summaryrefslogtreecommitdiff
path: root/includes/MediaWiki.php
blob: a902f367b9ff3cf9786dbb9e00ddd500fa6c0fe1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
<?php
/**
 * Helper class for the index.php entry point.
 *
 * 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
 */

use MediaWiki\Logger\LoggerFactory;

/**
 * The MediaWiki class is the helper class for the index.php entry point.
 */
class MediaWiki {
	/**
	 * @var IContextSource
	 */
	private $context;

	/**
	 * @var Config
	 */
	private $config;

	/**
	 * @var String Cache what action this request is
	 */
	private $action;

	/**
	 * @param IContextSource|null $context
	 */
	public function __construct( IContextSource $context = null ) {
		if ( !$context ) {
			$context = RequestContext::getMain();
		}

		$this->context = $context;
		$this->config = $context->getConfig();
	}

	/**
	 * Parse the request to get the Title object
	 *
	 * @throws MalformedTitleException If a title has been provided by the user, but is invalid.
	 * @return Title Title object to be $wgTitle
	 */
	private function parseTitle() {
		global $wgContLang;

		$request = $this->context->getRequest();
		$curid = $request->getInt( 'curid' );
		$title = $request->getVal( 'title' );
		$action = $request->getVal( 'action' );

		if ( $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 (bug 8054).
			$ret = SpecialPage::getTitleFor( 'Search' );
		} elseif ( $curid ) {
			// URLs like this are generated by RC, because rc_title isn't always accurate
			$ret = Title::newFromID( $curid );
		} else {
			$ret = Title::newFromURL( $title );
			// 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 ( !is_null( $ret ) && $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
			if ( count( $wgContLang->getVariants() ) > 1
				&& !is_null( $ret ) && $ret->getArticleID() == 0
			) {
				$wgContLang->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 ? $oldid : $request->getInt( 'diff' );
			// Allow oldid to override a changed or missing title
			if ( $oldid ) {
				$rev = Revision::newFromId( $oldid );
				$ret = $rev ? $rev->getTitle() : $ret;
			}
		}

		// Use the main page as default title if nothing else has been provided
		if ( $ret === null
			&& strval( $title ) === ''
			&& !$request->getCheck( 'curid' )
			&& $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;
	}

	/**
	 * Get the Title object that we'll be acting on, as specified in the WebRequest
	 * @return Title
	 */
	public function getTitle() {
		if ( !$this->context->hasTitle() ) {
			try {
				$this->context->setTitle( $this->parseTitle() );
			} catch ( MalformedTitleException $ex ) {
				$this->context->setTitle( SpecialPage::getTitleFor( 'Badtitle' ) );
			}
		}
		return $this->context->getTitle();
	}

	/**
	 * Returns the name of the action that will be executed.
	 *
	 * @return string Action
	 */
	public function getAction() {
		if ( $this->action === null ) {
			$this->action = Action::getActionName( $this->context );
		}

		return $this->action;
	}

	/**
	 * Performs the request.
	 * - bad titles
	 * - read restriction
	 * - local interwiki redirects
	 * - redirect loop
	 * - special pages
	 * - normal pages
	 *
	 * @throws MWException|PermissionsError|BadTitleError|HttpError
	 * @return void
	 */
	private function performRequest() {
		global $wgTitle;

		$request = $this->context->getRequest();
		$requestTitle = $title = $this->context->getTitle();
		$output = $this->context->getOutput();
		$user = $this->context->getUser();

		if ( $request->getVal( 'printable' ) === 'yes' ) {
			$output->setPrintable();
		}

		$unused = null; // To pass it by reference
		Hooks::run( 'BeforeInitialize', array( &$title, &$unused, &$output, &$user, $request, $this ) );

		// Invalid titles. Bug 21776: The interwikis must redirect even if the page name is empty.
		if ( is_null( $title ) || ( $title->getDBkey() == '' && !$title->isExternal() )
			|| $title->isSpecial( 'Badtitle' )
		) {
			$this->context->setTitle( SpecialPage::getTitleFor( 'Badtitle' ) );
			try {
				$this->parseTitle();
			} 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().
		$permErrors = $title->isSpecial( 'RunJobs' )
			? array() // relies on HMAC key signature alone
			: $title->getUserPermissionsErrors( 'read', $user );
		if ( count( $permErrors ) ) {
			// Bug 32276: allowing the skin to generate output with $wgTitle or
			// $this->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 $this->context->getTitle() these days, but some extensions
			// still use $wgTitle.

			$badTitle = SpecialPage::getTitleFor( 'Badtitle' );
			$this->context->setTitle( $badTitle );
			$wgTitle = $badTitle;

			throw new PermissionsError( 'read', $permErrors );
		}

		// Interwiki redirects
		if ( $title->isExternal() ) {
			$rdfrom = $request->getVal( 'rdfrom' );
			if ( $rdfrom ) {
				$url = $title->getFullURL( array( 'rdfrom' => $rdfrom ) );
			} else {
				$query = $request->getValues();
				unset( $query['title'] );
				$url = $title->getFullURL( $query );
			}
			// Check for a redirect loop
			if ( !preg_match( '/^' . preg_quote( $this->config->get( 'Server' ), '/' ) . '/', $url )
				&& $title->isLocal()
			) {
				// 301 so google et al report the target as the actual url.
				$output->redirect( $url, 301 );
			} else {
				$this->context->setTitle( SpecialPage::getTitleFor( 'Badtitle' ) );
				try {
					$this->parseTitle();
				} 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)
			if ( $title->isSpecialPage() ) {
				$specialPage = SpecialPageFactory::getPage( $title->getDBKey() );
				if ( $specialPage instanceof RedirectSpecialPage
					&& $this->config->get( 'HideIdentifiableRedirects' )
					&& $specialPage->personallyIdentifiableTarget()
				) {
					list( , $subpage ) = SpecialPageFactory::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 ) {
						$query = $specialPage->getRedirectQuery() ?: array();
						$request = new DerivativeRequest( $this->context->getRequest(), $query );
						$request->setRequestURL( $this->context->getRequest()->getRequestURL() );
						$this->context->setRequest( $request );
						// Do not varnish cache these. May vary even for anons
						$this->context->getOutput()->lowerCdnMaxage( 0 );
						$this->context->setTitle( $target );
						$wgTitle = $target;
						// Reset action type cache. (Special pages have only view)
						$this->action = null;
						$title = $target;
						$output->addJsConfigVars( array(
							'wgInternalRedirectTargetUrl' => $target->getFullURL( $query ),
						) );
						$output->addModules( 'mediawiki.action.view.redirect' );
					}
				}
			}

			// Special pages ($title may have changed since if statement above)
			if ( NS_SPECIAL == $title->getNamespace() ) {
				// Actions that need to be made when we have a special pages
				SpecialPageFactory::executePath( $title, $this->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 MWException( "Shouldn't happen: MediaWiki::initializeArticle()"
						. " returned neither an object nor a URL" );
				}
			}
		}
	}

	/**
	 * Handle redirects for uncanonical title requests.
	 *
	 * Handles:
	 * - Redirect loops.
	 * - No title in URL.
	 * - $wgUsePathInfo URLs.
	 * - URLs with a variant.
	 * - Other non-standard URLs (as long as they have no extra query parameters).
	 *
	 * Behaviour:
	 * - Normalise title values:
	 *   /wiki/Foo%20Bar -> /wiki/Foo_Bar
	 * - Normalise empty title:
	 *   /wiki/ -> /wiki/Main
	 *   /w/index.php?title= -> /wiki/Main
	 * - Normalise non-standard title urls:
	 *   /w/index.php?title=Foo_Bar -> /wiki/Foo_Bar
	 * - Don't redirect anything with query parameters other than 'title' or 'action=view'.
	 *
	 * @param Title $title
	 * @return bool True if a redirect was set.
	 * @throws HttpError
	 */
	private function tryNormaliseRedirect( Title $title ) {
		$request = $this->context->getRequest();
		$output = $this->context->getOutput();

		if ( $request->getVal( 'action', 'view' ) != 'view'
			|| $request->wasPosted()
			|| count( $request->getValueNames( array( 'action', 'title' ) ) )
			|| !Hooks::run( 'TestCanonicalRedirect', array( $request, $title, $output ) )
		) {
			return false;
		}

		if ( $title->isSpecialPage() ) {
			list( $name, $subpage ) = SpecialPageFactory::resolveAlias( $title->getDBkey() );
			if ( $name ) {
				$title = SpecialPage::getTitleFor( $name, $subpage );
			}
		}
		// Redirect to canonical url, make it a 301 to allow caching
		$targetUrl = wfExpandUrl( $title->getFullURL(), PROTO_CURRENT );

		if ( $targetUrl != $request->getFullRequestURL() ) {
			$output->setSquidMaxage( 1200 );
			$output->redirect( $targetUrl, '301' );
			return true;
		}

		// If there is no title, or the title is in a non-standard encoding, we demand
		// a redirect. If cgi somehow changed the 'title' query to be non-standard while
		// the url is standard, the server is misconfigured.
		if ( $request->getVal( 'title' ) === null
			|| $title->getPrefixedDBkey() != $request->getVal( 'title' )
		) {
			$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->config->get( '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 );
		}
		return false;
	}

	/**
	 * Initialize the main Article object for "standard" actions (view, etc)
	 * Create an Article object for the page, following redirects if needed.
	 *
	 * @return mixed An Article, or a string to redirect to another URL
	 */
	private function initializeArticle() {

		$title = $this->context->getTitle();
		if ( $this->context->canUseWikiPage() ) {
			// Try to use request context wiki page, as there
			// is already data from db saved in per process
			// cache there from this->getAction() call.
			$page = $this->context->getWikiPage();
			$article = Article::newFromWikiPage( $page, $this->context );
		} else {
			// This case should not happen, but just in case.
			$article = Article::newFromTitle( $title, $this->context );
			$this->context->setWikiPage( $article->getPage() );
		}

		// Skip some unnecessary code if the content model doesn't support redirects
		if ( !ContentHandler::getForTitle( $title )->supportsRedirects() ) {
			return $article;
		}

		$request = $this->context->getRequest();

		// Namespace might change when using redirects
		// Check for redirects ...
		$action = $request->getVal( 'action', 'view' );
		$file = ( $title->getNamespace() == NS_FILE ) ? $article->getFile() : null;
		if ( ( $action == 'view' || $action == 'render' ) // ... for actions that show content
			&& !$request->getVal( 'oldid' ) // ... and are not old revisions
			&& !$request->getVal( 'diff' ) // ... and not when showing diff
			&& $request->getVal( '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;

			Hooks::run( 'InitializeArticleMaybeRedirect',
				array( &$title, &$request, &$ignoreRedirect, &$target, &$article ) );

			// Follow redirects only for... redirects.
			// If $target is set, then a hook wanted to redirect.
			if ( !$ignoreRedirect && ( $target || $article->isRedirect() ) ) {
				// Is the target already set by an extension?
				$target = $target ? $target : $article->followRedirect();
				if ( is_string( $target ) ) {
					if ( !$this->config->get( 'DisableHardRedirects' ) ) {
						// we'll need to redirect
						return $target;
					}
				}
				if ( is_object( $target ) ) {
					// Rewrite environment to redirected article
					$rarticle = Article::newFromTitle( $target, $this->context );
					$rarticle->loadPageData();
					if ( $rarticle->exists() || ( is_object( $file ) && !$file->isLocal() ) ) {
						$rarticle->setRedirectedFrom( $title );
						$article = $rarticle;
						$this->context->setTitle( $target );
						$this->context->setWikiPage( $article->getPage() );
					}
				}
			} else {
				$this->context->setTitle( $article->getTitle() );
				$this->context->setWikiPage( $article->getPage() );
			}
		}

		return $article;
	}

	/**
	 * Perform one of the "standard" actions
	 *
	 * @param Page $page
	 * @param Title $requestTitle The original title, before any redirects were applied
	 */
	private function performAction( Page $page, Title $requestTitle ) {

		$request = $this->context->getRequest();
		$output = $this->context->getOutput();
		$title = $this->context->getTitle();
		$user = $this->context->getUser();

		if ( !Hooks::run( 'MediaWikiPerformAction',
				array( $output, $page, $title, $user, $request, $this ) )
		) {
			return;
		}

		$act = $this->getAction();

		$action = Action::factory( $act, $page, $this->context );

		if ( $action instanceof Action ) {
			# Let Squid cache things if we can purge them.
			if ( $this->config->get( 'UseSquid' ) &&
				in_array(
					// Use PROTO_INTERNAL because that's what getSquidURLs() uses
					wfExpandUrl( $request->getRequestURL(), PROTO_INTERNAL ),
					$requestTitle->getSquidURLs()
				)
			) {
				$output->setSquidMaxage( $this->config->get( 'SquidMaxage' ) );
			}

			$action->show();
			return;
		}

		if ( Hooks::run( 'UnknownAction', array( $request->getVal( 'action', 'view' ), $page ) ) ) {
			$output->setStatusCode( 404 );
			$output->showErrorPage( 'nosuchaction', 'nosuchactiontext' );
		}

	}

	/**
	 * Run the current MediaWiki instance; index.php just calls this
	 */
	public function run() {
		try {
			$this->checkMaxLag();
			try {
				$this->main();
			} catch ( ErrorPageError $e ) {
				// Bug 62091: 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->doPreOutputCommit();
				$e->report(); // display the GUI error
			}
		} catch ( Exception $e ) {
			MWExceptionHandler::handleException( $e );
		}

		$this->doPostOutputShutdown( 'normal' );
	}

	/**
	 * This function commits all DB changes as needed before
	 * the user can receive a response (in case commit fails)
	 *
	 * @since 1.26
	 */
	public function doPreOutputCommit() {
		// Either all DBs should commit or none
		ignore_user_abort( true );

		// Commit all changes and record ChronologyProtector positions
		$factory = wfGetLBFactory();
		$factory->commitMasterChanges();
		$factory->shutdown();

		wfDebug( __METHOD__ . ' completed; all transactions committed' );
	}

	/**
	 * This function does work that can be done *after* the
	 * user gets the HTTP response so they don't block on it
	 *
	 * This manages deferred updates, job insertion,
	 * final commit, and the logging of profiling data
	 *
	 * @param string $mode Use 'fast' to always skip job running
	 * @since 1.26
	 */
	public function doPostOutputShutdown( $mode = 'normal' ) {
		// Show visible profiling data if enabled (which cannot be post-send)
		Profiler::instance()->logDataPageOutputOnly();

		$that = $this;
		$callback = function () use ( $that, $mode ) {
			try {
				$that->restInPeace( $mode );
			} catch ( Exception $e ) {
				MWExceptionHandler::handleException( $e );
			}
		};

		// Defer everything else...
		if ( function_exists( 'register_postsend_function' ) ) {
			// https://github.com/facebook/hhvm/issues/1230
			register_postsend_function( $callback );
		} else {
			if ( function_exists( 'fastcgi_finish_request' ) ) {
				fastcgi_finish_request();
			} else {
				// Either all DB and deferred updates should happen or none.
				// The later should not be cancelled due to client disconnect.
				ignore_user_abort( true );
			}

			$callback();
		}
	}

	/**
	 * Checks if the request should abort due to a lagged server,
	 * for given maxlag parameter.
	 * @return bool
	 */
	private function checkMaxLag() {
		$maxLag = $this->context->getRequest()->getVal( 'maxlag' );
		if ( !is_null( $maxLag ) ) {
			list( $host, $lag ) = wfGetLB()->getMaxLag();
			if ( $lag > $maxLag ) {
				$resp = $this->context->getRequest()->response();
				$resp->statusHeader( 503 );
				$resp->header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
				$resp->header( 'X-Database-Lag: ' . intval( $lag ) );
				$resp->header( 'Content-Type: text/plain' );
				if ( $this->config->get( 'ShowHostnames' ) ) {
					echo "Waiting for $host: $lag seconds lagged\n";
				} else {
					echo "Waiting for a database server: $lag seconds lagged\n";
				}

				exit;
			}
		}
		return true;
	}

	private function main() {
		global $wgTitle, $wgTrxProfilerLimits;

		$request = $this->context->getRequest();

		// Send Ajax requests to the Ajax dispatcher.
		if ( $this->config->get( 'UseAjax' ) && $request->getVal( 'action' ) === 'ajax' ) {
			// Set a dummy title, because $wgTitle == null might break things
			$title = Title::makeTitle( NS_SPECIAL, 'Badtitle/performing an AJAX call in '
				. __METHOD__
			);
			$this->context->setTitle( $title );
			$wgTitle = $title;

			$dispatcher = new AjaxDispatcher( $this->config );
			$dispatcher->performAction( $this->context->getUser() );
			return;
		}

		// Get title from request parameters,
		// is set on the fly by parseTitle the first time.
		$title = $this->getTitle();
		$action = $this->getAction();
		$wgTitle = $title;

		$trxProfiler = Profiler::instance()->getTransactionProfiler();
		$trxProfiler->setLogger( LoggerFactory::getInstance( 'DBPerformance' ) );

		// Aside from rollback, master queries should not happen on GET requests.
		// Periodic or "in passing" updates on GET should use the job queue.
		if ( !$request->wasPosted()
			&& in_array( $action, array( 'view', 'edit', 'history' ) )
		) {
			$trxProfiler->setExpectations( $wgTrxProfilerLimits['GET'], __METHOD__ );
		} else {
			$trxProfiler->setExpectations( $wgTrxProfilerLimits['POST'], __METHOD__ );
		}

		// If the user has forceHTTPS set to true, or if the user
		// is in a group requiring HTTPS, or if they have the HTTPS
		// preference set, redirect them to HTTPS.
		// Note: Do this after $wgTitle is setup, otherwise the hooks run from
		// isLoggedIn() will do all sorts of weird stuff.
		if (
			$request->getProtocol() == 'http' &&
			(
				$request->getCookie( 'forceHTTPS', '' ) ||
				// check for prefixed version for currently logged in users
				$request->getCookie( 'forceHTTPS' ) ||
				// Avoid checking the user and groups unless it's enabled.
				(
					$this->context->getUser()->isLoggedIn()
					&& $this->context->getUser()->requiresHTTPS()
				)
			)
		) {
			$oldUrl = $request->getFullRequestURL();
			$redirUrl = preg_replace( '#^http://#', 'https://', $oldUrl );

			// ATTENTION: This hook is likely to be removed soon due to overall design of the system.
			if ( Hooks::run( 'BeforeHttpsRedirect', array( $this->context, &$redirUrl ) ) ) {

				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 );
				$this->context->setTitle( $title );
				$output = $this->context->getOutput();
				// Since we only do this redir to change proto, always send a vary header
				$output->addVaryHeader( 'X-Forwarded-Proto' );
				$output->redirect( $redirUrl );
				$output->output();
				return;
			}
		}

		if ( $this->config->get( 'UseFileCache' ) && $title->getNamespace() >= 0 ) {
			if ( HTMLFileCache::useFileCache( $this->context ) ) {
				// 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 = $cache->cacheTimestamp();
					if ( !$this->context->getOutput()->checkLastModified( $timestamp ) ) {
						$cache->loadFromFileCache( $this->context );
					}
					// Do any stats increment/watchlist stuff
					// Assume we're viewing the latest revision (this should always be the case with file cache)
					$this->context->getWikiPage()->doViewUpdates( $this->context->getUser() );
					// Tell OutputPage that output is taken care of
					$this->context->getOutput()->disable();
					return;
				}
			}
		}

		// Actually do the work of the request and build up any output
		$this->performRequest();

		// Now commit any transactions, so that unreported errors after
		// output() don't roll back the whole DB transaction and so that
		// we avoid having both success and error text in the response
		$this->doPreOutputCommit();

		// Output everything!
		$this->context->getOutput()->output();
	}

	/**
	 * Ends this task peacefully
	 * @param string $mode Use 'fast' to always skip job running
	 */
	public function restInPeace( $mode = 'fast' ) {
		// Assure deferred updates are not in the main transaction
		wfGetLBFactory()->commitMasterChanges();

		// Ignore things like master queries/connections on GET requests
		// as long as they are in deferred updates (which catch errors).
		Profiler::instance()->getTransactionProfiler()->resetExpectations();

		// Do any deferred jobs
		DeferredUpdates::doUpdates( 'commit' );

		// Make sure any lazy jobs are pushed
		JobQueueGroup::pushLazyJobs();

		// Now that everything specific to this request is done,
		// try to occasionally run jobs (if enabled) from the queues
		if ( $mode === 'normal' ) {
			$this->triggerJobs();
		}

		// Log profiling data, e.g. in the database or UDP
		wfLogProfilingData();

		// Commit and close up!
		$factory = wfGetLBFactory();
		$factory->commitMasterChanges();
		$factory->shutdown();

		wfDebug( "Request ended normally\n" );
	}

	/**
	 * Potentially open a socket and sent an HTTP request back to the server
	 * to run a specified number of jobs. This registers a callback to cleanup
	 * the socket once it's done.
	 */
	public function triggerJobs() {
		$jobRunRate = $this->config->get( 'JobRunRate' );
		if ( $jobRunRate <= 0 || wfReadOnly() ) {
			return;
		} elseif ( $this->getTitle()->isSpecial( 'RunJobs' ) ) {
			return; // recursion guard
		}

		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 );
		}

		$runJobsLogger = LoggerFactory::getInstance( 'runJobs' );

		if ( !$this->config->get( 'RunJobsAsync' ) ) {
			// Fall back to running the job here while the user waits
			$runner = new JobRunner( $runJobsLogger );
			$runner->run( array( 'maxJobs'  => $n ) );
			return;
		}

		try {
			if ( !JobQueueGroup::singleton()->queuesHaveJobs( JobQueueGroup::TYPE_DEFAULT ) ) {
				return; // do not send request if there are probably no jobs
			}
		} catch ( JobQueueError $e ) {
			MWExceptionHandler::logException( $e );
			return; // do not make the site unavailable
		}

		$query = array( 'title' => 'Special:RunJobs',
			'tasks' => 'jobs', 'maxjobs' => $n, 'sigexpiry' => time() + 5 );
		$query['signature'] = SpecialRunJobs::getQuerySignature(
			$query, $this->config->get( 'SecretKey' ) );

		$errno = $errstr = null;
		$info = wfParseUrl( $this->config->get( 'Server' ) );
		MediaWiki\suppressWarnings();
		$host = $info['host'];
		$port = 80;
		if ( isset( $info['scheme'] ) && $info['scheme'] == 'https' ) {
			$host = "tls://" . $host;
			$port = 443;
		}
		if ( isset( $info['port'] ) ) {
			$port = $info['port'];
		}
		$sock = fsockopen(
			$host,
			$port,
			$errno,
			$errstr,
			// If it takes more than 100ms to connect to ourselves there
			// is a problem elsewhere.
			0.1
		);
		MediaWiki\restoreWarnings();
		if ( !$sock ) {
			$runJobsLogger->error( "Failed to start cron API (socket error $errno): $errstr" );
			// Fall back to running the job here while the user waits
			$runner = new JobRunner( $runJobsLogger );
			$runner->run( array( 'maxJobs'  => $n ) );
			return;
		}

		$url = wfAppendQuery( wfScript( 'index' ), $query );
		$req = (
			"POST $url HTTP/1.1\r\n" .
			"Host: {$info['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, 1 );
		$bytes = fwrite( $sock, $req );
		if ( $bytes !== strlen( $req ) ) {
			$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().
			$status = fgets( $sock );
			if ( !preg_match( '#^HTTP/\d\.\d 202 #', $status ) ) {
				$runJobsLogger->error( "Failed to start cron API: received '$status'" );
			}
		}
		fclose( $sock );
	}
}