wikimedia/mediawiki-core

<?php

/**
 * Copyright (C) 2011-2020 Wikimedia Foundation and others.
 *
 * 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.
 */

namespace MediaWiki\Rest\Handler;

use MediaWiki\Rest\Handler\Helper\ParsoidFormatHelper;
use MediaWiki\Rest\HttpException;
use MediaWiki\Rest\LocalizedHttpException;
use MediaWiki\Rest\Response;
use Wikimedia\Message\MessageValue;
use Wikimedia\ParamValidator\ParamValidator;

/**
 * Handler for transforming content given in the request.
 * - /v1/transform/{from}/to/{format}
 * - /v1/transform/{from}/to/{format}/{title}
 * - /v1/transform/{from}/to/{format}/{title}/{revision}
 *
 * @see https://www.mediawiki.org/wiki/Parsoid/API#POST
 */
class TransformHandler extends ParsoidHandler {

    /** @inheritDoc */
    public function getParamSettings() {
        return [
            'from' => [ self::PARAM_SOURCE => 'path',
                ParamValidator::PARAM_TYPE => 'string',
                ParamValidator::PARAM_REQUIRED => true, ],
            'format' => [ self::PARAM_SOURCE => 'path',
                ParamValidator::PARAM_TYPE => 'string',
                ParamValidator::PARAM_REQUIRED => true, ],
            'title' => [ self::PARAM_SOURCE => 'path',
                ParamValidator::PARAM_TYPE => 'string',
                ParamValidator::PARAM_REQUIRED => false, ],
            'revision' => [ self::PARAM_SOURCE => 'path',
                ParamValidator::PARAM_TYPE => 'string',
                ParamValidator::PARAM_REQUIRED => false, ], ];
    }

    /**
     * @inheritDoc
     */
    public function needsWriteAccess() {
        return false;
    }

    public function checkPreconditions() {
        // NOTE: disable all precondition checks.
        // If-(not)-Modified-Since is not supported by the /transform/ handler.
        // If-None-Match is not supported by the /transform/ handler.
        // If-Match for wt2html is handled in getRequestAttributes.
    }

    protected function &getRequestAttributes(): array {
        $attribs =& parent::getRequestAttributes();

        $request = $this->getRequest();

        // NOTE: If there is more than one ETag, this will break.
        //       We don't have a good way to test multiple ETag to see if one of them is a working stash key.
        $ifMatch = $request->getHeaderLine( 'If-Match' );

        if ( $ifMatch ) {
            $attribs['opts']['original']['etag'] = $ifMatch;
        }

        return $attribs;
    }

    /**
     * Transform content given in the request from or to wikitext.
     *
     * @return Response
     * @throws HttpException
     */
    public function execute(): Response {
        $request = $this->getRequest();
        $from = $request->getPathParam( 'from' );
        $format = $request->getPathParam( 'format' );

        // XXX: Fallback to the default valid transforms in case the request is
        //      coming from a legacy client (restbase) that supports everything
        //      in the default valid transforms.
        $validTransformations = $this->getConfig()['transformations'] ?? ParsoidFormatHelper::VALID_TRANSFORM;

        if ( !isset( $validTransformations[$from] ) || !in_array( $format,
                $validTransformations[$from],
                true ) ) {
            throw new LocalizedHttpException( new MessageValue( "rest-invalid-transform", [ $from, $format ] ), 404 );
        }
        $attribs = &$this->getRequestAttributes();
        if ( !$this->acceptable( $attribs ) ) { // mutates $attribs
            throw new LocalizedHttpException( new MessageValue( "rest-unsupported-target-format" ), 406 );
        }
        if ( $from === ParsoidFormatHelper::FORMAT_WIKITEXT ) {
            // Accept wikitext as a string or object{body,headers}
            $wikitext = $attribs['opts']['wikitext'] ?? null;
            if ( is_array( $wikitext ) ) {
                $wikitext = $wikitext['body'];
                // We've been given a pagelanguage for this page.
                if ( isset( $attribs['opts']['wikitext']['headers']['content-language'] ) ) {
                    $attribs['pagelanguage'] = $attribs['opts']['wikitext']['headers']['content-language'];
                }
            }
            // We've been given source for this page
            if ( $wikitext === null && isset( $attribs['opts']['original']['wikitext'] ) ) {
                $wikitext = $attribs['opts']['original']['wikitext']['body'];
                // We've been given a pagelanguage for this page.
                if ( isset( $attribs['opts']['original']['wikitext']['headers']['content-language'] ) ) {
                    $attribs['pagelanguage'] = $attribs['opts']['original']['wikitext']['headers']['content-language'];
                }
            }
            // Abort if no wikitext or title.
            if ( $wikitext === null && empty( $attribs['pageName'] ) ) {
                throw new LocalizedHttpException( new MessageValue( "rest-transform-missing-title" ), 400 );
            }
            $pageConfig = $this->tryToCreatePageConfig( $attribs, $wikitext );

            return $this->wt2html( $pageConfig,
                $attribs,
                $wikitext );
        } elseif ( $format === ParsoidFormatHelper::FORMAT_WIKITEXT ) {
            $html = $attribs['opts']['html'] ?? null;
            // Accept html as a string or object{body,headers}
            if ( is_array( $html ) ) {
                $html = $html['body'];
            }
            if ( $html === null ) {
                throw new LocalizedHttpException( new MessageValue( "rest-transform-missing-html" ), 400 );
            }

            // TODO: use ETag from If-Match header, for compat!

            $page = $this->tryToCreatePageIdentity( $attribs );

            return $this->html2wt(
                $page,
                $attribs,
                $html
            );
        } else {
            return $this->pb2pb( $attribs );
        }
    }
}