[Summary view] [Print] [Text view]

   1  <?php
   2  /**
   3   * Implements Special:Randompage
   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 SpecialPage
  22   * @author Rob Church <[email protected]>, Ilmari Karonen
  23   */
  24  
  25  /**
  26   * Special page to direct the user to a random page
  27   *
  28   * @ingroup SpecialPage
  29   */
  30  class RandomPage extends SpecialPage {
  31      private $namespaces; // namespaces to select pages from
  32      protected $isRedir = false; // should the result be a redirect?
  33      protected $extra = array(); // Extra SQL statements
  34  
  35  	public function __construct( $name = 'Randompage' ) {
  36          $this->namespaces = MWNamespace::getContentNamespaces();
  37          parent::__construct( $name );
  38      }
  39  
  40  	public function getNamespaces() {
  41          return $this->namespaces;
  42      }
  43  
  44  	public function setNamespace( $ns ) {
  45          if ( !$ns || $ns < NS_MAIN ) {
  46              $ns = NS_MAIN;
  47          }
  48          $this->namespaces = array( $ns );
  49      }
  50  
  51      // select redirects instead of normal pages?
  52  	public function isRedirect() {
  53          return $this->isRedir;
  54      }
  55  
  56  	public function execute( $par ) {
  57          global $wgContLang;
  58  
  59          if ( is_string( $par ) ) {
  60              // Testing for stringiness since we want to catch
  61              // the empty string to mean main namespace only.
  62              $this->setNamespace( $wgContLang->getNsIndex( $par ) );
  63          }
  64  
  65          $title = $this->getRandomTitle();
  66  
  67          if ( is_null( $title ) ) {
  68              $this->setHeaders();
  69              // Message: randompage-nopages, randomredirect-nopages
  70              $this->getOutput()->addWikiMsg( strtolower( $this->getName() ) . '-nopages',
  71                  $this->getNsList(), count( $this->namespaces ) );
  72  
  73              return;
  74          }
  75  
  76          $redirectParam = $this->isRedirect() ? array( 'redirect' => 'no' ) : array();
  77          $query = array_merge( $this->getRequest()->getValues(), $redirectParam );
  78          unset( $query['title'] );
  79          $this->getOutput()->redirect( $title->getFullURL( $query ) );
  80      }
  81  
  82      /**
  83       * Get a comma-delimited list of namespaces we don't have
  84       * any pages in
  85       * @return string
  86       */
  87  	private function getNsList() {
  88          global $wgContLang;
  89          $nsNames = array();
  90          foreach ( $this->namespaces as $n ) {
  91              if ( $n === NS_MAIN ) {
  92                  $nsNames[] = $this->msg( 'blanknamespace' )->plain();
  93              } else {
  94                  $nsNames[] = $wgContLang->getNsText( $n );
  95              }
  96          }
  97  
  98          return $wgContLang->commaList( $nsNames );
  99      }
 100  
 101      /**
 102       * Choose a random title.
 103       * @return Title|null Title object (or null if nothing to choose from)
 104       */
 105  	public function getRandomTitle() {
 106          $randstr = wfRandom();
 107          $title = null;
 108  
 109          if ( !wfRunHooks(
 110              'SpecialRandomGetRandomTitle',
 111              array( &$randstr, &$this->isRedir, &$this->namespaces, &$this->extra, &$title )
 112          ) ) {
 113              return $title;
 114          }
 115  
 116          $row = $this->selectRandomPageFromDB( $randstr );
 117  
 118          /* If we picked a value that was higher than any in
 119           * the DB, wrap around and select the page with the
 120           * lowest value instead!  One might think this would
 121           * skew the distribution, but in fact it won't cause
 122           * any more bias than what the page_random scheme
 123           * causes anyway.  Trust me, I'm a mathematician. :)
 124           */
 125          if ( !$row ) {
 126              $row = $this->selectRandomPageFromDB( "0" );
 127          }
 128  
 129          if ( $row ) {
 130              return Title::makeTitleSafe( $row->page_namespace, $row->page_title );
 131          }
 132  
 133          return null;
 134      }
 135  
 136  	protected function getQueryInfo( $randstr ) {
 137          $redirect = $this->isRedirect() ? 1 : 0;
 138  
 139          return array(
 140              'tables' => array( 'page' ),
 141              'fields' => array( 'page_title', 'page_namespace' ),
 142              'conds' => array_merge( array(
 143                  'page_namespace' => $this->namespaces,
 144                  'page_is_redirect' => $redirect,
 145                  'page_random >= ' . $randstr
 146              ), $this->extra ),
 147              'options' => array(
 148                  'ORDER BY' => 'page_random',
 149                  'LIMIT' => 1,
 150              ),
 151              'join_conds' => array()
 152          );
 153      }
 154  
 155  	private function selectRandomPageFromDB( $randstr, $fname = __METHOD__ ) {
 156          $dbr = wfGetDB( DB_SLAVE );
 157  
 158          $query = $this->getQueryInfo( $randstr );
 159          $res = $dbr->select(
 160              $query['tables'],
 161              $query['fields'],
 162              $query['conds'],
 163              $fname,
 164              $query['options'],
 165              $query['join_conds']
 166          );
 167  
 168          return $dbr->fetchObject( $res );
 169      }
 170  
 171  	protected function getGroupName() {
 172          return 'redirects';
 173      }
 174  }