includes/Rest/Handler/Helper/PageContentHelper.php
<?php
namespace MediaWiki\Rest\Handler\Helper;
use MediaWiki\ChangeTags\ChangeTagsStore;
use MediaWiki\Config\ServiceOptions;
use MediaWiki\Content\TextContent;
use MediaWiki\Content\WikitextContent;
use MediaWiki\MainConfigNames;
use MediaWiki\Message\Message;
use MediaWiki\Page\ExistingPageRecord;
use MediaWiki\Page\PageIdentity;
use MediaWiki\Page\PageLookup;
use MediaWiki\Permissions\Authority;
use MediaWiki\Rest\Handler;
use MediaWiki\Rest\LocalizedHttpException;
use MediaWiki\Rest\ResponseInterface;
use MediaWiki\Revision\MutableRevisionRecord;
use MediaWiki\Revision\RevisionAccessException;
use MediaWiki\Revision\RevisionLookup;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Revision\SlotRecord;
use MediaWiki\Revision\SuppressedDataException;
use MediaWiki\Title\Title;
use MediaWiki\Title\TitleFactory;
use MediaWiki\Title\TitleFormatter;
use Wikimedia\Message\MessageValue;
use Wikimedia\ParamValidator\ParamValidator;
use Wikimedia\Rdbms\IConnectionProvider;
/**
* @internal for use by core REST infrastructure
*/
class PageContentHelper {
/**
* The maximum cache duration for page content.
*
* If this is set to a value higher than about 60 seconds, active purging
* will have to be employed to make sure clients do not receive overly stale
* content. This is especially important to avoid distributing vandalized
* content for too long.
*
* Active purging can be enabled by adding the relevant URLs to
* HTMLCacheUpdater. See T365630 for more discussion.
*/
private const MAX_AGE_200 = 5;
/**
* @internal
*/
public const CONSTRUCTOR_OPTIONS = [
MainConfigNames::RightsUrl,
MainConfigNames::RightsText,
];
protected ServiceOptions $options;
protected RevisionLookup $revisionLookup;
protected TitleFormatter $titleFormatter;
protected PageLookup $pageLookup;
private TitleFactory $titleFactory;
private IConnectionProvider $connectionProvider;
private ChangeTagsStore $changeTagStore;
/** @var Authority|null */
protected $authority = null;
/** @var string[] */
protected $parameters = null;
/** @var RevisionRecord|false|null */
protected $targetRevision = false;
/** @var ExistingPageRecord|false|null */
protected $pageRecord = false;
/** @var PageIdentity|false|null */
private $pageIdentity = false;
public function __construct(
ServiceOptions $options,
RevisionLookup $revisionLookup,
TitleFormatter $titleFormatter,
PageLookup $pageLookup,
TitleFactory $titleFactory,
IConnectionProvider $connectionProvider,
ChangeTagsStore $changeTagStore
) {
$this->options = $options;
$this->revisionLookup = $revisionLookup;
$this->titleFormatter = $titleFormatter;
$this->pageLookup = $pageLookup;
$this->titleFactory = $titleFactory;
$this->connectionProvider = $connectionProvider;
$this->changeTagStore = $changeTagStore;
}
/**
* @param Authority $authority
* @param string[] $parameters validated parameters
*/
public function init( Authority $authority, array $parameters ) {
$this->authority = $authority;
$this->parameters = $parameters;
}
/**
* @return string|null title text or null if unable to retrieve title
*/
public function getTitleText(): ?string {
return $this->parameters['title'] ?? null;
}
/**
* @return ExistingPageRecord|null
*/
public function getPage(): ?ExistingPageRecord {
if ( $this->pageRecord === false ) {
$titleText = $this->getTitleText();
if ( $titleText === null ) {
return null;
}
$this->pageRecord = $this->pageLookup->getExistingPageByText( $titleText );
}
return $this->pageRecord;
}
public function getPageIdentity(): ?PageIdentity {
if ( $this->pageIdentity === false ) {
$this->pageIdentity = $this->getPage();
}
if ( $this->pageIdentity === null ) {
$titleText = $this->getTitleText();
if ( $titleText === null ) {
return null;
}
$this->pageIdentity = $this->pageLookup->getPageByText( $titleText );
}
return $this->pageIdentity;
}
/**
* Returns the target revision. No permission checks are applied.
*
* @return RevisionRecord|null latest revision or null if unable to retrieve revision
*/
public function getTargetRevision(): ?RevisionRecord {
if ( $this->targetRevision === false ) {
$page = $this->getPage();
if ( $page ) {
$this->targetRevision = $this->revisionLookup->getRevisionByTitle( $page );
} else {
$this->targetRevision = null;
}
}
return $this->targetRevision;
}
// Default to main slot
public function getRole(): string {
return SlotRecord::MAIN;
}
/**
* @return TextContent
* @throws LocalizedHttpException slot content is not TextContent or RevisionRecord/Slot is inaccessible
*/
public function getContent(): TextContent {
$revision = $this->getTargetRevision();
if ( !$revision ) {
$titleText = $this->getTitleText() ?? '';
throw new LocalizedHttpException(
MessageValue::new( 'rest-no-revision' )->plaintextParams( $titleText ),
404
);
}
$slotRole = $this->getRole();
try {
$content = $revision
->getSlot( $slotRole, RevisionRecord::FOR_THIS_USER, $this->authority )
->getContent()
->convert( CONTENT_MODEL_TEXT );
if ( !( $content instanceof TextContent ) ) {
throw new LocalizedHttpException( MessageValue::new( 'rest-page-source-type-error' ), 400 );
}
} catch ( SuppressedDataException $e ) {
throw new LocalizedHttpException(
MessageValue::new( 'rest-permission-denied-revision' )->numParams( $revision->getId() ),
403
);
} catch ( RevisionAccessException $e ) {
throw new LocalizedHttpException(
MessageValue::new( 'rest-nonexistent-revision' )->numParams( $revision->getId() ),
404
);
}
return $content;
}
/**
* @return bool
*/
public function isAccessible(): bool {
$page = $this->getPageIdentity();
return $page && $this->authority->probablyCan( 'read', $page );
}
/**
* Returns an ETag representing a page's source. The ETag assumes a page's source has changed
* if the latest revision of a page has been made private, un-readable for another reason,
* or a newer revision exists.
* @return string|null
*/
public function getETag(): ?string {
$revision = $this->getTargetRevision();
$revId = $revision ? $revision->getId() : 'e0';
$isAccessible = $this->isAccessible();
$accessibleTag = $isAccessible ? 'a1' : 'a0';
$revisionTag = $revId . $accessibleTag;
return '"' . sha1( $revisionTag ) . '"';
}
/**
* @return string|null
*/
public function getLastModified(): ?string {
if ( !$this->isAccessible() ) {
return null;
}
$revision = $this->getTargetRevision();
if ( $revision ) {
return $revision->getTimestamp();
}
return null;
}
/**
* Checks whether content exists. Permission checks are not considered.
*
* @return bool
*/
public function hasContent(): bool {
return $this->useDefaultSystemMessage() || (bool)$this->getPage();
}
/**
* @return array
*/
public function constructMetadata(): array {
$revision = $this->getRevisionRecordForMetadata();
$page = $revision->getPage();
return [
'id' => $page->getId(),
'key' => $this->titleFormatter->getPrefixedDBkey( $page ),
'title' => $this->titleFormatter->getPrefixedText( $page ),
'latest' => [
'id' => $revision->getId(),
'timestamp' => wfTimestampOrNull( TS_ISO_8601, $revision->getTimestamp() )
],
'content_model' => $revision->getSlot( SlotRecord::MAIN, RevisionRecord::RAW )
->getModel(),
'license' => [
'url' => $this->options->get( MainConfigNames::RightsUrl ),
'title' => $this->options->get( MainConfigNames::RightsText )
],
];
}
/**
* @return array
*/
public function constructRestbaseCompatibleMetadata(): array {
$revision = $this->getRevisionRecordForMetadata();
$page = $revision->getPage();
$title = $this->titleFactory->newFromPageIdentity( $page );
$tags = $this->changeTagStore->getTags(
$this->connectionProvider->getReplicaDatabase(),
null, $revision->getId(), null
);
$restrictions = [];
if ( $revision->isDeleted( RevisionRecord::DELETED_COMMENT ) ) {
$restrictions[] = 'commenthidden';
}
if ( $revision->isDeleted( RevisionRecord::DELETED_USER ) ) {
$restrictions[] = 'userhidden';
}
return [
'title' => $title->getPrefixedDBkey(),
'page_id' => $page->getId(),
'rev' => $revision->getId(),
// We could look up the tid from a ParserOutput, but it's expensive,
// and the tid can't be used for anything anymore anyway.
// Don't use an empty string though, that may break routing when the
// value is used as a path parameter.
'tid' => 'DUMMY',
'namespace' => $page->getNamespace(),
'user_id' => $revision->getUser( RevisionRecord::RAW )->getId(),
'user_text' => $revision->getUser( RevisionRecord::FOR_PUBLIC )->getName(),
'timestamp' => wfTimestampOrNull( TS_ISO_8601, $revision->getTimestamp() ),
'comment' => $revision->getComment()->text,
'tags' => $tags,
'restrictions' => $restrictions,
'page_language' => $title->getPageLanguage()->getCode(),
'redirect' => $title->isRedirect()
];
}
/**
* @return array[]
*/
public function getParamSettings(): array {
return [
'title' => [
Handler::PARAM_SOURCE => 'path',
ParamValidator::PARAM_TYPE => 'string',
ParamValidator::PARAM_REQUIRED => true,
],
'redirect' => [
Handler::PARAM_SOURCE => 'query',
ParamValidator::PARAM_TYPE => [ 'no' ],
ParamValidator::PARAM_REQUIRED => false,
]
];
}
/**
* Sets the 'Cache-Control' header no more then provided $expiry.
* @param ResponseInterface $response
* @param int|null $expiry
*/
public function setCacheControl( ResponseInterface $response, int $expiry = null ) {
if ( $expiry === null ) {
$maxAge = self::MAX_AGE_200;
} else {
$maxAge = min( self::MAX_AGE_200, $expiry );
}
$response->setHeader(
'Cache-Control',
'max-age=' . $maxAge
);
}
/**
* If the page is a system message page. When the content gets
* overridden to create an actual page, this method returns false.
*
* @return bool
*/
public function useDefaultSystemMessage(): bool {
return $this->getDefaultSystemMessage() !== null && $this->getPage() === null;
}
/**
* @return Message|null
*/
public function getDefaultSystemMessage(): ?Message {
$title = Title::newFromText( $this->getTitleText() );
return $title ? $title->getDefaultSystemMessage() : null;
}
/**
* @throws LocalizedHttpException if access is not allowed
*/
public function checkAccessPermission() {
$titleText = $this->getTitleText() ?? '';
// @phan-suppress-next-line PhanTypeMismatchArgumentNullable Validated by hasContent
if ( !$this->isAccessible() || !$this->authority->authorizeRead( 'read', $this->getPageIdentity() ) ) {
throw new LocalizedHttpException(
MessageValue::new( 'rest-permission-denied-title' )->plaintextParams( $titleText ),
403
);
}
}
/**
* @throws LocalizedHttpException if no content is available
*/
public function checkHasContent() {
$titleText = $this->getTitleText() ?? '';
$page = $this->getPageIdentity();
if ( !$page ) {
throw new LocalizedHttpException(
MessageValue::new( 'rest-invalid-title' )->plaintextParams( $titleText ),
404
);
}
if ( !$this->hasContent() ) {
// needs to check if it's possibly a variant title
throw new LocalizedHttpException(
MessageValue::new( 'rest-nonexistent-title' )->plaintextParams( $titleText ),
404
);
}
$revision = $this->getTargetRevision();
if ( !$revision && !$this->useDefaultSystemMessage() ) {
throw new LocalizedHttpException(
MessageValue::new( 'rest-no-revision' )->plaintextParams( $titleText ),
404
);
}
}
/**
* @throws LocalizedHttpException if the content is not accessible
*/
public function checkAccess() {
$this->checkHasContent(); // Status 404: Not Found
$this->checkAccessPermission(); // Status 403: Forbidden
}
/**
* @return MutableRevisionRecord|RevisionRecord|null
*/
private function getRevisionRecordForMetadata() {
if ( $this->useDefaultSystemMessage() ) {
$title = Title::newFromText( $this->getTitleText() );
$content = new WikitextContent( $title->getDefaultMessageText() );
$revision = new MutableRevisionRecord( $title );
$revision->setPageId( 0 );
$revision->setId( 0 );
$revision->setContent(
SlotRecord::MAIN,
$content
);
} else {
$revision = $this->getTargetRevision();
}
return $revision;
}
}