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.
 107                 $charsLeft = 255 - strlen( $keyspace ) - count( $args );
 108
 109                 $args = array_map(
 110                         function ( $arg ) use ( &$charsLeft ) {
 111                                 $arg = strtr( $arg, ' ', '_' );
 112
 113                                 // Make sure %, #, and non-ASCII chars are escaped
 114                                 $arg = preg_replace_callback(
 115                                         '/[^\x21-\x22\x24\x26-\x39\x3b-\x7e]+/',
 116                                         function ( $m ) {
 117                                                 return rawurlencode( $m[0] );
 118                                         },
 119                                         $arg
 120                                 );
 121
 122                                 // 33 = 32 characters for the MD5 + 1 for the '#' prefix.
 123                                 if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
 124                                         $arg = '#' . md5( $arg );
 125                                 }
 126
 127                                 $charsLeft -= strlen( $arg );
 128                                 return $arg;
 129                         },
 130                         $args
 131                 );
 132
 133                 if ( $charsLeft < 0 ) {
 134                         return $keyspace . ':##' . md5( implode( ':', $args ) );
 135                 }
 136
 137                 return $keyspace . ':' . implode( ':', $args );
 138         }
 139
 140         /**
 141          * Ensure that a key is safe to use (contains no control characters and no
 142          * characters above the ASCII range.)
 143          *
 144          * @param string $key
 145          * @return string
 146          * @throws Exception
 147          */
 148         public function validateKeyEncoding( $key ) {
 149                 if ( preg_match( '/[^\x21-\x7e]+/', $key ) ) {
 150                         throw new Exception( "Key contains invalid characters: $key" );
 151                 }
 152                 return $key;
 153         }
 154
 155         /**
 156          * TTLs higher than 30 days will be detected as absolute TTLs
 157          * (UNIX timestamps), and will result in the cache entry being
 158          * discarded immediately because the expiry is in the past.
 159          * Clamp expires >30d at 30d, unless they're >=1e9 in which
 160          * case they are likely to really be absolute (1e9 = 2011-09-09)
 161          * @param int $expiry
 162          * @return int
 163          */
 164         function fixExpiry( $expiry ) {
 165                 if ( $expiry > 2592000 && $expiry < 1000000000 ) {
 166                         $expiry = 2592000;
 167                 }
 168                 return (int)$expiry;
 169         }
 170
 171         /**
 172          * Send a debug message to the log
 173          * @param string $text
 174          */
 175         protected function debugLog( $text ) {
 176                 $this->logger->debug( $text );
 177         }
 178
 179         public function modifySimpleRelayEvent( array $event ) {
 180                 if ( array_key_exists( 'val', $event ) ) {
 181                         $event['flg'] = 0; // data is not serialized nor gzipped (for memcached driver)
 182                 }
 183
 184                 return $event;
 185         }
 186 }