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