wikimedia/mediawiki-core

<?php

/**
 * Copyright © 2004 Brooke Vibber <bvibber@wikimedia.org>
 * https://www.mediawiki.org/
 *
 * 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
 */

namespace MediaWiki\Feed;

use MediaWiki\Html\TemplateParser;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Title\Title;

/**
 * Class to support the outputting of syndication feeds in Atom and RSS format.
 *
 * @stable to extend
 * @ingroup Feed
 */
abstract class ChannelFeed extends FeedItem {

    /** @var TemplateParser */
    protected $templateParser;

    /**
     * @stable to call
     *
     * @param string|Title $title Feed's title
     * @param string $description
     * @param string $url URL uniquely designating the feed.
     * @param string $date Feed's date
     * @param string $author Author's user name
     * @param string $comments
     *
     */
    public function __construct(
        $title, $description, $url, $date = '', $author = '', $comments = ''
    ) {
        parent::__construct( $title, $description, $url, $date, $author, $comments );
        $this->templateParser = new TemplateParser();
    }

    /**
     * Generate Header of the feed
     * @par Example:
     * @code
     * print "<feed>";
     * @endcode
     */
    abstract public function outHeader();

    /**
     * Generate an item
     * @par Example:
     * @code
     * print "<item>...</item>";
     * @endcode
     * @param FeedItem $item
     */
    abstract public function outItem( $item );

    /**
     * Generate Footer of the feed
     * @par Example:
     * @code
     * print "</feed>";
     * @endcode
     */
    abstract public function outFooter();

    /**
     * Setup and send HTTP headers. Don't send any content;
     * content might end up being cached and re-sent with
     * these same headers later.
     *
     * This should be called from the outHeader() method,
     * but can also be called separately.
     */
    public function httpHeaders() {
        global $wgOut;
        $varyOnXFP = MediaWikiServices::getInstance()->getMainConfig()
            ->get( MainConfigNames::VaryOnXFP );
        # We take over from $wgOut, excepting its cache header info
        $wgOut->disable();
        $mimetype = $this->contentType();
        header( "Content-type: $mimetype; charset=UTF-8" );

        // Set a sensible filename
        $mimeAnalyzer = MediaWikiServices::getInstance()->getMimeAnalyzer();
        $ext = $mimeAnalyzer->getExtensionFromMimeTypeOrNull( $mimetype ) ?? 'xml';
        header( "Content-Disposition: inline; filename=\"feed.{$ext}\"" );

        if ( $varyOnXFP ) {
            $wgOut->addVaryHeader( 'X-Forwarded-Proto' );
        }
        $wgOut->sendCacheControl();
    }

    /**
     * Return an internet media type to be sent in the headers.
     *
     * @stable to override
     *
     * @return string
     */
    private function contentType() {
        global $wgRequest;

        $ctype = $wgRequest->getVal( 'ctype', 'application/xml' );
        $allowedctypes = [
            'application/xml',
            'text/xml',
            'application/rss+xml',
            'application/atom+xml'
        ];

        return ( in_array( $ctype, $allowedctypes ) ? $ctype : 'application/xml' );
    }

    /**
     * Output the initial XML headers.
     */
    protected function outXmlHeader() {
        $this->httpHeaders();
        echo '<?xml version="1.0"?>' . "\n";
    }
}

/** @deprecated class alias since 1.40 */
class_alias( ChannelFeed::class, 'ChannelFeed' );