includes/search/SearchEngine.php

   1 <?php
   2 /**
   3  * Basic search engine
   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 Search
  22  */
  23
  24 /**
  25  * @defgroup Search Search
  26  */
  27
  28 use MediaWiki\MediaWikiServices;
  29
  30 /**
  31  * Contain a class for special pages
  32  * @ingroup Search
  33  */
  34 abstract class SearchEngine {
  35         /** @var string */
  36         public $prefix = '';
  37
  38         /** @var int[]|null */
  39         public $namespaces = [ NS_MAIN ];
  40
  41         /** @var int */
  42         protected $limit = 10;
  43
  44         /** @var int */
  45         protected $offset = 0;
  46
  47         /** @var array|string */
  48         protected $searchTerms = [];
  49
  50         /** @var bool */
  51         protected $showSuggestion = true;
  52         private $sort = 'relevance';
  53
  54         /** @var array Feature values */
  55         protected $features = [];
  56
  57         /** @const string profile type for completionSearch */
  58         const COMPLETION_PROFILE_TYPE = 'completionSearchProfile';
  59
  60         /** @const string profile type for query independent ranking features */
  61         const FT_QUERY_INDEP_PROFILE_TYPE = 'fulltextQueryIndepProfile';
  62
  63         /**
  64          * Perform a full text search query and return a result set.
  65          * If full text searches are not supported or disabled, return null.
  66          * STUB
  67          *
  68          * @param string $term Raw search term
  69          * @return SearchResultSet|Status|null
  70          */
  71         function searchText( $term ) {
  72                 return null;
  73         }
  74
  75         /**
  76          * Perform a title search in the article archive.
  77          * NOTE: these results still should be filtered by
  78          * matching against PageArchive, permissions checks etc
  79          * The results returned by this methods are only sugegstions and
  80          * may not end up being shown to the user.
  81          *
  82          * @param string $term Raw search term
  83          * @return Status<Title[]>
  84          * @since 1.29
  85          */
  86         function searchArchiveTitle( $term ) {
  87                 return Status::newGood( [] );
  88         }
  89
  90         /**
  91          * Perform a title-only search query and return a result set.
  92          * If title searches are not supported or disabled, return null.
  93          * STUB
  94          *
  95          * @param string $term Raw search term
  96          * @return SearchResultSet|null
  97          */
  98         function searchTitle( $term ) {
  99                 return null;
 100         }
 101
 102         /**
 103          * @since 1.18
 104          * @param string $feature
 105          * @return bool
 106          */
 107         public function supports( $feature ) {
 108                 switch ( $feature ) {
 109                 case 'search-update':
 110                         return true;
 111                 case 'title-suffix-filter':
 112                 default:
 113                         return false;
 114                 }
 115         }
 116
 117         /**
 118          * Way to pass custom data for engines
 119          * @since 1.18
 120          * @param string $feature
 121          * @param mixed $data
 122          */
 123         public function setFeatureData( $feature, $data ) {
 124                 $this->features[$feature] = $data;
 125         }
 126
 127         /**
 128          * Way to retrieve custom data set by setFeatureData
 129          * or by the engine itself.
 130          * @since 1.29
 131          * @param string $feature feature name
 132          * @return mixed the feature value or null if unset
 133          */
 134         public function getFeatureData( $feature ) {
 135                 if ( isset ( $this->features[$feature] ) ) {
 136                         return $this->features[$feature];
 137                 }
 138                 return null;
 139         }
 140
 141         /**
 142          * When overridden in derived class, performs database-specific conversions
 143          * on text to be used for searching or updating search index.
 144          * Default implementation does nothing (simply returns $string).
 145          *
 146          * @param string $string String to process
 147          * @return string
 148          */
 149         public function normalizeText( $string ) {
 150                 global $wgContLang;
 151
 152                 // Some languages such as Chinese require word segmentation
 153                 return $wgContLang->segmentByWord( $string );
 154         }
 155
 156         /**
 157          * Transform search term in cases when parts of the query came as different
 158          * GET params (when supported), e.g. for prefix queries:
 159          * search=test&prefix=Main_Page/Archive -> test prefix:Main Page/Archive
 160          * @param string $term
 161          * @return string
 162          */
 163         public function transformSearchTerm( $term ) {
 164                 return $term;
 165         }
 166
 167         /**
 168          * Get service class to finding near matches.
 169          * @param Config $config Configuration to use for the matcher.
 170          * @return SearchNearMatcher
 171          */
 172         public function getNearMatcher( Config $config ) {
 173                 global $wgContLang;
 174                 return new SearchNearMatcher( $config, $wgContLang );
 175         }
 176
 177         /**
 178          * Get near matcher for default SearchEngine.
 179          * @return SearchNearMatcher
 180          */
 181         protected static function defaultNearMatcher() {
 182                 $config = MediaWikiServices::getInstance()->getMainConfig();
 183                 return MediaWikiServices::getInstance()->newSearchEngine()->getNearMatcher( $config );
 184         }
 185
 186         /**
 187          * If an exact title match can be found, or a very slightly close match,
 188          * return the title. If no match, returns NULL.
 189          * @deprecated since 1.27; Use SearchEngine::getNearMatcher()
 190          * @param string $searchterm
 191          * @return Title
 192          */
 193         public static function getNearMatch( $searchterm ) {
 194                 return static::defaultNearMatcher()->getNearMatch( $searchterm );
 195         }
 196
 197         /**
 198          * Do a near match (see SearchEngine::getNearMatch) and wrap it into a
 199          * SearchResultSet.
 200          * @deprecated since 1.27; Use SearchEngine::getNearMatcher()
 201          * @param string $searchterm
 202          * @return SearchResultSet
 203          */
 204         public static function getNearMatchResultSet( $searchterm ) {
 205                 return static::defaultNearMatcher()->getNearMatchResultSet( $searchterm );
 206         }
 207
 208         /**
 209          * Get chars legal for search.
 210          * NOTE: usage as static is deprecated and preserved only as BC measure
 211          * @return string
 212          */
 213         public static function legalSearchChars() {
 214                 return "A-Za-z_'.0-9\\x80-\\xFF\\-";
 215         }
 216
 217         /**
 218          * Set the maximum number of results to return
 219          * and how many to skip before returning the first.
 220          *
 221          * @param int $limit
 222          * @param int $offset
 223          */
 224         function setLimitOffset( $limit, $offset = 0 ) {
 225                 $this->limit = intval( $limit );
 226                 $this->offset = intval( $offset );
 227         }
 228
 229         /**
 230          * Set which namespaces the search should include.
 231          * Give an array of namespace index numbers.
 232          *
 233          * @param int[]|null $namespaces
 234          */
 235         function setNamespaces( $namespaces ) {
 236                 if ( $namespaces ) {
 237                         // Filter namespaces to only keep valid ones
 238                         $validNs = $this->searchableNamespaces();
 239                         $namespaces = array_filter( $namespaces, function( $ns ) use( $validNs ) {
 240                                 return $ns < 0 || isset( $validNs[$ns] );
 241                         } );
 242                 } else {
 243                         $namespaces = [];
 244                 }
 245                 $this->namespaces = $namespaces;
 246         }
 247
 248         /**
 249          * Set whether the searcher should try to build a suggestion.  Note: some searchers
 250          * don't support building a suggestion in the first place and others don't respect
 251          * this flag.
 252          *
 253          * @param bool $showSuggestion Should the searcher try to build suggestions
 254          */
 255         function setShowSuggestion( $showSuggestion ) {
 256                 $this->showSuggestion = $showSuggestion;
 257         }
 258
 259         /**
 260          * Get the valid sort directions.  All search engines support 'relevance' but others
 261          * might support more. The default in all implementations should be 'relevance.'
 262          *
 263          * @since 1.25
 264          * @return array(string) the valid sort directions for setSort
 265          */
 266         public function getValidSorts() {
 267                 return [ 'relevance' ];
 268         }
 269
 270         /**
 271          * Set the sort direction of the search results. Must be one returned by
 272          * SearchEngine::getValidSorts()
 273          *
 274          * @since 1.25
 275          * @throws InvalidArgumentException
 276          * @param string $sort sort direction for query result
 277          */
 278         public function setSort( $sort ) {
 279                 if ( !in_array( $sort, $this->getValidSorts() ) ) {
 280                         throw new InvalidArgumentException( "Invalid sort: $sort. " .
 281                                 "Must be one of: " . implode( ', ', $this->getValidSorts() ) );
 282                 }
 283                 $this->sort = $sort;
 284         }
 285
 286         /**
 287          * Get the sort direction of the search results
 288          *
 289          * @since 1.25
 290          * @return string
 291          */
 292         public function getSort() {
 293                 return $this->sort;
 294         }
 295
 296         /**
 297          * Parse some common prefixes: all (search everything)
 298          * or namespace names and set the list of namespaces
 299          * of this class accordingly.
 300          *
 301          * @param string $query
 302          * @return string
 303          */
 304         function replacePrefixes( $query ) {
 305                 $queryAndNs = self::parseNamespacePrefixes( $query );
 306                 if ( $queryAndNs === false ) {
 307                         return $query;
 308                 }
 309                 $this->namespaces = $queryAndNs[1];
 310                 return $queryAndNs[0];
 311         }
 312
 313         /**
 314          * Parse some common prefixes: all (search everything)
 315          * or namespace names
 316          *
 317          * @param string $query
 318          * @return false|array false if no namespace was extracted, an array
 319          * with the parsed query at index 0 and an array of namespaces at index
 320          * 1 (or null for all namespaces).
 321          */
 322         public static function parseNamespacePrefixes( $query ) {
 323                 global $wgContLang;
 324
 325                 $parsed = $query;
 326                 if ( strpos( $query, ':' ) === false ) { // nothing to do
 327                         return false;
 328                 }
 329                 $extractedNamespace = null;
 330
 331                 $allkeyword = wfMessage( 'searchall' )->inContentLanguage()->text() . ":";
 332                 if ( strncmp( $query, $allkeyword, strlen( $allkeyword ) ) == 0 ) {
 333                         $extractedNamespace = null;
 334                         $parsed = substr( $query, strlen( $allkeyword ) );
 335                 } elseif ( strpos( $query, ':' ) !== false ) {
 336                         // TODO: should we unify with PrefixSearch::extractNamespace ?
 337                         $prefix = str_replace( ' ', '_', substr( $query, 0, strpos( $query, ':' ) ) );
 338                         $index = $wgContLang->getNsIndex( $prefix );
 339                         if ( $index !== false ) {
 340                                 $extractedNamespace = [ $index ];
 341                                 $parsed = substr( $query, strlen( $prefix ) + 1 );
 342                         } else {
 343                                 return false;
 344                         }
 345                 }
 346
 347                 if ( trim( $parsed ) == '' ) {
 348                         $parsed = $query; // prefix was the whole query
 349                 }
 350
 351                 return [ $parsed, $extractedNamespace ];
 352         }
 353
 354         /**
 355          * Find snippet highlight settings for all users
 356          * @return array Contextlines, contextchars
 357          */
 358         public static function userHighlightPrefs() {
 359                 $contextlines = 2; // Hardcode this. Old defaults sucked. :)
 360                 $contextchars = 75; // same as above.... :P
 361                 return [ $contextlines, $contextchars ];
 362         }
 363
 364         /**
 365          * Create or update the search index record for the given page.
 366          * Title and text should be pre-processed.
 367          * STUB
 368          *
 369          * @param int $id
 370          * @param string $title
 371          * @param string $text
 372          */
 373         function update( $id, $title, $text ) {
 374                 // no-op
 375         }
 376
 377         /**
 378          * Update a search index record's title only.
 379          * Title should be pre-processed.
 380          * STUB
 381          *
 382          * @param int $id
 383          * @param string $title
 384          */
 385         function updateTitle( $id, $title ) {
 386                 // no-op
 387         }
 388
 389         /**
 390          * Delete an indexed page
 391          * Title should be pre-processed.
 392          * STUB
 393          *
 394          * @param int $id Page id that was deleted
 395          * @param string $title Title of page that was deleted
 396          */
 397         function delete( $id, $title ) {
 398                 // no-op
 399         }
 400
 401         /**
 402          * Get OpenSearch suggestion template
 403          *
 404          * @deprecated since 1.25
 405          * @return string
 406          */
 407         public static function getOpenSearchTemplate() {
 408                 wfDeprecated( __METHOD__, '1.25' );
 409                 return ApiOpenSearch::getOpenSearchTemplate( 'application/x-suggestions+json' );
 410         }
 411
 412         /**
 413          * Get the raw text for updating the index from a content object
 414          * Nicer search backends could possibly do something cooler than
 415          * just returning raw text
 416          *
 417          * @todo This isn't ideal, we'd really like to have content-specific handling here
 418          * @param Title $t Title we're indexing
 419          * @param Content $c Content of the page to index
 420          * @return string
 421          */
 422         public function getTextFromContent( Title $t, Content $c = null ) {
 423                 return $c ? $c->getTextForSearchIndex() : '';
 424         }
 425
 426         /**
 427          * If an implementation of SearchEngine handles all of its own text processing
 428          * in getTextFromContent() and doesn't require SearchUpdate::updateText()'s
 429          * rather silly handling, it should return true here instead.
 430          *
 431          * @return bool
 432          */
 433         public function textAlreadyUpdatedForIndex() {
 434                 return false;
 435         }
 436
 437         /**
 438          * Makes search simple string if it was namespaced.
 439          * Sets namespaces of the search to namespaces extracted from string.
 440          * @param string $search
 441          * @return string Simplified search string
 442          */
 443         protected function normalizeNamespaces( $search ) {
 444                 // Find a Title which is not an interwiki and is in NS_MAIN
 445                 $title = Title::newFromText( $search );
 446                 $ns = $this->namespaces;
 447                 if ( $title && !$title->isExternal() ) {
 448                         $ns = [ $title->getNamespace() ];
 449                         $search = $title->getText();
 450                         if ( $ns[0] == NS_MAIN ) {
 451                                 $ns = $this->namespaces; // no explicit prefix, use default namespaces
 452                                 Hooks::run( 'PrefixSearchExtractNamespace', [ &$ns, &$search ] );
 453                         }
 454                 } else {
 455                         $title = Title::newFromText( $search . 'Dummy' );
 456                         if ( $title && $title->getText() == 'Dummy'
 457                                         && $title->getNamespace() != NS_MAIN
 458                                         && !$title->isExternal() )
 459                         {
 460                                 $ns = [ $title->getNamespace() ];
 461                                 $search = '';
 462                         } else {
 463                                 Hooks::run( 'PrefixSearchExtractNamespace', [ &$ns, &$search ] );
 464                         }
 465                 }
 466
 467                 $ns = array_map( function( $space ) {
 468                         return $space == NS_MEDIA ? NS_FILE : $space;
 469                 }, $ns );
 470
 471                 $this->setNamespaces( $ns );
 472                 return $search;
 473         }
 474
 475         /**
 476          * Perform a completion search.
 477          * Does not resolve namespaces and does not check variants.
 478          * Search engine implementations may want to override this function.
 479          * @param string $search
 480          * @return SearchSuggestionSet
 481          */
 482         protected function completionSearchBackend( $search ) {
 483                 $results = [];
 484
 485                 $search = trim( $search );
 486
 487                 if ( !in_array( NS_SPECIAL, $this->namespaces ) && // We do not run hook on Special: search
 488                          !Hooks::run( 'PrefixSearchBackend',
 489                                 [ $this->namespaces, $search, $this->limit, &$results, $this->offset ]
 490                 ) ) {
 491                         // False means hook worked.
 492                         // FIXME: Yes, the API is weird. That's why it is going to be deprecated.
 493
 494                         return SearchSuggestionSet::fromStrings( $results );
 495                 } else {
 496                         // Hook did not do the job, use default simple search
 497                         $results = $this->simplePrefixSearch( $search );
 498                         return SearchSuggestionSet::fromTitles( $results );
 499                 }
 500         }
 501
 502         /**
 503          * Perform a completion search.
 504          * @param string $search
 505          * @return SearchSuggestionSet
 506          */
 507         public function completionSearch( $search ) {
 508                 if ( trim( $search ) === '' ) {
 509                         return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
 510                 }
 511                 $search = $this->normalizeNamespaces( $search );
 512                 return $this->processCompletionResults( $search, $this->completionSearchBackend( $search ) );
 513         }
 514
 515         /**
 516          * Perform a completion search with variants.
 517          * @param string $search
 518          * @return SearchSuggestionSet
 519          */
 520         public function completionSearchWithVariants( $search ) {
 521                 if ( trim( $search ) === '' ) {
 522                         return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
 523                 }
 524                 $search = $this->normalizeNamespaces( $search );
 525
 526                 $results = $this->completionSearchBackend( $search );
 527                 $fallbackLimit = $this->limit - $results->getSize();
 528                 if ( $fallbackLimit > 0 ) {
 529                         global $wgContLang;
 530
 531                         $fallbackSearches = $wgContLang->autoConvertToAllVariants( $search );
 532                         $fallbackSearches = array_diff( array_unique( $fallbackSearches ), [ $search ] );
 533
 534                         foreach ( $fallbackSearches as $fbs ) {
 535                                 $this->setLimitOffset( $fallbackLimit );
 536                                 $fallbackSearchResult = $this->completionSearch( $fbs );
 537                                 $results->appendAll( $fallbackSearchResult );
 538                                 $fallbackLimit -= count( $fallbackSearchResult );
 539                                 if ( $fallbackLimit <= 0 ) {
 540                                         break;
 541                                 }
 542                         }
 543                 }
 544                 return $this->processCompletionResults( $search, $results );
 545         }
 546
 547         /**
 548          * Extract titles from completion results
 549          * @param SearchSuggestionSet $completionResults
 550          * @return Title[]
 551          */
 552         public function extractTitles( SearchSuggestionSet $completionResults ) {
 553                 return $completionResults->map( function( SearchSuggestion $sugg ) {
 554                         return $sugg->getSuggestedTitle();
 555                 } );
 556         }
 557
 558         /**
 559          * Process completion search results.
 560          * Resolves the titles and rescores.
 561          * @param SearchSuggestionSet $suggestions
 562          * @return SearchSuggestionSet
 563          */
 564         protected function processCompletionResults( $search, SearchSuggestionSet $suggestions ) {
 565                 $search = trim( $search );
 566                 // preload the titles with LinkBatch
 567                 $titles = $suggestions->map( function( SearchSuggestion $sugg ) {
 568                         return $sugg->getSuggestedTitle();
 569                 } );
 570                 $lb = new LinkBatch( $titles );
 571                 $lb->setCaller( __METHOD__ );
 572                 $lb->execute();
 573
 574                 $results = $suggestions->map( function( SearchSuggestion $sugg ) {
 575                         return $sugg->getSuggestedTitle()->getPrefixedText();
 576                 } );
 577
 578                 if ( $this->offset === 0 ) {
 579                         // Rescore results with an exact title match
 580                         // NOTE: in some cases like cross-namespace redirects
 581                         // (frequently used as shortcuts e.g. WP:WP on huwiki) some
 582                         // backends like Cirrus will return no results. We should still
 583                         // try an exact title match to workaround this limitation
 584                         $rescorer = new SearchExactMatchRescorer();
 585                         $rescoredResults = $rescorer->rescore( $search, $this->namespaces, $results, $this->limit );
 586                 } else {
 587                         // No need to rescore if offset is not 0
 588                         // The exact match must have been returned at position 0
 589                         // if it existed.
 590                         $rescoredResults = $results;
 591                 }
 592
 593                 if ( count( $rescoredResults ) > 0 ) {
 594                         $found = array_search( $rescoredResults[0], $results );
 595                         if ( $found === false ) {
 596                                 // If the first result is not in the previous array it
 597                                 // means that we found a new exact match
 598                                 $exactMatch = SearchSuggestion::fromTitle( 0, Title::newFromText( $rescoredResults[0] ) );
 599                                 $suggestions->prepend( $exactMatch );
 600                                 $suggestions->shrink( $this->limit );
 601                         } else {
 602                                 // if the first result is not the same we need to rescore
 603                                 if ( $found > 0 ) {
 604                                         $suggestions->rescore( $found );
 605                                 }
 606                         }
 607                 }
 608
 609                 return $suggestions;
 610         }
 611
 612         /**
 613          * Simple prefix search for subpages.
 614          * @param string $search
 615          * @return Title[]
 616          */
 617         public function defaultPrefixSearch( $search ) {
 618                 if ( trim( $search ) === '' ) {
 619                         return [];
 620                 }
 621
 622                 $search = $this->normalizeNamespaces( $search );
 623                 return $this->simplePrefixSearch( $search );
 624         }
 625
 626         /**
 627          * Call out to simple search backend.
 628          * Defaults to TitlePrefixSearch.
 629          * @param string $search
 630          * @return Title[]
 631          */
 632         protected function simplePrefixSearch( $search ) {
 633                 // Use default database prefix search
 634                 $backend = new TitlePrefixSearch;
 635                 return $backend->defaultSearchBackend( $this->namespaces, $search, $this->limit, $this->offset );
 636         }
 637
 638         /**
 639          * Make a list of searchable namespaces and their canonical names.
 640          * @deprecated since 1.27; use SearchEngineConfig::searchableNamespaces()
 641          * @return array
 642          */
 643         public static function searchableNamespaces() {
 644                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->searchableNamespaces();
 645         }
 646
 647         /**
 648          * Extract default namespaces to search from the given user's
 649          * settings, returning a list of index numbers.
 650          * @deprecated since 1.27; use SearchEngineConfig::userNamespaces()
 651          * @param user $user
 652          * @return array
 653          */
 654         public static function userNamespaces( $user ) {
 655                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->userNamespaces( $user );
 656         }
 657
 658         /**
 659          * An array of namespaces indexes to be searched by default
 660          * @deprecated since 1.27; use SearchEngineConfig::defaultNamespaces()
 661          * @return array
 662          */
 663         public static function defaultNamespaces() {
 664                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->defaultNamespaces();
 665         }
 666
 667         /**
 668          * Get a list of namespace names useful for showing in tooltips
 669          * and preferences
 670          * @deprecated since 1.27; use SearchEngineConfig::namespacesAsText()
 671          * @param array $namespaces
 672          * @return array
 673          */
 674         public static function namespacesAsText( $namespaces ) {
 675                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->namespacesAsText( $namespaces );
 676         }
 677
 678         /**
 679          * Load up the appropriate search engine class for the currently
 680          * active database backend, and return a configured instance.
 681          * @deprecated since 1.27; Use SearchEngineFactory::create
 682          * @param string $type Type of search backend, if not the default
 683          * @return SearchEngine
 684          */
 685         public static function create( $type = null ) {
 686                 return MediaWikiServices::getInstance()->getSearchEngineFactory()->create( $type );
 687         }
 688
 689         /**
 690          * Return the search engines we support. If only $wgSearchType
 691          * is set, it'll be an array of just that one item.
 692          * @deprecated since 1.27; use SearchEngineConfig::getSearchTypes()
 693          * @return array
 694          */
 695         public static function getSearchTypes() {
 696                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->getSearchTypes();
 697         }
 698
 699         /**
 700          * Get a list of supported profiles.
 701          * Some search engine implementations may expose specific profiles to fine-tune
 702          * its behaviors.
 703          * The profile can be passed as a feature data with setFeatureData( $profileType, $profileName )
 704          * The array returned by this function contains the following keys:
 705          * - name: the profile name to use with setFeatureData
 706          * - desc-message: the i18n description
 707          * - default: set to true if this profile is the default
 708          *
 709          * @since 1.28
 710          * @param string $profileType the type of profiles
 711          * @param User|null $user the user requesting the list of profiles
 712          * @return array|null the list of profiles or null if none available
 713          */
 714         public function getProfiles( $profileType, User $user = null ) {
 715                 return null;
 716         }
 717
 718         /**
 719          * Create a search field definition.
 720          * Specific search engines should override this method to create search fields.
 721          * @param string $name
 722          * @param int    $type One of the types in SearchIndexField::INDEX_TYPE_*
 723          * @return SearchIndexField
 724          * @since 1.28
 725          */
 726         public function makeSearchFieldMapping( $name, $type ) {
 727                 return new NullIndexField();
 728         }
 729
 730         /**
 731          * Get fields for search index
 732          * @since 1.28
 733          * @return SearchIndexField[] Index field definitions for all content handlers
 734          */
 735         public function getSearchIndexFields() {
 736                 $models = ContentHandler::getContentModels();
 737                 $fields = [];
 738                 $seenHandlers = new SplObjectStorage();
 739                 foreach ( $models as $model ) {
 740                         try {
 741                                 $handler = ContentHandler::getForModelID( $model );
 742                         }
 743                         catch ( MWUnknownContentModelException $e ) {
 744                                 // If we can find no handler, ignore it
 745                                 continue;
 746                         }
 747                         // Several models can have the same handler, so avoid processing it repeatedly
 748                         if ( $seenHandlers->contains( $handler ) ) {
 749                                 // We already did this one
 750                                 continue;
 751                         }
 752                         $seenHandlers->attach( $handler );
 753                         $handlerFields = $handler->getFieldsForSearchIndex( $this );
 754                         foreach ( $handlerFields as $fieldName => $fieldData ) {
 755                                 if ( empty( $fields[$fieldName] ) ) {
 756                                         $fields[$fieldName] = $fieldData;
 757                                 } else {
 758                                         // TODO: do we allow some clashes with the same type or reject all of them?
 759                                         $mergeDef = $fields[$fieldName]->merge( $fieldData );
 760                                         if ( !$mergeDef ) {
 761                                                 throw new InvalidArgumentException( "Duplicate field $fieldName for model $model" );
 762                                         }
 763                                         $fields[$fieldName] = $mergeDef;
 764                                 }
 765                         }
 766                 }
 767                 // Hook to allow extensions to produce search mapping fields
 768                 Hooks::run( 'SearchIndexFields', [ &$fields, $this ] );
 769                 return $fields;
 770         }
 771
 772         /**
 773          * Augment search results with extra data.
 774          *
 775          * @param SearchResultSet $resultSet
 776          */
 777         public function augmentSearchResults( SearchResultSet $resultSet ) {
 778                 $setAugmentors = [];
 779                 $rowAugmentors = [];
 780                 Hooks::run( "SearchResultsAugment", [ &$setAugmentors, &$rowAugmentors ] );
 781
 782                 if ( !$setAugmentors && !$rowAugmentors ) {
 783                         // We're done here
 784                         return;
 785                 }
 786
 787                 // Convert row augmentors to set augmentor
 788                 foreach ( $rowAugmentors as $name => $row ) {
 789                         if ( isset( $setAugmentors[$name] ) ) {
 790                                 throw new InvalidArgumentException( "Both row and set augmentors are defined for $name" );
 791                         }
 792                         $setAugmentors[$name] = new PerRowAugmentor( $row );
 793                 }
 794
 795                 foreach ( $setAugmentors as $name => $augmentor ) {
 796                         $data = $augmentor->augmentAll( $resultSet );
 797                         if ( $data ) {
 798                                 $resultSet->setAugmentedData( $name, $data );
 799                         }
 800                 }
 801         }
 802 }
 803
 804 /**
 805  * Dummy class to be used when non-supported Database engine is present.
 806  * @todo FIXME: Dummy class should probably try something at least mildly useful,
 807  * such as a LIKE search through titles.
 808  * @ingroup Search
 809  */
 810 class SearchEngineDummy extends SearchEngine {
 811         // no-op
 812 }