includes/interwiki/ClassicInterwikiLookup.php

   1 <?php
   2 /**
   3  * InterwikiLookup implementing the "classic" interwiki storage (hardcoded up to MW 1.26).
   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  */
  22
  23 namespace MediaWiki\Interwiki;
  24
  25 use Cdb\Exception as CdbException;
  26 use Cdb\Reader as CdbReader;
  27 use Hooks;
  28 use Interwiki;
  29 use Language;
  30 use WikiMap;
  31 use MapCacheLRU;
  32 use WANObjectCache;
  33 use Wikimedia\Rdbms\Database;
  34
  35 /**
  36  * InterwikiLookup implementing the "classic" interwiki storage (hardcoded up to MW 1.26).
  37  *
  38  * This implements two levels of caching (in-process array and a WANObjectCache)
  39  * and tree storage backends (SQL, CDB, and plain PHP arrays).
  40  *
  41  * All information is loaded on creation when called by $this->fetch( $prefix ).
  42  * All work is done on replica DB, because this should *never* change (except during
  43  * schema updates etc, which aren't wiki-related)
  44  *
  45  * @since 1.28
  46  */
  47 class ClassicInterwikiLookup implements InterwikiLookup {
  48
  49         /**
  50          * @var MapCacheLRU
  51          */
  52         private $localCache;
  53
  54         /**
  55          * @var Language
  56          */
  57         private $contLang;
  58
  59         /**
  60          * @var WANObjectCache
  61          */
  62         private $objectCache;
  63
  64         /**
  65          * @var int
  66          */
  67         private $objectCacheExpiry;
  68
  69         /**
  70          * @var bool|array|string
  71          */
  72         private $cdbData;
  73
  74         /**
  75          * @var int
  76          */
  77         private $interwikiScopes;
  78
  79         /**
  80          * @var string
  81          */
  82         private $fallbackSite;
  83
  84         /**
  85          * @var CdbReader|null
  86          */
  87         private $cdbReader = null;
  88
  89         /**
  90          * @var string|null
  91          */
  92         private $thisSite = null;
  93
  94         /**
  95          * @param Language $contLang Language object used to convert prefixes to lower case
  96          * @param WANObjectCache $objectCache Cache for interwiki info retrieved from the database
  97          * @param int $objectCacheExpiry Expiry time for $objectCache, in seconds
  98          * @param bool|array|string $cdbData The path of a CDB file, or
  99          *        an array resembling the contents of a CDB file,
 100          *        or false to use the database.
 101          * @param int $interwikiScopes Specify number of domains to check for messages:
 102          *    - 1: Just local wiki level
 103          *    - 2: wiki and global levels
 104          *    - 3: site level as well as wiki and global levels
 105          * @param string $fallbackSite The code to assume for the local site,
 106          */
 107         function __construct(
 108                 Language $contLang,
 109                 WANObjectCache $objectCache,
 110                 $objectCacheExpiry,
 111                 $cdbData,
 112                 $interwikiScopes,
 113                 $fallbackSite
 114         ) {
 115                 $this->localCache = new MapCacheLRU( 100 );
 116
 117                 $this->contLang = $contLang;
 118                 $this->objectCache = $objectCache;
 119                 $this->objectCacheExpiry = $objectCacheExpiry;
 120                 $this->cdbData = $cdbData;
 121                 $this->interwikiScopes = $interwikiScopes;
 122                 $this->fallbackSite = $fallbackSite;
 123         }
 124
 125         /**
 126          * Check whether an interwiki prefix exists
 127          *
 128          * @param string $prefix Interwiki prefix to use
 129          * @return bool Whether it exists
 130          */
 131         public function isValidInterwiki( $prefix ) {
 132                 $result = $this->fetch( $prefix );
 133
 134                 return (bool)$result;
 135         }
 136
 137         /**
 138          * Fetch an Interwiki object
 139          *
 140          * @param string $prefix Interwiki prefix to use
 141          * @return Interwiki|null|bool
 142          */
 143         public function fetch( $prefix ) {
 144                 if ( $prefix == '' ) {
 145                         return null;
 146                 }
 147
 148                 $prefix = $this->contLang->lc( $prefix );
 149                 if ( $this->localCache->has( $prefix ) ) {
 150                         return $this->localCache->get( $prefix );
 151                 }
 152
 153                 if ( $this->cdbData ) {
 154                         $iw = $this->getInterwikiCached( $prefix );
 155                 } else {
 156                         $iw = $this->load( $prefix );
 157                         if ( !$iw ) {
 158                                 $iw = false;
 159                         }
 160                 }
 161                 $this->localCache->set( $prefix, $iw );
 162
 163                 return $iw;
 164         }
 165
 166         /**
 167          * Resets locally cached Interwiki objects. This is intended for use during testing only.
 168          * This does not invalidate entries in the persistent cache, as invalidateCache() does.
 169          * @since 1.27
 170          */
 171         public function resetLocalCache() {
 172                 $this->localCache->clear();
 173         }
 174
 175         /**
 176          * Purge the in-process and object cache for an interwiki prefix
 177          * @param string $prefix
 178          */
 179         public function invalidateCache( $prefix ) {
 180                 $this->localCache->clear( $prefix );
 181
 182                 $key = $this->objectCache->makeKey( 'interwiki', $prefix );
 183                 $this->objectCache->delete( $key );
 184         }
 185
 186         /**
 187          * Fetch interwiki prefix data from local cache in constant database.
 188          *
 189          * @note More logic is explained in DefaultSettings.
 190          *
 191          * @param string $prefix Interwiki prefix
 192          * @return Interwiki|false
 193          */
 194         private function getInterwikiCached( $prefix ) {
 195                 $value = $this->getInterwikiCacheEntry( $prefix );
 196
 197                 if ( $value ) {
 198                         // Split values
 199                         list( $local, $url ) = explode( ' ', $value, 2 );
 200                         return new Interwiki( $prefix, $url, '', '', (int)$local );
 201                 } else {
 202                         return false;
 203                 }
 204         }
 205
 206         /**
 207          * Get entry from interwiki cache
 208          *
 209          * @note More logic is explained in DefaultSettings.
 210          *
 211          * @param string $prefix Database key
 212          * @return bool|string The interwiki entry or false if not found
 213          */
 214         private function getInterwikiCacheEntry( $prefix ) {
 215                 wfDebug( __METHOD__ . "( $prefix )\n" );
 216
 217                 $wikiId = WikiMap::getWikiIdFromDbDomain( WikiMap::getCurrentWikiDbDomain() );
 218
 219                 $value = false;
 220                 try {
 221                         // Resolve site name
 222                         if ( $this->interwikiScopes >= 3 && !$this->thisSite ) {
 223                                 $this->thisSite = $this->getCacheValue( '__sites:' . $wikiId );
 224                                 if ( $this->thisSite == '' ) {
 225                                         $this->thisSite = $this->fallbackSite;
 226                                 }
 227                         }
 228
 229                         $value = $this->getCacheValue( $wikiId . ':' . $prefix );
 230                         // Site level
 231                         if ( $value == '' && $this->interwikiScopes >= 3 ) {
 232                                 $value = $this->getCacheValue( "_{$this->thisSite}:{$prefix}" );
 233                         }
 234                         // Global Level
 235                         if ( $value == '' && $this->interwikiScopes >= 2 ) {
 236                                 $value = $this->getCacheValue( "__global:{$prefix}" );
 237                         }
 238                         if ( $value == 'undef' ) {
 239                                 $value = '';
 240                         }
 241                 } catch ( CdbException $e ) {
 242                         wfDebug( __METHOD__ . ": CdbException caught, error message was "
 243                                 . $e->getMessage() );
 244                 }
 245
 246                 return $value;
 247         }
 248
 249         private function getCacheValue( $key ) {
 250                 if ( $this->cdbReader === null ) {
 251                         if ( is_string( $this->cdbData ) ) {
 252                                 $this->cdbReader = \Cdb\Reader::open( $this->cdbData );
 253                         } elseif ( is_array( $this->cdbData ) ) {
 254                                 $this->cdbReader = new \Cdb\Reader\Hash( $this->cdbData );
 255                         } else {
 256                                 $this->cdbReader = false;
 257                         }
 258                 }
 259
 260                 if ( $this->cdbReader ) {
 261                         return $this->cdbReader->get( $key );
 262                 } else {
 263                         return false;
 264                 }
 265         }
 266
 267         /**
 268          * Load the interwiki, trying first memcached then the DB
 269          *
 270          * @param string $prefix The interwiki prefix
 271          * @return Interwiki|bool Interwiki if $prefix is valid, otherwise false
 272          */
 273         private function load( $prefix ) {
 274                 $iwData = [];
 275                 if ( !Hooks::run( 'InterwikiLoadPrefix', [ $prefix, &$iwData ] ) ) {
 276                         return $this->loadFromArray( $iwData );
 277                 }
 278
 279                 if ( is_array( $iwData ) ) {
 280                         $iw = $this->loadFromArray( $iwData );
 281                         if ( $iw ) {
 282                                 return $iw; // handled by hook
 283                         }
 284                 }
 285
 286                 $fname = __METHOD__;
 287                 $iwData = $this->objectCache->getWithSetCallback(
 288                         $this->objectCache->makeKey( 'interwiki', $prefix ),
 289                         $this->objectCacheExpiry,
 290                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $prefix, $fname ) {
 291                                 $dbr = wfGetDB( DB_REPLICA ); // TODO: inject LoadBalancer
 292
 293                                 $setOpts += Database::getCacheSetOptions( $dbr );
 294
 295                                 $row = $dbr->selectRow(
 296                                         'interwiki',
 297                                         self::selectFields(),
 298                                         [ 'iw_prefix' => $prefix ],
 299                                         $fname
 300                                 );
 301
 302                                 return $row ? (array)$row : '!NONEXISTENT';
 303                         }
 304                 );
 305
 306                 if ( is_array( $iwData ) ) {
 307                         return $this->loadFromArray( $iwData ) ?: false;
 308                 }
 309
 310                 return false;
 311         }
 312
 313         /**
 314          * Fill in member variables from an array (e.g. memcached result, Database::fetchRow, etc)
 315          *
 316          * @param array $mc Associative array: row from the interwiki table
 317          * @return Interwiki|bool Interwiki object or false if $mc['iw_url'] is not set
 318          */
 319         private function loadFromArray( $mc ) {
 320                 if ( isset( $mc['iw_url'] ) ) {
 321                         $url = $mc['iw_url'];
 322                         $local = $mc['iw_local'] ?? 0;
 323                         $trans = $mc['iw_trans'] ?? 0;
 324                         $api = $mc['iw_api'] ?? '';
 325                         $wikiId = $mc['iw_wikiid'] ?? '';
 326
 327                         return new Interwiki( null, $url, $api, $wikiId, $local, $trans );
 328                 }
 329
 330                 return false;
 331         }
 332
 333         /**
 334          * Fetch all interwiki prefixes from interwiki cache
 335          *
 336          * @param null|string $local If not null, limits output to local/non-local interwikis
 337          * @return array List of prefixes, where each row is an associative array
 338          */
 339         private function getAllPrefixesCached( $local ) {
 340                 wfDebug( __METHOD__ . "()\n" );
 341
 342                 $wikiId = WikiMap::getWikiIdFromDbDomain( WikiMap::getCurrentWikiDbDomain() );
 343
 344                 $data = [];
 345                 try {
 346                         /* Resolve site name */
 347                         if ( $this->interwikiScopes >= 3 && !$this->thisSite ) {
 348                                 $site = $this->getCacheValue( '__sites:' . $wikiId );
 349
 350                                 if ( $site == '' ) {
 351                                         $this->thisSite = $this->fallbackSite;
 352                                 } else {
 353                                         $this->thisSite = $site;
 354                                 }
 355                         }
 356
 357                         // List of interwiki sources
 358                         $sources = [];
 359                         // Global Level
 360                         if ( $this->interwikiScopes >= 2 ) {
 361                                 $sources[] = '__global';
 362                         }
 363                         // Site level
 364                         if ( $this->interwikiScopes >= 3 ) {
 365                                 $sources[] = '_' . $this->thisSite;
 366                         }
 367                         $sources[] = $wikiId;
 368
 369                         foreach ( $sources as $source ) {
 370                                 $list = $this->getCacheValue( '__list:' . $source );
 371                                 foreach ( explode( ' ', $list ) as $iw_prefix ) {
 372                                         $row = $this->getCacheValue( "{$source}:{$iw_prefix}" );
 373                                         if ( !$row ) {
 374                                                 continue;
 375                                         }
 376
 377                                         list( $iw_local, $iw_url ) = explode( ' ', $row );
 378
 379                                         if ( $local !== null && $local != $iw_local ) {
 380                                                 continue;
 381                                         }
 382
 383                                         $data[$iw_prefix] = [
 384                                                 'iw_prefix' => $iw_prefix,
 385                                                 'iw_url' => $iw_url,
 386                                                 'iw_local' => $iw_local,
 387                                         ];
 388                                 }
 389                         }
 390                 } catch ( CdbException $e ) {
 391                         wfDebug( __METHOD__ . ": CdbException caught, error message was "
 392                                 . $e->getMessage() );
 393                 }
 394
 395                 return array_values( $data );
 396         }
 397
 398         /**
 399          * Fetch all interwiki prefixes from DB
 400          *
 401          * @param string|null $local If not null, limits output to local/non-local interwikis
 402          * @return array[] Interwiki rows
 403          */
 404         private function getAllPrefixesDB( $local ) {
 405                 $db = wfGetDB( DB_REPLICA ); // TODO: inject DB LoadBalancer
 406
 407                 $where = [];
 408
 409                 if ( $local !== null ) {
 410                         if ( $local == 1 ) {
 411                                 $where['iw_local'] = 1;
 412                         } elseif ( $local == 0 ) {
 413                                 $where['iw_local'] = 0;
 414                         }
 415                 }
 416
 417                 $res = $db->select( 'interwiki',
 418                         self::selectFields(),
 419                         $where, __METHOD__, [ 'ORDER BY' => 'iw_prefix' ]
 420                 );
 421
 422                 $retval = [];
 423                 foreach ( $res as $row ) {
 424                         $retval[] = (array)$row;
 425                 }
 426
 427                 return $retval;
 428         }
 429
 430         /**
 431          * Returns all interwiki prefixes
 432          *
 433          * @param string|null $local If set, limits output to local/non-local interwikis
 434          * @return array[] Interwiki rows, where each row is an associative array
 435          */
 436         public function getAllPrefixes( $local = null ) {
 437                 if ( $this->cdbData ) {
 438                         return $this->getAllPrefixesCached( $local );
 439                 }
 440
 441                 return $this->getAllPrefixesDB( $local );
 442         }
 443
 444         /**
 445          * Return the list of interwiki fields that should be selected to create
 446          * a new Interwiki object.
 447          * @return string[]
 448          */
 449         private static function selectFields() {
 450                 return [
 451                         'iw_prefix',
 452                         'iw_url',
 453                         'iw_api',
 454                         'iw_wikiid',
 455                         'iw_local',
 456                         'iw_trans'
 457                 ];
 458         }
 459
 460 }