<?php
/**
 * Raw page text accessor
 *
 * Copyright © 2004 Gabriel Wicke <wicke@wikidev.net>
 * http://wikidev.net/
 *
 * Based on HistoryAction and SpecialExport
 *
 * 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
 *
 * @author Gabriel Wicke <wicke@wikidev.net>
 * @file
 */

use MediaWiki\Logger\LoggerFactory;

/**
 * A simple method to retrieve the plain source of an article,
 * using "action=raw" in the GET request string.
 *
 * @ingroup Actions
 */
class RawAction extends FormlessAction {
	public function getName() {
		return 'raw';
	}

	public function requiresWrite() {
		return false;
	}

	public function requiresUnblock() {
		return false;
	}

	function onView() {
		$this->getOutput()->disable();
		$request = $this->getRequest();
		$response = $request->response();
		$config = $this->context->getConfig();

		if ( !$request->checkUrlExtension() ) {
			return;
		}

		if ( $this->getOutput()->checkLastModified( $this->page->getTouched() ) ) {
			return; // Client cache fresh and headers sent, nothing more to do.
		}

		$contentType = $this->getContentType();

		$maxage = $request->getInt( 'maxage', $config->get( 'SquidMaxage' ) );
		$smaxage = $request->getIntOrNull( 'smaxage' );
		if ( $smaxage === null ) {
			if (
				$contentType == 'text/css' ||
				$contentType == 'application/json' ||
				$contentType == 'text/javascript'
			) {
				// CSS/JSON/JS raw content has its own CDN max age configuration.
				// Note: Title::getCdnUrls() includes action=raw for css/json/js
				// pages, so if using the canonical url, this will get HTCP purges.
				$smaxage = intval( $config->get( 'ForcedRawSMaxage' ) );
			} else {
				// No CDN cache for anything else
				$smaxage = 0;
			}
		}

		// Set standard Vary headers so cache varies on cookies and such (T125283)
		$response->header( $this->getOutput()->getVaryHeader() );
		if ( $config->get( 'UseKeyHeader' ) ) {
			$response->header( $this->getOutput()->getKeyHeader() );
		}

		// Output may contain user-specific data;
		// vary generated content for open sessions on private wikis
		$privateCache = !User::isEveryoneAllowed( 'read' ) &&
			( $smaxage == 0 || MediaWiki\Session\SessionManager::getGlobalSession()->isPersistent() );
		// Don't accidentally cache cookies if user is logged in (T55032)
		$privateCache = $privateCache || $this->getUser()->isLoggedIn();
		$mode = $privateCache ? 'private' : 'public';
		$response->header(
			'Cache-Control: ' . $mode . ', s-maxage=' . $smaxage . ', max-age=' . $maxage
		);

		// In the event of user JS, don't allow loading a user JS/CSS/Json
		// subpage that has no registered user associated with, as
		// someone could register the account and take control of the
		// JS/CSS/Json page.
		$title = $this->getTitle();
		if ( $title->isUserConfigPage() && $contentType !== 'text/x-wiki' ) {
			// not using getRootText() as we want this to work
			// even if subpages are disabled.
			$rootPage = strtok( $title->getText(), '/' );
			$userFromTitle = User::newFromName( $rootPage, 'usable' );
			if ( !$userFromTitle || $userFromTitle->getId() === 0 ) {
				$log = LoggerFactory::getInstance( "security" );
				$log->warning(
					"Unsafe JS/CSS/Json load - {user} loaded {title} with {ctype}",
					[
						'user' => $this->getUser()->getName(),
						'title' => $title->getPrefixedDBKey(),
						'ctype' => $contentType,
					]
				);
				$msg = wfMessage( 'unregistered-user-config' );
				throw new HttpError( 403, $msg );
			}
		}

		// Don't allow loading non-protected pages as javascript.
		// In future we may further restrict this to only CONTENT_MODEL_JAVASCRIPT
		// in NS_MEDIAWIKI or NS_USER, as well as including other config types,
		// but for now be more permissive. Allowing protected pages outside of
		// NS_USER and NS_MEDIAWIKI in particular should be considered a temporary
		// allowance.
		if (
			$contentType === 'text/javascript' &&
			!$title->isUserJsConfigPage() &&
			!$title->inNamespace( NS_MEDIAWIKI ) &&
			!in_array( 'sysop', $title->getRestrictions( 'edit' ) ) &&
			!in_array( 'editprotected', $title->getRestrictions( 'edit' ) )
		) {

			$log = LoggerFactory::getInstance( "security" );
			$log->info( "Blocked loading unprotected JS {title} for {user}",
				[
					'user' => $this->getUser()->getName(),
					'title' => $title->getPrefixedDBKey(),
				]
			);
			throw new HttpError( 403, wfMessage( 'unprotected-js' ) );
		}

		$response->header( 'Content-type: ' . $contentType . '; charset=UTF-8' );

		$text = $this->getRawText();

		// Don't return a 404 response for CSS or JavaScript;
		// 404s aren't generally cached and it would create
		// extra hits when user CSS/JS are on and the user doesn't
		// have the pages.
		if ( $text === false && $contentType == 'text/x-wiki' ) {
			$response->statusHeader( 404 );
		}

		// Avoid PHP 7.1 warning of passing $this by reference
		$rawAction = $this;
		if ( !Hooks::run( 'RawPageViewBeforeOutput', [ &$rawAction, &$text ] ) ) {
			wfDebug( __METHOD__ . ": RawPageViewBeforeOutput hook broke raw page output.\n" );
		}

		echo $text;
	}

	/**
	 * Get the text that should be returned, or false if the page or revision
	 * was not found.
	 *
	 * @return string|bool
	 */
	public function getRawText() {
		global $wgParser;

		$text = false;
		$title = $this->getTitle();
		$request = $this->getRequest();

		// If it's a MediaWiki message we can just hit the message cache
		if ( $request->getBool( 'usemsgcache' ) && $title->getNamespace() == NS_MEDIAWIKI ) {
			// The first "true" is to use the database, the second is to use
			// the content langue and the last one is to specify the message
			// key already contains the language in it ("/de", etc.).
			$text = MessageCache::singleton()->get( $title->getDBkey(), true, true, true );
			// If the message doesn't exist, return a blank
			if ( $text === false ) {
				$text = '';
			}
		} else {
			// Get it from the DB
			$rev = Revision::newFromTitle( $title, $this->getOldId() );
			if ( $rev ) {
				$lastmod = wfTimestamp( TS_RFC2822, $rev->getTimestamp() );
				$request->response()->header( "Last-modified: $lastmod" );

				// Public-only due to cache headers
				$content = $rev->getContent();

				if ( $content === null ) {
					// revision not found (or suppressed)
					$text = false;
				} elseif ( !$content instanceof TextContent ) {
					// non-text content
					wfHttpError( 415, "Unsupported Media Type", "The requested page uses the content model `"
						. $content->getModel() . "` which is not supported via this interface." );
					die();
				} else {
					// want a section?
					$section = $request->getIntOrNull( 'section' );
					if ( $section !== null ) {
						$content = $content->getSection( $section );
					}

					if ( $content === null || $content === false ) {
						// section not found (or section not supported, e.g. for JS, JSON, and CSS)
						$text = false;
					} else {
						$text = $content->getNativeData();
					}
				}
			}
		}

		if ( $text !== false && $text !== '' && $request->getRawVal( 'templates' ) === 'expand' ) {
			$text = $wgParser->preprocess(
				$text,
				$title,
				ParserOptions::newFromContext( $this->getContext() )
			);
		}

		return $text;
	}

	/**
	 * Get the ID of the revision that should used to get the text.
	 *
	 * @return int
	 */
	public function getOldId() {
		$oldid = $this->getRequest()->getInt( 'oldid' );
		switch ( $this->getRequest()->getText( 'direction' ) ) {
			case 'next':
				# output next revision, or nothing if there isn't one
				$nextid = 0;
				if ( $oldid ) {
					$nextid = $this->getTitle()->getNextRevisionID( $oldid );
				}
				$oldid = $nextid ?: -1;
				break;
			case 'prev':
				# output previous revision, or nothing if there isn't one
				if ( !$oldid ) {
					# get the current revision so we can get the penultimate one
					$oldid = $this->page->getLatest();
				}
				$previd = $this->getTitle()->getPreviousRevisionID( $oldid );
				$oldid = $previd ?: -1;
				break;
			case 'cur':
				$oldid = 0;
				break;
		}

		return $oldid;
	}

	/**
	 * Get the content type to use for the response
	 *
	 * @return string
	 */
	public function getContentType() {
		// Use getRawVal instead of getVal because we only
		// need to match against known strings, there is no
		// storing of localised content or other user input.
		$ctype = $this->getRequest()->getRawVal( 'ctype' );

		if ( $ctype == '' ) {
			// Legacy compatibilty
			$gen = $this->getRequest()->getRawVal( 'gen' );
			if ( $gen == 'js' ) {
				$ctype = 'text/javascript';
			} elseif ( $gen == 'css' ) {
				$ctype = 'text/css';
			}
		}

		$allowedCTypes = [
			'text/x-wiki',
			'text/javascript',
			'text/css',
			// FIXME: Should we still allow Zope editing? External editing feature was dropped
			'application/x-zope-edit',
			'application/json'
		];
		if ( $ctype == '' || !in_array( $ctype, $allowedCTypes ) ) {
			$ctype = 'text/x-wiki';
		}

		return $ctype;
	}
}
