includes/libs/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 MemcachedClient|Memcached */
  31         protected $client;
  32
  33         function __construct( array $params ) {
  34                 parent::__construct( $params );
  35
  36                 $this->attrMap[self::ATTR_SYNCWRITES] = self::QOS_SYNCWRITES_BE; // unreliable
  37         }
  38
  39         /**
  40          * Fill in some defaults for missing keys in $params.
  41          *
  42          * @param array $params
  43          * @return array
  44          */
  45         protected function applyDefaultParams( $params ) {
  46                 if ( !isset( $params['compress_threshold'] ) ) {
  47                         $params['compress_threshold'] = 1500;
  48                 }
  49                 if ( !isset( $params['connect_timeout'] ) ) {
  50                         $params['connect_timeout'] = 0.5;
  51                 }
  52                 return $params;
  53         }
  54
  55         protected function doGet( $key, $flags = 0 ) {
  56                 $casToken = null;
  57
  58                 return $this->getWithToken( $key, $casToken, $flags );
  59         }
  60
  61         protected function getWithToken( $key, &$casToken, $flags = 0 ) {
  62                 return $this->client->get( $this->validateKeyEncoding( $key ), $casToken );
  63         }
  64
  65         public function set( $key, $value, $exptime = 0, $flags = 0 ) {
  66                 return $this->client->set( $this->validateKeyEncoding( $key ), $value,
  67                         $this->fixExpiry( $exptime ) );
  68         }
  69
  70         protected function cas( $casToken, $key, $value, $exptime = 0 ) {
  71                 return $this->client->cas( $casToken, $this->validateKeyEncoding( $key ),
  72                         $value, $this->fixExpiry( $exptime ) );
  73         }
  74
  75         public function delete( $key ) {
  76                 return $this->client->delete( $this->validateKeyEncoding( $key ) );
  77         }
  78
  79         public function add( $key, $value, $exptime = 0 ) {
  80                 return $this->client->add( $this->validateKeyEncoding( $key ), $value,
  81                         $this->fixExpiry( $exptime ) );
  82         }
  83
  84         public function merge( $key, callable $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
  85                 return $this->mergeViaCas( $key, $callback, $exptime, $attempts );
  86         }
  87
  88         public function changeTTL( $key, $exptime = 0 ) {
  89                 return $this->client->touch( $this->validateKeyEncoding( $key ),
  90                         $this->fixExpiry( $exptime ) );
  91         }
  92
  93         /**
  94          * Get the underlying client object. This is provided for debugging
  95          * purposes.
  96          * @return MemcachedClient|Memcached
  97          */
  98         public function getClient() {
  99                 return $this->client;
 100         }
 101
 102         /**
 103          * Construct a cache key.
 104          *
 105          * @since 1.27
 106          * @param string $keyspace
 107          * @param array $args
 108          * @return string
 109          */
 110         public function makeKeyInternal( $keyspace, $args ) {
 111                 // Memcached keys have a maximum length of 255 characters. From that,
 112                 // subtract the number of characters we need for the keyspace and for
 113                 // the separator character needed for each argument. To handle some
 114                 // custom prefixes used by thing like WANObjectCache, limit to 205.
 115                 $charsLeft = 205 - strlen( $keyspace ) - count( $args );
 116
 117                 $args = array_map(
 118                         function ( $arg ) use ( &$charsLeft ) {
 119                                 $arg = strtr( $arg, ' ', '_' );
 120
 121                                 // Make sure %, #, and non-ASCII chars are escaped
 122                                 $arg = preg_replace_callback(
 123                                         '/[^\x21-\x22\x24\x26-\x39\x3b-\x7e]+/',
 124                                         function ( $m ) {
 125                                                 return rawurlencode( $m[0] );
 126                                         },
 127                                         $arg
 128                                 );
 129
 130                                 // 33 = 32 characters for the MD5 + 1 for the '#' prefix.
 131                                 if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
 132                                         $arg = '#' . md5( $arg );
 133                                 }
 134
 135                                 $charsLeft -= strlen( $arg );
 136                                 return $arg;
 137                         },
 138                         $args
 139                 );
 140
 141                 if ( $charsLeft < 0 ) {
 142                         return $keyspace . ':##' . md5( implode( ':', $args ) );
 143                 }
 144
 145                 return $keyspace . ':' . implode( ':', $args );
 146         }
 147
 148         /**
 149          * Ensure that a key is safe to use (contains no control characters and no
 150          * characters above the ASCII range.)
 151          *
 152          * @param string $key
 153          * @return string
 154          * @throws Exception
 155          */
 156         public function validateKeyEncoding( $key ) {
 157                 if ( preg_match( '/[^\x21-\x7e]+/', $key ) ) {
 158                         throw new Exception( "Key contains invalid characters: $key" );
 159                 }
 160                 return $key;
 161         }
 162
 163         /**
 164          * TTLs higher than 30 days will be detected as absolute TTLs
 165          * (UNIX timestamps), and will result in the cache entry being
 166          * discarded immediately because the expiry is in the past.
 167          * Clamp expires >30d at 30d, unless they're >=1e9 in which
 168          * case they are likely to really be absolute (1e9 = 2011-09-09)
 169          * @param int $expiry
 170          * @return int
 171          */
 172         function fixExpiry( $expiry ) {
 173                 if ( $expiry > 2592000 && $expiry < 1000000000 ) {
 174                         $expiry = 2592000;
 175                 }
 176                 return (int)$expiry;
 177         }
 178
 179         /**
 180          * Send a debug message to the log
 181          * @param string $text
 182          */
 183         protected function debugLog( $text ) {
 184                 $this->logger->debug( $text );
 185         }
 186
 187         public function modifySimpleRelayEvent( array $event ) {
 188                 if ( array_key_exists( 'val', $event ) ) {
 189                         $event['flg'] = 0; // data is not serialized nor gzipped (for memcached driver)
 190                 }
 191
 192                 return $event;
 193         }
 194 }