<?php
/**
* Basic search engine
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @ingroup Search
*/
/**
* @defgroup Search Search
*/
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\MediaWikiServices;
/**
* Contain a class for special pages
* @stable to extend
* @ingroup Search
*/
abstract class SearchEngine {
public const DEFAULT_SORT = 'relevance';
/** @var string */
public $prefix = '';
/** @var int[]|null */
public $namespaces = [ NS_MAIN ];
/** @var int */
protected $limit = 10;
/** @var int */
protected $offset = 0;
/**
* @var string[]
* @deprecated since 1.34
*/
protected $searchTerms = [];
/** @var bool */
protected $showSuggestion = true;
private $sort = self::DEFAULT_SORT;
/** @var array Feature values */
protected $features = [];
/** @var HookContainer */
private $hookContainer;
/** @var HookRunner */
private $hookRunner;
/** Profile type for completionSearch */
public const COMPLETION_PROFILE_TYPE = 'completionSearchProfile';
/** Profile type for query independent ranking features */
public const FT_QUERY_INDEP_PROFILE_TYPE = 'fulltextQueryIndepProfile';
/** Integer flag for legalSearchChars: includes all chars allowed in a search query */
protected const CHARS_ALL = 1;
/** Integer flag for legalSearchChars: includes all chars allowed in a search term */
protected const CHARS_NO_SYNTAX = 2;
/**
* Perform a full text search query and return a result set.
* If full text searches are not supported or disabled, return null.
*
* @note As of 1.32 overriding this function is deprecated. It will
* be converted to final in 1.34. Override self::doSearchText().
*
* @param string $term Raw search term
* @return ISearchResultSet|Status|null
*/
public function searchText( $term ) {
return $this->maybePaginate( function () use ( $term ) {
return $this->doSearchText( $term );
} );
}
/**
* Perform a full text search query and return a result set.
*
* @stable to override
*
* @param string $term Raw search term
* @return ISearchResultSet|Status|null
* @since 1.32
*/
protected function doSearchText( $term ) {
return null;
}
/**
* Perform a title search in the article archive.
* NOTE: these results still should be filtered by
* matching against PageArchive, permissions checks etc
* The results returned by this methods are only sugegstions and
* may not end up being shown to the user.
*
* @note As of 1.32 overriding this function is deprecated. It will
* be converted to final in 1.34. Override self::doSearchArchiveTitle().
*
* @param string $term Raw search term
* @return Status
* @since 1.29
*/
public function searchArchiveTitle( $term ) {
return $this->doSearchArchiveTitle( $term );
}
/**
* Perform a title search in the article archive.
*
* @stable to override
*
* @param string $term Raw search term
* @return Status
* @since 1.32
*/
protected function doSearchArchiveTitle( $term ) {
return Status::newGood( [] );
}
/**
* Perform a title-only search query and return a result set.
* If title searches are not supported or disabled, return null.
* STUB
*
* @note As of 1.32 overriding this function is deprecated. It will
* be converted to final in 1.34. Override self::doSearchTitle().
*
* @param string $term Raw search term
* @return ISearchResultSet|null
*/
public function searchTitle( $term ) {
return $this->maybePaginate( function () use ( $term ) {
return $this->doSearchTitle( $term );
} );
}
/**
* Perform a title-only search query and return a result set.
*
* @stable to override
*
* @param string $term Raw search term
* @return ISearchResultSet|null
* @since 1.32
*/
protected function doSearchTitle( $term ) {
return null;
}
/**
* Performs an overfetch and shrink operation to determine if
* the next page is available for search engines that do not
* explicitly implement their own pagination.
*
* @param Closure $fn Takes no arguments
* @return ISearchResultSet|Status<ISearchResultSet>|null Result of calling $fn
*/
private function maybePaginate( Closure $fn ) {
if ( $this instanceof PaginatingSearchEngine ) {
return $fn();
}
$this->limit++;
try {
$resultSetOrStatus = $fn();
} finally {
$this->limit--;
}
$resultSet = null;
if ( $resultSetOrStatus instanceof ISearchResultSet ) {
$resultSet = $resultSetOrStatus;
} elseif ( $resultSetOrStatus instanceof Status &&
$resultSetOrStatus->getValue() instanceof ISearchResultSet
) {
$resultSet = $resultSetOrStatus->getValue();
}
if ( $resultSet ) {
$resultSet->shrink( $this->limit );
}
return $resultSetOrStatus;
}
/**
* @since 1.18
* @stable to override
*
* @param string $feature
* @return bool
*/
public function supports( $feature ) {
switch ( $feature ) {
case 'search-update':
return true;
case 'title-suffix-filter':
default:
return false;
}
}
/**
* Way to pass custom data for engines
* @since 1.18
* @param string $feature
* @param mixed $data
*/
public function setFeatureData( $feature, $data ) {
$this->features[$feature] = $data;
}
/**
* Way to retrieve custom data set by setFeatureData
* or by the engine itself.
* @since 1.29
* @param string $feature feature name
* @return mixed the feature value or null if unset
*/
public function getFeatureData( $feature ) {
return $this->features[$feature] ?? null;
}
/**
* When overridden in derived class, performs database-specific conversions
* on text to be used for searching or updating search index.
* Default implementation does nothing (simply returns $string).
*
* @param string $string String to process
* @return string
*/
public function normalizeText( $string ) {
// Some languages such as Chinese require word segmentation
return MediaWikiServices::getInstance()->getContentLanguage()->segmentByWord( $string );
}
/**
* Get service class to finding near matches.
* @param Config $config Configuration to use for the matcher.
* @return SearchNearMatcher
*/
public function getNearMatcher( Config $config ) {
return new SearchNearMatcher( $config,
MediaWikiServices::getInstance()->getContentLanguage(),
$this->getHookContainer()
);
}
/**
* Get near matcher for default SearchEngine.
* @return SearchNearMatcher
*/
protected static function defaultNearMatcher() {
$services = MediaWikiServices::getInstance();
$config = $services->getMainConfig();
return $services->newSearchEngine()->getNearMatcher( $config );
}
/**
* Get chars legal for search
* @param int $type type of search chars (see self::CHARS_ALL
* and self::CHARS_NO_SYNTAX). Defaults to CHARS_ALL
* @return string
*/
public function legalSearchChars( $type = self::CHARS_ALL ) {
return "A-Za-z_'.0-9\\x80-\\xFF\\-";
}
/**
* Set the maximum number of results to return
* and how many to skip before returning the first.
*
* @param int $limit
* @param int $offset
*/
public function setLimitOffset( $limit, $offset = 0 ) {
$this->limit = intval( $limit );
$this->offset = intval( $offset );
}
/**
* Set which namespaces the search should include.
* Give an array of namespace index numbers.
*
* @param int[]|null $namespaces
*/
public function setNamespaces( $namespaces ) {
if ( $namespaces ) {
// Filter namespaces to only keep valid ones
$validNs = MediaWikiServices::getInstance()->getSearchEngineConfig()->searchableNamespaces();
$namespaces = array_filter( $namespaces, function ( $ns ) use( $validNs ) {
return $ns < 0 || isset( $validNs[$ns] );
} );
} else {
$namespaces = [];
}
$this->namespaces = $namespaces;
}
/**
* Set whether the searcher should try to build a suggestion. Note: some searchers
* don't support building a suggestion in the first place and others don't respect
* this flag.
*
* @param bool $showSuggestion Should the searcher try to build suggestions
*/
public function setShowSuggestion( $showSuggestion ) {
$this->showSuggestion = $showSuggestion;
}
/**
* Get the valid sort directions. All search engines support 'relevance' but others
* might support more. The default in all implementations must be 'relevance.'
*
* @since 1.25
* @stable to override
*
* @return string[] the valid sort directions for setSort
*/
public function getValidSorts() {
return [ self::DEFAULT_SORT ];
}
/**
* Set the sort direction of the search results. Must be one returned by
* SearchEngine::getValidSorts()
*
* @since 1.25
* @throws InvalidArgumentException
* @param string $sort sort direction for query result
*/
public function setSort( $sort ) {
if ( !in_array( $sort, $this->getValidSorts() ) ) {
throw new InvalidArgumentException( "Invalid sort: $sort. " .
"Must be one of: " . implode( ', ', $this->getValidSorts() ) );
}
$this->sort = $sort;
}
/**
* Get the sort direction of the search results
*
* @since 1.25
* @return string
*/
public function getSort() {
return $this->sort;
}
/**
* Parse some common prefixes: all (search everything)
* or namespace names and set the list of namespaces
* of this class accordingly.
*
* @deprecated since 1.32; should be handled internally by the search engine
* @param string $query
* @return string
*/
public function replacePrefixes( $query ) {
return $query;
}
/**
* Parse some common prefixes: all (search everything)
* or namespace names
*
* @param string $query
* @param bool $withAllKeyword activate support of the "all:" keyword and its
* translations to activate searching on all namespaces.
* @param bool $withPrefixSearchExtractNamespaceHook call the PrefixSearchExtractNamespace hook
* if classic namespace identification did not match.
* @return false|array false if no namespace was extracted, an array
* with the parsed query at index 0 and an array of namespaces at index
* 1 (or null for all namespaces).
* @throws FatalError
* @throws MWException
*/
public static function parseNamespacePrefixes(
$query,
$withAllKeyword = true,
$withPrefixSearchExtractNamespaceHook = false
) {
$parsed = $query;
if ( strpos( $query, ':' ) === false ) { // nothing to do
return false;
}
$extractedNamespace = null;
$allQuery = false;
if ( $withAllKeyword ) {
$allkeywords = [];
$allkeywords[] = wfMessage( 'searchall' )->inContentLanguage()->text() . ":";
// force all: so that we have a common syntax for all the wikis
if ( !in_array( 'all:', $allkeywords ) ) {
$allkeywords[] = 'all:';
}
foreach ( $allkeywords as $kw ) {
if ( strncmp( $query, $kw, strlen( $kw ) ) == 0 ) {
$extractedNamespace = null;
$parsed = substr( $query, strlen( $kw ) );
$allQuery = true;
break;
}
}
}
if ( !$allQuery && strpos( $query, ':' ) !== false ) {
$prefix = str_replace( ' ', '_', substr( $query, 0, strpos( $query, ':' ) ) );
$index = MediaWikiServices::getInstance()->getContentLanguage()->getNsIndex( $prefix );
if ( $index !== false ) {
$extractedNamespace = [ $index ];
$parsed = substr( $query, strlen( $prefix ) + 1 );
} elseif ( $withPrefixSearchExtractNamespaceHook ) {
$hookNamespaces = [ NS_MAIN ];
$hookQuery = $query;
Hooks::runner()->onPrefixSearchExtractNamespace( $hookNamespaces, $hookQuery );
if ( $hookQuery !== $query ) {
$parsed = $hookQuery;
$extractedNamespace = $hookNamespaces;
} else {
return false;
}
} else {
return false;
}
}
return [ $parsed, $extractedNamespace ];
}
/**
* Find snippet highlight settings for all users
* @return array Contextlines, contextchars
* @deprecated in 1.34 use the SearchHighlighter constants directly
* @see SearchHighlighter::DEFAULT_CONTEXT_CHARS
* @see SearchHighlighter::DEFAULT_CONTEXT_LINES
*/
public static function userHighlightPrefs() {
$contextlines = SearchHighlighter::DEFAULT_CONTEXT_LINES;
$contextchars = SearchHighlighter::DEFAULT_CONTEXT_CHARS;
return [ $contextlines, $contextchars ];
}
/**
* Create or update the search index record for the given page.
* Title and text should be pre-processed.
* STUB
*
* @param int $id
* @param string $title
* @param string $text
*/
public function update( $id, $title, $text ) {
// no-op
}
/**
* Update a search index record's title only.
* Title should be pre-processed.
* STUB
*
* @param int $id
* @param string $title
*/
public function updateTitle( $id, $title ) {
// no-op
}
/**
* Delete an indexed page
* Title should be pre-processed.
* STUB
*
* @param int $id Page id that was deleted
* @param string $title Title of page that was deleted
*/
public function delete( $id, $title ) {
// no-op
}
/**
* Get the raw text for updating the index from a content object
* Nicer search backends could possibly do something cooler than
* just returning raw text
*
* @todo This isn't ideal, we'd really like to have content-specific handling here
* @param Title $t Title we're indexing
* @param Content|null $c Content of the page to index
* @return string
* @deprecated since 1.34 use Content::getTextForSearchIndex directly
*/
public function getTextFromContent( Title $t, Content $c = null ) {
return $c ? $c->getTextForSearchIndex() : '';
}
/**
* If an implementation of SearchEngine handles all of its own text processing
* in getTextFromContent() and doesn't require SearchUpdate::updateText()'s
* rather silly handling, it should return true here instead.
*
* @return bool
* @deprecated since 1.34 no longer needed since getTextFromContent is being deprecated
*/
public function textAlreadyUpdatedForIndex() {
return false;
}
/**
* Makes search simple string if it was namespaced.
* Sets namespaces of the search to namespaces extracted from string.
* @param string $search
* @return string Simplified search string
*/
protected function normalizeNamespaces( $search ) {
$queryAndNs = self::parseNamespacePrefixes( $search, false, true );
if ( $queryAndNs !== false ) {
$this->setNamespaces( $queryAndNs[1] );
return $queryAndNs[0];
}
return $search;
}
/**
* Perform an overfetch of completion search results. This allows
* determining if another page of results is available.
*
* @param string $search
* @return SearchSuggestionSet
*/
protected function completionSearchBackendOverfetch( $search ) {
$this->limit++;
try {
return $this->completionSearchBackend( $search );
} finally {
$this->limit--;
}
}
/**
* Perform a completion search.
* Does not resolve namespaces and does not check variants.
* Search engine implementations may want to override this function.
*
* @stable to override
*
* @param string $search
* @return SearchSuggestionSet
*/
protected function completionSearchBackend( $search ) {
$results = [];
$search = trim( $search );
if ( !in_array( NS_SPECIAL, $this->namespaces ) && // We do not run hook on Special: search
!$this->getHookRunner()->onPrefixSearchBackend(
$this->namespaces, $search, $this->limit, $results, $this->offset )
) {
// False means hook worked.
// FIXME: Yes, the API is weird. That's why it is going to be deprecated.
return SearchSuggestionSet::fromStrings( $results );
} else {
// Hook did not do the job, use default simple search
$results = $this->simplePrefixSearch( $search );
return SearchSuggestionSet::fromTitles( $results );
}
}
/**
* Perform a completion search.
* @param string $search
* @return SearchSuggestionSet
*/
public function completionSearch( $search ) {
if ( trim( $search ) === '' ) {
return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
}
$search = $this->normalizeNamespaces( $search );
$suggestions = $this->completionSearchBackendOverfetch( $search );
return $this->processCompletionResults( $search, $suggestions );
}
/**
* Perform a completion search with variants.
* @stable to override
*
* @param string $search
* @return SearchSuggestionSet
*/
public function completionSearchWithVariants( $search ) {
if ( trim( $search ) === '' ) {
return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
}
$search = $this->normalizeNamespaces( $search );
$results = $this->completionSearchBackendOverfetch( $search );
$fallbackLimit = 1 + $this->limit - $results->getSize();
if ( $fallbackLimit > 0 ) {
$fallbackSearches = MediaWikiServices::getInstance()->getContentLanguage()->
autoConvertToAllVariants( $search );
$fallbackSearches = array_diff( array_unique( $fallbackSearches ), [ $search ] );
foreach ( $fallbackSearches as $fbs ) {
$this->setLimitOffset( $fallbackLimit );
$fallbackSearchResult = $this->completionSearch( $fbs );
$results->appendAll( $fallbackSearchResult );
$fallbackLimit -= $fallbackSearchResult->getSize();
if ( $fallbackLimit <= 0 ) {
break;
}
}
}
return $this->processCompletionResults( $search, $results );
}
/**
* Extract titles from completion results
* @param SearchSuggestionSet $completionResults
* @return Title[]
*/
public function extractTitles( SearchSuggestionSet $completionResults ) {
return $completionResults->map( function ( SearchSuggestion $sugg ) {
return $sugg->getSuggestedTitle();
} );
}
/**
* Process completion search results.
* Resolves the titles and rescores.
* @param string $search
* @param SearchSuggestionSet $suggestions
* @return SearchSuggestionSet
*/
protected function processCompletionResults( $search, SearchSuggestionSet $suggestions ) {
// We over-fetched to determine pagination. Shrink back down if we have extra results
// and mark if pagination is possible
$suggestions->shrink( $this->limit );
$search = trim( $search );
// preload the titles with LinkBatch
$lb = new LinkBatch( $suggestions->map( function ( SearchSuggestion $sugg ) {
return $sugg->getSuggestedTitle();
} ) );
$lb->setCaller( __METHOD__ );
$lb->execute();
$diff = $suggestions->filter( function ( SearchSuggestion $sugg ) {
return $sugg->getSuggestedTitle()->isKnown();
} );
if ( $diff > 0 ) {
MediaWikiServices::getInstance()->getStatsdDataFactory()
->updateCount( 'search.completion.missing', $diff );
}
$results = $suggestions->map( function ( SearchSuggestion $sugg ) {
return $sugg->getSuggestedTitle()->getPrefixedText();
} );
if ( $this->offset === 0 ) {
// Rescore results with an exact title match
// NOTE: in some cases like cross-namespace redirects
// (frequently used as shortcuts e.g. WP:WP on huwiki) some
// backends like Cirrus will return no results. We should still
// try an exact title match to workaround this limitation
$rescorer = new SearchExactMatchRescorer();
$rescoredResults = $rescorer->rescore( $search, $this->namespaces, $results, $this->limit );
} else {
// No need to rescore if offset is not 0
// The exact match must have been returned at position 0
// if it existed.
$rescoredResults = $results;
}
if ( count( $rescoredResults ) > 0 ) {
$found = array_search( $rescoredResults[0], $results );
if ( $found === false ) {
// If the first result is not in the previous array it
// means that we found a new exact match
$exactMatch = SearchSuggestion::fromTitle( 0, Title::newFromText( $rescoredResults[0] ) );
$suggestions->prepend( $exactMatch );
$suggestions->shrink( $this->limit );
} else {
// if the first result is not the same we need to rescore
if ( $found > 0 ) {
$suggestions->rescore( $found );
}
}
}
return $suggestions;
}
/**
* Simple prefix search for subpages.
* @param string $search
* @return Title[]
*/
public function defaultPrefixSearch( $search ) {
if ( trim( $search ) === '' ) {
return [];
}
$search = $this->normalizeNamespaces( $search );
return $this->simplePrefixSearch( $search );
}
/**
* Call out to simple search backend.
* Defaults to TitlePrefixSearch.
* @param string $search
* @return Title[]
*/
protected function simplePrefixSearch( $search ) {
// Use default database prefix search
$backend = new TitlePrefixSearch;
return $backend->defaultSearchBackend( $this->namespaces, $search, $this->limit, $this->offset );
}
/**
* Get a list of supported profiles.
* Some search engine implementations may expose specific profiles to fine-tune
* its behaviors.
* The profile can be passed as a feature data with setFeatureData( $profileType, $profileName )
* The array returned by this function contains the following keys:
* - name: the profile name to use with setFeatureData
* - desc-message: the i18n description
* - default: set to true if this profile is the default
*
* @since 1.28
* @stable to override
*
* @param string $profileType the type of profiles
* @param User|null $user the user requesting the list of profiles
* @return array|null the list of profiles or null if none available
* @phan-return null|array{name:string,desc-message:string,default?:bool}
*/
public function getProfiles( $profileType, User $user = null ) {
return null;
}
/**
* Create a search field definition.
* Specific search engines should override this method to create search fields.
* @stable to override
*
* @param string $name
* @param string $type One of the types in SearchIndexField::INDEX_TYPE_*
* @return SearchIndexField
* @since 1.28
*/
public function makeSearchFieldMapping( $name, $type ) {
return new NullIndexField();
}
/**
* Get fields for search index
* @since 1.28
* @return SearchIndexField[] Index field definitions for all content handlers
*/
public function getSearchIndexFields() {
$models = MediaWikiServices::getInstance()->getContentHandlerFactory()->getContentModels();
$fields = [];
$seenHandlers = new SplObjectStorage();
foreach ( $models as $model ) {
try {
$handler = MediaWikiServices::getInstance()
->getContentHandlerFactory()
->getContentHandler( $model );
}
catch ( MWUnknownContentModelException $e ) {
// If we can find no handler, ignore it
continue;
}
// Several models can have the same handler, so avoid processing it repeatedly
if ( $seenHandlers->contains( $handler ) ) {
// We already did this one
continue;
}
$seenHandlers->attach( $handler );
$handlerFields = $handler->getFieldsForSearchIndex( $this );
foreach ( $handlerFields as $fieldName => $fieldData ) {
if ( empty( $fields[$fieldName] ) ) {
$fields[$fieldName] = $fieldData;
} else {
// TODO: do we allow some clashes with the same type or reject all of them?
$mergeDef = $fields[$fieldName]->merge( $fieldData );
if ( !$mergeDef ) {
throw new InvalidArgumentException( "Duplicate field $fieldName for model $model" );
}
$fields[$fieldName] = $mergeDef;
}
}
}
// Hook to allow extensions to produce search mapping fields
$this->getHookRunner()->onSearchIndexFields( $fields, $this );
return $fields;
}
/**
* Augment search results with extra data.
*
* @param ISearchResultSet $resultSet
*/
public function augmentSearchResults( ISearchResultSet $resultSet ) {
$setAugmentors = [];
$rowAugmentors = [];
$this->getHookRunner()->onSearchResultsAugment( $setAugmentors, $rowAugmentors );
if ( !$setAugmentors && !$rowAugmentors ) {
// We're done here
return;
}
// Convert row augmentors to set augmentor
foreach ( $rowAugmentors as $name => $row ) {
if ( isset( $setAugmentors[$name] ) ) {
throw new InvalidArgumentException( "Both row and set augmentors are defined for $name" );
}
$setAugmentors[$name] = new PerRowAugmentor( $row );
}
/**
* @var string $name
* @var ResultSetAugmentor $augmentor
*/
foreach ( $setAugmentors as $name => $augmentor ) {
$data = $augmentor->augmentAll( $resultSet );
if ( $data ) {
$resultSet->setAugmentedData( $name, $data );
}
}
}
/**
* @since 1.35
* @internal
* @param HookContainer $hookContainer
*/
public function setHookContainer( HookContainer $hookContainer ) {
$this->hookContainer = $hookContainer;
$this->hookRunner = new HookRunner( $hookContainer );
}
/**
* Get a HookContainer, for running extension hooks or for hook metadata.
*
* @since 1.35
* @return HookContainer
*/
protected function getHookContainer() : HookContainer {
if ( !$this->hookContainer ) {
$this->hookContainer = MediaWikiServices::getInstance()->getHookContainer();
}
return $this->hookContainer;
}
/**
* Get a HookRunner for running core hooks.
*
* @internal This is for use by core only. Hook interfaces may be removed
* without notice.
* @since 1.35
* @return HookRunner
*/
protected function getHookRunner() : HookRunner {
if ( !$this->hookRunner ) {
$this->hookRunner = new HookRunner( $this->getHookContainer() );
}
return $this->hookRunner;
}
}