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
  26 /**
  27  * Base search engine base class for database-backed searches
  28  * @ingroup Search
  29  * @since 1.23
  30  */
  31 abstract class SearchDatabase extends SearchEngine {
  32         /**
  33          * @var IDatabase Replica database from which to read results
  34          */
  35         protected $db;
  36
  37         /**
  38          * @param IDatabase|null $db The database to search from
  39          */
  40         public function __construct( IDatabase $db = null ) {
  41                 if ( $db ) {
  42                         $this->db = $db;
  43                 } else {
  44                         $this->db = wfGetDB( DB_REPLICA );
  45                 }
  46         }
  47
  48         /**
  49          * @param string $term
  50          * @return SearchResultSet|Status|null
  51          */
  52         final public function doSearchText( $term ) {
  53                 return $this->doSearchTextInDB( $this->extractNamespacePrefix( $term ) );
  54         }
  55
  56         /**
  57          * Perform a full text search query and return a result set.
  58          *
  59          * @param string $term Raw search term
  60          * @return SqlSearchResultSet
  61          */
  62         abstract protected function doSearchTextInDB( $term );
  63
  64         /**
  65          * @param string $term
  66          * @return SearchResultSet|null
  67          */
  68         final public function doSearchTitle( $term ) {
  69                 return $this->doSearchTitleInDB( $this->extractNamespacePrefix( $term ) );
  70         }
  71
  72         /**
  73          * Perform a title-only search query and return a result set.
  74          *
  75          * @param string $term Raw search term
  76          * @return SqlSearchResultSet
  77          */
  78         abstract protected function doSearchTitleInDB( $term );
  79
  80         /**
  81          * Return a 'cleaned up' search string
  82          *
  83          * @param string $text
  84          * @return string
  85          */
  86         protected function filter( $text ) {
  87                 // List of chars allowed in the search query.
  88                 // This must include chars used in the search syntax.
  89                 // Usually " (phrase) or * (wildcards) if supported by the engine
  90                 $lc = $this->legalSearchChars( self::CHARS_ALL );
  91                 return trim( preg_replace( "/[^{$lc}]/", " ", $text ) );
  92         }
  93
  94         /**
  95          * Extract the optional namespace prefix and set self::namespaces
  96          * accordingly and return the query string
  97          * @param string $term
  98          * @return string the query string without any namespace prefix
  99          */
 100         final protected function extractNamespacePrefix( $term ) {
 101                 $queryAndNs = self::parseNamespacePrefixes( $term );
 102                 if ( $queryAndNs === false ) {
 103                         return $term;
 104                 }
 105                 $this->namespaces = $queryAndNs[1];
 106                 return $queryAndNs[0];
 107         }
 108 }