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[mediawiki.git] / includes / api / ApiQueryCategoryMembers.php

<?php
/**
 *
 *
 * Created on June 14, 2007
 *
 * Copyright © 2006 Yuri Astrakhan "<Firstname><Lastname>@gmail.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
 */

/**
 * A query module to enumerate pages that belong to a category.
 *
 * @ingroup API
 */
class ApiQueryCategoryMembers extends ApiQueryGeneratorBase {

        public function __construct( ApiQuery $query, $moduleName ) {
                parent::__construct( $query, $moduleName, 'cm' );
        }

        public function execute() {
                $this->run();
        }

        public function getCacheMode( $params ) {
                return 'public';
        }

        public function executeGenerator( $resultPageSet ) {
                $this->run( $resultPageSet );
        }

        /**
         * @param ApiPageSet $resultPageSet
         * @return void
         */
        private function run( $resultPageSet = null ) {
                $params = $this->extractRequestParams();

                $categoryTitle = $this->getTitleOrPageId( $params )->getTitle();
                if ( $categoryTitle->getNamespace() != NS_CATEGORY ) {
                        $this->dieUsage( 'The category name you entered is not valid', 'invalidcategory' );
                }

                $prop = array_flip( $params['prop'] );
                $fld_ids = isset( $prop['ids'] );
                $fld_title = isset( $prop['title'] );
                $fld_sortkey = isset( $prop['sortkey'] );
                $fld_sortkeyprefix = isset( $prop['sortkeyprefix'] );
                $fld_timestamp = isset( $prop['timestamp'] );
                $fld_type = isset( $prop['type'] );

                if ( is_null( $resultPageSet ) ) {
                        $this->addFields( array( 'cl_from', 'cl_sortkey', 'cl_type', 'page_namespace', 'page_title' ) );
                        $this->addFieldsIf( 'page_id', $fld_ids );
                        $this->addFieldsIf( 'cl_sortkey_prefix', $fld_sortkeyprefix );
                } else {
                        $this->addFields( $resultPageSet->getPageTableFields() ); // will include page_ id, ns, title
                        $this->addFields( array( 'cl_from', 'cl_sortkey', 'cl_type' ) );
                }

                $this->addFieldsIf( 'cl_timestamp', $fld_timestamp || $params['sort'] == 'timestamp' );

                $this->addTables( array( 'page', 'categorylinks' ) ); // must be in this order for 'USE INDEX'

                $this->addWhereFld( 'cl_to', $categoryTitle->getDBkey() );
                $queryTypes = $params['type'];
                $contWhere = false;

                // Scanning large datasets for rare categories sucks, and I already told
                // how to have efficient subcategory access :-) ~~~~ (oh well, domas)
                $miser_ns = array();
                if ( $this->getConfig()->get( 'MiserMode' ) ) {
                        $miser_ns = $params['namespace'];
                } else {
                        $this->addWhereFld( 'page_namespace', $params['namespace'] );
                }

                $dir = in_array( $params['dir'], array( 'asc', 'ascending', 'newer' ) ) ? 'newer' : 'older';

                if ( $params['sort'] == 'timestamp' ) {
                        $this->addTimestampWhereRange( 'cl_timestamp',
                                $dir,
                                $params['start'],
                                $params['end'] );
                        // Include in ORDER BY for uniqueness
                        $this->addWhereRange( 'cl_from', $dir, null, null );

                        if ( !is_null( $params['continue'] ) ) {
                                $cont = explode( '|', $params['continue'] );
                                $this->dieContinueUsageIf( count( $cont ) != 2 );
                                $op = ( $dir === 'newer' ? '>' : '<' );
                                $db = $this->getDB();
                                $continueTimestamp = $db->addQuotes( $db->timestamp( $cont[0] ) );
                                $continueFrom = (int)$cont[1];
                                $this->dieContinueUsageIf( $continueFrom != $cont[1] );
                                $this->addWhere( "cl_timestamp $op $continueTimestamp OR " .
                                        "(cl_timestamp = $continueTimestamp AND " .
                                        "cl_from $op= $continueFrom)"
                                );
                        }

                        $this->addOption( 'USE INDEX', 'cl_timestamp' );
                } else {
                        if ( $params['continue'] ) {
                                $cont = explode( '|', $params['continue'], 3 );
                                $this->dieContinueUsageIf( count( $cont ) != 3 );

                                // Remove the types to skip from $queryTypes
                                $contTypeIndex = array_search( $cont[0], $queryTypes );
                                $queryTypes = array_slice( $queryTypes, $contTypeIndex );

                                // Add a WHERE clause for sortkey and from
                                // pack( "H*", $foo ) is used to convert hex back to binary
                                $escSortkey = $this->getDB()->addQuotes( pack( 'H*', $cont[1] ) );
                                $from = intval( $cont[2] );
                                $op = $dir == 'newer' ? '>' : '<';
                                // $contWhere is used further down
                                $contWhere = "cl_sortkey $op $escSortkey OR " .
                                        "(cl_sortkey = $escSortkey AND " .
                                        "cl_from $op= $from)";
                                // The below produces ORDER BY cl_sortkey, cl_from, possibly with DESC added to each of them
                                $this->addWhereRange( 'cl_sortkey', $dir, null, null );
                                $this->addWhereRange( 'cl_from', $dir, null, null );
                        } else {
                                if ( $params['startsortkeyprefix'] !== null ) {
                                        $startsortkey = Collation::singleton()->getSortkey( $params['startsortkeyprefix'] );
                                } elseif ( $params['starthexsortkey'] !== null ) {
                                        $startsortkey = pack( 'H*', $params['starthexsortkey'] );
                                } else {
                                        $this->logFeatureUsage( 'list=categorymembers&cmstartsortkey' );
                                        $startsortkey = $params['startsortkey'];
                                }
                                if ( $params['endsortkeyprefix'] !== null ) {
                                        $endsortkey = Collation::singleton()->getSortkey( $params['endsortkeyprefix'] );
                                } elseif ( $params['endhexsortkey'] !== null ) {
                                        $endsortkey = pack( 'H*', $params['endhexsortkey'] );
                                } else {
                                        $this->logFeatureUsage( 'list=categorymembers&cmendsortkey' );
                                        $endsortkey = $params['endsortkey'];
                                }

                                // The below produces ORDER BY cl_sortkey, cl_from, possibly with DESC added to each of them
                                $this->addWhereRange( 'cl_sortkey',
                                        $dir,
                                        $startsortkey,
                                        $endsortkey );
                                $this->addWhereRange( 'cl_from', $dir, null, null );
                        }
                        $this->addOption( 'USE INDEX', 'cl_sortkey' );
                }

                $this->addWhere( 'cl_from=page_id' );

                $limit = $params['limit'];
                $this->addOption( 'LIMIT', $limit + 1 );

                if ( $params['sort'] == 'sortkey' ) {
                        // Run a separate SELECT query for each value of cl_type.
                        // This is needed because cl_type is an enum, and MySQL has
                        // inconsistencies between ORDER BY cl_type and
                        // WHERE cl_type >= 'foo' making proper paging impossible
                        // and unindexed.
                        $rows = array();
                        $first = true;
                        foreach ( $queryTypes as $type ) {
                                $extraConds = array( 'cl_type' => $type );
                                if ( $first && $contWhere ) {
                                        // Continuation condition. Only added to the
                                        // first query, otherwise we'll skip things
                                        $extraConds[] = $contWhere;
                                }
                                $res = $this->select( __METHOD__, array( 'where' => $extraConds ) );
                                $rows = array_merge( $rows, iterator_to_array( $res ) );
                                if ( count( $rows ) >= $limit + 1 ) {
                                        break;
                                }
                                $first = false;
                        }
                } else {
                        // Sorting by timestamp
                        // No need to worry about per-type queries because we
                        // aren't sorting or filtering by type anyway
                        $res = $this->select( __METHOD__ );
                        $rows = iterator_to_array( $res );
                }

                $result = $this->getResult();
                $count = 0;
                foreach ( $rows as $row ) {
                        if ( ++$count > $limit ) {
                                // We've reached the one extra which shows that there are
                                // additional pages to be had. Stop here...
                                // @todo Security issue - if the user has no right to view next
                                // title, it will still be shown
                                if ( $params['sort'] == 'timestamp' ) {
                                        $this->setContinueEnumParameter( 'continue', "$row->cl_timestamp|$row->cl_from" );
                                } else {
                                        $sortkey = bin2hex( $row->cl_sortkey );
                                        $this->setContinueEnumParameter( 'continue',
                                                "{$row->cl_type}|$sortkey|{$row->cl_from}"
                                        );
                                }
                                break;
                        }

                        // Since domas won't tell anyone what he told long ago, apply
                        // cmnamespace here. This means the query may return 0 actual
                        // results, but on the other hand it could save returning 5000
                        // useless results to the client. ~~~~
                        if ( count( $miser_ns ) && !in_array( $row->page_namespace, $miser_ns ) ) {
                                continue;
                        }

                        if ( is_null( $resultPageSet ) ) {
                                $vals = array();
                                if ( $fld_ids ) {
                                        $vals['pageid'] = intval( $row->page_id );
                                }
                                if ( $fld_title ) {
                                        $title = Title::makeTitle( $row->page_namespace, $row->page_title );
                                        ApiQueryBase::addTitleInfo( $vals, $title );
                                }
                                if ( $fld_sortkey ) {
                                        $vals['sortkey'] = bin2hex( $row->cl_sortkey );
                                }
                                if ( $fld_sortkeyprefix ) {
                                        $vals['sortkeyprefix'] = $row->cl_sortkey_prefix;
                                }
                                if ( $fld_type ) {
                                        $vals['type'] = $row->cl_type;
                                }
                                if ( $fld_timestamp ) {
                                        $vals['timestamp'] = wfTimestamp( TS_ISO_8601, $row->cl_timestamp );
                                }
                                $fit = $result->addValue( array( 'query', $this->getModuleName() ),
                                        null, $vals );
                                if ( !$fit ) {
                                        if ( $params['sort'] == 'timestamp' ) {
                                                $this->setContinueEnumParameter( 'continue', "$row->cl_timestamp|$row->cl_from" );
                                        } else {
                                                $sortkey = bin2hex( $row->cl_sortkey );
                                                $this->setContinueEnumParameter( 'continue',
                                                        "{$row->cl_type}|$sortkey|{$row->cl_from}"
                                                );
                                        }
                                        break;
                                }
                        } else {
                                $resultPageSet->processDbRow( $row );
                        }
                }

                if ( is_null( $resultPageSet ) ) {
                        $result->setIndexedTagName_internal(
                                array( 'query', $this->getModuleName() ), 'cm' );
                }
        }

        public function getAllowedParams() {
                $ret = array(
                        'title' => array(
                                ApiBase::PARAM_TYPE => 'string',
                        ),
                        'pageid' => array(
                                ApiBase::PARAM_TYPE => 'integer'
                        ),
                        'prop' => array(
                                ApiBase::PARAM_DFLT => 'ids|title',
                                ApiBase::PARAM_ISMULTI => true,
                                ApiBase::PARAM_TYPE => array(
                                        'ids',
                                        'title',
                                        'sortkey',
                                        'sortkeyprefix',
                                        'type',
                                        'timestamp',
                                )
                        ),
                        'namespace' => array(
                                ApiBase::PARAM_ISMULTI => true,
                                ApiBase::PARAM_TYPE => 'namespace',
                        ),
                        'type' => array(
                                ApiBase::PARAM_ISMULTI => true,
                                ApiBase::PARAM_DFLT => 'page|subcat|file',
                                ApiBase::PARAM_TYPE => array(
                                        'page',
                                        'subcat',
                                        'file'
                                )
                        ),
                        'continue' => array(
                                ApiBase::PARAM_HELP_MSG => 'api-help-param-continue',
                        ),
                        'limit' => array(
                                ApiBase::PARAM_TYPE => 'limit',
                                ApiBase::PARAM_DFLT => 10,
                                ApiBase::PARAM_MIN => 1,
                                ApiBase::PARAM_MAX => ApiBase::LIMIT_BIG1,
                                ApiBase::PARAM_MAX2 => ApiBase::LIMIT_BIG2
                        ),
                        'sort' => array(
                                ApiBase::PARAM_DFLT => 'sortkey',
                                ApiBase::PARAM_TYPE => array(
                                        'sortkey',
                                        'timestamp'
                                )
                        ),
                        'dir' => array(
                                ApiBase::PARAM_DFLT => 'ascending',
                                ApiBase::PARAM_TYPE => array(
                                        'asc',
                                        'desc',
                                        // Normalising with other modules
                                        'ascending',
                                        'descending',
                                        'newer',
                                        'older',
                                )
                        ),
                        'start' => array(
                                ApiBase::PARAM_TYPE => 'timestamp'
                        ),
                        'end' => array(
                                ApiBase::PARAM_TYPE => 'timestamp'
                        ),
                        'starthexsortkey' => null,
                        'endhexsortkey' => null,
                        'startsortkeyprefix' => null,
                        'endsortkeyprefix' => null,
                        'startsortkey' => array(
                                ApiBase::PARAM_DEPRECATED => true,
                        ),
                        'endsortkey' => array(
                                ApiBase::PARAM_DEPRECATED => true,
                        ),
                );

                if ( $this->getConfig()->get( 'MiserMode' ) ) {
                        $ret['namespace'][ApiBase::PARAM_HELP_MSG_APPEND] = array(
                                'api-help-param-limited-in-miser-mode',
                        );
                }

                return $ret;
        }

        public function getExamplesMessages() {
                return array(
                        'action=query&list=categorymembers&cmtitle=Category:Physics'
                                => 'apihelp-query+categorymembers-example-simple',
                        'action=query&generator=categorymembers&gcmtitle=Category:Physics&prop=info'
                                => 'apihelp-query+categorymembers-example-generator',
                );
        }

        public function getHelpUrls() {
                return 'https://www.mediawiki.org/wiki/API:Categorymembers';
        }
}