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         const DEFAULT_SORT = 'relevance';
  36
  37         /** @var string */
  38         public $prefix = '';
  39
  40         /** @var int[]|null */
  41         public $namespaces = [ NS_MAIN ];
  42
  43         /** @var int */
  44         protected $limit = 10;
  45
  46         /** @var int */
  47         protected $offset = 0;
  48
  49         /** @var array|string */
  50         protected $searchTerms = [];
  51
  52         /** @var bool */
  53         protected $showSuggestion = true;
  54         private $sort = self::DEFAULT_SORT;
  55
  56         /** @var array Feature values */
  57         protected $features = [];
  58
  59         /** Profile type for completionSearch */
  60         const COMPLETION_PROFILE_TYPE = 'completionSearchProfile';
  61
  62         /** Profile type for query independent ranking features */
  63         const FT_QUERY_INDEP_PROFILE_TYPE = 'fulltextQueryIndepProfile';
  64
  65         /** Integer flag for legalSearchChars: includes all chars allowed in a search query */
  66         const CHARS_ALL = 1;
  67
  68         /** Integer flag for legalSearchChars: includes all chars allowed in a search term */
  69         const CHARS_NO_SYNTAX = 2;
  70
  71         /**
  72          * Perform a full text search query and return a result set.
  73          * If full text searches are not supported or disabled, return null.
  74          *
  75          * As of 1.32 overriding this function is deprecated. It will
  76          * be converted to final in 1.34. Override self::doSearchText().
  77          *
  78          * @param string $term Raw search term
  79          * @return SearchResultSet|Status|null
  80          */
  81         public function searchText( $term ) {
  82                 return $this->maybePaginate( function () use ( $term ) {
  83                         return $this->doSearchText( $term );
  84                 } );
  85         }
  86
  87         /**
  88          * Perform a full text search query and return a result set.
  89          *
  90          * @param string $term Raw search term
  91          * @return SearchResultSet|Status|null
  92          * @since 1.32
  93          */
  94         protected function doSearchText( $term ) {
  95                 return null;
  96         }
  97
  98         /**
  99          * Perform a title search in the article archive.
 100          * NOTE: these results still should be filtered by
 101          * matching against PageArchive, permissions checks etc
 102          * The results returned by this methods are only sugegstions and
 103          * may not end up being shown to the user.
 104          *
 105          * As of 1.32 overriding this function is deprecated. It will
 106          * be converted to final in 1.34. Override self::doSearchArchiveTitle().
 107          *
 108          * @param string $term Raw search term
 109          * @return Status<Title[]>
 110          * @since 1.29
 111          */
 112         public function searchArchiveTitle( $term ) {
 113                 return $this->doSearchArchiveTitle( $term );
 114         }
 115
 116         /**
 117          * Perform a title search in the article archive.
 118          *
 119          * @param string $term Raw search term
 120          * @return Status<Title[]>
 121          * @since 1.32
 122          */
 123         protected function doSearchArchiveTitle( $term ) {
 124                 return Status::newGood( [] );
 125         }
 126
 127         /**
 128          * Perform a title-only search query and return a result set.
 129          * If title searches are not supported or disabled, return null.
 130          * STUB
 131          *
 132          * As of 1.32 overriding this function is deprecated. It will
 133          * be converted to final in 1.34. Override self::doSearchTitle().
 134          *
 135          * @param string $term Raw search term
 136          * @return SearchResultSet|null
 137          */
 138         public function searchTitle( $term ) {
 139                 return $this->maybePaginate( function () use ( $term ) {
 140                         return $this->doSearchTitle( $term );
 141                 } );
 142         }
 143
 144         /**
 145          * Perform a title-only search query and return a result set.
 146          *
 147          * @param string $term Raw search term
 148          * @return SearchResultSet|null
 149          * @since 1.32
 150          */
 151         protected function doSearchTitle( $term ) {
 152                 return null;
 153         }
 154
 155         /**
 156          * Performs an overfetch and shrink operation to determine if
 157          * the next page is available for search engines that do not
 158          * explicitly implement their own pagination.
 159          *
 160          * @param Closure $fn Takes no arguments
 161          * @return SearchResultSet|Status<SearchResultSet>|null Result of calling $fn
 162          */
 163         private function maybePaginate( Closure $fn ) {
 164                 if ( $this instanceof PaginatingSearchEngine ) {
 165                         return $fn();
 166                 }
 167                 $this->limit++;
 168                 try {
 169                         $resultSetOrStatus = $fn();
 170                 } finally {
 171                         $this->limit--;
 172                 }
 173
 174                 $resultSet = null;
 175                 if ( $resultSetOrStatus instanceof SearchResultSet ) {
 176                         $resultSet = $resultSetOrStatus;
 177                 } elseif ( $resultSetOrStatus instanceof Status &&
 178                         $resultSetOrStatus->getValue() instanceof SearchResultSet
 179                 ) {
 180                         $resultSet = $resultSetOrStatus->getValue();
 181                 }
 182                 if ( $resultSet ) {
 183                         $resultSet->shrink( $this->limit );
 184                 }
 185
 186                 return $resultSetOrStatus;
 187         }
 188
 189         /**
 190          * @since 1.18
 191          * @param string $feature
 192          * @return bool
 193          */
 194         public function supports( $feature ) {
 195                 switch ( $feature ) {
 196                         case 'search-update':
 197                                 return true;
 198                         case 'title-suffix-filter':
 199                         default:
 200                                 return false;
 201                 }
 202         }
 203
 204         /**
 205          * Way to pass custom data for engines
 206          * @since 1.18
 207          * @param string $feature
 208          * @param mixed $data
 209          */
 210         public function setFeatureData( $feature, $data ) {
 211                 $this->features[$feature] = $data;
 212         }
 213
 214         /**
 215          * Way to retrieve custom data set by setFeatureData
 216          * or by the engine itself.
 217          * @since 1.29
 218          * @param string $feature feature name
 219          * @return mixed the feature value or null if unset
 220          */
 221         public function getFeatureData( $feature ) {
 222                 return $this->features[$feature] ?? null;
 223         }
 224
 225         /**
 226          * When overridden in derived class, performs database-specific conversions
 227          * on text to be used for searching or updating search index.
 228          * Default implementation does nothing (simply returns $string).
 229          *
 230          * @param string $string String to process
 231          * @return string
 232          */
 233         public function normalizeText( $string ) {
 234                 // Some languages such as Chinese require word segmentation
 235                 return MediaWikiServices::getInstance()->getContentLanguage()->segmentByWord( $string );
 236         }
 237
 238         /**
 239          * Transform search term in cases when parts of the query came as different
 240          * GET params (when supported), e.g. for prefix queries:
 241          * search=test&prefix=Main_Page/Archive -> test prefix:Main Page/Archive
 242          * @param string $term
 243          * @return string
 244          * @deprecated since 1.32 this should now be handled internally by the
 245          * search engine
 246          */
 247         public function transformSearchTerm( $term ) {
 248                 return $term;
 249         }
 250
 251         /**
 252          * Get service class to finding near matches.
 253          * @param Config $config Configuration to use for the matcher.
 254          * @return SearchNearMatcher
 255          */
 256         public function getNearMatcher( Config $config ) {
 257                 return new SearchNearMatcher( $config,
 258                         MediaWikiServices::getInstance()->getContentLanguage() );
 259         }
 260
 261         /**
 262          * Get near matcher for default SearchEngine.
 263          * @return SearchNearMatcher
 264          */
 265         protected static function defaultNearMatcher() {
 266                 $services = MediaWikiServices::getInstance();
 267                 $config = $services->getMainConfig();
 268                 return $services->newSearchEngine()->getNearMatcher( $config );
 269         }
 270
 271         /**
 272          * If an exact title match can be found, or a very slightly close match,
 273          * return the title. If no match, returns NULL.
 274          * @deprecated since 1.27; Use SearchEngine::getNearMatcher()
 275          * @param string $searchterm
 276          * @return Title
 277          */
 278         public static function getNearMatch( $searchterm ) {
 279                 wfDeprecated( __METHOD__, '1.27' );
 280
 281                 return static::defaultNearMatcher()->getNearMatch( $searchterm );
 282         }
 283
 284         /**
 285          * Get chars legal for search
 286          * @param int $type type of search chars (see self::CHARS_ALL
 287          * and self::CHARS_NO_SYNTAX). Defaults to CHARS_ALL
 288          * @return string
 289          */
 290         public function legalSearchChars( $type = self::CHARS_ALL ) {
 291                 return "A-Za-z_'.0-9\\x80-\\xFF\\-";
 292         }
 293
 294         /**
 295          * Set the maximum number of results to return
 296          * and how many to skip before returning the first.
 297          *
 298          * @param int $limit
 299          * @param int $offset
 300          */
 301         function setLimitOffset( $limit, $offset = 0 ) {
 302                 $this->limit = intval( $limit );
 303                 $this->offset = intval( $offset );
 304         }
 305
 306         /**
 307          * Set which namespaces the search should include.
 308          * Give an array of namespace index numbers.
 309          *
 310          * @param int[]|null $namespaces
 311          */
 312         function setNamespaces( $namespaces ) {
 313                 if ( $namespaces ) {
 314                         // Filter namespaces to only keep valid ones
 315                         $validNs = MediaWikiServices::getInstance()->getSearchEngineConfig()->searchableNamespaces();
 316                         $namespaces = array_filter( $namespaces, function ( $ns ) use( $validNs ) {
 317                                 return $ns < 0 || isset( $validNs[$ns] );
 318                         } );
 319                 } else {
 320                         $namespaces = [];
 321                 }
 322                 $this->namespaces = $namespaces;
 323         }
 324
 325         /**
 326          * Set whether the searcher should try to build a suggestion.  Note: some searchers
 327          * don't support building a suggestion in the first place and others don't respect
 328          * this flag.
 329          *
 330          * @param bool $showSuggestion Should the searcher try to build suggestions
 331          */
 332         function setShowSuggestion( $showSuggestion ) {
 333                 $this->showSuggestion = $showSuggestion;
 334         }
 335
 336         /**
 337          * Get the valid sort directions.  All search engines support 'relevance' but others
 338          * might support more. The default in all implementations must be 'relevance.'
 339          *
 340          * @since 1.25
 341          * @return string[] the valid sort directions for setSort
 342          */
 343         public function getValidSorts() {
 344                 return [ self::DEFAULT_SORT ];
 345         }
 346
 347         /**
 348          * Set the sort direction of the search results. Must be one returned by
 349          * SearchEngine::getValidSorts()
 350          *
 351          * @since 1.25
 352          * @throws InvalidArgumentException
 353          * @param string $sort sort direction for query result
 354          */
 355         public function setSort( $sort ) {
 356                 if ( !in_array( $sort, $this->getValidSorts() ) ) {
 357                         throw new InvalidArgumentException( "Invalid sort: $sort. " .
 358                                 "Must be one of: " . implode( ', ', $this->getValidSorts() ) );
 359                 }
 360                 $this->sort = $sort;
 361         }
 362
 363         /**
 364          * Get the sort direction of the search results
 365          *
 366          * @since 1.25
 367          * @return string
 368          */
 369         public function getSort() {
 370                 return $this->sort;
 371         }
 372
 373         /**
 374          * Parse some common prefixes: all (search everything)
 375          * or namespace names and set the list of namespaces
 376          * of this class accordingly.
 377          *
 378          * @deprecated since 1.32; should be handled internally by the search engine
 379          * @param string $query
 380          * @return string
 381          */
 382         function replacePrefixes( $query ) {
 383                 return $query;
 384         }
 385
 386         /**
 387          * Parse some common prefixes: all (search everything)
 388          * or namespace names
 389          *
 390          * @param string $query
 391          * @param bool $withAllKeyword activate support of the "all:" keyword and its
 392          * translations to activate searching on all namespaces.
 393          * @param bool $withPrefixSearchExtractNamespaceHook call the PrefixSearchExtractNamespace hook
 394          *  if classic namespace identification did not match.
 395          * @return false|array false if no namespace was extracted, an array
 396          * with the parsed query at index 0 and an array of namespaces at index
 397          * 1 (or null for all namespaces).
 398          * @throws FatalError
 399          * @throws MWException
 400          */
 401         public static function parseNamespacePrefixes(
 402                 $query,
 403                 $withAllKeyword = true,
 404                 $withPrefixSearchExtractNamespaceHook = false
 405         ) {
 406                 $parsed = $query;
 407                 if ( strpos( $query, ':' ) === false ) { // nothing to do
 408                         return false;
 409                 }
 410                 $extractedNamespace = null;
 411
 412                 $allQuery = false;
 413                 if ( $withAllKeyword ) {
 414                         $allkeywords = [];
 415
 416                         $allkeywords[] = wfMessage( 'searchall' )->inContentLanguage()->text() . ":";
 417                         // force all: so that we have a common syntax for all the wikis
 418                         if ( !in_array( 'all:', $allkeywords ) ) {
 419                                 $allkeywords[] = 'all:';
 420                         }
 421
 422                         foreach ( $allkeywords as $kw ) {
 423                                 if ( strncmp( $query, $kw, strlen( $kw ) ) == 0 ) {
 424                                         $extractedNamespace = null;
 425                                         $parsed = substr( $query, strlen( $kw ) );
 426                                         $allQuery = true;
 427                                         break;
 428                                 }
 429                         }
 430                 }
 431
 432                 if ( !$allQuery && strpos( $query, ':' ) !== false ) {
 433                         $prefix = str_replace( ' ', '_', substr( $query, 0, strpos( $query, ':' ) ) );
 434                         $index = MediaWikiServices::getInstance()->getContentLanguage()->getNsIndex( $prefix );
 435                         if ( $index !== false ) {
 436                                 $extractedNamespace = [ $index ];
 437                                 $parsed = substr( $query, strlen( $prefix ) + 1 );
 438                         } elseif ( $withPrefixSearchExtractNamespaceHook ) {
 439                                 $hookNamespaces = [ NS_MAIN ];
 440                                 $hookQuery = $query;
 441                                 Hooks::run( 'PrefixSearchExtractNamespace', [ &$hookNamespaces, &$hookQuery ] );
 442                                 if ( $hookQuery !== $query ) {
 443                                         $parsed = $hookQuery;
 444                                         $extractedNamespace = $hookNamespaces;
 445                                 } else {
 446                                         return false;
 447                                 }
 448                         } else {
 449                                 return false;
 450                         }
 451                 }
 452
 453                 return [ $parsed, $extractedNamespace ];
 454         }
 455
 456         /**
 457          * Find snippet highlight settings for all users
 458          * @return array Contextlines, contextchars
 459          */
 460         public static function userHighlightPrefs() {
 461                 $contextlines = 2; // Hardcode this. Old defaults sucked. :)
 462                 $contextchars = 75; // same as above.... :P
 463                 return [ $contextlines, $contextchars ];
 464         }
 465
 466         /**
 467          * Create or update the search index record for the given page.
 468          * Title and text should be pre-processed.
 469          * STUB
 470          *
 471          * @param int $id
 472          * @param string $title
 473          * @param string $text
 474          */
 475         function update( $id, $title, $text ) {
 476                 // no-op
 477         }
 478
 479         /**
 480          * Update a search index record's title only.
 481          * Title should be pre-processed.
 482          * STUB
 483          *
 484          * @param int $id
 485          * @param string $title
 486          */
 487         function updateTitle( $id, $title ) {
 488                 // no-op
 489         }
 490
 491         /**
 492          * Delete an indexed page
 493          * Title should be pre-processed.
 494          * STUB
 495          *
 496          * @param int $id Page id that was deleted
 497          * @param string $title Title of page that was deleted
 498          */
 499         function delete( $id, $title ) {
 500                 // no-op
 501         }
 502
 503         /**
 504          * Get the raw text for updating the index from a content object
 505          * Nicer search backends could possibly do something cooler than
 506          * just returning raw text
 507          *
 508          * @todo This isn't ideal, we'd really like to have content-specific handling here
 509          * @param Title $t Title we're indexing
 510          * @param Content|null $c Content of the page to index
 511          * @return string
 512          */
 513         public function getTextFromContent( Title $t, Content $c = null ) {
 514                 return $c ? $c->getTextForSearchIndex() : '';
 515         }
 516
 517         /**
 518          * If an implementation of SearchEngine handles all of its own text processing
 519          * in getTextFromContent() and doesn't require SearchUpdate::updateText()'s
 520          * rather silly handling, it should return true here instead.
 521          *
 522          * @return bool
 523          */
 524         public function textAlreadyUpdatedForIndex() {
 525                 return false;
 526         }
 527
 528         /**
 529          * Makes search simple string if it was namespaced.
 530          * Sets namespaces of the search to namespaces extracted from string.
 531          * @param string $search
 532          * @return string Simplified search string
 533          */
 534         protected function normalizeNamespaces( $search ) {
 535                 $queryAndNs = self::parseNamespacePrefixes( $search, false, true );
 536                 if ( $queryAndNs !== false ) {
 537                         $this->setNamespaces( $queryAndNs[1] );
 538                         return $queryAndNs[0];
 539                 }
 540                 return $search;
 541         }
 542
 543         /**
 544          * Perform an overfetch of completion search results. This allows
 545          * determining if another page of results is available.
 546          *
 547          * @param string $search
 548          * @return SearchSuggestionSet
 549          */
 550         protected function completionSearchBackendOverfetch( $search ) {
 551                 $this->limit++;
 552                 try {
 553                         return $this->completionSearchBackend( $search );
 554                 } finally {
 555                         $this->limit--;
 556                 }
 557         }
 558
 559         /**
 560          * Perform a completion search.
 561          * Does not resolve namespaces and does not check variants.
 562          * Search engine implementations may want to override this function.
 563          * @param string $search
 564          * @return SearchSuggestionSet
 565          */
 566         protected function completionSearchBackend( $search ) {
 567                 $results = [];
 568
 569                 $search = trim( $search );
 570
 571                 if ( !in_array( NS_SPECIAL, $this->namespaces ) && // We do not run hook on Special: search
 572                          !Hooks::run( 'PrefixSearchBackend',
 573                                 [ $this->namespaces, $search, $this->limit, &$results, $this->offset ]
 574                 ) ) {
 575                         // False means hook worked.
 576                         // FIXME: Yes, the API is weird. That's why it is going to be deprecated.
 577
 578                         return SearchSuggestionSet::fromStrings( $results );
 579                 } else {
 580                         // Hook did not do the job, use default simple search
 581                         $results = $this->simplePrefixSearch( $search );
 582                         return SearchSuggestionSet::fromTitles( $results );
 583                 }
 584         }
 585
 586         /**
 587          * Perform a completion search.
 588          * @param string $search
 589          * @return SearchSuggestionSet
 590          */
 591         public function completionSearch( $search ) {
 592                 if ( trim( $search ) === '' ) {
 593                         return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
 594                 }
 595                 $search = $this->normalizeNamespaces( $search );
 596                 $suggestions = $this->completionSearchBackendOverfetch( $search );
 597                 return $this->processCompletionResults( $search, $suggestions );
 598         }
 599
 600         /**
 601          * Perform a completion search with variants.
 602          * @param string $search
 603          * @return SearchSuggestionSet
 604          */
 605         public function completionSearchWithVariants( $search ) {
 606                 if ( trim( $search ) === '' ) {
 607                         return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
 608                 }
 609                 $search = $this->normalizeNamespaces( $search );
 610
 611                 $results = $this->completionSearchBackendOverfetch( $search );
 612                 $fallbackLimit = 1 + $this->limit - $results->getSize();
 613                 if ( $fallbackLimit > 0 ) {
 614                         $fallbackSearches = MediaWikiServices::getInstance()->getContentLanguage()->
 615                                 autoConvertToAllVariants( $search );
 616                         $fallbackSearches = array_diff( array_unique( $fallbackSearches ), [ $search ] );
 617
 618                         foreach ( $fallbackSearches as $fbs ) {
 619                                 $this->setLimitOffset( $fallbackLimit );
 620                                 $fallbackSearchResult = $this->completionSearch( $fbs );
 621                                 $results->appendAll( $fallbackSearchResult );
 622                                 $fallbackLimit -= $fallbackSearchResult->getSize();
 623                                 if ( $fallbackLimit <= 0 ) {
 624                                         break;
 625                                 }
 626                         }
 627                 }
 628                 return $this->processCompletionResults( $search, $results );
 629         }
 630
 631         /**
 632          * Extract titles from completion results
 633          * @param SearchSuggestionSet $completionResults
 634          * @return Title[]
 635          */
 636         public function extractTitles( SearchSuggestionSet $completionResults ) {
 637                 return $completionResults->map( function ( SearchSuggestion $sugg ) {
 638                         return $sugg->getSuggestedTitle();
 639                 } );
 640         }
 641
 642         /**
 643          * Process completion search results.
 644          * Resolves the titles and rescores.
 645          * @param string $search
 646          * @param SearchSuggestionSet $suggestions
 647          * @return SearchSuggestionSet
 648          */
 649         protected function processCompletionResults( $search, SearchSuggestionSet $suggestions ) {
 650                 // We over-fetched to determine pagination. Shrink back down if we have extra results
 651                 // and mark if pagination is possible
 652                 $suggestions->shrink( $this->limit );
 653
 654                 $search = trim( $search );
 655                 // preload the titles with LinkBatch
 656                 $lb = new LinkBatch( $suggestions->map( function ( SearchSuggestion $sugg ) {
 657                         return $sugg->getSuggestedTitle();
 658                 } ) );
 659                 $lb->setCaller( __METHOD__ );
 660                 $lb->execute();
 661
 662                 $diff = $suggestions->filter( function ( SearchSuggestion $sugg ) {
 663                         return $sugg->getSuggestedTitle()->isKnown();
 664                 } );
 665                 if ( $diff > 0 ) {
 666                         MediaWikiServices::getInstance()->getStatsdDataFactory()
 667                                 ->updateCount( 'search.completion.missing', $diff );
 668                 }
 669
 670                 $results = $suggestions->map( function ( SearchSuggestion $sugg ) {
 671                         return $sugg->getSuggestedTitle()->getPrefixedText();
 672                 } );
 673
 674                 if ( $this->offset === 0 ) {
 675                         // Rescore results with an exact title match
 676                         // NOTE: in some cases like cross-namespace redirects
 677                         // (frequently used as shortcuts e.g. WP:WP on huwiki) some
 678                         // backends like Cirrus will return no results. We should still
 679                         // try an exact title match to workaround this limitation
 680                         $rescorer = new SearchExactMatchRescorer();
 681                         $rescoredResults = $rescorer->rescore( $search, $this->namespaces, $results, $this->limit );
 682                 } else {
 683                         // No need to rescore if offset is not 0
 684                         // The exact match must have been returned at position 0
 685                         // if it existed.
 686                         $rescoredResults = $results;
 687                 }
 688
 689                 if ( count( $rescoredResults ) > 0 ) {
 690                         $found = array_search( $rescoredResults[0], $results );
 691                         if ( $found === false ) {
 692                                 // If the first result is not in the previous array it
 693                                 // means that we found a new exact match
 694                                 $exactMatch = SearchSuggestion::fromTitle( 0, Title::newFromText( $rescoredResults[0] ) );
 695                                 $suggestions->prepend( $exactMatch );
 696                                 $suggestions->shrink( $this->limit );
 697                         } else {
 698                                 // if the first result is not the same we need to rescore
 699                                 if ( $found > 0 ) {
 700                                         $suggestions->rescore( $found );
 701                                 }
 702                         }
 703                 }
 704
 705                 return $suggestions;
 706         }
 707
 708         /**
 709          * Simple prefix search for subpages.
 710          * @param string $search
 711          * @return Title[]
 712          */
 713         public function defaultPrefixSearch( $search ) {
 714                 if ( trim( $search ) === '' ) {
 715                         return [];
 716                 }
 717
 718                 $search = $this->normalizeNamespaces( $search );
 719                 return $this->simplePrefixSearch( $search );
 720         }
 721
 722         /**
 723          * Call out to simple search backend.
 724          * Defaults to TitlePrefixSearch.
 725          * @param string $search
 726          * @return Title[]
 727          */
 728         protected function simplePrefixSearch( $search ) {
 729                 // Use default database prefix search
 730                 $backend = new TitlePrefixSearch;
 731                 return $backend->defaultSearchBackend( $this->namespaces, $search, $this->limit, $this->offset );
 732         }
 733
 734         /**
 735          * Make a list of searchable namespaces and their canonical names.
 736          * @deprecated since 1.27; use SearchEngineConfig::searchableNamespaces()
 737          * @return array
 738          */
 739         public static function searchableNamespaces() {
 740                 wfDeprecated( __METHOD__, '1.27' );
 741
 742                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->searchableNamespaces();
 743         }
 744
 745         /**
 746          * Extract default namespaces to search from the given user's
 747          * settings, returning a list of index numbers.
 748          * @deprecated since 1.27; use SearchEngineConfig::userNamespaces()
 749          * @param user $user
 750          * @return array
 751          */
 752         public static function userNamespaces( $user ) {
 753                 wfDeprecated( __METHOD__, '1.27' );
 754
 755                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->userNamespaces( $user );
 756         }
 757
 758         /**
 759          * An array of namespaces indexes to be searched by default
 760          * @deprecated since 1.27; use SearchEngineConfig::defaultNamespaces()
 761          * @return array
 762          */
 763         public static function defaultNamespaces() {
 764                 wfDeprecated( __METHOD__, '1.27' );
 765
 766                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->defaultNamespaces();
 767         }
 768
 769         /**
 770          * Get a list of namespace names useful for showing in tooltips
 771          * and preferences
 772          * @deprecated since 1.27; use SearchEngineConfig::namespacesAsText()
 773          * @param array $namespaces
 774          * @return array
 775          */
 776         public static function namespacesAsText( $namespaces ) {
 777                 wfDeprecated( __METHOD__, '1.27' );
 778
 779                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->namespacesAsText( $namespaces );
 780         }
 781
 782         /**
 783          * Load up the appropriate search engine class for the currently
 784          * active database backend, and return a configured instance.
 785          * @deprecated since 1.27; Use SearchEngineFactory::create
 786          * @param string $type Type of search backend, if not the default
 787          * @return SearchEngine
 788          */
 789         public static function create( $type = null ) {
 790                 wfDeprecated( __METHOD__, '1.27' );
 791
 792                 return MediaWikiServices::getInstance()->getSearchEngineFactory()->create( $type );
 793         }
 794
 795         /**
 796          * Return the search engines we support. If only $wgSearchType
 797          * is set, it'll be an array of just that one item.
 798          * @deprecated since 1.27; use SearchEngineConfig::getSearchTypes()
 799          * @return array
 800          */
 801         public static function getSearchTypes() {
 802                 wfDeprecated( __METHOD__, '1.27' );
 803
 804                 return MediaWikiServices::getInstance()->getSearchEngineConfig()->getSearchTypes();
 805         }
 806
 807         /**
 808          * Get a list of supported profiles.
 809          * Some search engine implementations may expose specific profiles to fine-tune
 810          * its behaviors.
 811          * The profile can be passed as a feature data with setFeatureData( $profileType, $profileName )
 812          * The array returned by this function contains the following keys:
 813          * - name: the profile name to use with setFeatureData
 814          * - desc-message: the i18n description
 815          * - default: set to true if this profile is the default
 816          *
 817          * @since 1.28
 818          * @param string $profileType the type of profiles
 819          * @param User|null $user the user requesting the list of profiles
 820          * @return array|null the list of profiles or null if none available
 821          */
 822         public function getProfiles( $profileType, User $user = null ) {
 823                 return null;
 824         }
 825
 826         /**
 827          * Create a search field definition.
 828          * Specific search engines should override this method to create search fields.
 829          * @param string $name
 830          * @param int $type One of the types in SearchIndexField::INDEX_TYPE_*
 831          * @return SearchIndexField
 832          * @since 1.28
 833          */
 834         public function makeSearchFieldMapping( $name, $type ) {
 835                 return new NullIndexField();
 836         }
 837
 838         /**
 839          * Get fields for search index
 840          * @since 1.28
 841          * @return SearchIndexField[] Index field definitions for all content handlers
 842          */
 843         public function getSearchIndexFields() {
 844                 $models = ContentHandler::getContentModels();
 845                 $fields = [];
 846                 $seenHandlers = new SplObjectStorage();
 847                 foreach ( $models as $model ) {
 848                         try {
 849                                 $handler = ContentHandler::getForModelID( $model );
 850                         }
 851                         catch ( MWUnknownContentModelException $e ) {
 852                                 // If we can find no handler, ignore it
 853                                 continue;
 854                         }
 855                         // Several models can have the same handler, so avoid processing it repeatedly
 856                         if ( $seenHandlers->contains( $handler ) ) {
 857                                 // We already did this one
 858                                 continue;
 859                         }
 860                         $seenHandlers->attach( $handler );
 861                         $handlerFields = $handler->getFieldsForSearchIndex( $this );
 862                         foreach ( $handlerFields as $fieldName => $fieldData ) {
 863                                 if ( empty( $fields[$fieldName] ) ) {
 864                                         $fields[$fieldName] = $fieldData;
 865                                 } else {
 866                                         // TODO: do we allow some clashes with the same type or reject all of them?
 867                                         $mergeDef = $fields[$fieldName]->merge( $fieldData );
 868                                         if ( !$mergeDef ) {
 869                                                 throw new InvalidArgumentException( "Duplicate field $fieldName for model $model" );
 870                                         }
 871                                         $fields[$fieldName] = $mergeDef;
 872                                 }
 873                         }
 874                 }
 875                 // Hook to allow extensions to produce search mapping fields
 876                 Hooks::run( 'SearchIndexFields', [ &$fields, $this ] );
 877                 return $fields;
 878         }
 879
 880         /**
 881          * Augment search results with extra data.
 882          *
 883          * @param SearchResultSet $resultSet
 884          */
 885         public function augmentSearchResults( SearchResultSet $resultSet ) {
 886                 $setAugmentors = [];
 887                 $rowAugmentors = [];
 888                 Hooks::run( "SearchResultsAugment", [ &$setAugmentors, &$rowAugmentors ] );
 889                 if ( !$setAugmentors && !$rowAugmentors ) {
 890                         // We're done here
 891                         return;
 892                 }
 893
 894                 // Convert row augmentors to set augmentor
 895                 foreach ( $rowAugmentors as $name => $row ) {
 896                         if ( isset( $setAugmentors[$name] ) ) {
 897                                 throw new InvalidArgumentException( "Both row and set augmentors are defined for $name" );
 898                         }
 899                         $setAugmentors[$name] = new PerRowAugmentor( $row );
 900                 }
 901
 902                 foreach ( $setAugmentors as $name => $augmentor ) {
 903                         $data = $augmentor->augmentAll( $resultSet );
 904                         if ( $data ) {
 905                                 $resultSet->setAugmentedData( $name, $data );
 906                         }
 907                 }
 908         }
 909 }