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<?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\MediaWikiServices;
/**
* Contain a class for special pages
* @ingroup Search
*/
abstract class SearchEngine {
/** @var string */
public $prefix = '';
/** @var int[]|null */
public $namespaces = [ NS_MAIN ];
/** @var int */
protected $limit = 10;
/** @var int */
protected $offset = 0;
/** @var array|string */
protected $searchTerms = [];
/** @var bool */
protected $showSuggestion = true;
private $sort = 'relevance';
/** @var array Feature values */
protected $features = [];
/** @const string profile type for completionSearch */
const COMPLETION_PROFILE_TYPE = 'completionSearchProfile';
/** @const string profile type for query independent ranking features */
const FT_QUERY_INDEP_PROFILE_TYPE = 'fulltextQueryIndepProfile';
/** @const int flag for legalSearchChars: includes all chars allowed in a search query */
const CHARS_ALL = 1;
/** @const int flag for legalSearchChars: includes all chars allowed in a search term */
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.
* STUB
*
* @param string $term Raw search term
* @return SearchResultSet|Status|null
*/
function searchText( $term ) {
return null;
}
/**
* Perform a title-only search query and return a result set.
* If title searches are not supported or disabled, return null.
* STUB
*
* @param string $term Raw search term
* @return SearchResultSet|null
*/
function searchTitle( $term ) {
return null;
}
/**
* @since 1.18
* @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
* @return bool
*/
public function setFeatureData( $feature, $data ) {
$this->features[$feature] = $data;
}
/**
* 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 ) {
global $wgContLang;
// Some languages such as Chinese require word segmentation
return $wgContLang->segmentByWord( $string );
}
/**
* Transform search term in cases when parts of the query came as different
* GET params (when supported), e.g. for prefix queries:
* search=test&prefix=Main_Page/Archive -> test prefix:Main Page/Archive
* @param string $term
* @return string
*/
public function transformSearchTerm( $term ) {
return $term;
}
/**
* Get service class to finding near matches.
* @param Config $config Configuration to use for the matcher.
* @return SearchNearMatcher
*/
public function getNearMatcher( Config $config ) {
global $wgContLang;
return new SearchNearMatcher( $config, $wgContLang );
}
/**
* Get near matcher for default SearchEngine.
* @return SearchNearMatcher
*/
protected static function defaultNearMatcher() {
$config = MediaWikiServices::getInstance()->getMainConfig();
return MediaWikiServices::getInstance()->newSearchEngine()->getNearMatcher( $config );
}
/**
* If an exact title match can be found, or a very slightly close match,
* return the title. If no match, returns NULL.
* @deprecated since 1.27; Use SearchEngine::getNearMatcher()
* @param string $searchterm
* @return Title
*/
public static function getNearMatch( $searchterm ) {
return static::defaultNearMatcher()->getNearMatch( $searchterm );
}
/**
* Do a near match (see SearchEngine::getNearMatch) and wrap it into a
* SearchResultSet.
* @deprecated since 1.27; Use SearchEngine::getNearMatcher()
* @param string $searchterm
* @return SearchResultSet
*/
public static function getNearMatchResultSet( $searchterm ) {
return static::defaultNearMatcher()->getNearMatchResultSet( $searchterm );
}
/**
* Get chars legal for search
* NOTE: usage as static is deprecated and preserved only as BC measure
* @param int $type type of search chars (see self::CHARS_ALL
* and self::CHARS_NO_SYNTAX). Defaults to CHARS_ALL
* @return string
*/
public static 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
*/
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
*/
function setNamespaces( $namespaces ) {
if ( $namespaces ) {
// Filter namespaces to only keep valid ones
$validNs = $this->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
*/
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 should be 'relevance.'
*
* @since 1.25
* @return array(string) the valid sort directions for setSort
*/
public function getValidSorts() {
return [ 'relevance' ];
}
/**
* 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.
*
* @param string $query
* @return string
*/
function replacePrefixes( $query ) {
$queryAndNs = self::parseNamespacePrefixes( $query );
if ( $queryAndNs === false ) {
return $query;
}
$this->namespaces = $queryAndNs[1];
return $queryAndNs[0];
}
/**
* Parse some common prefixes: all (search everything)
* or namespace names
*
* @param string $query
* @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).
*/
public static function parseNamespacePrefixes( $query ) {
global $wgContLang;
$parsed = $query;
if ( strpos( $query, ':' ) === false ) { // nothing to do
return false;
}
$extractedNamespace = null;
$allkeyword = wfMessage( 'searchall' )->inContentLanguage()->text() . ":";
if ( strncmp( $query, $allkeyword, strlen( $allkeyword ) ) == 0 ) {
$extractedNamespace = null;
$parsed = substr( $query, strlen( $allkeyword ) );
} elseif ( strpos( $query, ':' ) !== false ) {
// TODO: should we unify with PrefixSearch::extractNamespace ?
$prefix = str_replace( ' ', '_', substr( $query, 0, strpos( $query, ':' ) ) );
$index = $wgContLang->getNsIndex( $prefix );
if ( $index !== false ) {
$extractedNamespace = [ $index ];
$parsed = substr( $query, strlen( $prefix ) + 1 );
} else {
return false;
}
}
if ( trim( $parsed ) == '' ) {
$parsed = $query; // prefix was the whole query
}
return [ $parsed, $extractedNamespace ];
}
/**
* Find snippet highlight settings for all users
* @return array Contextlines, contextchars
*/
public static function userHighlightPrefs() {
$contextlines = 2; // Hardcode this. Old defaults sucked. :)
$contextchars = 75; // same as above.... :P
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
*/
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
*/
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
*/
function delete( $id, $title ) {
// no-op
}
/**
* Get OpenSearch suggestion template
*
* @deprecated since 1.25
* @return string
*/
public static function getOpenSearchTemplate() {
wfDeprecated( __METHOD__, '1.25' );
return ApiOpenSearch::getOpenSearchTemplate( 'application/x-suggestions+json' );
}
/**
* 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 $c Content of the page to index
* @return string
*/
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
*/
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 ) {
// Find a Title which is not an interwiki and is in NS_MAIN
$title = Title::newFromText( $search );
$ns = $this->namespaces;
if ( $title && !$title->isExternal() ) {
$ns = [ $title->getNamespace() ];
$search = $title->getText();
if ( $ns[0] == NS_MAIN ) {
$ns = $this->namespaces; // no explicit prefix, use default namespaces
Hooks::run( 'PrefixSearchExtractNamespace', [ &$ns, &$search ] );
}
} else {
$title = Title::newFromText( $search . 'Dummy' );
if ( $title && $title->getText() == 'Dummy'
&& $title->getNamespace() != NS_MAIN
&& !$title->isExternal() )
{
$ns = [ $title->getNamespace() ];
$search = '';
} else {
Hooks::run( 'PrefixSearchExtractNamespace', [ &$ns, &$search ] );
}
}
$ns = array_map( function( $space ) {
return $space == NS_MEDIA ? NS_FILE : $space;
}, $ns );
$this->setNamespaces( $ns );
return $search;
}
/**
* Perform a completion search.
* Does not resolve namespaces and does not check variants.
* Search engine implementations may want to override this function.
* @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
!Hooks::run( 'PrefixSearchBackend',
[ $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 );
return $this->processCompletionResults( $search, $this->completionSearchBackend( $search ) );
}
/**
* Perform a completion search with variants.
* @param string $search
* @return SearchSuggestionSet
*/
public function completionSearchWithVariants( $search ) {
if ( trim( $search ) === '' ) {
return SearchSuggestionSet::emptySuggestionSet(); // Return empty result
}
$search = $this->normalizeNamespaces( $search );
$results = $this->completionSearchBackend( $search );
$fallbackLimit = $this->limit - $results->getSize();
if ( $fallbackLimit > 0 ) {
global $wgContLang;
$fallbackSearches = $wgContLang->autoConvertToAllVariants( $search );
$fallbackSearches = array_diff( array_unique( $fallbackSearches ), [ $search ] );
foreach ( $fallbackSearches as $fbs ) {
$this->setLimitOffset( $fallbackLimit );
$fallbackSearchResult = $this->completionSearch( $fbs );
$results->appendAll( $fallbackSearchResult );
$fallbackLimit -= count( $fallbackSearchResult );
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 SearchSuggestionSet $suggestions
* @return SearchSuggestionSet
*/
protected function processCompletionResults( $search, SearchSuggestionSet $suggestions ) {
$search = trim( $search );
// preload the titles with LinkBatch
$titles = $suggestions->map( function( SearchSuggestion $sugg ) {
return $sugg->getSuggestedTitle();
} );
$lb = new LinkBatch( $titles );
$lb->setCaller( __METHOD__ );
$lb->execute();
$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 );
}
/**
* Make a list of searchable namespaces and their canonical names.
* @deprecated since 1.27; use SearchEngineConfig::searchableNamespaces()
* @return array
*/
public static function searchableNamespaces() {
return MediaWikiServices::getInstance()->getSearchEngineConfig()->searchableNamespaces();
}
/**
* Extract default namespaces to search from the given user's
* settings, returning a list of index numbers.
* @deprecated since 1.27; use SearchEngineConfig::userNamespaces()
* @param user $user
* @return array
*/
public static function userNamespaces( $user ) {
return MediaWikiServices::getInstance()->getSearchEngineConfig()->userNamespaces( $user );
}
/**
* An array of namespaces indexes to be searched by default
* @deprecated since 1.27; use SearchEngineConfig::defaultNamespaces()
* @return array
*/
public static function defaultNamespaces() {
return MediaWikiServices::getInstance()->getSearchEngineConfig()->defaultNamespaces();
}
/**
* Get a list of namespace names useful for showing in tooltips
* and preferences
* @deprecated since 1.27; use SearchEngineConfig::namespacesAsText()
* @param array $namespaces
* @return array
*/
public static function namespacesAsText( $namespaces ) {
return MediaWikiServices::getInstance()->getSearchEngineConfig()->namespacesAsText( $namespaces );
}
/**
* Load up the appropriate search engine class for the currently
* active database backend, and return a configured instance.
* @deprecated since 1.27; Use SearchEngineFactory::create
* @param string $type Type of search backend, if not the default
* @return SearchEngine
*/
public static function create( $type = null ) {
return MediaWikiServices::getInstance()->getSearchEngineFactory()->create( $type );
}
/**
* Return the search engines we support. If only $wgSearchType
* is set, it'll be an array of just that one item.
* @deprecated since 1.27; use SearchEngineConfig::getSearchTypes()
* @return array
*/
public static function getSearchTypes() {
return MediaWikiServices::getInstance()->getSearchEngineConfig()->getSearchTypes();
}
/**
* 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
* @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
*/
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.
* @param string $name
* @param int $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 = ContentHandler::getContentModels();
$fields = [];
foreach ( $models as $model ) {
$handler = ContentHandler::getForModelID( $model );
$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] = $mergeDef;
}
}
}
// Hook to allow extensions to produce search mapping fields
Hooks::run( 'SearchIndexFields', [ &$fields, $this ] );
return $fields;
}
/**
* Augment search results with extra data.
*
* @param SearchResultSet $resultSet
*/
public function augmentSearchResults( SearchResultSet $resultSet ) {
$setAugmentors = [];
$rowAugmentors = [];
Hooks::run( "SearchResultsAugment", [ &$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 );
}
foreach ( $setAugmentors as $name => $augmentor ) {
$data = $augmentor->augmentAll( $resultSet );
if ( $data ) {
$resultSet->setAugmentedData( $name, $data );
}
}
}
}
/**
* Dummy class to be used when non-supported Database engine is present.
* @todo FIXME: Dummy class should probably try something at least mildly useful,
* such as a LIKE search through titles.
* @ingroup Search
*/
class SearchEngineDummy extends SearchEngine {
// no-op
}