includes/interwiki/ClassicInterwikiLookup.php

   1 <?php
   2 namespace MediaWiki\Interwiki;
   3
   4 /**
   5  * InterwikiLookup implementing the "classic" interwiki storage (hardcoded up to MW 1.26).
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  */
  24 use \Cdb\Exception as CdbException;
  25 use \Cdb\Reader as CdbReader;
  26 use Database;
  27 use Hooks;
  28 use Interwiki;
  29 use Language;
  30 use MapCacheLRU;
  31 use WANObjectCache;
  32
  33 /**
  34  * InterwikiLookup implementing the "classic" interwiki storage (hardcoded up to MW 1.26).
  35  *
  36  * This implements two levels of caching (in-process array and a WANObjectCache)
  37  * and tree storage backends (SQL, CDB, and plain PHP arrays).
  38  *
  39  * All information is loaded on creation when called by $this->fetch( $prefix ).
  40  * All work is done on replica DB, because this should *never* change (except during
  41  * schema updates etc, which aren't wiki-related)
  42  *
  43  * @since 1.28
  44  */
  45 class ClassicInterwikiLookup implements InterwikiLookup {
  46
  47         /**
  48          * @var MapCacheLRU
  49          */
  50         private $localCache;
  51
  52         /**
  53          * @var Language
  54          */
  55         private $contentLanguage;
  56
  57         /**
  58          * @var WANObjectCache
  59          */
  60         private $objectCache;
  61
  62         /**
  63          * @var int
  64          */
  65         private $objectCacheExpiry;
  66
  67         /**
  68          * @var bool|array|string
  69          */
  70         private $cdbData;
  71
  72         /**
  73          * @var int
  74          */
  75         private $interwikiScopes;
  76
  77         /**
  78          * @var string
  79          */
  80         private $fallbackSite;
  81
  82         /**
  83          * @var CdbReader|null
  84          */
  85         private $cdbReader = null;
  86
  87         /**
  88          * @var string|null
  89          */
  90         private $thisSite = null;
  91
  92         /**
  93          * @param Language $contentLanguage Language object used to convert prefixes to lower case
  94          * @param WANObjectCache $objectCache Cache for interwiki info retrieved from the database
  95          * @param int $objectCacheExpiry Expiry time for $objectCache, in seconds
  96          * @param bool|array|string $cdbData The path of a CDB file, or
  97          *        an array resembling the contents of a CDB file,
  98          *        or false to use the database.
  99          * @param int $interwikiScopes Specify number of domains to check for messages:
 100          *    - 1: Just local wiki level
 101          *    - 2: wiki and global levels
 102          *    - 3: site level as well as wiki and global levels
 103          * @param string $fallbackSite The code to assume for the local site,
 104          */
 105         function __construct(
 106                 Language $contentLanguage,
 107                 WANObjectCache $objectCache,
 108                 $objectCacheExpiry,
 109                 $cdbData,
 110                 $interwikiScopes,
 111                 $fallbackSite
 112         ) {
 113                 $this->localCache = new MapCacheLRU( 100 );
 114
 115                 $this->contentLanguage = $contentLanguage;
 116                 $this->objectCache = $objectCache;
 117                 $this->objectCacheExpiry = $objectCacheExpiry;
 118                 $this->cdbData = $cdbData;
 119                 $this->interwikiScopes = $interwikiScopes;
 120                 $this->fallbackSite = $fallbackSite;
 121         }
 122
 123         /**
 124          * Check whether an interwiki prefix exists
 125          *
 126          * @param string $prefix Interwiki prefix to use
 127          * @return bool Whether it exists
 128          */
 129         public function isValidInterwiki( $prefix ) {
 130                 $result = $this->fetch( $prefix );
 131
 132                 return (bool)$result;
 133         }
 134
 135         /**
 136          * Fetch an Interwiki object
 137          *
 138          * @param string $prefix Interwiki prefix to use
 139          * @return Interwiki|null|bool
 140          */
 141         public function fetch( $prefix ) {
 142                 if ( $prefix == '' ) {
 143                         return null;
 144                 }
 145
 146                 $prefix = $this->contentLanguage->lc( $prefix );
 147                 if ( $this->localCache->has( $prefix ) ) {
 148                         return $this->localCache->get( $prefix );
 149                 }
 150
 151                 if ( $this->cdbData ) {
 152                         $iw = $this->getInterwikiCached( $prefix );
 153                 } else {
 154                         $iw = $this->load( $prefix );
 155                         if ( !$iw ) {
 156                                 $iw = false;
 157                         }
 158                 }
 159                 $this->localCache->set( $prefix, $iw );
 160
 161                 return $iw;
 162         }
 163
 164         /**
 165          * Resets locally cached Interwiki objects. This is intended for use during testing only.
 166          * This does not invalidate entries in the persistent cache, as invalidateCache() does.
 167          * @since 1.27
 168          */
 169         public function resetLocalCache() {
 170                 $this->localCache->clear();
 171         }
 172
 173         /**
 174          * Purge the in-process and object cache for an interwiki prefix
 175          * @param string $prefix
 176          */
 177         public function invalidateCache( $prefix ) {
 178                 $this->localCache->clear( $prefix );
 179
 180                 $key = $this->objectCache->makeKey( 'interwiki', $prefix );
 181                 $this->objectCache->delete( $key );
 182         }
 183
 184         /**
 185          * Fetch interwiki prefix data from local cache in constant database.
 186          *
 187          * @note More logic is explained in DefaultSettings.
 188          *
 189          * @param string $prefix Interwiki prefix
 190          * @return Interwiki
 191          */
 192         private function getInterwikiCached( $prefix ) {
 193                 $value = $this->getInterwikiCacheEntry( $prefix );
 194
 195                 if ( $value ) {
 196                         // Split values
 197                         list( $local, $url ) = explode( ' ', $value, 2 );
 198                         return new Interwiki( $prefix, $url, '', '', (int)$local );
 199                 } else {
 200                         return false;
 201                 }
 202         }
 203
 204         /**
 205          * Get entry from interwiki cache
 206          *
 207          * @note More logic is explained in DefaultSettings.
 208          *
 209          * @param string $prefix Database key
 210          * @return bool|string The interwiki entry or false if not found
 211          */
 212         private function getInterwikiCacheEntry( $prefix ) {
 213                 wfDebug( __METHOD__ . "( $prefix )\n" );
 214                 $value = false;
 215                 try {
 216                         // Resolve site name
 217                         if ( $this->interwikiScopes >= 3 && !$this->thisSite ) {
 218                                 $this->thisSite = $this->getCacheValue( '__sites:' . wfWikiID() );
 219                                 if ( $this->thisSite == '' ) {
 220                                         $this->thisSite = $this->fallbackSite;
 221                                 }
 222                         }
 223
 224                         $value = $this->getCacheValue( wfMemcKey( $prefix ) );
 225                         // Site level
 226                         if ( $value == '' && $this->interwikiScopes >= 3 ) {
 227                                 $value = $this->getCacheValue( "_{$this->thisSite}:{$prefix}" );
 228                         }
 229                         // Global Level
 230                         if ( $value == '' && $this->interwikiScopes >= 2 ) {
 231                                 $value = $this->getCacheValue( "__global:{$prefix}" );
 232                         }
 233                         if ( $value == 'undef' ) {
 234                                 $value = '';
 235                         }
 236                 } catch ( CdbException $e ) {
 237                         wfDebug( __METHOD__ . ": CdbException caught, error message was "
 238                                 . $e->getMessage() );
 239                 }
 240
 241                 return $value;
 242         }
 243
 244         private function getCacheValue( $key ) {
 245                 if ( $this->cdbReader === null ) {
 246                         if ( is_string( $this->cdbData ) ) {
 247                                 $this->cdbReader = \Cdb\Reader::open( $this->cdbData );
 248                         } elseif ( is_array( $this->cdbData ) ) {
 249                                 $this->cdbReader = new \Cdb\Reader\Hash( $this->cdbData );
 250                         } else {
 251                                 $this->cdbReader = false;
 252                         }
 253                 }
 254
 255                 if ( $this->cdbReader ) {
 256                         return $this->cdbReader->get( $key );
 257                 } else {
 258                         return false;
 259                 }
 260         }
 261
 262         /**
 263          * Load the interwiki, trying first memcached then the DB
 264          *
 265          * @param string $prefix The interwiki prefix
 266          * @return Interwiki|bool Interwiki if $prefix is valid, otherwise false
 267          */
 268         private function load( $prefix ) {
 269                 $iwData = [];
 270                 if ( !Hooks::run( 'InterwikiLoadPrefix', [ $prefix, &$iwData ] ) ) {
 271                         return $this->loadFromArray( $iwData );
 272                 }
 273
 274                 if ( is_array( $iwData ) ) {
 275                         $iw = $this->loadFromArray( $iwData );
 276                         if ( $iw ) {
 277                                 return $iw; // handled by hook
 278                         }
 279                 }
 280
 281                 $iwData = $this->objectCache->getWithSetCallback(
 282                         $this->objectCache->makeKey( 'interwiki', $prefix ),
 283                         $this->objectCacheExpiry,
 284                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $prefix ) {
 285                                 $dbr = wfGetDB( DB_REPLICA ); // TODO: inject LoadBalancer
 286
 287                                 $setOpts += Database::getCacheSetOptions( $dbr );
 288
 289                                 $row = $dbr->selectRow(
 290                                         'interwiki',
 291                                         ClassicInterwikiLookup::selectFields(),
 292                                         [ 'iw_prefix' => $prefix ],
 293                                         __METHOD__
 294                                 );
 295
 296                                 return $row ? (array)$row : '!NONEXISTENT';
 297                         }
 298                 );
 299
 300                 if ( is_array( $iwData ) ) {
 301                         return $this->loadFromArray( $iwData ) ?: false;
 302                 }
 303
 304                 return false;
 305         }
 306
 307         /**
 308          * Fill in member variables from an array (e.g. memcached result, Database::fetchRow, etc)
 309          *
 310          * @param array $mc Associative array: row from the interwiki table
 311          * @return Interwiki|bool Interwiki object or false if $mc['iw_url'] is not set
 312          */
 313         private function loadFromArray( $mc ) {
 314                 if ( isset( $mc['iw_url'] ) ) {
 315                         $url = $mc['iw_url'];
 316                         $local = isset( $mc['iw_local'] ) ? $mc['iw_local'] : 0;
 317                         $trans = isset( $mc['iw_trans'] ) ? $mc['iw_trans'] : 0;
 318                         $api = isset( $mc['iw_api'] ) ? $mc['iw_api'] : '';
 319                         $wikiId = isset( $mc['iw_wikiid'] ) ? $mc['iw_wikiid'] : '';
 320
 321                         return new Interwiki( null, $url, $api, $wikiId, $local, $trans );
 322                 }
 323
 324                 return false;
 325         }
 326
 327         /**
 328          * Fetch all interwiki prefixes from interwiki cache
 329          *
 330          * @param null|string $local If not null, limits output to local/non-local interwikis
 331          * @return array List of prefixes, where each row is an associative array
 332          */
 333         private function getAllPrefixesCached( $local ) {
 334                 wfDebug( __METHOD__ . "()\n" );
 335                 $data = [];
 336                 try {
 337                         /* Resolve site name */
 338                         if ( $this->interwikiScopes >= 3 && !$this->thisSite ) {
 339                                 $site = $this->getCacheValue( '__sites:' . wfWikiID() );
 340
 341                                 if ( $site == '' ) {
 342                                         $this->thisSite = $this->fallbackSite;
 343                                 } else {
 344                                         $this->thisSite = $site;
 345                                 }
 346                         }
 347
 348                         // List of interwiki sources
 349                         $sources = [];
 350                         // Global Level
 351                         if ( $this->interwikiScopes >= 2 ) {
 352                                 $sources[] = '__global';
 353                         }
 354                         // Site level
 355                         if ( $this->interwikiScopes >= 3 ) {
 356                                 $sources[] = '_' . $this->thisSite;
 357                         }
 358                         $sources[] = wfWikiID();
 359
 360                         foreach ( $sources as $source ) {
 361                                 $list = $this->getCacheValue( '__list:' . $source );
 362                                 foreach ( explode( ' ', $list ) as $iw_prefix ) {
 363                                         $row = $this->getCacheValue( "{$source}:{$iw_prefix}" );
 364                                         if ( !$row ) {
 365                                                 continue;
 366                                         }
 367
 368                                         list( $iw_local, $iw_url ) = explode( ' ', $row );
 369
 370                                         if ( $local !== null && $local != $iw_local ) {
 371                                                 continue;
 372                                         }
 373
 374                                         $data[$iw_prefix] = [
 375                                                 'iw_prefix' => $iw_prefix,
 376                                                 'iw_url' => $iw_url,
 377                                                 'iw_local' => $iw_local,
 378                                         ];
 379                                 }
 380                         }
 381                 } catch ( CdbException $e ) {
 382                         wfDebug( __METHOD__ . ": CdbException caught, error message was "
 383                                 . $e->getMessage() );
 384                 }
 385
 386                 ksort( $data );
 387
 388                 return array_values( $data );
 389         }
 390
 391         /**
 392          * Fetch all interwiki prefixes from DB
 393          *
 394          * @param string|null $local If not null, limits output to local/non-local interwikis
 395          * @return array[] Interwiki rows
 396          */
 397         private function getAllPrefixesDB( $local ) {
 398                 $db = wfGetDB( DB_REPLICA ); // TODO: inject DB LoadBalancer
 399
 400                 $where = [];
 401
 402                 if ( $local !== null ) {
 403                         if ( $local == 1 ) {
 404                                 $where['iw_local'] = 1;
 405                         } elseif ( $local == 0 ) {
 406                                 $where['iw_local'] = 0;
 407                         }
 408                 }
 409
 410                 $res = $db->select( 'interwiki',
 411                         $this->selectFields(),
 412                         $where, __METHOD__, [ 'ORDER BY' => 'iw_prefix' ]
 413                 );
 414
 415                 $retval = [];
 416                 foreach ( $res as $row ) {
 417                         $retval[] = (array)$row;
 418                 }
 419
 420                 return $retval;
 421         }
 422
 423         /**
 424          * Returns all interwiki prefixes
 425          *
 426          * @param string|null $local If set, limits output to local/non-local interwikis
 427          * @return array[] Interwiki rows, where each row is an associative array
 428          */
 429         public function getAllPrefixes( $local = null ) {
 430                 if ( $this->cdbData ) {
 431                         return $this->getAllPrefixesCached( $local );
 432                 }
 433
 434                 return $this->getAllPrefixesDB( $local );
 435         }
 436
 437         /**
 438          * Return the list of interwiki fields that should be selected to create
 439          * a new Interwiki object.
 440          * @return string[]
 441          */
 442         private static function selectFields() {
 443                 return [
 444                         'iw_prefix',
 445                         'iw_url',
 446                         'iw_api',
 447                         'iw_wikiid',
 448                         'iw_local',
 449                         'iw_trans'
 450                 ];
 451         }
 452
 453 }