includes/objectcache/MemcachedBagOStuff.php

   1 <?php
   2 /**
   3  * Base class for memcached clients.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Cache
  22  */
  23
  24 /**
  25  * Base class for memcached clients.
  26  *
  27  * @ingroup Cache
  28  */
  29 class MemcachedBagOStuff extends BagOStuff {
  30         /** @var MWMemcached|Memcached */
  31         protected $client;
  32
  33         /**
  34          * Fill in the defaults for any parameters missing from $params, using the
  35          * backwards-compatible global variables
  36          * @param array $params
  37          * @return array
  38          */
  39         protected function applyDefaultParams( $params ) {
  40                 if ( !isset( $params['servers'] ) ) {
  41                         $params['servers'] = $GLOBALS['wgMemCachedServers'];
  42                 }
  43                 if ( !isset( $params['debug'] ) ) {
  44                         $params['debug'] = $GLOBALS['wgMemCachedDebug'];
  45                 }
  46                 if ( !isset( $params['persistent'] ) ) {
  47                         $params['persistent'] = $GLOBALS['wgMemCachedPersistent'];
  48                 }
  49                 if ( !isset( $params['compress_threshold'] ) ) {
  50                         $params['compress_threshold'] = 1500;
  51                 }
  52                 if ( !isset( $params['timeout'] ) ) {
  53                         $params['timeout'] = $GLOBALS['wgMemCachedTimeout'];
  54                 }
  55                 if ( !isset( $params['connect_timeout'] ) ) {
  56                         $params['connect_timeout'] = 0.5;
  57                 }
  58                 return $params;
  59         }
  60
  61         protected function doGet( $key, $flags = 0 ) {
  62                 $casToken = null;
  63
  64                 return $this->getWithToken( $key, $casToken, $flags );
  65         }
  66
  67         protected function getWithToken( $key, &$casToken, $flags = 0 ) {
  68                 return $this->client->get( $this->validateKeyEncoding( $key ), $casToken );
  69         }
  70
  71         public function set( $key, $value, $exptime = 0, $flags = 0 ) {
  72                 return $this->client->set( $this->validateKeyEncoding( $key ), $value,
  73                         $this->fixExpiry( $exptime ) );
  74         }
  75
  76         protected function cas( $casToken, $key, $value, $exptime = 0 ) {
  77                 return $this->client->cas( $casToken, $this->validateKeyEncoding( $key ),
  78                         $value, $this->fixExpiry( $exptime ) );
  79         }
  80
  81         public function delete( $key ) {
  82                 return $this->client->delete( $this->validateKeyEncoding( $key ) );
  83         }
  84
  85         public function add( $key, $value, $exptime = 0 ) {
  86                 return $this->client->add( $this->validateKeyEncoding( $key ), $value,
  87                         $this->fixExpiry( $exptime ) );
  88         }
  89
  90         public function merge( $key, $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
  91                 if ( !is_callable( $callback ) ) {
  92                         throw new Exception( "Got invalid callback." );
  93                 }
  94
  95                 return $this->mergeViaCas( $key, $callback, $exptime, $attempts );
  96         }
  97
  98         /**
  99          * Get the underlying client object. This is provided for debugging
 100          * purposes.
 101          * @return BagOStuff
 102          */
 103         public function getClient() {
 104                 return $this->client;
 105         }
 106
 107         /**
 108          * Construct a cache key.
 109          *
 110          * @since 1.27
 111          * @param string $keyspace
 112          * @param array $args
 113          * @return string
 114          */
 115         public function makeKeyInternal( $keyspace, $args ) {
 116                 // Memcached keys have a maximum length of 255 characters. From that,
 117                 // subtract the number of characters we need for the keyspace and for
 118                 // the separator character needed for each argument.
 119                 $charsLeft = 255 - strlen( $keyspace ) - count( $args );
 120
 121                 $that = $this;
 122                 $args = array_map(
 123                         function ( $arg ) use ( $that, &$charsLeft ) {
 124                                 // Make sure %, #, and non-ASCII chars are escaped
 125                                 $arg = preg_replace_callback(
 126                                         '/[^\x21-\x22\x24\x26-\x7e]+/',
 127                                         function ( $m ) {
 128                                                 return rawurlencode( $m[0] );
 129                                         },
 130                                         $arg
 131                                 );
 132
 133                                 // 33 = 32 characters for the MD5 + 1 for the '#' prefix.
 134                                 if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
 135                                         $arg = '#' . md5( $arg );
 136                                 }
 137
 138                                 $charsLeft -= strlen( $arg );
 139                                 return $arg;
 140                         },
 141                         $args
 142                 );
 143
 144                 if ( $charsLeft < 0 ) {
 145                         $args = array( '##' . md5( implode( ':', $args ) ) );
 146                 }
 147
 148                 return parent::makeKeyInternal( $keyspace, $args );
 149         }
 150
 151         /**
 152          * Ensure that a key is safe to use (contains no control characters and no
 153          * characters above the ASCII range.)
 154          *
 155          * @param string $key
 156          * @return string
 157          * @throws Exception
 158          */
 159         public function validateKeyEncoding( $key ) {
 160                 if ( preg_match( '/[^\x21-\x7e]+/', $key ) ) {
 161                         throw new Exception( "Key contains invalid characters: $key" );
 162                 }
 163                 return $key;
 164         }
 165
 166         /**
 167          * TTLs higher than 30 days will be detected as absolute TTLs
 168          * (UNIX timestamps), and will result in the cache entry being
 169          * discarded immediately because the expiry is in the past.
 170          * Clamp expires >30d at 30d, unless they're >=1e9 in which
 171          * case they are likely to really be absolute (1e9 = 2011-09-09)
 172          * @param int $expiry
 173          * @return int
 174          */
 175         function fixExpiry( $expiry ) {
 176                 if ( $expiry > 2592000 && $expiry < 1000000000 ) {
 177                         $expiry = 2592000;
 178                 }
 179                 return (int)$expiry;
 180         }
 181
 182         /**
 183          * Send a debug message to the log
 184          * @param string $text
 185          */
 186         protected function debugLog( $text ) {
 187                 $this->logger->debug( $text );
 188         }
 189
 190         public function modifySimpleRelayEvent( array $event ) {
 191                 if ( array_key_exists( 'val', $event ) ) {
 192                         $event['flg'] = 0; // data is not serialized nor gzipped (for memcached driver)
 193                 }
 194
 195                 return $event;
 196         }
 197 }