Followup r82727, improve comments, cast return value to bool

[mediawiki.git] / includes / specials / SpecialExport.php

<?php
/**
 * Implements Special:Export
 *
 * Copyright © 2003-2008 Brion Vibber <brion@pobox.com>
 *
 * 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 SpecialPage
 */

/**
 * A special page that allows users to export pages in a XML file
 *
 * @ingroup SpecialPage
 */
class SpecialExport extends SpecialPage {

        private $curonly, $doExport, $pageLinkDepth, $templates;
        private $images;

        public function __construct() {
                parent::__construct( 'Export' );
        }

        public function execute( $par ) {
                global $wgOut, $wgRequest, $wgSitename, $wgExportAllowListContributors;
                global $wgExportAllowHistory, $wgExportMaxHistory, $wgExportMaxLinkDepth;
                global $wgExportFromNamespaces, $wgUser;

                $this->setHeaders();
                $this->outputHeader();

                // Set some variables
                $this->curonly = true;
                $this->doExport = false;
                $this->templates = $wgRequest->getCheck( 'templates' );
                $this->images = $wgRequest->getCheck( 'images' ); // Doesn't do anything yet
                $this->pageLinkDepth = $this->validateLinkDepth(
                        $wgRequest->getIntOrNull( 'pagelink-depth' )
                );
                $nsindex = '';

                if ( $wgRequest->getCheck( 'addcat' ) ) {
                        $page = $wgRequest->getText( 'pages' );
                        $catname = $wgRequest->getText( 'catname' );

                        if ( $catname !== '' && $catname !== null && $catname !== false ) {
                                $t = Title::makeTitleSafe( NS_MAIN, $catname );
                                if ( $t ) {
                                        /**
                                         * @todo Fixme: this can lead to hitting memory limit for very large
                                         * categories. Ideally we would do the lookup synchronously
                                         * during the export in a single query.
                                         */
                                        $catpages = $this->getPagesFromCategory( $t );
                                        if ( $catpages ) {
                                                $page .= "\n" . implode( "\n", $catpages );
                                        }
                                }
                        }
                }
                else if( $wgRequest->getCheck( 'addns' ) && $wgExportFromNamespaces ) {
                        $page = $wgRequest->getText( 'pages' );
                        $nsindex = $wgRequest->getText( 'nsindex', '' );

                        if ( strval( $nsindex ) !== ''  ) {
                                /**
                                 * Same implementation as above, so same @todo
                                 */
                                $nspages = $this->getPagesFromNamespace( $nsindex );
                                if ( $nspages ) {
                                        $page .= "\n" . implode( "\n", $nspages );
                                }
                        }
                }
                else if( $wgRequest->wasPosted() && $par == '' ) {
                        $page = $wgRequest->getText( 'pages' );
                        $this->curonly = $wgRequest->getCheck( 'curonly' );
                        $rawOffset = $wgRequest->getVal( 'offset' );
                        
                        if( $rawOffset ) {
                                $offset = wfTimestamp( TS_MW, $rawOffset );
                        } else {
                                $offset = null;
                        }
                        
                        $limit = $wgRequest->getInt( 'limit' );
                        $dir = $wgRequest->getVal( 'dir' );
                        $history = array(
                                'dir' => 'asc',
                                'offset' => false,
                                'limit' => $wgExportMaxHistory,
                        );
                        $historyCheck = $wgRequest->getCheck( 'history' );
                        
                        if ( $this->curonly ) {
                                $history = WikiExporter::CURRENT;
                        } elseif ( !$historyCheck ) {
                                if ( $limit > 0 && ($wgExportMaxHistory == 0 || $limit < $wgExportMaxHistory ) ) {
                                        $history['limit'] = $limit;
                                }
                                if ( !is_null( $offset ) ) {
                                        $history['offset'] = $offset;
                                }
                                if ( strtolower( $dir ) == 'desc' ) {
                                        $history['dir'] = 'desc';
                                }
                        }

                        if( $page != '' ) {
                                $this->doExport = true;
                        }
                } else {
                        // Default to current-only for GET requests.
                        $page = $wgRequest->getText( 'pages', $par );
                        $historyCheck = $wgRequest->getCheck( 'history' );
                        
                        if( $historyCheck ) {
                                $history = WikiExporter::FULL;
                        } else {
                                $history = WikiExporter::CURRENT;
                        }

                        if( $page != '' ) {
                                $this->doExport = true;
                        }
                }

                if( !$wgExportAllowHistory ) {
                        // Override
                        $history = WikiExporter::CURRENT;
                }

                $list_authors = $wgRequest->getCheck( 'listauthors' );
                if ( !$this->curonly || !$wgExportAllowListContributors ) {
                        $list_authors = false ;
                }

                if ( $this->doExport ) {
                        $wgOut->disable();
                        
                        // Cancel output buffering and gzipping if set
                        // This should provide safer streaming for pages with history
                        wfResetOutputBuffers();
                        $wgRequest->response()->header( "Content-type: application/xml; charset=utf-8" );
                        
                        if( $wgRequest->getCheck( 'wpDownload' ) ) {
                                // Provide a sane filename suggestion
                                $filename = urlencode( $wgSitename . '-' . wfTimestampNow() . '.xml' );
                                $wgRequest->response()->header( "Content-disposition: attachment;filename={$filename}" );
                        }
                        
                        $this->doExport( $page, $history, $list_authors );
                        
                        return;
                }

                $wgOut->addWikiMsg( 'exporttext' );

                $form = Xml::openElement( 'form', array( 'method' => 'post',
                        'action' => $this->getTitle()->getLocalUrl( 'action=submit' ) ) );
                $form .= Xml::inputLabel( wfMsg( 'export-addcattext' )    , 'catname', 'catname', 40 ) . '&#160;';
                $form .= Xml::submitButton( wfMsg( 'export-addcat' ), array( 'name' => 'addcat' ) ) . '<br />';

                if ( $wgExportFromNamespaces ) {
                        $form .= Xml::namespaceSelector( $nsindex, null, 'nsindex', wfMsg( 'export-addnstext' ) ) . '&#160;';
                        $form .= Xml::submitButton( wfMsg( 'export-addns' ), array( 'name' => 'addns' ) ) . '<br />';
                }

                $form .= Xml::element( 'textarea', array( 'name' => 'pages', 'cols' => 40, 'rows' => 10 ), $page, false );
                $form .= '<br />';

                if( $wgExportAllowHistory ) {
                        $form .= Xml::checkLabel( wfMsg( 'exportcuronly' ), 'curonly', 'curonly', true ) . '<br />';
                } else {
                        $wgOut->addHTML( wfMsgExt( 'exportnohistory', 'parse' ) );
                }
                
                $form .= Xml::checkLabel( wfMsg( 'export-templates' ), 'templates', 'wpExportTemplates', false ) . '<br />';
                
                if( $wgExportMaxLinkDepth || $this->userCanOverrideExportDepth() ) {
                        $form .= Xml::inputLabel( wfMsg( 'export-pagelinks' ), 'pagelink-depth', 'pagelink-depth', 20, 0 ) . '<br />';
                }
                // Enable this when we can do something useful exporting/importing image information. :)
                //$form .= Xml::checkLabel( wfMsg( 'export-images' ), 'images', 'wpExportImages', false ) . '<br />';
                $form .= Xml::checkLabel( wfMsg( 'export-download' ), 'wpDownload', 'wpDownload', true ) . '<br />';

                $form .= Xml::submitButton( wfMsg( 'export-submit' ), $wgUser->getSkin()->tooltipAndAccessKeyAttribs( 'export' ) );
                $form .= Xml::closeElement( 'form' );
                
                $wgOut->addHTML( $form );
        }

        private function userCanOverrideExportDepth() {
                global $wgUser;
                return $wgUser->isAllowed( 'override-export-depth' );
        }

        /**
         * Do the actual page exporting
         *
         * @param $page String: user input on what page(s) to export
         * @param $history Mixed: one of the WikiExporter history export constants
         * @param $list_authors Boolean: Whether to add distinct author list (when
         *                      not returning full history)
         */
        private function doExport( $page, $history, $list_authors ) {
                $pageSet = array(); // Inverted index of all pages to look up

                // Split up and normalize input
                foreach( explode( "\n", $page ) as $pageName ) {
                        $pageName = trim( $pageName );
                        $title = Title::newFromText( $pageName );
                        if( $title && $title->getInterwiki() == '' && $title->getText() !== '' ) {
                                // Only record each page once!
                                $pageSet[$title->getPrefixedText()] = true;
                        }
                }

                // Set of original pages to pass on to further manipulation...
                $inputPages = array_keys( $pageSet );

                // Look up any linked pages if asked...
                if( $this->templates ) {
                        $pageSet = $this->getTemplates( $inputPages, $pageSet );
                }
                $linkDepth = $this->pageLinkDepth;
                if( $linkDepth ) {
                        $pageSet = $this->getPageLinks( $inputPages, $pageSet, $linkDepth );
                }

                /*
                 // Enable this when we can do something useful exporting/importing image information. :)
                 if( $this->images ) ) {
                 $pageSet = $this->getImages( $inputPages, $pageSet );
                 }
                 */

                $pages = array_keys( $pageSet );

                // Normalize titles to the same format and remove dupes, see bug 17374
                foreach( $pages as $k => $v ) {
                        $pages[$k] = str_replace( " ", "_", $v );
                }
                
                $pages = array_unique( $pages );

                /* Ok, let's get to it... */
                if( $history == WikiExporter::CURRENT ) {
                        $lb = false;
                        $db = wfGetDB( DB_SLAVE );
                        $buffer = WikiExporter::BUFFER;
                } else {
                        // Use an unbuffered query; histories may be very long!
                        $lb = wfGetLBFactory()->newMainLB();
                        $db = $lb->getConnection( DB_SLAVE );
                        $buffer = WikiExporter::STREAM;

                        // This might take a while... :D
                        wfSuppressWarnings();
                        set_time_limit(0);
                        wfRestoreWarnings();
                }
                
                $exporter = new WikiExporter( $db, $history, $buffer );
                $exporter->list_authors = $list_authors;
                $exporter->openStream();
                
                foreach( $pages as $page ) {
                        /*
                         if( $wgExportMaxHistory && !$this->curonly ) {
                         $title = Title::newFromText( $page );
                         if( $title ) {
                         $count = Revision::countByTitle( $db, $title );
                         if( $count > $wgExportMaxHistory ) {
                         wfDebug( __FUNCTION__ .
                         ": Skipped $page, $count revisions too big\n" );
                         continue;
                         }
                         }
                         }*/
                        #Bug 8824: Only export pages the user can read
                        $title = Title::newFromText( $page );
                        if( is_null( $title ) ) {
                                continue; #TODO: perhaps output an <error> tag or something.
                        }
                        if( !$title->userCanRead() ) {
                                continue; #TODO: perhaps output an <error> tag or something.
                        }

                        $exporter->pageByTitle( $title );
                }

                $exporter->closeStream();
                
                if( $lb ) {
                        $lb->closeAll();
                }
        }

        private function getPagesFromCategory( $title ) {
                global $wgContLang;

                $name = $title->getDBkey();

                $dbr = wfGetDB( DB_SLAVE );
                $res = $dbr->select(
                        array( 'page', 'categorylinks' ),
                        array( 'page_namespace', 'page_title' ),
                        array( 'cl_from=page_id', 'cl_to' => $name ),
                        __METHOD__,
                        array( 'LIMIT' => '5000' )
                );

                $pages = array();
                
                foreach ( $res as $row ) {
                        $n = $row->page_title;
                        if ($row->page_namespace) {
                                $ns = $wgContLang->getNsText( $row->page_namespace );
                                $n = $ns . ':' . $n;
                        }

                        $pages[] = $n;
                }
                return $pages;
        }

        private function getPagesFromNamespace( $nsindex ) {
                global $wgContLang;

                $dbr = wfGetDB( DB_SLAVE );
                $res = $dbr->select(
                        'page',
                        array( 'page_namespace', 'page_title' ),
                        array( 'page_namespace' => $nsindex ),
                        __METHOD__,
                        array( 'LIMIT' => '5000' )
                );

                $pages = array();
                
                foreach ( $res as $row ) {
                        $n = $row->page_title;
                        
                        if ( $row->page_namespace ) {
                                $ns = $wgContLang->getNsText( $row->page_namespace );
                                $n = $ns . ':' . $n;
                        }

                        $pages[] = $n;
                }
                return $pages;
        }

        /**
         * Expand a list of pages to include templates used in those pages.
         * @param $inputPages array, list of titles to look up
         * @param $pageSet array, associative array indexed by titles for output
         * @return array associative array index by titles
         */
        private function getTemplates( $inputPages, $pageSet ) {
                return $this->getLinks( $inputPages, $pageSet,
                        'templatelinks',
                        array( 'tl_namespace AS namespace', 'tl_title AS title' ),
                        array( 'page_id=tl_from' )
                );
        }

        /**
         * Validate link depth setting, if available.
         */
        private function validateLinkDepth( $depth ) {
                global $wgExportMaxLinkDepth;
                
                if( $depth < 0 ) {
                        return 0;
                }
                
                if ( !$this->userCanOverrideExportDepth() ) {
                        if( $depth > $wgExportMaxLinkDepth ) {
                                return $wgExportMaxLinkDepth;
                        }
                }
                
                /*
                 * There's a HARD CODED limit of 5 levels of recursion here to prevent a
                 * crazy-big export from being done by someone setting the depth
                 * number too high. In other words, last resort safety net.
                 */
                return intval( min( $depth, 5 ) );
        }

        /** Expand a list of pages to include pages linked to from that page. */
        private function getPageLinks( $inputPages, $pageSet, $depth ) {
                for( ; $depth > 0; --$depth ) {
                        $pageSet = $this->getLinks(
                                $inputPages, $pageSet, 'pagelinks',
                                array( 'pl_namespace AS namespace', 'pl_title AS title' ),
                                array( 'page_id=pl_from' )
                        );
                        $inputPages = array_keys( $pageSet );
                }
                
                return $pageSet;
        }

        /**
         * Expand a list of pages to include images used in those pages.
         * 
         * @param $inputPages array, list of titles to look up
         * @param $pageSet array, associative array indexed by titles for output
         * 
         * @return array associative array index by titles
         */
        private function getImages( $inputPages, $pageSet ) {
                return $this->getLinks(
                        $inputPages,
                        $pageSet,
                        'imagelinks',
                        array( NS_FILE . ' AS namespace', 'il_to AS title' ),
                        array( 'page_id=il_from' )
                );
        }

        /**
         * Expand a list of pages to include items used in those pages.
         */
        private function getLinks( $inputPages, $pageSet, $table, $fields, $join ) {
                $dbr = wfGetDB( DB_SLAVE );
                
                foreach( $inputPages as $page ) {
                        $title = Title::newFromText( $page );
                        
                        if( $title ) {
                                $pageSet[$title->getPrefixedText()] = true;
                                /// @todo Fixme: May or may not be more efficient to batch these
                                ///        by namespace when given multiple input pages.
                                $result = $dbr->select(
                                        array( 'page', $table ),
                                        $fields,
                                        array_merge(
                                                $join,
                                                array(
                                                        'page_namespace' => $title->getNamespace(),
                                                        'page_title' => $title->getDBkey()
                                                )
                                        ),
                                        __METHOD__
                                );
                                
                                foreach( $result as $row ) {
                                        $template = Title::makeTitle( $row->namespace, $row->title );
                                        $pageSet[$template->getPrefixedText()] = true;
                                }
                        }
                }
                
                return $pageSet;
        }
        
}