MediaWikiEntryPoint.php

Go to the documentation of this file.

<?php
namespace MediaWiki;
 
use LogicException;
use MediaWiki\Block\BlockManager;
use MediaWiki\Config\Config;
use MediaWiki\Context\IContextSource;
use MediaWiki\Deferred\DeferredUpdates;
use MediaWiki\Deferred\TransactionRoundDefiningUpdate;
use MediaWiki\Exception\MWExceptionHandler;
use MediaWiki\JobQueue\JobQueueGroup;
use MediaWiki\JobQueue\JobQueueGroupFactory;
use MediaWiki\JobQueue\JobRunner;
use MediaWiki\Language\MessageCache;
use MediaWiki\Logger\LoggerFactory;
use MediaWiki\Profiler\Profiler;
use MediaWiki\Request\WebRequest;
use MediaWiki\Request\WebResponse;
use MediaWiki\SpecialPage\SpecialPageFactory;
use MediaWiki\Specials\SpecialRunJobs;
use MediaWiki\Utils\UrlUtils;
use MediaWiki\WikiMap\WikiMap;
use Psr\Log\LoggerInterface;
use RuntimeException;
use Throwable;
use Wikimedia\Http\HttpStatus;
use Wikimedia\Rdbms\ChronologyProtector;
use Wikimedia\Rdbms\LBFactory;
use Wikimedia\Rdbms\ReadOnlyMode;
use Wikimedia\ScopedCallback;
use Wikimedia\Stats\IBufferingStatsdDataFactory;
use Wikimedia\Stats\StatsFactory;
use Wikimedia\Telemetry\SpanInterface;
use Wikimedia\Telemetry\TracerState;
 
abstract class MediaWikiEntryPoint {
    private IContextSource $context;
    private Config $config;
    private ?int $outputCaptureLevel = null;
 
    private bool $postSendMode = false;
 
    private int $postSendStrategy;
 
    private const DEFER_FASTCGI_FINISH_REQUEST = 1;
 
    private const DEFER_SET_LENGTH_AND_FLUSH = 2;
 
    private const DEFER_CLI_MODE = 3;
 
    private bool $preparedForOutput = false;
 
    protected EntryPointEnvironment $environment;
 
    protected MediaWikiServices $mediaWikiServices;
 
    public function __construct(
        IContextSource $context,
        EntryPointEnvironment $environment,
        MediaWikiServices $mediaWikiServices
    ) {
        $this->context = $context;
        $this->config = $this->context->getConfig();
        $this->environment = $environment;
        $this->mediaWikiServices = $mediaWikiServices;
 
        if ( $environment->isCli() ) {
            $this->postSendStrategy = self::DEFER_CLI_MODE;
        } elseif ( $environment->hasFastCgi() ) {
            $this->postSendStrategy = self::DEFER_FASTCGI_FINISH_REQUEST;
        } else {
            $this->postSendStrategy = self::DEFER_SET_LENGTH_AND_FLUSH;
        }
    }
 
    final protected function setup() {
        // Much of the functionality in WebStart.php and Setup.php should be moved here eventually.
        // As of MW 1.41, a lot of it still wants to run in file scope.
 
        // TODO: move define( 'MW_ENTRY_POINT' here )
        // TODO: move ProfilingContext::singleton()->init( ... ) here.
 
        $this->doSetup();
    }
 
    protected function doSetup() {
        // no-op
        // TODO: move ob_start( [ MediaWiki\Output\OutputHandler::class, 'handle' ] ) here
        // TODO: move MW_NO_OUTPUT_COMPRESSION handling here.
        // TODO: move HeaderCallback::register() here
        // TODO: move RequestContext::getMain()->getRequest()->getSession() here (from Setup.php)
        // TODO: move AuthManager::autoCreateUser here (from Setup.php)
        // TODO: move pingback here (from Setup.php)
    }
 
    final protected function prepareForOutput() {
        if ( $this->preparedForOutput ) {
            // only do this once.
            return;
        }
 
        $this->preparedForOutput = true;
 
        $this->doPrepareForOutput();
    }
 
    protected function doPrepareForOutput() {
        // Commit any changes in the current transaction round so that:
        // a) the transaction is not rolled back after success output was already sent
        // b) error output is not jumbled together with success output in the response
        // TODO: split this up and pull out stuff like spreading cookie blocks
        $this->commitMainTransaction();
    }
 
    final public function run() {
        $this->setup();
 
        try {
            $this->execute();
 
            // Prepare for flushing the output. Will do nothing if it was already called by execute().
            $this->prepareForOutput();
        } catch ( Throwable $e ) {
            $this->status( 500 );
            $this->handleTopLevelError( $e );
        }
 
        $this->postOutputShutdown();
    }
 
    protected function handleTopLevelError( Throwable $e ) {
        // Type errors and such: at least handle it now and clean up the LBFactory state
        MWExceptionHandler::handleException( $e, MWExceptionHandler::CAUGHT_BY_ENTRYPOINT );
    }
 
    abstract protected function execute();
 
    protected function schedulePostSendJobs() {
        $jobRunRate = $this->config->get( MainConfigNames::JobRunRate );
        if (
            // Post-send job running disabled
            $jobRunRate <= 0 ||
            // Jobs cannot run due to site read-only mode
            $this->getReadOnlyMode()->isReadOnly() ||
            // HTTP response body and Content-Length headers likely to not match,
            // causing post-send updates to block the client when using mod_php
            $this->context->getRequest()->getMethod() === 'HEAD' ||
            $this->context->getRequest()->getHeader( 'If-Modified-Since' ) ||
            $this->context->getRequest()->getHeader( 'If-None-Match' )
        ) {
            return;
        }
 
        if ( $jobRunRate < 1 ) {
            $max = mt_getrandmax();
            if ( mt_rand( 0, $max ) > $max * $jobRunRate ) {
                return; // the higher the job run rate, the less likely we return here
            }
            $n = 1;
        } else {
            $n = intval( $jobRunRate );
        }
 
        // Note that DeferredUpdates will catch and log any errors (T88312)
        DeferredUpdates::addUpdate( new TransactionRoundDefiningUpdate( function () use ( $n ) {
            $logger = LoggerFactory::getInstance( 'runJobs' );
            if ( $this->config->get( MainConfigNames::RunJobsAsync ) ) {
                // Send an HTTP request to the job RPC entry point if possible
                $invokedWithSuccess = $this->triggerAsyncJobs( $n, $logger );
                if ( !$invokedWithSuccess ) {
                    // Fall back to blocking on running the job(s)
                    $logger->warning( "Jobs switched to blocking; Special:RunJobs disabled" );
                    $this->triggerSyncJobs( $n );
                }
            } else {
                $this->triggerSyncJobs( $n );
            }
        }, __METHOD__ ) );
    }
 
    protected function commitMainTransaction() {
        $context = $this->context;
 
        $config = $context->getConfig();
        $request = $context->getRequest();
        $output = $context->getOutput();
 
        // Try to make sure that all RDBMs, session, and other storage updates complete
        ignore_user_abort( true );
 
        $lbFactory = $this->getDBLoadBalancerFactory();
 
        // Commit all RDBMs changes from the main transaction round
        $lbFactory->commitPrimaryChanges(
            __METHOD__,
            // Abort if any transaction was too big
            $config->get( MainConfigNames::MaxUserDBWriteDuration )
        );
        wfDebug( __METHOD__ . ': primary transaction round committed' );
 
        // Run updates that need to block the client or affect output (this is the last chance)
        DeferredUpdates::doUpdates(
            $config->get( MainConfigNames::ForceDeferredUpdatesPreSend )
                ? DeferredUpdates::ALL
                : DeferredUpdates::PRESEND
        );
 
        wfDebug( __METHOD__ . ': pre-send deferred updates completed' );
 
        if ( !defined( 'MW_NO_SESSION' ) ) {
            // Persist the session to avoid race conditions on subsequent requests by the client
            $request->getSession()->save(); // T214471
            wfDebug( __METHOD__ . ': session changes committed' );
        }
 
        // Subsequent requests by the client should see the DB replication positions, as written
        // to ChronologyProtector during the shutdown() call below.
        // Setting the cpPosIndex cookie is normally enough. However, this will not work for
        // cross-wiki redirects within the same wiki farm, so set the ?cpPoxIndex in that case.
        $isCrossWikiRedirect = (
            $output->getRedirect() &&
            $lbFactory->hasOrMadeRecentPrimaryChanges( INF ) &&
            self::getUrlDomainDistance( $output->getRedirect() ) === 'remote'
        );
 
        // Persist replication positions for DBs modified by this request (at this point).
        // These help provide "session consistency" for the client on their next requests.
        $cpIndex = null;
        $cpClientId = null;
        $lbFactory->shutdown(
            $lbFactory::SHUTDOWN_NORMAL,
            null,
            $cpIndex,
            $cpClientId
        );
        $now = time();
 
        $allowHeaders = !( $output->isDisabled() || $this->getResponse()->headersSent() );
 
        if ( $cpIndex > 0 ) {
            if ( $allowHeaders ) {
                $expires = $now + ChronologyProtector::POSITION_COOKIE_TTL;
                $options = [ 'prefix' => '' ];
                $value = ChronologyProtector::makeCookieValueFromCPIndex( $cpIndex, $now, $cpClientId );
                $request->response()->setCookie( 'cpPosIndex', $value, $expires, $options );
            }
 
            if ( $isCrossWikiRedirect ) {
                if ( $output->getRedirect() ) {
                    $url = $output->getRedirect();
                    if ( $lbFactory->hasStreamingReplicaServers() ) {
                        $url .= str_contains( $url, '?' ) ? '&' : '?';
                        $url .= 'cpPosIndex=' . $cpIndex;
                    }
                    $output->redirect( $url );
                } else {
                    MWExceptionHandler::logException(
                        new LogicException( "No redirect; cannot append cpPosIndex parameter." ),
                        MWExceptionHandler::CAUGHT_BY_ENTRYPOINT
                    );
                }
            }
        }
 
        if ( $allowHeaders ) {
            // Set a cookie to tell all CDN edge nodes to "stick" the user to the DC that
            // handles this POST request (e.g. the "primary" data center). Also have the user
            // briefly bypass CDN so ChronologyProtector works for cacheable URLs.
            if ( $request->wasPosted() && $lbFactory->hasOrMadeRecentPrimaryChanges() ) {
                $expires = $now + max(
                        ChronologyProtector::POSITION_COOKIE_TTL,
                        $config->get( MainConfigNames::DataCenterUpdateStickTTL )
                    );
                $options = [ 'prefix' => '' ];
                $request->response()->setCookie( 'UseDC', 'master', $expires, $options );
            }
 
            // Avoid letting a few seconds of replica DB lag cause a month of stale data.
            // This logic is also intimately related to the value of $wgCdnReboundPurgeDelay.
            if ( $lbFactory->laggedReplicaUsed() ) {
                $maxAge = $config->get( MainConfigNames::CdnMaxageLagged );
                $output->lowerCdnMaxage( $maxAge );
                $request->response()->header( "X-Database-Lagged: true" );
                wfDebugLog( 'replication',
                    "Lagged DB used; CDN cache TTL limited to $maxAge seconds" );
            }
 
            // Avoid long-term cache pollution due to message cache rebuild timeouts (T133069)
            if ( $this->getMessageCache()->isDisabled() ) {
                $maxAge = $config->get( MainConfigNames::CdnMaxageSubstitute );
                $output->lowerCdnMaxage( $maxAge );
                $request->response()->header( "X-Response-Substitute: true" );
            }
 
            if ( !$output->couldBePublicCached() || $output->haveCacheVaryCookies() ) {
                // Autoblocks: If this user is autoblocked (and the cookie block feature is enabled
                // for autoblocks), then set a cookie to track this block.
                // This has to be done on all logged-in page loads (not just upon saving edits),
                // because an autoblocked editor might not edit again from the same IP address.
                //
                // IP blocks: For anons, if their IP is blocked (and cookie block feature is enabled
                // for IP blocks), we also want to set the cookie whenever it is safe to do.
                // Basically from any url that are definitely not publicly cacheable (like viewing
                // EditPage), or when the HTTP response is personalised for other reasons (e.g. viewing
                // articles within the same browsing session after making an edit).
                $user = $context->getUser();
                $this->getBlockManager()->trackBlockWithCookie( $user, $request->response() );
            }
        }
    }
 
    private static function getUrlDomainDistance( $url ) {
        $clusterWiki = WikiMap::getWikiFromUrl( $url );
        if ( WikiMap::isCurrentWikiId( $clusterWiki ) ) {
            return 'local'; // the current wiki
        }
        if ( $clusterWiki !== false ) {
            return 'remote'; // another wiki in this cluster/farm
        }
 
        return 'external';
    }
 
    public function getRequestPathSuffix( $basePath ) {
        return WebRequest::getRequestPathSuffix(
            $basePath,
            $this->getRequestURL()
        );
    }
 
    final protected function postOutputShutdown() {
        $this->doPostOutputShutdown();
 
        // Just in case doPostOutputShutdown() was overwritten...
        if ( !$this->inPostSendMode() ) {
            $this->flushOutputBuffer();
            $this->enterPostSendMode();
        }
    }
 
    protected function doPostOutputShutdown() {
        // Record backend request timing
        $timing = $this->context->getTiming();
        $timing->mark( 'requestShutdown' );
 
        // Defer everything else if possible...
        if ( $this->postSendStrategy === self::DEFER_FASTCGI_FINISH_REQUEST ) {
            // Flush the output to the client, continue processing, and avoid further output
            $this->fastCgiFinishRequest();
        } elseif ( $this->postSendStrategy === self::DEFER_SET_LENGTH_AND_FLUSH ) {
            // Flush the output to the client, continue processing, and avoid further output
            $this->flushOutputBuffer();
        }
 
        // Since the headers and output where already flushed, disable WebResponse setters
        // during post-send processing to warnings and unexpected behavior (T191537)
        $this->enterPostSendMode();
 
        // Run post-send updates while preventing further output...
        $this->startOutputBuffer( static function () {
            return ''; // do not output uncaught exceptions
        } );
        try {
            $this->restInPeace();
        } catch ( Throwable $e ) {
            MWExceptionHandler::rollbackPrimaryChangesAndLog(
                $e,
                MWExceptionHandler::CAUGHT_BY_ENTRYPOINT
            );
        }
        $length = $this->getOutputBufferLength();
        if ( $length > 0 ) {
            $this->triggerError(
                __METHOD__ . ": suppressed $length byte(s)",
                E_USER_NOTICE
            );
        }
        $this->discardOutputBuffer();
    }
 
    protected function shouldDoHttpRedirect() {
        $request = $this->context->getRequest();
 
        // Don't redirect if we're already on HTTPS
        if ( $request->getProtocol() !== 'http' ) {
            return false;
        }
 
        $force = $this->config->get( MainConfigNames::ForceHTTPS );
 
        // Don't redirect if $wgServer is explicitly HTTP. We test for this here
        // by checking whether UrlUtils::expand() is able to force HTTPS.
        if (
            !preg_match(
                '#^https://#',
                (string)$this->getUrlUtils()->expand(
                    $request->getRequestURL(),
                    PROTO_HTTPS
                )
            )
        ) {
            if ( $force ) {
                throw new RuntimeException( '$wgForceHTTPS is true but the server is not HTTPS' );
            }
            return false;
        }
 
        // Configured $wgForceHTTPS overrides the remaining conditions
        if ( $force ) {
            return true;
        }
 
        // Check if HTTPS is required by the session or user preferences
        return $request->getSession()->shouldForceHTTPS() ||
            // Check the cookie manually, for paranoia
            $request->getCookie( 'forceHTTPS', '' ) ||
            $this->context->getUser()->requiresHTTPS();
    }
 
    protected function outputResponsePayload( $content ) {
        // Append any visible profiling data in a manner appropriate for the Content-Type
        $this->startOutputBuffer();
        try {
            Profiler::instance()->logDataPageOutputOnly();
        } finally {
            $content .= $this->drainOutputBuffer();
        }
 
        // By default, usually one output buffer is active now, either the internal PHP buffer
        // started by "output_buffering" in php.ini or the buffer started by MW_SETUP_CALLBACK.
        // The MW_SETUP_CALLBACK buffer has an unlimited chunk size, while the internal PHP
        // buffer only has an unlimited chunk size if output_buffering="On". If the buffer was
        // filled up to the chunk size with printed data, then HTTP headers will have already
        // been sent. Also, if the entry point had to stream content to the client, then HTTP
        // headers will have already been sent as well, regardless of chunk size.
 
        // Disable mod_deflate compression since it interferes with the output buffer set
        // by MW_SETUP_CALLBACK and can also cause the client to wait on deferred updates
        $this->disableModDeflate();
 
        if ( $this->inPostSendMode() ) {
            // Output already sent. This may happen for actions or special pages
            // that generate raw output and disable OutputPage. In that case,
            // we should just exit, but we should log an error if $content
            // was not empty.
            if ( $content !== '' ) {
                $length = strlen( $content );
                $this->triggerError(
                    __METHOD__ . ": discarded $length byte(s) of output",
                    E_USER_NOTICE
                );
            }
            return;
        }
 
        if (
            // "Content-Length" is used to prevent clients from waiting on deferred updates
            $this->postSendStrategy === self::DEFER_SET_LENGTH_AND_FLUSH &&
            !$this->getResponse()->headersSent() &&
            // The HTTP response code clearly allows for a meaningful body
            in_array( $this->getStatusCode(), [ 200, 404 ], true ) &&
            // The queue of (post-send) deferred updates is non-empty
            DeferredUpdates::pendingUpdatesCount() &&
            // Any buffered output is not spread out across multiple output buffers
            $this->getOutputBufferLevel() <= 1
        ) {
            $response = $this->context->getRequest()->response();
 
            $obStatus = $this->getOutputBufferStatus();
            if ( !isset( $obStatus['name'] ) ) {
                // No output buffer is active
                $response->header( 'Content-Length: ' . strlen( $content ) );
            } elseif ( $obStatus['name'] === 'default output handler' ) {
                // Internal PHP "output_buffering" output buffer (note that the internal PHP
                // "zlib.output_compression" output buffer is named "zlib output compression")
                $response->header( 'Content-Length: ' .
                    ( $this->getOutputBufferLength() + strlen( $content ) ) );
            }
 
            // The MW_SETUP_CALLBACK output buffer ("MediaWiki\OutputHandler::handle") sets
            // "Content-Length" where applicable. Other output buffer types might not set this
            // header, and since they might mangle or compress the payload, it is not possible
            // to determine the final payload size here.
 
            // Tell the client to immediately end the connection as soon as the response payload
            // has been read (informed by any "Content-Length" header). This prevents the client
            // from waiting on deferred updates.
            // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Connection
            if ( $this->getServerInfo( 'SERVER_PROTOCOL' ) === 'HTTP/1.1' ) {
                $response->header( 'Connection: close' );
            }
        }
 
        // Print the content *after* adjusting HTTP headers and disabling mod_deflate since
        // calling "print" will send the output to the client if there is no output buffer or
        // if the output buffer chunk size is reached
        $this->print( $content );
    }
 
    protected function restInPeace() {
        // Either all DB and deferred updates should happen or none.
        // The latter should not be cancelled due to client disconnect.
        ignore_user_abort( true );
 
        // Assure deferred updates are not in the main transaction
        $lbFactory = $this->getDBLoadBalancerFactory();
        $lbFactory->commitPrimaryChanges( __METHOD__ );
 
        // Loosen DB query expectations since the HTTP client is unblocked
        $profiler = Profiler::instance();
        $trxProfiler = $profiler->getTransactionProfiler();
        $trxProfiler->redefineExpectations(
            $this->context->getRequest()->hasSafeMethod()
                ? $this->config->get( MainConfigNames::TrxProfilerLimits )['PostSend-GET']
                : $this->config->get( MainConfigNames::TrxProfilerLimits )['PostSend-POST'],
            __METHOD__
        );
 
        // Do any deferred jobs; preferring to run them now if a client will not wait on them
        DeferredUpdates::doUpdates();
 
        // Handle external profiler outputs.
        // Any embedded profiler outputs were already processed in outputResponsePayload().
        $profiler->logData();
 
        self::emitBufferedStats( $this->getStatsFactory() );
 
        // Commit and close up!
        $lbFactory->commitPrimaryChanges( __METHOD__ );
        $lbFactory->shutdown( $lbFactory::SHUTDOWN_NO_CHRONPROT );
 
        // End the root span of this request or process and export trace data.
        $isServerError = $this->getStatusCode() >= 500 && $this->getStatusCode() < 600;
        // This is too generic a place to determine if the request was truly successful.
        // Err on the side of unset.
        $spanStatus = $isServerError ? SpanInterface::SPAN_STATUS_ERROR : SpanInterface::SPAN_STATUS_UNSET;
        TracerState::getInstance()->endRootSpan( $spanStatus );
        $this->mediaWikiServices->getTracer()->shutdown();
 
        wfDebug( "Request ended normally" );
    }
 
    public static function emitBufferedStats(
        StatsFactory $statsFactory
    ) {
        // Send metrics gathered by StatsFactory
        $statsFactory->flush();
    }
 
    protected function triggerSyncJobs( $n ) {
        $scope = Profiler::instance()->getTransactionProfiler()->silenceForScope();
        $this->getJobRunner()->run( [ 'maxJobs' => $n ] );
        ScopedCallback::consume( $scope );
    }
 
    protected function triggerAsyncJobs( $n, LoggerInterface $runJobsLogger ) {
        // Do not send request if there are probably no jobs
        $group = $this->getJobQueueGroupFactory()->makeJobQueueGroup();
        if ( !$group->queuesHaveJobs( JobQueueGroup::TYPE_DEFAULT ) ) {
            return true;
        }
 
        $query = [ 'title' => 'Special:RunJobs',
            'tasks' => 'jobs', 'maxjobs' => $n, 'sigexpiry' => time() + 5 ];
        $query['signature'] = SpecialRunJobs::getQuerySignature(
            $query, $this->config->get( MainConfigNames::SecretKey ) );
 
        $errno = $errstr = null;
        $info = $this->getUrlUtils()->parse( $this->config->get( MainConfigNames::CanonicalServer ) ) ?? [];
        $https = ( $info['scheme'] ?? null ) === 'https';
        $host = $info['host'] ?? null;
        $port = $info['port'] ?? ( $https ? 443 : 80 );
 
        // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
        $sock = $host ? @fsockopen(
            $https ? 'tls://' . $host : $host,
            $port,
            $errno,
            $errstr,
            // If it takes more than 100ms to connect to ourselves there is a problem...
            0.100
        ) : false;
 
        $invokedWithSuccess = true;
        if ( $sock ) {
            $special = $this->getSpecialPageFactory()->getPage( 'RunJobs' );
            $url = $special->getPageTitle()->getCanonicalURL( $query );
            $req = (
                "POST $url HTTP/1.1\r\n" .
                "Host: $host\r\n" .
                "Connection: Close\r\n" .
                "Content-Length: 0\r\n\r\n"
            );
 
            $runJobsLogger->info( "Running $n job(s) via '$url'" );
            // Send a cron API request to be performed in the background.
            // Give up if this takes too long to send (which should be rare).
            stream_set_timeout( $sock, 2 );
            $bytes = fwrite( $sock, $req );
            if ( $bytes !== strlen( $req ) ) {
                $invokedWithSuccess = false;
                $runJobsLogger->error( "Failed to start cron API (socket write error)" );
            } else {
                // Do not wait for the response (the script should handle client aborts).
                // Make sure that we don't close before that script reaches ignore_user_abort().
                $start = microtime( true );
                $status = fgets( $sock );
                $sec = microtime( true ) - $start;
                if ( !preg_match( '#^HTTP/\d\.\d 202 #', $status ) ) {
                    $invokedWithSuccess = false;
                    $runJobsLogger->error( "Failed to start cron API: received '$status' ($sec)" );
                }
            }
            fclose( $sock );
        } else {
            $invokedWithSuccess = false;
            $runJobsLogger->error( "Failed to start cron API (socket error $errno): $errstr" );
        }
 
        return $invokedWithSuccess;
    }
 
    protected function getServiceContainer(): MediaWikiServices {
        return $this->mediaWikiServices;
    }
 
    protected function getUrlUtils(): UrlUtils {
        return $this->mediaWikiServices->getUrlUtils();
    }
 
    protected function getReadOnlyMode(): ReadOnlyMode {
        return $this->mediaWikiServices->getReadOnlyMode();
    }
 
    protected function getJobRunner(): JobRunner {
        return $this->mediaWikiServices->getJobRunner();
    }
 
    protected function getDBLoadBalancerFactory(): LBFactory {
        return $this->mediaWikiServices->getDBLoadBalancerFactory();
    }
 
    protected function getMessageCache(): MessageCache {
        return $this->mediaWikiServices->getMessageCache();
    }
 
    protected function getBlockManager(): BlockManager {
        return $this->mediaWikiServices->getBlockManager();
    }
 
    protected function getStatsFactory(): StatsFactory {
        return $this->mediaWikiServices->getStatsFactory();
    }
 
    protected function getStatsdDataFactory(): IBufferingStatsdDataFactory {
        return $this->mediaWikiServices->getStatsdDataFactory();
    }
 
    protected function getJobQueueGroupFactory(): JobQueueGroupFactory {
        return $this->mediaWikiServices->getJobQueueGroupFactory();
    }
 
    protected function getSpecialPageFactory(): SpecialPageFactory {
        return $this->mediaWikiServices->getSpecialPageFactory();
    }
 
    protected function getContext(): IContextSource {
        return $this->context;
    }
 
    protected function getRequest(): WebRequest {
        return $this->context->getRequest();
    }
 
    protected function getResponse(): WebResponse {
        return $this->getRequest()->response();
    }
 
    protected function getConfig( string $key ) {
        return $this->config->get( $key );
    }
 
    protected function isCli(): bool {
        return $this->environment->isCli();
    }
 
    protected function hasFastCgi(): bool {
        return $this->environment->hasFastCgi();
    }
 
    protected function getServerInfo( string $key, $default = null ) {
        return $this->environment->getServerInfo( $key, $default );
    }
 
    protected function print( string $data ) {
        if ( $this->inPostSendMode() ) {
            throw new RuntimeException( 'Output already sent!' );
        }
 
        print $data;
    }
 
    protected function exit( int $code = 0 ): never {
        $this->environment->exit( $code );
    }
 
    protected function startOutputBuffer( ?callable $callback = null ): void {
        ob_start( $callback );
    }
 
    protected function drainOutputBuffer() {
        // NOTE: The ob_get_clean() would *disable* the current buffer,
        // we don't want that!
 
        $contents = ob_get_contents();
        ob_clean();
        return $contents;
    }
 
    public function enableOutputCapture(): void {
        $level = ob_get_level();
 
        if ( $level <= 0 ) {
            throw new RuntimeException(
                'No capture buffer available, call ob_start first.'
            );
        }
 
        $this->outputCaptureLevel = $level;
    }
 
    protected function getOutputBufferLevel(): int {
        return max( 0, ob_get_level() - ( $this->outputCaptureLevel ?? 0 ) );
    }
 
    protected function commitOutputBuffer(): bool {
        if ( $this->inPostSendMode() ) {
            throw new RuntimeException( 'Output already sent!' );
        }
 
        $level = $this->getOutputBufferLevel();
        if ( $level === 0 ) {
            return false;
        } else {
            //phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
            return @ob_end_flush();
        }
    }
 
    public function getCapturedOutput(): string {
        if ( $this->outputCaptureLevel === null ) {
            throw new LogicException(
                'getCapturedOutput() requires enableOutputCapture() to be called first'
            );
        }
 
        $this->flushOutputBuffer();
        return $this->drainOutputBuffer();
    }
 
    protected function flushOutputBuffer(): void {
        // NOTE: Use a for-loop, so we don't loop indefinitely in case
        // we fail to delete a buffer. This will routinely happen for
        // PHP's zlib.compression buffer.
        // See https://www.php.net/manual/en/function.ob-end-flush.php#103387
        $levels = $this->getOutputBufferLevel();
 
        // If we are in post-send mode, throw away any buffered output.
        // Only complain if there actually is buffered output.
        if ( $this->inPostSendMode() ) {
            for ( $i = 0; $i < $levels; $i++ ) {
                $length = $this->getOutputBufferLength();
 
                // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
                @ob_end_clean();
 
                if ( $length > 0 ) {
                    $this->triggerError(
                        __METHOD__ . ": suppressed $length byte(s)",
                        E_USER_NOTICE
                    );
                }
            }
            return;
        }
 
        for ( $i = 0; $i < $levels; $i++ ) {
            // Note that ob_end_flush() will fail for buffers created without
            // the PHP_OUTPUT_HANDLER_FLUSHABLE flag. So we use a for-loop
            // to avoid looping forever when ob_get_level() won't go down.
 
            // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
            @ob_end_flush();
        }
 
        // Flush the system buffer so the response is actually sent to the client,
        // unless we intend to capture the output, for testing or otherwise.
        // Capturing would be enabled by $this->outputCaptureLevel being set.
        // Note that, when not capturing the output, we want to flush response
        // to the client even if the loop above did not result in ob_get_level()
        // to return 0. This would be the case e.g. when zlib.compression
        // is enabled.
        // See https://www.php.net/manual/en/function.ob-end-flush.php#103387
        if ( $this->outputCaptureLevel === null || ob_get_level() === 0 ) {
            // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
            @flush();
        }
        wfDebug( "Output buffer flushed" );
    }
 
    protected function discardAllOutput() {
        // NOTE: use a for-loop, in case one of the buffers is non-removable.
        // In that case, getOutputBufferLevel() will never return 0.
        $levels = $this->getOutputBufferLevel();
        for ( $i = 0; $i < $levels; $i++ ) {
            // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
            @ob_end_clean();
        }
    }
 
    protected function getOutputBufferLength() {
        return ob_get_length();
    }
 
    protected function getOutputBufferStatus(): array {
        return ob_get_status();
    }
 
    protected function discardOutputBuffer(): bool {
        return ob_end_clean();
    }
 
    protected function disableModDeflate(): void {
        $this->environment->disableModDeflate();
    }
 
    protected function getStatusCode() {
        return $this->getResponse()->getStatusCode();
    }
 
    protected function inPostSendMode(): bool {
        return $this->postSendMode;
    }
 
    protected function triggerError( string $message, int $level = E_USER_NOTICE ): bool {
        return $this->environment->triggerError( $message, $level );
    }
 
    protected function getEnv( string $name ) {
        return $this->environment->getEnv( $name );
    }
 
    protected function getIni( string $name ) {
        return $this->environment->getIni( $name );
    }
 
    protected function setIniOption( string $name, $value ) {
        return $this->environment->setIniOption( $name, $value );
    }
 
    protected function header( string $header, bool $replace = true, int $status = 0 ): void {
        $this->getResponse()->header( $header, $replace, $status );
    }
 
    protected function status( int $code ): void {
        $this->header( HttpStatus::getHeader( $code ), true, $code );
    }
 
    protected function fastCgiFinishRequest(): bool {
        if ( !$this->inPostSendMode() ) {
            $this->flushOutputBuffer();
        }
 
        // Don't mess with fastcgi on CLI mode.
        if ( $this->isCli() ) {
            return false;
        }
 
        // Only mess with fastcgi if we really have no buffers left.
        if ( ob_get_level() > 0 ) {
            return false;
        }
 
        $success = $this->environment->fastCgiFinishRequest();
        wfDebug( $success ? 'FastCGI request finished' : 'FastCGI request finish failed' );
        return $success;
    }
 
    protected function getRequestURL(): string {
        // Despite the name, this just returns the path and query string
        return $this->getRequest()->getRequestURL();
    }
 
    protected function enterPostSendMode() {
        $this->postSendMode = true;
 
        $this->getResponse()->disableForPostSend();
    }
 
}