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                 $this->db = $db ?: wfGetDB( DB_REPLICA );
  42         }
  43
  44         /**
  45          * @param string $term
  46          * @return SearchResultSet|Status|null
  47          */
  48         final public function doSearchText( $term ) {
  49                 return $this->doSearchTextInDB( $this->extractNamespacePrefix( $term ) );
  50         }
  51
  52         /**
  53          * Perform a full text search query and return a result set.
  54          *
  55          * @param string $term Raw search term
  56          * @return SqlSearchResultSet
  57          */
  58         abstract protected function doSearchTextInDB( $term );
  59
  60         /**
  61          * @param string $term
  62          * @return SearchResultSet|null
  63          */
  64         final public function doSearchTitle( $term ) {
  65                 return $this->doSearchTitleInDB( $this->extractNamespacePrefix( $term ) );
  66         }
  67
  68         /**
  69          * Perform a title-only search query and return a result set.
  70          *
  71          * @param string $term Raw search term
  72          * @return SqlSearchResultSet
  73          */
  74         abstract protected function doSearchTitleInDB( $term );
  75
  76         /**
  77          * Return a 'cleaned up' search string
  78          *
  79          * @param string $text
  80          * @return string
  81          */
  82         protected function filter( $text ) {
  83                 // List of chars allowed in the search query.
  84                 // This must include chars used in the search syntax.
  85                 // Usually " (phrase) or * (wildcards) if supported by the engine
  86                 $lc = $this->legalSearchChars( self::CHARS_ALL );
  87                 return trim( preg_replace( "/[^{$lc}]/", " ", $text ) );
  88         }
  89
  90         /**
  91          * Extract the optional namespace prefix and set self::namespaces
  92          * accordingly and return the query string
  93          * @param string $term
  94          * @return string the query string without any namespace prefix
  95          */
  96         final protected function extractNamespacePrefix( $term ) {
  97                 $queryAndNs = self::parseNamespacePrefixes( $term );
  98                 if ( $queryAndNs === false ) {
  99                         return $term;
 100                 }
 101                 $this->namespaces = $queryAndNs[1];
 102                 return $queryAndNs[0];
 103         }
 104 }