includes/search/SearchMySQL.php
<?php
/**
* MySQL search engine
*
* Copyright (C) 2004 Brooke Vibber <bvibber@wikimedia.org>
* https://www.mediawiki.org/
*
* 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
*/
use MediaWiki\MediaWikiServices;
use Wikimedia\AtEase\AtEase;
use Wikimedia\Rdbms\IDatabase;
use Wikimedia\Rdbms\IExpression;
use Wikimedia\Rdbms\LikeValue;
use Wikimedia\Rdbms\SelectQueryBuilder;
/**
* Search engine hook for MySQL
* @ingroup Search
*/
class SearchMySQL extends SearchDatabase {
/** @var bool */
protected $strictMatching = true;
/** @var int|null */
private static $mMinSearchLength;
/**
* Parse the user's query and transform it into two SQL fragments:
* a WHERE condition and an ORDER BY expression
*
* @param string $filteredText
* @param bool $fulltext
*
* @return array
*/
private function parseQuery( $filteredText, $fulltext ) {
$lc = $this->legalSearchChars( self::CHARS_NO_SYNTAX ); // Minus syntax chars (" and *)
$searchon = '';
$this->searchTerms = [];
# @todo FIXME: This doesn't handle parenthetical expressions.
$m = [];
if ( preg_match_all( '/([-+<>~]?)(([' . $lc . ']+)(\*?)|"[^"]*")/',
$filteredText, $m, PREG_SET_ORDER )
) {
$services = MediaWikiServices::getInstance();
$contLang = $services->getContentLanguage();
$langConverter = $services->getLanguageConverterFactory()->getLanguageConverter( $contLang );
foreach ( $m as $bits ) {
AtEase::suppressWarnings();
[ /* all */, $modifier, $term, $nonQuoted, $wildcard ] = $bits;
AtEase::restoreWarnings();
if ( $nonQuoted != '' ) {
$term = $nonQuoted;
$quote = '';
} else {
$term = str_replace( '"', '', $term );
$quote = '"';
}
if ( $searchon !== '' ) {
$searchon .= ' ';
}
if ( $this->strictMatching && ( $modifier == '' ) ) {
// If we leave this out, boolean op defaults to OR which is rarely helpful.
$modifier = '+';
}
// Some languages such as Serbian store the input form in the search index,
// so we may need to search for matches in multiple writing system variants.
$convertedVariants = $langConverter->autoConvertToAllVariants( $term );
if ( is_array( $convertedVariants ) ) {
$variants = array_unique( array_values( $convertedVariants ) );
} else {
$variants = [ $term ];
}
// The low-level search index does some processing on input to work
// around problems with minimum lengths and encoding in MySQL's
// fulltext engine.
// For Chinese this also inserts spaces between adjacent Han characters.
$strippedVariants = array_map( [ $contLang, 'normalizeForSearch' ], $variants );
// Some languages such as Chinese force all variants to a canonical
// form when stripping to the low-level search index, so to be sure
// let's check our variants list for unique items after stripping.
$strippedVariants = array_unique( $strippedVariants );
$searchon .= $modifier;
if ( count( $strippedVariants ) > 1 ) {
$searchon .= '(';
}
foreach ( $strippedVariants as $stripped ) {
$stripped = $this->normalizeText( $stripped );
if ( $nonQuoted && strpos( $stripped, ' ' ) !== false ) {
// Hack for Chinese: we need to toss in quotes for
// multiple-character phrases since normalizeForSearch()
// added spaces between them to make word breaks.
$stripped = '"' . trim( $stripped ) . '"';
}
$searchon .= "$quote$stripped$quote$wildcard ";
}
if ( count( $strippedVariants ) > 1 ) {
$searchon .= ')';
}
// Match individual terms or quoted phrase in result highlighting...
// Note that variants will be introduced in a later stage for highlighting!
$regexp = $this->regexTerm( $term, $wildcard );
$this->searchTerms[] = $regexp;
}
wfDebug( __METHOD__ . ": Would search with '$searchon'" );
wfDebug( __METHOD__ . ': Match with /' . implode( '|', $this->searchTerms ) . "/" );
} else {
wfDebug( __METHOD__ . ": Can't understand search query '{$filteredText}'" );
}
$dbr = $this->dbProvider->getReplicaDatabase();
$searchon = $dbr->addQuotes( $searchon );
$field = $this->getIndexField( $fulltext );
return [
" MATCH($field) AGAINST($searchon IN BOOLEAN MODE) ",
" MATCH($field) AGAINST($searchon IN NATURAL LANGUAGE MODE) DESC "
];
}
private function regexTerm( $string, $wildcard ) {
$regex = preg_quote( $string, '/' );
if ( MediaWikiServices::getInstance()->getContentLanguage()->hasWordBreaks() ) {
if ( $wildcard ) {
// Don't cut off the final bit!
$regex = "\b$regex";
} else {
$regex = "\b$regex\b";
}
} else {
// For Chinese, words may legitimately abut other words in the text literal.
// Don't add \b boundary checks... note this could cause false positives
// for Latin chars.
}
return $regex;
}
public function legalSearchChars( $type = self::CHARS_ALL ) {
$searchChars = parent::legalSearchChars( $type );
if ( $type === self::CHARS_ALL ) {
// " for phrase, * for wildcard
$searchChars = "\"*" . $searchChars;
}
return $searchChars;
}
/**
* Perform a full text search query and return a result set.
*
* @param string $term Raw search term
* @return SqlSearchResultSet|null
*/
protected function doSearchTextInDB( $term ) {
return $this->searchInternal( $term, true );
}
/**
* Perform a title-only search query and return a result set.
*
* @param string $term Raw search term
* @return SqlSearchResultSet|null
*/
protected function doSearchTitleInDB( $term ) {
return $this->searchInternal( $term, false );
}
protected function searchInternal( $term, $fulltext ) {
// This seems out of place, why is this called with empty term?
if ( trim( $term ) === '' ) {
return null;
}
$filteredTerm = $this->filter( $term );
$queryBuilder = $this->getQueryBuilder( $filteredTerm, $fulltext );
$resultSet = $queryBuilder->caller( __METHOD__ )->fetchResultSet();
$total = null;
$queryBuilder = $this->getCountQueryBuilder( $filteredTerm, $fulltext );
$totalResult = $queryBuilder->caller( __METHOD__ )->fetchResultSet();
$row = $totalResult->fetchObject();
if ( $row ) {
$total = intval( $row->c );
}
$totalResult->free();
return new SqlSearchResultSet( $resultSet, $this->searchTerms, $total );
}
public function supports( $feature ) {
switch ( $feature ) {
case 'title-suffix-filter':
return true;
default:
return parent::supports( $feature );
}
}
/**
* Add special conditions
* @param SelectQueryBuilder $queryBuilder
* @since 1.18
*/
protected function queryFeatures( SelectQueryBuilder $queryBuilder ) {
foreach ( $this->features as $feature => $value ) {
if ( $feature === 'title-suffix-filter' && $value ) {
$dbr = $this->dbProvider->getReplicaDatabase();
$queryBuilder->andWhere(
$dbr->expr( 'page_title', IExpression::LIKE, new LikeValue( $dbr->anyString(), $value ) )
);
}
}
}
/**
* Add namespace conditions
* @param SelectQueryBuilder $queryBuilder
* @since 1.18 (changed)
*/
private function queryNamespaces( $queryBuilder ) {
if ( is_array( $this->namespaces ) ) {
if ( count( $this->namespaces ) === 0 ) {
$this->namespaces[] = NS_MAIN;
}
$queryBuilder->andWhere( [ 'page_namespace' => $this->namespaces ] );
}
}
/**
* Construct the SQL query builder to do the search.
* @param string $filteredTerm
* @param bool $fulltext
* @return SelectQueryBuilder
* @since 1.41
*/
private function getQueryBuilder( $filteredTerm, $fulltext ): SelectQueryBuilder {
$queryBuilder = $this->dbProvider->getReplicaDatabase()->newSelectQueryBuilder();
$this->queryMain( $queryBuilder, $filteredTerm, $fulltext );
$this->queryFeatures( $queryBuilder );
$this->queryNamespaces( $queryBuilder );
$queryBuilder->limit( $this->limit )
->offset( $this->offset );
return $queryBuilder;
}
/**
* Picks which field to index on, depending on what type of query.
* @param bool $fulltext
* @return string
*/
private function getIndexField( $fulltext ) {
return $fulltext ? 'si_text' : 'si_title';
}
/**
* Get the base part of the search query.
*
* @param SelectQueryBuilder $queryBuilder Search query builder
* @param string $filteredTerm
* @param bool $fulltext
* @since 1.18 (changed)
*/
private function queryMain( SelectQueryBuilder $queryBuilder, $filteredTerm, $fulltext ) {
$match = $this->parseQuery( $filteredTerm, $fulltext );
$queryBuilder->select( [ 'page_id', 'page_namespace', 'page_title' ] )
->from( 'page' )
->join( 'searchindex', null, 'page_id=si_page' )
->where( $match[0] )
->orderBy( $match[1] );
}
/**
* @since 1.41 (changed)
* @param string $filteredTerm
* @param bool $fulltext
* @return SelectQueryBuilder
*/
private function getCountQueryBuilder( $filteredTerm, $fulltext ): SelectQueryBuilder {
$match = $this->parseQuery( $filteredTerm, $fulltext );
$queryBuilder = $this->dbProvider->getReplicaDatabase()->newSelectQueryBuilder()
->select( [ 'c' => 'COUNT(*)' ] )
->from( 'page' )
->join( 'searchindex', null, 'page_id=si_page' )
->where( $match[0] );
$this->queryFeatures( $queryBuilder );
$this->queryNamespaces( $queryBuilder );
return $queryBuilder;
}
/**
* Create or update the search index record for the given page.
* Title and text should be pre-processed.
*
* @param int $id
* @param string $title
* @param string $text
*/
public function update( $id, $title, $text ) {
$this->dbProvider->getPrimaryDatabase()->newReplaceQueryBuilder()
->replaceInto( 'searchindex' )
->uniqueIndexFields( [ 'si_page' ] )
->row( [
'si_page' => $id,
'si_title' => $this->normalizeText( $title ),
'si_text' => $this->normalizeText( $text )
] )
->caller( __METHOD__ )->execute();
}
/**
* Update a search index record's title only.
* Title should be pre-processed.
*
* @param int $id
* @param string $title
*/
public function updateTitle( $id, $title ) {
$this->dbProvider->getPrimaryDatabase()->newUpdateQueryBuilder()
->update( 'searchindex' )
->set( [ 'si_title' => $this->normalizeText( $title ) ] )
->where( [ 'si_page' => $id ] )
->caller( __METHOD__ )->execute();
}
/**
* Delete an indexed page
* Title should be pre-processed.
*
* @param int $id Page id that was deleted
* @param string $title Title of page that was deleted
*/
public function delete( $id, $title ) {
$this->dbProvider->getPrimaryDatabase()->newDeleteQueryBuilder()
->deleteFrom( 'searchindex' )
->where( [ 'si_page' => $id ] )
->caller( __METHOD__ )->execute();
}
/**
* Converts some characters for MySQL's indexing to grok it correctly,
* and pads short words to overcome limitations.
* @param string $string
* @return string
*/
public function normalizeText( $string ) {
$out = parent::normalizeText( $string );
// MySQL fulltext index doesn't grok utf-8, so we
// need to fold cases and convert to hex
$out = preg_replace_callback(
"/([\\xc0-\\xff][\\x80-\\xbf]*)/",
[ $this, 'stripForSearchCallback' ],
MediaWikiServices::getInstance()->getContentLanguage()->lc( $out ) );
// And to add insult to injury, the default indexing
// ignores short words... Pad them so we can pass them
// through without reconfiguring the server...
$minLength = $this->minSearchLength();
if ( $minLength > 1 ) {
$n = $minLength - 1;
$out = preg_replace(
"/\b(\w{1,$n})\b/",
"$1u800",
$out );
}
// Periods within things like hostnames and IP addresses
// are also important -- we want a search for "example.com"
// or "192.168.1.1" to work sensibly.
// MySQL's search seems to ignore them, so you'd match on
// "example.wikipedia.com" and "192.168.83.1" as well.
return preg_replace(
"/(\w)\.(\w|\*)/u",
"$1u82e$2",
$out
);
}
/**
* Armor a case-folded UTF-8 string to get through MySQL's
* fulltext search without being mucked up by funny charset
* settings or anything else of the sort.
* @param array $matches
* @return string
*/
protected function stripForSearchCallback( $matches ) {
return 'u8' . bin2hex( $matches[1] );
}
/**
* Check MySQL server's ft_min_word_len setting so we know
* if we need to pad short words...
*
* @return int
*/
protected function minSearchLength() {
if ( self::$mMinSearchLength === null ) {
$sql = "SHOW GLOBAL VARIABLES LIKE 'ft\\_min\\_word\\_len'";
$dbr = $this->dbProvider->getReplicaDatabase();
// The real type is still IDatabase, but IReplicaDatabase is used for safety.
'@phan-var IDatabase $dbr';
// phpcs:ignore MediaWiki.Usage.DbrQueryUsage.DbrQueryFound
$result = $dbr->query( $sql, __METHOD__ );
$row = $result->fetchObject();
$result->free();
if ( $row && $row->Variable_name == 'ft_min_word_len' ) {
self::$mMinSearchLength = intval( $row->Value );
} else {
self::$mMinSearchLength = 0;
}
}
return self::$mMinSearchLength;
}
}