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' => 0.5,
  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, $flags = 0 ) {
  69                 return $this->client->cas( $casToken, $this->validateKeyEncoding( $key ),
  70                         $value, $this->fixExpiry( $exptime ) );
  71         }
  72
  73         public function delete( $key, $flags = 0 ) {
  74                 return $this->client->delete( $this->validateKeyEncoding( $key ) );
  75         }
  76
  77         public function add( $key, $value, $exptime = 0, $flags = 0 ) {
  78                 return $this->client->add( $this->validateKeyEncoding( $key ), $value,
  79                         $this->fixExpiry( $exptime ) );
  80         }
  81
  82         public function incr( $key, $value = 1 ) {
  83                 $n = $this->client->incr( $this->validateKeyEncoding( $key ), $value );
  84
  85                 return ( $n !== false && $n !== null ) ? $n : false;
  86         }
  87
  88         public function decr( $key, $value = 1 ) {
  89                 $n = $this->client->decr( $this->validateKeyEncoding( $key ), $value );
  90
  91                 return ( $n !== false && $n !== null ) ? $n : false;
  92         }
  93
  94         public function merge( $key, callable $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
  95                 return $this->mergeViaCas( $key, $callback, $exptime, $attempts );
  96         }
  97
  98         public function changeTTL( $key, $exptime = 0, $flags = 0 ) {
  99                 return $this->client->touch( $this->validateKeyEncoding( $key ),
 100                         $this->fixExpiry( $exptime ) );
 101         }
 102
 103         /**
 104          * Get the underlying client object. This is provided for debugging
 105          * purposes.
 106          * @return MemcachedClient|Memcached
 107          */
 108         public function getClient() {
 109                 return $this->client;
 110         }
 111
 112         /**
 113          * Construct a cache key.
 114          *
 115          * @since 1.27
 116          * @param string $keyspace
 117          * @param array $args
 118          * @return string
 119          */
 120         public function makeKeyInternal( $keyspace, $args ) {
 121                 // Memcached keys have a maximum length of 255 characters. From that,
 122                 // subtract the number of characters we need for the keyspace and for
 123                 // the separator character needed for each argument. To handle some
 124                 // custom prefixes used by thing like WANObjectCache, limit to 205.
 125                 $charsLeft = 205 - strlen( $keyspace ) - count( $args );
 126
 127                 $args = array_map(
 128                         function ( $arg ) use ( &$charsLeft ) {
 129                                 $arg = strtr( $arg, ' ', '_' );
 130
 131                                 // Make sure %, #, and non-ASCII chars are escaped
 132                                 $arg = preg_replace_callback(
 133                                         '/[^\x21-\x22\x24\x26-\x39\x3b-\x7e]+/',
 134                                         function ( $m ) {
 135                                                 return rawurlencode( $m[0] );
 136                                         },
 137                                         $arg
 138                                 );
 139
 140                                 // 33 = 32 characters for the MD5 + 1 for the '#' prefix.
 141                                 if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
 142                                         $arg = '#' . md5( $arg );
 143                                 }
 144
 145                                 $charsLeft -= strlen( $arg );
 146                                 return $arg;
 147                         },
 148                         $args
 149                 );
 150
 151                 if ( $charsLeft < 0 ) {
 152                         return $keyspace . ':BagOStuff-long-key:##' . md5( implode( ':', $args ) );
 153                 }
 154
 155                 return $keyspace . ':' . implode( ':', $args );
 156         }
 157
 158         /**
 159          * Ensure that a key is safe to use (contains no control characters and no
 160          * characters above the ASCII range.)
 161          *
 162          * @param string $key
 163          * @return string
 164          * @throws Exception
 165          */
 166         public function validateKeyEncoding( $key ) {
 167                 if ( preg_match( '/[^\x21-\x7e]+/', $key ) ) {
 168                         throw new Exception( "Key contains invalid characters: $key" );
 169                 }
 170                 return $key;
 171         }
 172
 173         /**
 174          * TTLs higher than 30 days will be detected as absolute TTLs
 175          * (UNIX timestamps), and will result in the cache entry being
 176          * discarded immediately because the expiry is in the past.
 177          * Clamp expires >30d at 30d, unless they're >=1e9 in which
 178          * case they are likely to really be absolute (1e9 = 2011-09-09)
 179          * @param int $expiry
 180          * @return int
 181          */
 182         function fixExpiry( $expiry ) {
 183                 if ( $expiry > 2592000 && $expiry < 1000000000 ) {
 184                         $expiry = 2592000;
 185                 }
 186                 return (int)$expiry;
 187         }
 188
 189         /**
 190          * Send a debug message to the log
 191          * @param string $text
 192          */
 193         protected function debugLog( $text ) {
 194                 $this->logger->debug( $text );
 195         }
 196 }