includes/search/SearchDatabase.php

   1 <?php
   2 /**
   3  * Database 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 use Wikimedia\Rdbms\IDatabase;
  25 use Wikimedia\Rdbms\ILoadBalancer;
  26
  27 /**
  28  * Base search engine base class for database-backed searches
  29  * @ingroup Search
  30  * @since 1.23
  31  */
  32 abstract class SearchDatabase extends SearchEngine {
  33         /** @var ILoadBalancer */
  34         protected $lb;
  35         /** @var IDatabase (backwards compatibility) */
  36         protected $db;
  37
  38         /**
  39          * @param ILoadBalancer $lb The load balancer for the DB cluster to search on
  40          */
  41         public function __construct( ILoadBalancer $lb ) {
  42                 $this->lb = $lb;
  43                 // @TODO: remove this deprecated field in 1.35
  44                 $this->db = $lb->getLazyConnectionRef( DB_REPLICA ); // b/c
  45         }
  46
  47         /**
  48          * @param string $term
  49          * @return SearchResultSet|Status|null
  50          */
  51         final public function doSearchText( $term ) {
  52                 return $this->doSearchTextInDB( $this->extractNamespacePrefix( $term ) );
  53         }
  54
  55         /**
  56          * Perform a full text search query and return a result set.
  57          *
  58          * @param string $term Raw search term
  59          * @return SqlSearchResultSet
  60          */
  61         abstract protected function doSearchTextInDB( $term );
  62
  63         /**
  64          * @param string $term
  65          * @return SearchResultSet|null
  66          */
  67         final public function doSearchTitle( $term ) {
  68                 return $this->doSearchTitleInDB( $this->extractNamespacePrefix( $term ) );
  69         }
  70
  71         /**
  72          * Perform a title-only search query and return a result set.
  73          *
  74          * @param string $term Raw search term
  75          * @return SqlSearchResultSet
  76          */
  77         abstract protected function doSearchTitleInDB( $term );
  78
  79         /**
  80          * Return a 'cleaned up' search string
  81          *
  82          * @param string $text
  83          * @return string
  84          */
  85         protected function filter( $text ) {
  86                 // List of chars allowed in the search query.
  87                 // This must include chars used in the search syntax.
  88                 // Usually " (phrase) or * (wildcards) if supported by the engine
  89                 $lc = $this->legalSearchChars( self::CHARS_ALL );
  90                 return trim( preg_replace( "/[^{$lc}]/", " ", $text ) );
  91         }
  92
  93         /**
  94          * Extract the optional namespace prefix and set self::namespaces
  95          * accordingly and return the query string
  96          * @param string $term
  97          * @return string the query string without any namespace prefix
  98          */
  99         final protected function extractNamespacePrefix( $term ) {
 100                 $queryAndNs = self::parseNamespacePrefixes( $term );
 101                 if ( $queryAndNs === false ) {
 102                         return $term;
 103                 }
 104                 $this->namespaces = $queryAndNs[1];
 105                 return $queryAndNs[0];
 106         }
 107 }