Expose $wgMaxArticleSize in siteinfo query api

[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;

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

        public function execute( $par ) {
                $this->setHeaders();
                $this->outputHeader();
                $config = $this->getConfig();

                // Set some variables
                $this->curonly = true;
                $this->doExport = false;
                $request = $this->getRequest();
                $this->templates = $request->getCheck( 'templates' );
                $this->pageLinkDepth = $this->validateLinkDepth(
                        $request->getIntOrNull( 'pagelink-depth' )
                );
                $nsindex = '';
                $exportall = false;

                if ( $request->getCheck( 'addcat' ) ) {
                        $page = $request->getText( 'pages' );
                        $catname = $request->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 ) {
                                                if ( $page !== '' ) {
                                                        $page .= "\n";
                                                }
                                                $page .= implode( "\n", $catpages );
                                        }
                                }
                        }
                } elseif ( $request->getCheck( 'addns' ) && $config->get( 'ExportFromNamespaces' ) ) {
                        $page = $request->getText( 'pages' );
                        $nsindex = $request->getText( 'nsindex', '' );

                        if ( strval( $nsindex ) !== '' ) {
                                /**
                                 * Same implementation as above, so same @todo
                                 */
                                $nspages = $this->getPagesFromNamespace( $nsindex );
                                if ( $nspages ) {
                                        $page .= "\n" . implode( "\n", $nspages );
                                }
                        }
                } elseif ( $request->getCheck( 'exportall' ) && $config->get( 'ExportAllowAll' ) ) {
                        $this->doExport = true;
                        $exportall = true;

                        /* Although $page and $history are not used later on, we
                        nevertheless set them to avoid that PHP notices about using
                        undefined variables foul up our XML output (see call to
                        doExport(...) further down) */
                        $page = '';
                        $history = '';
                } elseif ( $request->wasPosted() && $par == '' ) {
                        $page = $request->getText( 'pages' );
                        $this->curonly = $request->getCheck( 'curonly' );
                        $rawOffset = $request->getVal( 'offset' );

                        if ( $rawOffset ) {
                                $offset = wfTimestamp( TS_MW, $rawOffset );
                        } else {
                                $offset = null;
                        }

                        $maxHistory = $config->get( 'ExportMaxHistory' );
                        $limit = $request->getInt( 'limit' );
                        $dir = $request->getVal( 'dir' );
                        $history = [
                                'dir' => 'asc',
                                'offset' => false,
                                'limit' => $maxHistory,
                        ];
                        $historyCheck = $request->getCheck( 'history' );

                        if ( $this->curonly ) {
                                $history = WikiExporter::CURRENT;
                        } elseif ( !$historyCheck ) {
                                if ( $limit > 0 && ( $maxHistory == 0 || $limit < $maxHistory ) ) {
                                        $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 = $request->getText( 'pages', $par );
                        $historyCheck = $request->getCheck( 'history' );

                        if ( $historyCheck ) {
                                $history = WikiExporter::FULL;
                        } else {
                                $history = WikiExporter::CURRENT;
                        }

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

                if ( !$config->get( 'ExportAllowHistory' ) ) {
                        // Override
                        $history = WikiExporter::CURRENT;
                }

                $list_authors = $request->getCheck( 'listauthors' );
                if ( !$this->curonly || !$config->get( 'ExportAllowListContributors' ) ) {
                        $list_authors = false;
                }

                if ( $this->doExport ) {
                        $this->getOutput()->disable();

                        // Cancel output buffering and gzipping if set
                        // This should provide safer streaming for pages with history
                        wfResetOutputBuffers();
                        $request->response()->header( "Content-type: application/xml; charset=utf-8" );
                        $request->response()->header( "X-Robots-Tag: noindex,nofollow" );

                        if ( $request->getCheck( 'wpDownload' ) ) {
                                // Provide a sane filename suggestion
                                $filename = urlencode( $config->get( 'Sitename' ) . '-' . wfTimestampNow() . '.xml' );
                                $request->response()->header( "Content-disposition: attachment;filename={$filename}" );
                        }

                        $this->doExport( $page, $history, $list_authors, $exportall );

                        return;
                }

                $out = $this->getOutput();
                $out->addWikiMsg( 'exporttext' );

                if ( $page == '' ) {
                        $categoryName = $request->getText( 'catname' );
                } else {
                        $categoryName = '';
                }

                $formDescriptor = [
                        'catname' => [
                                'type' => 'textwithbutton',
                                'name' => 'catname',
                                'horizontal-label' => true,
                                'label-message' => 'export-addcattext',
                                'default' => $categoryName,
                                'size' => 40,
                                'buttontype' => 'submit',
                                'buttonname' => 'addcat',
                                'buttondefault' => $this->msg( 'export-addcat' )->text(),
                        ],
                ];
                if ( $config->get( 'ExportFromNamespaces' ) ) {
                        $formDescriptor += [
                                'nsindex' => [
                                        'type' => 'namespaceselectwithbutton',
                                        'default' => $nsindex,
                                        'label-message' => 'export-addnstext',
                                        'horizontal-label' => true,
                                        'name' => 'nsindex',
                                        'id' => 'namespace',
                                        'cssclass' => 'namespaceselector',
                                        'buttontype' => 'submit',
                                        'buttonname' => 'addns',
                                        'buttondefault' => $this->msg( 'export-addns' )->text(),
                                ],
                        ];
                }

                if ( $config->get( 'ExportAllowAll' ) ) {
                        $formDescriptor += [
                                'exportall' => [
                                        'type' => 'check',
                                        'label-message' => 'exportall',
                                        'name' => 'exportall',
                                        'id' => 'exportall',
                                        'default' => $request->wasPosted() ? $request->getCheck( 'exportall' ) : false,
                                ],
                        ];
                }

                $formDescriptor += [
                        'textarea' => [
                                'class' => 'HTMLTextAreaField',
                                'name' => 'pages',
                                'label-message' => 'export-manual',
                                'nodata' => true,
                                'rows' => 10,
                                'default' => $page,
                        ],
                ];

                if ( $config->get( 'ExportAllowHistory' ) ) {
                        $formDescriptor += [
                                'curonly' => [
                                        'type' => 'check',
                                        'label-message' => 'exportcuronly',
                                        'name' => 'curonly',
                                        'id' => 'curonly',
                                        'default' => $request->wasPosted() ? $request->getCheck( 'curonly' ) : true,
                                ],
                        ];
                } else {
                        $out->addWikiMsg( 'exportnohistory' );
                }

                $formDescriptor += [
                        'templates' => [
                                'type' => 'check',
                                'label-message' => 'export-templates',
                                'name' => 'templates',
                                'id' => 'wpExportTemplates',
                                'default' => $request->wasPosted() ? $request->getCheck( 'templates' ) : false,
                        ],
                ];

                if ( $config->get( 'ExportMaxLinkDepth' ) || $this->userCanOverrideExportDepth() ) {
                        $formDescriptor += [
                                'pagelink-depth' => [
                                        'type' => 'text',
                                        'name' => 'pagelink-depth',
                                        'id' => 'pagelink-depth',
                                        'label-message' => 'export-pagelinks',
                                        'default' => '0',
                                        'size' => 20,
                                ],
                        ];
                }

                $formDescriptor += [
                        'wpDownload' => [
                                'type' => 'check',
                                'name' =>'wpDownload',
                                'id' => 'wpDownload',
                                'default' => $request->wasPosted() ? $request->getCheck( 'wpDownload' ) : true,
                                'label-message' => 'export-download',
                        ],
                ];

                if ( $config->get( 'ExportAllowListContributors' ) ) {
                        $formDescriptor += [
                                'listauthors' => [
                                        'type' => 'check',
                                        'label-message' => 'exportlistauthors',
                                        'default' => $request->wasPosted() ? $request->getCheck( 'listauthors' ) : false,
                                        'name' => 'listauthors',
                                        'id' => 'listauthors',
                                ],
                        ];
                }

                $htmlForm = HTMLForm::factory( 'ooui', $formDescriptor, $this->getContext() );
                $htmlForm->setSubmitTextMsg( 'export-submit' );
                $htmlForm->prepareForm()->displayForm( false );
                $this->addHelpLink( 'Help:Export' );
        }

        /**
         * @return bool
         */
        private function userCanOverrideExportDepth() {
                return $this->getUser()->isAllowed( 'override-export-depth' );
        }

        /**
         * Do the actual page exporting
         *
         * @param string $page User input on what page(s) to export
         * @param int $history One of the WikiExporter history export constants
         * @param bool $list_authors Whether to add distinct author list (when
         *   not returning full history)
         * @param bool $exportall Whether to export everything
         */
        private function doExport( $page, $history, $list_authors, $exportall ) {

                // If we are grabbing everything, enable full history and ignore the rest
                if ( $exportall ) {
                        $history = WikiExporter::FULL;
                } else {
                        $pageSet = []; // 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->isExternal() && $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 );
                        }

                        $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
                        MediaWiki\suppressWarnings();
                        set_time_limit( 0 );
                        MediaWiki\restoreWarnings();
                }

                $exporter = new WikiExporter( $db, $history, $buffer );
                $exporter->list_authors = $list_authors;
                $exporter->openStream();

                if ( $exportall ) {
                        $exporter->allPages();
                } else {
                        foreach ( $pages as $page ) {
                                # Bug 8824: Only export pages the user can read
                                $title = Title::newFromText( $page );
                                if ( is_null( $title ) ) {
                                        // @todo Perhaps output an <error> tag or something.
                                        continue;
                                }

                                if ( !$title->userCan( 'read', $this->getUser() ) ) {
                                        // @todo Perhaps output an <error> tag or something.
                                        continue;
                                }

                                $exporter->pageByTitle( $title );
                        }
                }

                $exporter->closeStream();

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

        /**
         * @param Title $title
         * @return array
         */
        private function getPagesFromCategory( $title ) {
                global $wgContLang;

                $maxPages = $this->getConfig()->get( 'ExportPagelistLimit' );

                $name = $title->getDBkey();

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

                $pages = [];

                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;
        }

        /**
         * @param int $nsindex
         * @return array
         */
        private function getPagesFromNamespace( $nsindex ) {
                global $wgContLang;

                $maxPages = $this->getConfig()->get( 'ExportPagelistLimit' );

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

                $pages = [];

                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 array $inputPages List of titles to look up
         * @param array $pageSet 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',
                        [ 'namespace' => 'tl_namespace', 'title' => 'tl_title' ],
                        [ 'page_id=tl_from' ]
                );
        }

        /**
         * Validate link depth setting, if available.
         * @param int $depth
         * @return int
         */
        private function validateLinkDepth( $depth ) {
                if ( $depth < 0 ) {
                        return 0;
                }

                if ( !$this->userCanOverrideExportDepth() ) {
                        $maxLinkDepth = $this->getConfig()->get( 'ExportMaxLinkDepth' );
                        if ( $depth > $maxLinkDepth ) {
                                return $maxLinkDepth;
                        }
                }

                /*
                 * 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.
         * @param array $inputPages
         * @param array $pageSet
         * @param int $depth
         * @return array
         */
        private function getPageLinks( $inputPages, $pageSet, $depth ) {
                // @codingStandardsIgnoreStart Squiz.WhiteSpace.SemicolonSpacing.Incorrect
                for ( ; $depth > 0; --$depth ) {
                        // @codingStandardsIgnoreEnd
                        $pageSet = $this->getLinks(
                                $inputPages, $pageSet, 'pagelinks',
                                [ 'namespace' => 'pl_namespace', 'title' => 'pl_title' ],
                                [ 'page_id=pl_from' ]
                        );
                        $inputPages = array_keys( $pageSet );
                }

                return $pageSet;
        }

        /**
         * Expand a list of pages to include items used in those pages.
         * @param array $inputPages Array of page titles
         * @param array $pageSet
         * @param string $table
         * @param array $fields Array of field names
         * @param array $join
         * @return array
         */
        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(
                                        [ 'page', $table ],
                                        $fields,
                                        array_merge(
                                                $join,
                                                [
                                                        '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;
        }

        protected function getGroupName() {
                return 'pagetools';
        }
}