ApiQueryCategoryMembers.php

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<?php
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 );
    }

    private function validateHexSortkey( $hexSortkey ) {
        // A hex sortkey has an unbound number of 2 letter pairs
        return (bool)preg_match( '/^(?:[a-fA-F0-9]{2})*$/D', $hexSortkey );
    }

    private function run( $resultPageSet = null ) {
        $params = $this->extractRequestParams();

        $categoryTitle = $this->getTitleOrPageId( $params )->getTitle();
        if ( $categoryTitle->getNamespace() != NS_CATEGORY ) {
            $this->dieWithError( 'apierror-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( [ '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( [ 'cl_from', 'cl_sortkey', 'cl_type' ] );
        }

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

        $this->addTables( [ '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 = [];
        if ( $this->getConfig()->get( 'MiserMode' ) ) {
            $miser_ns = $params['namespace'] ?: [];
        } else {
            $this->addWhereFld( 'page_namespace', $params['namespace'] );
        }

        $dir = in_array( $params['dir'], [ '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
                $this->dieContinueUsageIf( !$this->validateHexSortkey( $cont[1] ) );
                $escSortkey = $this->getDB()->addQuotes( hex2bin( $cont[1] ) );
                $from = (int)$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 ( $params['starthexsortkey'] !== null ) {
                    if ( !$this->validateHexSortkey( $params['starthexsortkey'] ) ) {
                        $encParamName = $this->encodeParamName( 'starthexsortkey' );
                        $this->dieWithError( [ 'apierror-badparameter', $encParamName ], "badvalue_$encParamName" );
                    }
                    $startsortkey = hex2bin( $params['starthexsortkey'] );
                } else {
                    $startsortkey = $params['startsortkey'];
                }
                if ( $params['endsortkeyprefix'] !== null ) {
                    $endsortkey = Collation::singleton()->getSortKey( $params['endsortkeyprefix'] );
                } elseif ( $params['endhexsortkey'] !== null ) {
                    if ( !$this->validateHexSortkey( $params['endhexsortkey'] ) ) {
                        $encParamName = $this->encodeParamName( 'endhexsortkey' );
                        $this->dieWithError( [ 'apierror-badparameter', $encParamName ], "badvalue_$encParamName" );
                    }
                    $endsortkey = hex2bin( $params['endhexsortkey'] );
                } else {
                    $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 = [];
            $first = true;
            foreach ( $queryTypes as $type ) {
                $extraConds = [ '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__, [ '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 = [
                    ApiResult::META_TYPE => 'assoc',
                ];
                if ( $fld_ids ) {
                    $vals['pageid'] = (int)$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( [ '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->addIndexedTagName(
                [ 'query', $this->getModuleName() ], 'cm' );
        }
    }

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

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

        return $ret;
    }

    protected function getExamplesMessages() {
        return [
            '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/Special:MyLanguage/API:Categorymembers';
    }
}