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\Helper;

use InvalidArgumentException;
use MediaWiki\Rest\ResponseInterface;

/**
 * Format-related REST API helper.
 * Probably should be turned into an object encapsulating format and content version at some point.
 */
class ParsoidFormatHelper {

    public const FORMAT_WIKITEXT = 'wikitext';
    public const FORMAT_HTML = 'html';
    public const FORMAT_PAGEBUNDLE = 'pagebundle';
    public const FORMAT_LINT = 'lint';

    public const ERROR_ENCODING = [
        self::FORMAT_WIKITEXT => 'plain',
        self::FORMAT_HTML => 'html',
        self::FORMAT_PAGEBUNDLE => 'json',
        self::FORMAT_LINT => 'json',
    ];

    public const VALID_PAGE = [
        self::FORMAT_WIKITEXT, self::FORMAT_HTML, self::FORMAT_PAGEBUNDLE, self::FORMAT_LINT
    ];

    public const VALID_TRANSFORM = [
        self::FORMAT_WIKITEXT => [ self::FORMAT_HTML, self::FORMAT_PAGEBUNDLE, self::FORMAT_LINT ],
        self::FORMAT_HTML => [ self::FORMAT_WIKITEXT ],
        self::FORMAT_PAGEBUNDLE => [ self::FORMAT_WIKITEXT, self::FORMAT_PAGEBUNDLE ],
    ];

    /**
     * Get the content type appropriate for a given response format.
     * @param string $format One of the FORMAT_* constants
     * @param ?string $contentVersion Output version, only for HTML and pagebundle
     *   formats. See Env::getcontentVersion().
     * @return string
     */
    public static function getContentType(
        string $format, ?string $contentVersion = null
    ): string {
        if ( $format !== self::FORMAT_WIKITEXT && !$contentVersion ) {
            throw new InvalidArgumentException( '$contentVersion is required for this format' );
        }

        switch ( $format ) {
            case self::FORMAT_WIKITEXT:
                $contentType = 'text/plain';
                // PORT-FIXME in the original the version number is from MWParserEnvironment.wikitextVersion
                // but it did not seem to be used anywhere
                $profile = 'https://www.mediawiki.org/wiki/Specs/wikitext/1.0.0';
                break;
            case self::FORMAT_HTML:
                $contentType = 'text/html';
                $profile = 'https://www.mediawiki.org/wiki/Specs/HTML/' . $contentVersion;
                break;
            case self::FORMAT_PAGEBUNDLE:
                $contentType = 'application/json';
                $profile = 'https://www.mediawiki.org/wiki/Specs/pagebundle/' . $contentVersion;
                break;
            default:
                throw new InvalidArgumentException( "Invalid format $format" );
        }
        return "$contentType; charset=utf-8; profile=\"$profile\"";
    }

    /**
     * Set the Content-Type header appropriate for a given response format.
     * @param ResponseInterface $response
     * @param string $format One of the FORMAT_* constants
     * @param ?string $contentVersion Output version, only for HTML and pagebundle
     *   formats. See Env::getcontentVersion().
     */
    public static function setContentType(
        ResponseInterface $response, string $format,
        ?string $contentVersion = null
    ): void {
        $response->setHeader( 'Content-Type', self::getContentType( $format, $contentVersion ) );
    }

    /**
     * Parse a Content-Type header and return the format type and version.
     * Mostly the inverse of getContentType() but also accounts for legacy formats.
     * @param string $contentTypeHeader The value of the Content-Type header.
     * @param ?string &$format Format type will be set here (as a FORMAT_* constant).
     * @return ?string Format version, or null if it couldn't be identified.
     * @see Env::getInputContentVersion()
     */
    public static function parseContentTypeHeader(
        string $contentTypeHeader, ?string &$format = null
    ): ?string {
        $newProfileSyntax = 'https://www.mediawiki.org/wiki/Specs/(HTML|pagebundle)/';
        $oldProfileSyntax = 'mediawiki.org/specs/(html)/';
        $profileRegex = "#\bprofile=\"(?:$newProfileSyntax|$oldProfileSyntax)(\d+\.\d+\.\d+)\"#";
        preg_match( $profileRegex, $contentTypeHeader, $m );
        if ( $m ) {
            switch ( $m[1] ?: $m[2] ) {
                case 'HTML':
                case 'html':
                    $format = self::FORMAT_HTML;
                    break;
                case 'pagebundle':
                    $format = self::FORMAT_PAGEBUNDLE;
                    break;
            }
            return $m[3];
        }
        return null;
    }

}