ActionEntryPoint.php

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<?php
 
namespace MediaWiki\Actions;
 
use MediaWiki\Cache\HTMLFileCache;
use MediaWiki\Context\RequestContext;
use MediaWiki\Exception\BadTitleError;
use MediaWiki\Exception\ErrorPageError;
use MediaWiki\Exception\HttpError;
use MediaWiki\Exception\MWExceptionRenderer;
use MediaWiki\Exception\PermissionsError;
use MediaWiki\HookContainer\HookRunner;
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiEntryPoint;
use MediaWiki\Output\OutputPage;
use MediaWiki\Page\Article;
use MediaWiki\Page\WikiFilePage;
use MediaWiki\Permissions\PermissionStatus;
use MediaWiki\Profiler\Profiler;
use MediaWiki\Profiler\ProfilingContext;
use MediaWiki\Request\DerivativeRequest;
use MediaWiki\Request\FauxRequest;
use MediaWiki\Request\WebRequest;
use MediaWiki\SpecialPage\RedirectSpecialPage;
use MediaWiki\SpecialPage\SpecialPage;
use MediaWiki\Title\MalformedTitleException;
use MediaWiki\Title\Title;
use MediaWiki\User\User;
use Throwable;
use UnexpectedValueException;
use Wikimedia\Rdbms\DBConnectionError;
 
class ActionEntryPoint extends MediaWikiEntryPoint {
 
    protected function getContext(): RequestContext {
        $context = parent::getContext();
 
        // @phan-suppress-next-line PhanTypeMismatchReturnSuperType see $context in the constructor
        return $context;
    }
 
    protected function getOutput(): OutputPage {
        return $this->getContext()->getOutput();
    }
 
    protected function getUser(): User {
        return $this->getContext()->getUser();
    }
 
    protected function handleTopLevelError( Throwable $e ) {
        $context = $this->getContext();
        $action = $context->getRequest()->getRawVal( 'action' ) ?? 'view';
        if (
            $e instanceof DBConnectionError &&
            $context->hasTitle() &&
            $context->getTitle()->canExist() &&
            in_array( $action, [ 'view', 'history' ], true ) &&
            HTMLFileCache::useFileCache( $context, HTMLFileCache::MODE_OUTAGE )
        ) {
            // Try to use any (even stale) file during outages...
            $cache = new HTMLFileCache( $context->getTitle(), $action );
            if ( $cache->isCached() ) {
                $cache->loadFromFileCache( $context, HTMLFileCache::MODE_OUTAGE );
                $this->print( MWExceptionRenderer::getHTML( $e ) );
                $this->exit();
            }
        }
 
        parent::handleTopLevelError( $e );
    }
 
    protected function execute() {
        // phpcs:ignore MediaWiki.Usage.DeprecatedGlobalVariables.Deprecated$wgTitle
        global $wgTitle;
 
        // Get title from request parameters,
        // is set on the fly by parseTitle the first time.
        $title = $this->getTitle();
        $wgTitle = $title;
 
        $request = $this->getContext()->getRequest();
        // Set DB query expectations for this HTTP request
        $trxLimits = $this->getConfig( MainConfigNames::TrxProfilerLimits );
        $trxProfiler = Profiler::instance()->getTransactionProfiler();
        $trxProfiler->setLogger( LoggerFactory::getInstance( 'rdbms' ) );
        $trxProfiler->setStatsFactory( $this->getStatsFactory() );
        $trxProfiler->setRequestMethod( $request->getMethod() );
        if ( $request->hasSafeMethod() ) {
            $trxProfiler->setExpectations( $trxLimits['GET'], __METHOD__ );
        } else {
            $trxProfiler->setExpectations( $trxLimits['POST'], __METHOD__ );
        }
 
        if ( $this->maybeDoHttpsRedirect() ) {
            return;
        }
 
        $context = $this->getContext();
        $output = $context->getOutput();
 
        // NOTE: HTMLFileCache::useFileCache() is not used in WMF production but is
        //       here to provide third-party wikis with a way to enable caching for
        //       "view" and "history" actions. It's triggered by the use of $wgUseFileCache
        //       when set to true in LocalSettings.php.
        if ( $title->canExist() && HTMLFileCache::useFileCache( $context ) ) {
            // getAction() may trigger DB queries, so avoid eagerly initializing it if possible.
            // This reduces the cost of requests that exit early due to tryNormaliseRedirect()
            // or a MediaWikiPerformAction / BeforeInitialize hook handler.
            $action = $this->getAction();
            // Try low-level file cache hit
            $cache = new HTMLFileCache( $title, $action );
            if ( $cache->isCacheGood( /* Assume up to date */ ) ) {
                // Check incoming headers to see if client has this cached
                $timestamp = $cache->cacheTimestamp();
                if ( !$output->checkLastModified( $timestamp ) ) {
                    $cache->loadFromFileCache( $context );
                }
                // Do any stats increment/watchlist stuff, assuming user is viewing the
                // latest revision (which should always be the case for file cache)
                $context->getWikiPage()->doViewUpdates( $context->getAuthority() );
                // Tell OutputPage that output is taken care of
                $output->disable();
 
                return;
            }
        }
 
        try {
            // Actually do the work of the request and build up any output
            $this->performRequest();
        } catch ( ErrorPageError $e ) {
            // TODO: Should ErrorPageError::report accept a OutputPage parameter?
            $e->report( ErrorPageError::STAGE_OUTPUT );
            $output->considerCacheSettingsFinal();
            // T64091: while exceptions are convenient to bubble up GUI errors,
            // they are not internal application faults. As with normal requests, this
            // should commit, print the output, do deferred updates, jobs, and profiling.
        }
 
        $this->prepareForOutput();
 
        // Ask OutputPage/Skin to stage the output (HTTP response body and headers).
        // Flush the output to the client unless an exception occurred.
        // Note that the OutputPage object in $context may have been replaced,
        // so better fetch it again here.
        $output = $context->getOutput();
        $this->outputResponsePayload( $output->output( true ) );
    }
 
    protected function maybeDoHttpsRedirect() {
        if ( !$this->shouldDoHttpRedirect() ) {
            return false;
        }
 
        $context = $this->getContext();
        $request = $context->getRequest();
        $oldUrl = $request->getFullRequestURL();
        $redirUrl = preg_replace( '#^http://#', 'https://', $oldUrl );
 
        if ( $request->wasPosted() ) {
            // This is weird and we'd hope it almost never happens. This
            // means that a POST came in via HTTP and policy requires us
            // redirecting to HTTPS. It's likely such a request is going
            // to fail due to post data being lost, but let's try anyway
            // and just log the instance.
 
            // @todo FIXME: See if we could issue a 307 or 308 here, need
            // to see how clients (automated & browser) behave when we do
            wfDebugLog( 'RedirectedPosts', "Redirected from HTTP to HTTPS: $oldUrl" );
        }
        // Setup dummy Title, otherwise OutputPage::redirect will fail
        $title = Title::newFromText( 'REDIR', NS_MAIN );
        $context->setTitle( $title );
        // Since we only do this redir to change proto, always send a vary header
        $output = $context->getOutput();
        $output->addVaryHeader( 'X-Forwarded-Proto' );
        $output->redirect( $redirUrl );
        $output->output();
 
        return true;
    }
 
    protected function doPrepareForOutput() {
        parent::doPrepareForOutput();
 
        // If needed, push a deferred update to run jobs after the output is sent
        $this->schedulePostSendJobs();
    }
 
    protected function schedulePostSendJobs() {
        // Recursion guard for $wgRunJobsAsync
        if ( $this->getTitle()->isSpecial( 'RunJobs' ) ) {
            return;
        }
 
        parent::schedulePostSendJobs();
    }
 
    protected function parseTitle( $request ) {
        $curid = $request->getInt( 'curid' );
        $title = $request->getText( 'title' );
 
        $ret = null;
        if ( $curid ) {
            // URLs like this are generated by RC, because rc_title isn't always accurate
            $ret = Title::newFromID( $curid );
        }
        if ( $ret === null ) {
            $ret = Title::newFromURL( $title );
            if ( $ret !== null ) {
                // Alias NS_MEDIA page URLs to NS_FILE...we only use NS_MEDIA
                // in wikitext links to tell Parser to make a direct file link
                if ( $ret->getNamespace() === NS_MEDIA ) {
                    $ret = Title::makeTitle( NS_FILE, $ret->getDBkey() );
                }
                // Check variant links so that interwiki links don't have to worry
                // about the possible different language variants
                $services = $this->getServiceContainer();
                $languageConverter = $services
                    ->getLanguageConverterFactory()
                    ->getLanguageConverter( $services->getContentLanguage() );
                if ( $languageConverter->hasVariants() && !$ret->exists() ) {
                    $languageConverter->findVariantLink( $title, $ret );
                }
            }
        }
 
        // If title is not provided, always allow oldid and diff to set the title.
        // If title is provided, allow oldid and diff to override the title, unless
        // we are talking about a special page which might use these parameters for
        // other purposes.
        if ( $ret === null || !$ret->isSpecialPage() ) {
            // We can have urls with just ?diff=,?oldid= or even just ?diff=
            $oldid = $request->getInt( 'oldid' );
            $oldid = $oldid ?: $request->getInt( 'diff' );
            // Allow oldid to override a changed or missing title
            if ( $oldid ) {
                $revRecord = $this->getServiceContainer()
                    ->getRevisionLookup()
                    ->getRevisionById( $oldid );
                if ( $revRecord ) {
                    $ret = Title::newFromPageIdentity( $revRecord->getPage() );
                }
            }
        }
 
        if ( $ret === null && $request->getCheck( 'search' ) ) {
            // Compatibility with old search URLs which didn't use Special:Search
            // Just check for presence here, so blank requests still
            // show the search page when using ugly URLs (T10054).
            $ret = SpecialPage::getTitleFor( 'Search' );
        }
 
        if ( $ret === null || !$ret->isSpecialPage() ) {
            // Compatibility with old URLs for Special:RevisionDelete/Special:EditTags (T323338)
            $actionName = $request->getRawVal( 'action' );
            if (
                $actionName === 'revisiondelete' ||
                ( $actionName === 'historysubmit' && $request->getBool( 'revisiondelete' ) )
            ) {
                $ret = SpecialPage::getTitleFor( 'Revisiondelete' );
            } elseif (
                $actionName === 'editchangetags' ||
                ( $actionName === 'historysubmit' && $request->getBool( 'editchangetags' ) )
            ) {
                $ret = SpecialPage::getTitleFor( 'EditTags' );
            }
        }
 
        // Use the main page as default title if nothing else has been provided
        if ( $ret === null
            && strval( $title ) === ''
            && !$request->getCheck( 'curid' )
            && $request->getRawVal( 'action' ) !== 'delete'
        ) {
            $ret = Title::newMainPage();
        }
 
        if ( $ret === null || ( $ret->getDBkey() == '' && !$ret->isExternal() ) ) {
            // If we get here, we definitely don't have a valid title; throw an exception.
            // Try to get detailed invalid title exception first, fall back to MalformedTitleException.
            Title::newFromTextThrow( $title );
            throw new MalformedTitleException( 'badtitletext', $title );
        }
 
        return $ret;
    }
 
    public function getTitle() {
        $context = $this->getContext();
 
        if ( !$context->hasTitle() ) {
            try {
                $context->setTitle( $this->parseTitle( $context->getRequest() ) );
            } catch ( MalformedTitleException ) {
                $context->setTitle( SpecialPage::getTitleFor( 'Badtitle' ) );
            }
        }
        return $context->getTitle();
    }
 
    public function getAction(): string {
        return $this->getContext()->getActionName();
    }
 
    private function getHookRunner(): HookRunner {
        return new HookRunner( $this->mediaWikiServices->getHookContainer() );
    }
 
    protected function performRequest() {
        // phpcs:ignore MediaWiki.Usage.DeprecatedGlobalVariables.Deprecated$wgTitle
        global $wgTitle;
 
        $context = $this->getContext();
 
        $request = $context->getRequest();
        $output = $context->getOutput();
 
        if ( $request->getRawVal( 'printable' ) === 'yes' ) {
            $output->setPrintable();
        }
 
        $user = $context->getUser();
        $title = $context->getTitle();
        $requestTitle = $title;
 
        $userOptionsLookup = $this->getServiceContainer()->getUserOptionsLookup();
        if ( $userOptionsLookup->getBoolOption( $user, 'forcesafemode' ) ) {
            $request->setVal( 'safemode', '1' );
        }
 
        $this->getHookRunner()->onBeforeInitialize( $title, null, $output, $user, $request, $this );
 
        // Invalid titles. T23776: The interwikis must redirect even if the page name is empty.
        if ( $title === null || ( $title->getDBkey() == '' && !$title->isExternal() )
            || $title->isSpecial( 'Badtitle' )
        ) {
            $context->setTitle( SpecialPage::getTitleFor( 'Badtitle' ) );
            try {
                $this->parseTitle( $request );
            } catch ( MalformedTitleException $ex ) {
                throw new BadTitleError( $ex );
            }
            throw new BadTitleError();
        }
 
        // Check user's permissions to read this page.
        // We have to check here to catch special pages etc.
        // We will check again in Article::view().
        $permissionStatus = PermissionStatus::newEmpty();
        if ( !$context->getAuthority()->authorizeRead( 'read', $title, $permissionStatus ) ) {
            // T34276: allowing the skin to generate output with $wgTitle or
            // $context->title set to the input title would allow anonymous users to
            // determine whether a page exists, potentially leaking private data. In fact, the
            // curid and oldid request  parameters would allow page titles to be enumerated even
            // when they are not guessable. So we reset the title to Special:Badtitle before the
            // permissions error is displayed.
 
            // The skin mostly uses $context->getTitle() these days, but some extensions
            // still use $wgTitle.
            $badTitle = SpecialPage::getTitleFor( 'Badtitle' );
            $context->setTitle( $badTitle );
            $wgTitle = $badTitle;
 
            throw new PermissionsError( 'read', $permissionStatus );
        }
 
        // Interwiki redirects
        if ( $title->isExternal() ) {
            $rdfrom = $request->getVal( 'rdfrom' );
            if ( $rdfrom ) {
                $url = $title->getFullURLForRedirect( [ 'rdfrom' => $rdfrom ] );
            } else {
                $query = $request->getQueryValues();
                unset( $query['title'] );
                $url = $title->getFullURLForRedirect( $query );
            }
            // Check for a redirect loop
            if ( $url !== $request->getFullRequestURL() ) {
                // 301 so google et al report the target as the actual url.
                $output->redirect( $url, 301 );
            } else {
                $context->setTitle( SpecialPage::getTitleFor( 'Badtitle' ) );
                try {
                    $this->parseTitle( $request );
                } catch ( MalformedTitleException $ex ) {
                    throw new BadTitleError( $ex );
                }
                throw new BadTitleError();
            }
            // Handle any other redirects.
            // Redirect loops, titleless URL, $wgUsePathInfo URLs, and URLs with a variant
        } elseif ( !$this->tryNormaliseRedirect( $title ) ) {
            // Prevent information leak via Special:MyPage et al (T109724)
            $spFactory = $this->getServiceContainer()->getSpecialPageFactory();
            if ( $title->isSpecialPage() ) {
                $specialPage = $spFactory->getPage( $title->getDBkey() );
                if ( $specialPage instanceof RedirectSpecialPage ) {
                    $specialPage->setContext( $context );
                    if ( $this->getConfig( MainConfigNames::HideIdentifiableRedirects )
                        && $specialPage->personallyIdentifiableTarget()
                    ) {
                        [ , $subpage ] = $spFactory->resolveAlias( $title->getDBkey() );
                        $target = $specialPage->getRedirect( $subpage );
                        // Target can also be true. We let that case fall through to normal processing.
                        if ( $target instanceof Title ) {
                            if ( $target->isExternal() ) {
                                // Handle interwiki redirects
                                $target = SpecialPage::getTitleFor(
                                    'GoToInterwiki',
                                    'force/' . $target->getPrefixedDBkey()
                                );
                            }
 
                            $query = $specialPage->getRedirectQuery( $subpage ) ?: [];
                            $derivateRequest = new DerivativeRequest( $request, $query );
                            $derivateRequest->setRequestURL( $request->getRequestURL() );
                            $context->setRequest( $derivateRequest );
                            // Do not varnish cache these. May vary even for anons
                            $output->lowerCdnMaxage( 0 );
                            // NOTE: This also clears any action cache.
                            // Action should not have been computed yet, but if it was,
                            // we reset it because special pages only support "view".
                            $context->setTitle( $target );
                            $wgTitle = $target;
                            $title = $target;
                            $output->addJsConfigVars( [
                                'wgInternalRedirectTargetUrl' => $target->getLinkURL( $query ),
                            ] );
                            $output->addModules( 'mediawiki.action.view.redirect' );
 
                            // If the title is invalid, redirect but show the correct bad title error - T297407
                            if ( !$target->isValid() ) {
                                try {
                                    $this->getServiceContainer()->getTitleParser()
                                        ->parseTitle( $target->getPrefixedText() );
                                } catch ( MalformedTitleException $ex ) {
                                    throw new BadTitleError( $ex );
                                }
                                throw new BadTitleError();
                            }
                        }
                    }
                }
            }
 
            // Special pages ($title may have changed since if statement above)
            if ( $title->isSpecialPage() ) {
                // Actions that need to be made when we have a special pages
                $spFactory->executePath( $title, $context );
            } else {
                // ...otherwise treat it as an article view. The article
                // may still be a wikipage redirect to another article or URL.
                $article = $this->initializeArticle();
                if ( is_object( $article ) ) {
                    $this->performAction( $article, $requestTitle );
                } elseif ( is_string( $article ) ) {
                    $output->redirect( $article );
                } else {
                    throw new UnexpectedValueException( "Shouldn't happen: MediaWiki::initializeArticle()"
                        . " returned neither an object nor a URL" );
                }
            }
 
            $contextRequest = $context->getRequest();
            if ( $contextRequest instanceof FauxRequest ) {
                $fauxResponse = $contextRequest->response();
                if ( $fauxResponse->getStatusCode() ) {
                    $request->response()->statusHeader( $fauxResponse->getStatusCode() );
                }
 
                foreach ( $fauxResponse->getHeaders() as $key => $value ) {
                    $request->response()->header( "$key: $value" );
                }
            }
 
            $output->considerCacheSettingsFinal();
        }
    }
 
    protected function tryNormaliseRedirect( Title $title ): bool {
        $request = $this->getRequest();
        $output = $this->getOutput();
 
        if ( ( $request->getRawVal( 'action' ) ?? 'view' ) !== 'view'
            || $request->wasPosted()
            || ( $request->getCheck( 'title' )
                && $title->getPrefixedDBkey() == $request->getText( 'title' ) )
            || count( $request->getValueNames( [ 'action', 'title' ] ) )
            || !$this->getHookRunner()->onTestCanonicalRedirect( $request, $title, $output )
        ) {
            return false;
        }
 
        if ( $this->getConfig( MainConfigNames::MainPageIsDomainRoot ) && $request->getRequestURL() === '/' ) {
            return false;
        }
 
        $services = $this->getServiceContainer();
 
        if ( $title->isSpecialPage() ) {
            [ $name, $subpage ] = $services->getSpecialPageFactory()
                ->resolveAlias( $title->getDBkey() );
 
            if ( $name ) {
                $title = SpecialPage::getTitleFor( $name, $subpage );
            }
        }
        // Redirect to canonical url, make it a 301 to allow caching
        $targetUrl = (string)$services->getUrlUtils()->expand( $title->getFullURL(), PROTO_CURRENT );
        if ( $targetUrl == $request->getFullRequestURL() ) {
            $message = "Redirect loop detected!\n\n" .
                "This means the wiki got confused about what page was " .
                "requested; this sometimes happens when moving a wiki " .
                "to a new server or changing the server configuration.\n\n";
 
            if ( $this->getConfig( MainConfigNames::UsePathInfo ) ) {
                $message .= "The wiki is trying to interpret the page " .
                    "title from the URL path portion (PATH_INFO), which " .
                    "sometimes fails depending on the web server. Try " .
                    "setting \"\$wgUsePathInfo = false;\" in your " .
                    "LocalSettings.php, or check that \$wgArticlePath " .
                    "is correct.";
            } else {
                $message .= "Your web server was detected as possibly not " .
                    "supporting URL path components (PATH_INFO) correctly; " .
                    "check your LocalSettings.php for a customized " .
                    "\$wgArticlePath setting and/or toggle \$wgUsePathInfo " .
                    "to true.";
            }
            throw new HttpError( 500, $message );
        }
        $output->setCdnMaxage( 1200 );
        $output->redirect( $targetUrl, '301' );
        return true;
    }
 
    protected function initializeArticle() {
        $context = $this->getContext();
 
        $title = $context->getTitle();
        $services = $this->getServiceContainer();
        if ( $context->canUseWikiPage() ) {
            // Optimization: Reuse the WikiPage instance from context, to avoid
            // repeat fetching or computation of data already loaded.
            $page = $context->getWikiPage();
        } else {
            // This case should not happen, but just in case.
            // @TODO: remove this or use an exception
            $page = $services->getWikiPageFactory()->newFromTitle( $title );
            $context->setWikiPage( $page );
            wfWarn( "RequestContext::canUseWikiPage() returned false" );
        }
 
        // Make GUI wrapper for the WikiPage
        $article = Article::newFromWikiPage( $page, $context );
 
        // Skip some unnecessary code if the content model doesn't support redirects
        // Use the page content model rather than invoking Title::getContentModel()
        // to avoid querying page data twice (T206498)
        if ( !$page->getContentHandler()->supportsRedirects() ) {
            return $article;
        }
 
        $request = $context->getRequest();
 
        // Namespace might change when using redirects
        // Check for redirects ...
        $action = $request->getRawVal( 'action' ) ?? 'view';
        $file = ( $page instanceof WikiFilePage ) ? $page->getFile() : null;
        if ( ( $action == 'view' || $action == 'render' ) // ... for actions that show content
            && !$request->getCheck( 'oldid' ) // ... and are not old revisions
            && !$request->getCheck( 'diff' ) // ... and not when showing diff
            && $request->getRawVal( 'redirect' ) !== 'no' // ... unless explicitly told not to
            // ... and the article is not a non-redirect image page with associated file
            && !( is_object( $file ) && $file->exists() && !$file->getRedirected() )
        ) {
            // Give extensions a change to ignore/handle redirects as needed
            $ignoreRedirect = $target = false;
 
            $this->getHookRunner()->onInitializeArticleMaybeRedirect( $title, $request,
                // @phan-suppress-next-line PhanTypeMismatchArgument Type mismatch on pass-by-ref args
                $ignoreRedirect, $target, $article );
            $page = $article->getPage(); // reflect any hook changes
 
            // Follow redirects only for... redirects.
            // If $target is set, then a hook wanted to redirect.
            if ( !$ignoreRedirect && ( $target || $page->isRedirect() ) ) {
                // Is the target already set by an extension?
                $target = $target ?: $page->followRedirect();
                if ( is_string( $target ) && !$this->getConfig( MainConfigNames::DisableHardRedirects ) ) {
                    // we'll need to redirect
                    return $target;
                }
                if ( is_object( $target ) ) {
                    // Rewrite environment to redirected article
                    $rpage = $services->getWikiPageFactory()->newFromTitle( $target );
                    $rpage->loadPageData();
                    if ( $target->isKnown() || ( is_object( $file ) && !$file->isLocal() ) ) {
                        $rarticle = Article::newFromWikiPage( $rpage, $context );
                        $rarticle->setRedirectedFrom( $title );
 
                        $article = $rarticle;
                        // NOTE: This also clears any action cache
                        $context->setTitle( $target );
                        $context->setWikiPage( $article->getPage() );
                    }
                }
            }
        }
 
        return $article;
    }
 
    protected function performAction( Article $article, Title $requestTitle ) {
        $request = $this->getRequest();
        $output = $this->getOutput();
        $title = $this->getTitle();
        $user = $this->getUser();
 
        if ( !$this->getHookRunner()->onMediaWikiPerformAction(
            $output, $article, $title, $user, $request, $this )
        ) {
            return;
        }
 
        $actionName = $this->getAction();
        $services = $this->getServiceContainer();
        // To avoid garbage in the data we do not submit this timer when:
        // * nosuchaction: The action is not defined in the code, e.g. action=blabla.
        // * PermissionsError: The action handler Action::show is not even called,
        //   and these fast errors should not influence the latency graph.
        $timer = $services->getStatsFactory()->getTiming( 'action_executeTiming_seconds' )
            ->setLabel( 'action', strtr( $actionName, '.', '_' ) )
            ->start();
 
        $action = $services->getActionFactory()->getAction( $actionName, $article, $this->getContext() );
        if ( $action instanceof Action ) {
            // Check read permissions
            if ( $action->needsReadRights() && !$user->isAllowed( 'read' ) ) {
                throw new PermissionsError( 'read' );
            }
 
            ProfilingContext::singleton()->init( MW_ENTRY_POINT, $actionName );
 
            // Narrow DB query expectations for this HTTP request
            if ( $request->wasPosted() && !$action->doesWrites() ) {
                $trxProfiler = Profiler::instance()->getTransactionProfiler();
                $trxLimits = $this->getConfig( MainConfigNames::TrxProfilerLimits );
                $trxProfiler->setExpectations( $trxLimits['POST-nonwrite'], __METHOD__ );
            }
 
            // Let CDN cache things if we can purge them.
            // Also unconditionally cache page views.
            if ( $this->getConfig( MainConfigNames::UseCdn ) ) {
                $htmlCacheUpdater = $services->getHTMLCacheUpdater();
                if ( $request->matchURLForCDN( $htmlCacheUpdater->getUrls( $requestTitle ) ) ) {
                    $output->setCdnMaxage( $this->getConfig( MainConfigNames::CdnMaxAge ) );
                } elseif ( $action instanceof ViewAction ) {
                    $output->setCdnMaxage( 3600 );
                }
            }
 
            $action->show();
 
            $timer->stop();
 
            return;
        }
 
        // If we've not found out which action it is by now, it's unknown
        $output->setStatusCode( 404 );
        $output->showErrorPage( 'nosuchaction', 'nosuchactiontext' );
    }
}