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                 return $params + [
  47                         'compress_threshold' => 1500,
  48                         'connect_timeout' => .5,
  49                         'debug' => false
  50                 ];
  51         }
  52
  53         protected function doGet( $key, $flags = 0 ) {
  54                 $casToken = null;
  55
  56                 return $this->getWithToken( $key, $casToken, $flags );
  57         }
  58
  59         protected function getWithToken( $key, &$casToken, $flags = 0 ) {
  60                 return $this->client->get( $this->validateKeyEncoding( $key ), $casToken );
  61         }
  62
  63         public function set( $key, $value, $exptime = 0, $flags = 0 ) {
  64                 return $this->client->set( $this->validateKeyEncoding( $key ), $value,
  65                         $this->fixExpiry( $exptime ) );
  66         }
  67
  68         protected function cas( $casToken, $key, $value, $exptime = 0 ) {
  69                 return $this->client->cas( $casToken, $this->validateKeyEncoding( $key ),
  70                         $value, $this->fixExpiry( $exptime ) );
  71         }
  72
  73         public function delete( $key ) {
  74                 return $this->client->delete( $this->validateKeyEncoding( $key ) );
  75         }
  76
  77         public function add( $key, $value, $exptime = 0 ) {
  78                 return $this->client->add( $this->validateKeyEncoding( $key ), $value,
  79                         $this->fixExpiry( $exptime ) );
  80         }
  81
  82         public function merge( $key, callable $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
  83                 return $this->mergeViaCas( $key, $callback, $exptime, $attempts );
  84         }
  85
  86         public function changeTTL( $key, $exptime = 0 ) {
  87                 return $this->client->touch( $this->validateKeyEncoding( $key ),
  88                         $this->fixExpiry( $exptime ) );
  89         }
  90
  91         /**
  92          * Get the underlying client object. This is provided for debugging
  93          * purposes.
  94          * @return MemcachedClient|Memcached
  95          */
  96         public function getClient() {
  97                 return $this->client;
  98         }
  99
 100         /**
 101          * Construct a cache key.
 102          *
 103          * @since 1.27
 104          * @param string $keyspace
 105          * @param array $args
 106          * @return string
 107          */
 108         public function makeKeyInternal( $keyspace, $args ) {
 109                 // Memcached keys have a maximum length of 255 characters. From that,
 110                 // subtract the number of characters we need for the keyspace and for
 111                 // the separator character needed for each argument. To handle some
 112                 // custom prefixes used by thing like WANObjectCache, limit to 205.
 113                 $charsLeft = 205 - strlen( $keyspace ) - count( $args );
 114
 115                 $args = array_map(
 116                         function ( $arg ) use ( &$charsLeft ) {
 117                                 $arg = strtr( $arg, ' ', '_' );
 118
 119                                 // Make sure %, #, and non-ASCII chars are escaped
 120                                 $arg = preg_replace_callback(
 121                                         '/[^\x21-\x22\x24\x26-\x39\x3b-\x7e]+/',
 122                                         function ( $m ) {
 123                                                 return rawurlencode( $m[0] );
 124                                         },
 125                                         $arg
 126                                 );
 127
 128                                 // 33 = 32 characters for the MD5 + 1 for the '#' prefix.
 129                                 if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
 130                                         $arg = '#' . md5( $arg );
 131                                 }
 132
 133                                 $charsLeft -= strlen( $arg );
 134                                 return $arg;
 135                         },
 136                         $args
 137                 );
 138
 139                 if ( $charsLeft < 0 ) {
 140                         return $keyspace . ':##' . md5( implode( ':', $args ) );
 141                 }
 142
 143                 return $keyspace . ':' . implode( ':', $args );
 144         }
 145
 146         /**
 147          * Ensure that a key is safe to use (contains no control characters and no
 148          * characters above the ASCII range.)
 149          *
 150          * @param string $key
 151          * @return string
 152          * @throws Exception
 153          */
 154         public function validateKeyEncoding( $key ) {
 155                 if ( preg_match( '/[^\x21-\x7e]+/', $key ) ) {
 156                         throw new Exception( "Key contains invalid characters: $key" );
 157                 }
 158                 return $key;
 159         }
 160
 161         /**
 162          * TTLs higher than 30 days will be detected as absolute TTLs
 163          * (UNIX timestamps), and will result in the cache entry being
 164          * discarded immediately because the expiry is in the past.
 165          * Clamp expires >30d at 30d, unless they're >=1e9 in which
 166          * case they are likely to really be absolute (1e9 = 2011-09-09)
 167          * @param int $expiry
 168          * @return int
 169          */
 170         function fixExpiry( $expiry ) {
 171                 if ( $expiry > 2592000 && $expiry < 1000000000 ) {
 172                         $expiry = 2592000;
 173                 }
 174                 return (int)$expiry;
 175         }
 176
 177         /**
 178          * Send a debug message to the log
 179          * @param string $text
 180          */
 181         protected function debugLog( $text ) {
 182                 $this->logger->debug( $text );
 183         }
 184
 185         public function modifySimpleRelayEvent( array $event ) {
 186                 if ( array_key_exists( 'val', $event ) ) {
 187                         $event['flg'] = 0; // data is not serialized nor gzipped (for memcached driver)
 188                 }
 189
 190                 return $event;
 191         }
 192 }