cache, 'get_mc' ) ) ) {
			$wp_admin_bar->add_menu( array(
				'id' => 'mcget',
				'parent' => 'mc',
				'title' => 'Get:' . ( isset( $wp_object_cache->stats['get'] ) ? $wp_object_cache->stats['get'] : 0 ),
				'href' => false,
				) );
			$wp_admin_bar->add_menu( array(
				'id' => 'mcset',
				'parent' => 'mc',
				'title' => 'Set:' . ( isset( $wp_object_cache->stats['set'] ) ? $wp_object_cache->stats['set'] : 0 ),
				'href' => false,
				) );
			$wp_admin_bar->add_menu( array(
				'id' => 'mcdelete',
				'parent' => 'mc',
				'title' => 'Delete:' . ( isset( $wp_object_cache->stats['delete'] ) ? $wp_object_cache->stats['delete'] : 0 ),
				'href' => false,
				) );
		} else {
			$wp_admin_bar->add_menu( array(
				'id' => 'mchits',
				'parent' => 'mc',
				'title' => 'Hits:' . ( isset( $wp_object_cache->cache_hits ) ? $wp_object_cache->cache_hits : 0 ),
				'href' => false,
				) );
			$wp_admin_bar->add_menu( array(
				'id' => 'mcmisses',
				'parent' => 'mc',
				'title' => 'Misses:' . ( isset( $wp_object_cache->cache_misses ) ? $wp_object_cache->cache_misses : 0 ),
				'href' => false,
				) );
		}
		global $wpdb;
		$wp_admin_bar->add_menu( array(
			'id' => 'mcqueries',
			'parent' => 'mc',
			'title' => 'Queries:' . ( isset( $wpdb->num_queries ) ? $wpdb->num_queries : 0 ),
			'href' => false,
			) );
	}
}

// Regular cache when ?memcache=skip
if ( isset( $_REQUEST['memcache'] ) && 'skip' == $_REQUEST['memcache'] ) {
	wp_start_default_object_cache();
	return;

// otherwise use memcache
} else {

	function wp_cache_add( $key, $data, $group = '', $expire = 0 ) {
		global $wp_object_cache;

		return $wp_object_cache->add( $key, $data, $group, $expire );
	}

	function wp_cache_incr( $key, $n = 1, $group = '' ) {
		global $wp_object_cache;

		return $wp_object_cache->incr( $key, $n, $group );
	}

	function wp_cache_decr( $key, $n = 1, $group = '' ) {
		global $wp_object_cache;

		return $wp_object_cache->decr( $key, $n, $group );
	}

	function wp_cache_close() {
		global $wp_object_cache;

		return $wp_object_cache->close();
	}

	function wp_cache_delete( $key, $group = '' ) {
		global $wp_object_cache;

		return $wp_object_cache->delete( $key, $group );
	}

	function wp_cache_flush() {
		global $wp_object_cache;

		return $wp_object_cache->flush();
	}

	function wp_cache_get( $key, $group = '', $force = false ) {
		global $wp_object_cache;
		if ( $force === false && isset( $_REQUEST['memcache'] ) && 'wipe-page-cache' == $_REQUEST['memcache'] ) {
			if ( false !== array_search( $group, $wp_object_cache->global_groups ) ) {
				$wp_object_cache->delete( $key, $group );
			}
		}
		return $wp_object_cache->get( $key, $group, $force );
	}

	function wp_cache_init() {
		global $wp_object_cache;

		$wp_object_cache = new WP_Object_Cache();
	}

	function wp_cache_replace( $key, $data, $group = '', $expire = 0 ) {
		global $wp_object_cache;

		return $wp_object_cache->replace( $key, $data, $group, $expire );
	}

	function wp_cache_set( $key, $data, $group = '', $expire = 0 ) {
		global $wp_object_cache;

		if ( defined( 'WP_INSTALLING' ) == false )
			return $wp_object_cache->set( $key, $data, $group, $expire );
		else
			return $wp_object_cache->delete( $key, $group );
	}

	function wp_cache_switch_to_blog( $blog_id ) {
		global $wp_object_cache;

		return $wp_object_cache->switch_to_blog( $blog_id );
	}

	function wp_cache_add_global_groups( $groups ) {
		global $wp_object_cache;

		$wp_object_cache->add_global_groups( $groups );
	}

	function wp_cache_add_non_persistent_groups( $groups ) {
		global $wp_object_cache;

		$wp_object_cache->add_non_persistent_groups( $groups );
	}

	class WP_Object_Cache {
		var $global_groups = array();

		var $no_mc_groups = array();

		var $cache = array();
		var $mc = array();
		var $stats = array();
		var $group_ops = array();

		var $debug = false;
		var $cache_enabled = true;
		var $default_expiration = 0;

		function add( $id, $data, $group = 'default', $expire = 0 ) {
			$key = $this->key( $id, $group );

			if ( is_object( $data ) )
				$data = clone $data;

			if ( in_array( $group, $this->no_mc_groups ) ) {
				$this->cache[$key] = $data;
				return true;
			} elseif ( isset( $this->cache[$key] ) && $this->cache[$key] !== false ) {
				return false;
			}

			$mc =& $this->get_mc( $group );
			$expire = ( $expire == 0 ) ? $this->default_expiration : $expire;
			$result = $mc->add( $key, $data, false, $expire );

			if ( false !== $result ) {
				@ ++$this->stats['add'];
				$this->group_ops[$group][] = "add $id";
				$this->cache[$key] = $data;
			}

			return $result;
		}

		function add_global_groups( $groups ) {
			if ( ! is_array( $groups ) )
				$groups = (array) $groups;

			$this->global_groups = array_merge( $this->global_groups, $groups );
			$this->global_groups = array_unique( $this->global_groups );
		}

		function add_non_persistent_groups( $groups ) {
			if ( ! is_array( $groups ) )
				$groups = (array) $groups;

			$this->no_mc_groups = array_merge( $this->no_mc_groups, $groups );
			$this->no_mc_groups = array_unique( $this->no_mc_groups );
		}

		function incr( $id, $n = 1, $group = 'default' ) {
			$key = $this->key( $id, $group );
			$mc =& $this->get_mc( $group );
			$this->cache[ $key ] = $mc->increment( $key, $n );
			return $this->cache[ $key ];
		}

		function decr( $id, $n = 1, $group = 'default' ) {
			$key = $this->key( $id, $group );
			$mc =& $this->get_mc( $group );
			$this->cache[ $key ] = $mc->decrement( $key, $n );
			return $this->cache[ $key ];
		}

		function close() {

			foreach ( $this->mc as $bucket => $mc )
				$mc->close();
		}

		function delete( $id, $group = 'default' ) {
			$key = $this->key( $id, $group );

			if ( in_array( $group, $this->no_mc_groups ) ) {
				unset( $this->cache[$key] );
				return true;
			}

			$mc =& $this->get_mc( $group );

			$result = $mc->delete( $key );

			@ ++$this->stats['delete'];
			$this->group_ops[$group][] = "delete $id";

			if ( false !== $result )
				unset( $this->cache[$key] );

			return $result;
		}

		function flush() {
			// Don't flush if multi-blog.
			if ( function_exists( 'is_site_admin' ) || defined( 'CUSTOM_USER_TABLE' ) && defined( 'CUSTOM_USER_META_TABLE' ) )
				return true;

			$ret = true;
			foreach ( array_keys( $this->mc ) as $group )
				$ret &= $this->mc[$group]->flush();
			return $ret;
		}

		function get( $id, $group = 'default', $force = false ) {
			$key = $this->key( $id, $group );
			$mc =& $this->get_mc( $group );

			if ( isset( $this->cache[$key] ) && ( !$force || in_array( $group, $this->no_mc_groups ) ) ) {
				if ( is_object( $this->cache[$key] ) )
					$value = clone $this->cache[$key];
				else
					$value = $this->cache[$key];
			} else if ( in_array( $group, $this->no_mc_groups ) ) {
				$this->cache[$key] = $value = false;
			} else {
				$value = $mc->get( $key );
				if ( NULL === $value )
					$value = false;
				$this->cache[$key] = $value;
			}

			@ ++$this->stats['get'];
			$this->group_ops[$group][] = "get $id";

			if ( 'checkthedatabaseplease' === $value ) {
				unset( $this->cache[$key] );
				$value = false;
			}

			return $value;
		}

		function get_multi( $groups ) {
		/*
		 * format: $get['group-name'] = array( 'key1', 'key2' );
		 */
		$return = array();
		foreach ( $groups as $group => $ids ) {
			$mc =& $this->get_mc( $group );
			foreach ( $ids as $id ) {
				$key = $this->key( $id, $group );
				if ( isset( $this->cache[$key] ) ) {
					if ( is_object( $this->cache[$key] ) )
						$return[$key] = clone $this->cache[$key];
					else
						$return[$key] = $this->cache[$key];
					continue;
				} else if ( in_array( $group, $this->no_mc_groups ) ) {
					$return[$key] = false;
					continue;
				} else {
					$return[$key] = $mc->get( $key );
				}
			}
			if ( $to_get ) {
				$vals = $mc->get_multi( $to_get );
				$return = array_merge( $return, $vals );
			}
		}
		@ ++$this->stats['get_multi'];
		$this->group_ops[$group][] = "get_multi $id";
		$this->cache = array_merge( $this->cache, $return );
		return $return;
	}

	function key( $key, $group ) {
		if ( empty( $group ) )
			$group = 'default';

		if ( false !== array_search( $group, $this->global_groups ) )
			$prefix = $this->global_prefix;
		else
			$prefix = $this->blog_prefix;

		return preg_replace( '/\s+/', '', WP_CACHE_KEY_SALT . "$prefix$group:$key" );
	}

	function replace( $id, $data, $group = 'default', $expire = 0 ) {
		$key = $this->key( $id, $group );
		$expire = ( $expire == 0 ) ? $this->default_expiration : $expire;
		$mc =& $this->get_mc( $group );

		if ( is_object( $data ) )
			$data = clone $data;

		$result = $mc->replace( $key, $data, false, $expire );
		if ( false !== $result )
			$this->cache[$key] = $data;
		return $result;
	}

	function set( $id, $data, $group = 'default', $expire = 0 ) {
		$key = $this->key( $id, $group );
		if ( isset( $this->cache[$key] ) && ( 'checkthedatabaseplease' === $this->cache[$key] ) )
			return false;

		if ( is_object( $data ) )
			$data = clone $data;

		$this->cache[$key] = $data;

		if ( in_array( $group, $this->no_mc_groups ) )
			return true;

		$expire = ( $expire == 0 ) ? $this->default_expiration : $expire;
		$mc =& $this->get_mc( $group );
		$result = $mc->set( $key, $data, false, $expire );

		return $result;
	}

	function switch_to_blog( $blog_id ) {
		$blog_id = (int) $blog_id;
		$this->blog_prefix = ( is_multisite() ? $blog_id : $table_prefix ) . ':';
	}

	function colorize_debug_line( $line ) {
		$colors = array(
			'get' => 'green',
			'set' => 'purple',
			'add' => 'blue',
			'delete' => 'red' );

		$cmd = substr( $line, 0, strpos( $line, ' ' ) );

		$cmd2 = "<span style='color:{$colors[$cmd]}'>$cmd</span>";

		return $cmd2 . substr( $line, strlen( $cmd ) ) . "\n";
	}

	function stats() {
		echo "<p>\n";
		foreach ( $this->stats as $stat => $n ) {
			echo "<strong>$stat</strong> $n";
			echo "<br/>\n";
		}
		echo "</p>\n";
		echo "<h3>Memcached:</h3>";
		foreach ( $this->group_ops as $group => $ops ) {
			if ( !isset( $_GET['debug_queries'] ) && 500 < count( $ops ) ) {
				$ops = array_slice( $ops, 0, 500 );
				echo "<big>Too many to show! <a href='" . add_query_arg( 'debug_queries', 'true' ) . "'>Show them anyway</a>.</big>\n";
			}
			echo "<h4>$group commands</h4>";
			echo "<pre>\n";
			$lines = array();
			foreach ( $ops as $op ) {
				$lines[] = $this->colorize_debug_line( $op );
			}
			print_r( $lines );
			echo "</pre>\n";
		}
	}

	function &get_mc( $group ) {
		if ( isset( $this->mc[$group] ) )
			return $this->mc[$group];
		return $this->mc['default'];
	}

	function failure_callback( $host, $port ) {
			//error_log("Connection failure for $host:$port\n", 3, '/tmp/memcached.txt');
	}

	function WP_Object_Cache() {
		global $memcached_servers;

		$this->debug = ( defined( 'WP_DEBUG' ) && WP_DEBUG ) ? true : false;
		if ( isset( $memcached_servers ) )
			$buckets = $memcached_servers;
		else
			$buckets = array( '127.0.0.1:11211' );

		reset( $buckets );
		if ( is_int( key( $buckets ) ) )
			$buckets = array( 'default' => $buckets );

		foreach ( $buckets as $bucket => $servers ) {
			$this->mc[$bucket] = new Memcache();
			foreach ( $servers as $server  ) {
				list ( $node, $port ) = explode( ':', $server );
				if ( !$port )
					$port = ini_get( 'memcache.default_port' );
				$port = intval( $port );
				if ( !$port )
					$port = 11211;
				$this->mc[$bucket]->addServer( $node, $port, true, 1, 1, 15, true, array( $this, 'failure_callback' ) );
				$this->mc[$bucket]->setCompressThreshold( 20000, 0.2 );
			}
		}

		global $blog_id, $table_prefix;
		$this->global_prefix = '';
		$this->blog_prefix = '';
		if ( function_exists( 'is_multisite' ) ) {
			$this->global_prefix = ( is_multisite() || defined( 'CUSTOM_USER_TABLE' ) && defined( 'CUSTOM_USER_META_TABLE' ) ) ? '' : $table_prefix;
			$this->blog_prefix = ( is_multisite() ? $blog_id : $table_prefix ) . ':';
		}

		$this->cache_hits =& $this->stats['get'];
		$this->cache_misses =& $this->stats['add'];
	}
}
}