MediaWiki REL1_32
CategoryMembershipChangeJob.php
Go to the documentation of this file.
1<?php
24
40 private $ticket;
41
43
44 public function __construct( Title $title, array $params ) {
45 parent::__construct( 'categoryMembershipChange', $title, $params );
46 // Only need one job per page. Note that ENQUEUE_FUDGE_SEC handles races where an
47 // older revision job gets inserted while the newer revision job is de-duplicated.
48 $this->removeDuplicates = true;
49 }
50
51 public function run() {
52 $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
53 $lb = $lbFactory->getMainLB();
54 $dbw = $lb->getConnection( DB_MASTER );
55
56 $this->ticket = $lbFactory->getEmptyTransactionTicket( __METHOD__ );
57
58 $page = WikiPage::newFromID( $this->params['pageId'], WikiPage::READ_LATEST );
59 if ( !$page ) {
60 $this->setLastError( "Could not find page #{$this->params['pageId']}" );
61 return false; // deleted?
62 }
63
64 // Cut down on the time spent in safeWaitForMasterPos() in the critical section
65 $dbr = $lb->getConnection( DB_REPLICA, [ 'recentchanges' ] );
66 if ( !$lb->safeWaitForMasterPos( $dbr ) ) {
67 $this->setLastError( "Timed out while pre-waiting for replica DB to catch up" );
68 return false;
69 }
70
71 // Use a named lock so that jobs for this page see each others' changes
72 $lockKey = "CategoryMembershipUpdates:{$page->getId()}";
73 $scopedLock = $dbw->getScopedLockAndFlush( $lockKey, __METHOD__, 3 );
74 if ( !$scopedLock ) {
75 $this->setLastError( "Could not acquire lock '$lockKey'" );
76 return false;
77 }
78
79 // Wait till replica DB is caught up so that jobs for this page see each others' changes
80 if ( !$lb->safeWaitForMasterPos( $dbr ) ) {
81 $this->setLastError( "Timed out while waiting for replica DB to catch up" );
82 return false;
83 }
84 // Clear any stale REPEATABLE-READ snapshot
85 $dbr->flushSnapshot( __METHOD__ );
86
87 $cutoffUnix = wfTimestamp( TS_UNIX, $this->params['revTimestamp'] );
88 // Using ENQUEUE_FUDGE_SEC handles jobs inserted out of revision order due to the delay
89 // between COMMIT and actual enqueueing of the CategoryMembershipChangeJob job.
90 $cutoffUnix -= self::ENQUEUE_FUDGE_SEC;
91
92 // Get the newest page revision that has a SRC_CATEGORIZE row.
93 // Assume that category changes before it were already handled.
94 $row = $dbr->selectRow(
95 'revision',
96 [ 'rev_timestamp', 'rev_id' ],
97 [
98 'rev_page' => $page->getId(),
99 'rev_timestamp >= ' . $dbr->addQuotes( $dbr->timestamp( $cutoffUnix ) ),
100 'EXISTS (' . $dbr->selectSQLText(
101 'recentchanges',
102 '1',
103 [
104 'rc_this_oldid = rev_id',
105 'rc_source' => RecentChange::SRC_CATEGORIZE,
106 // Allow rc_cur_id or rc_timestamp index usage
107 'rc_cur_id = rev_page',
108 'rc_timestamp = rev_timestamp'
109 ]
110 ) . ')'
111 ],
112 __METHOD__,
113 [ 'ORDER BY' => 'rev_timestamp DESC, rev_id DESC' ]
114 );
115 // Only consider revisions newer than any such revision
116 if ( $row ) {
117 $cutoffUnix = wfTimestamp( TS_UNIX, $row->rev_timestamp );
118 $lastRevId = (int)$row->rev_id;
119 } else {
120 $lastRevId = 0;
121 }
122
123 // Find revisions to this page made around and after this revision which lack category
124 // notifications in recent changes. This lets jobs pick up were the last one left off.
125 $encCutoff = $dbr->addQuotes( $dbr->timestamp( $cutoffUnix ) );
127 $res = $dbr->select(
128 $revQuery['tables'],
129 $revQuery['fields'],
130 [
131 'rev_page' => $page->getId(),
132 "rev_timestamp > $encCutoff" .
133 " OR (rev_timestamp = $encCutoff AND rev_id > $lastRevId)"
134 ],
135 __METHOD__,
136 [ 'ORDER BY' => 'rev_timestamp ASC, rev_id ASC' ],
137 $revQuery['joins']
138 );
139
140 // Apply all category updates in revision timestamp order
141 foreach ( $res as $row ) {
142 $this->notifyUpdatesForRevision( $lbFactory, $page, Revision::newFromRow( $row ) );
143 }
144
145 return true;
146 }
147
154 protected function notifyUpdatesForRevision(
155 LBFactory $lbFactory, WikiPage $page, Revision $newRev
156 ) {
157 $config = RequestContext::getMain()->getConfig();
158 $title = $page->getTitle();
159
160 // Get the new revision
161 if ( !$newRev->getContent() ) {
162 return; // deleted?
163 }
164
165 // Get the prior revision (the same for null edits)
166 if ( $newRev->getParentId() ) {
167 $oldRev = Revision::newFromId( $newRev->getParentId(), Revision::READ_LATEST );
168 if ( !$oldRev->getContent() ) {
169 return; // deleted?
170 }
171 } else {
172 $oldRev = null;
173 }
174
175 // Parse the new revision and get the categories
176 $categoryChanges = $this->getExplicitCategoriesChanges( $page, $newRev, $oldRev );
177 list( $categoryInserts, $categoryDeletes ) = $categoryChanges;
178 if ( !$categoryInserts && !$categoryDeletes ) {
179 return; // nothing to do
180 }
181
182 $catMembChange = new CategoryMembershipChange( $title, $newRev );
183 $catMembChange->checkTemplateLinks();
184
185 $batchSize = $config->get( 'UpdateRowsPerQuery' );
186 $insertCount = 0;
187
188 foreach ( $categoryInserts as $categoryName ) {
189 $categoryTitle = Title::makeTitle( NS_CATEGORY, $categoryName );
190 $catMembChange->triggerCategoryAddedNotification( $categoryTitle );
191 if ( $insertCount++ && ( $insertCount % $batchSize ) == 0 ) {
192 $lbFactory->commitAndWaitForReplication( __METHOD__, $this->ticket );
193 }
194 }
195
196 foreach ( $categoryDeletes as $categoryName ) {
197 $categoryTitle = Title::makeTitle( NS_CATEGORY, $categoryName );
198 $catMembChange->triggerCategoryRemovedNotification( $categoryTitle );
199 if ( $insertCount++ && ( $insertCount++ % $batchSize ) == 0 ) {
200 $lbFactory->commitAndWaitForReplication( __METHOD__, $this->ticket );
201 }
202 }
203 }
204
206 WikiPage $page, Revision $newRev, Revision $oldRev = null
207 ) {
208 // Inject the same timestamp for both revision parses to avoid seeing category changes
209 // due to time-based parser functions. Inject the same page title for the parses too.
210 // Note that REPEATABLE-READ makes template/file pages appear unchanged between parses.
211 $parseTimestamp = $newRev->getTimestamp();
212 // Parse the old rev and get the categories. Do not use link tables as that
213 // assumes these updates are perfectly FIFO and that link tables are always
214 // up to date, neither of which are true.
215 $oldCategories = $oldRev
216 ? $this->getCategoriesAtRev( $page, $oldRev, $parseTimestamp )
217 : [];
218 // Parse the new revision and get the categories
219 $newCategories = $this->getCategoriesAtRev( $page, $newRev, $parseTimestamp );
220
221 $categoryInserts = array_values( array_diff( $newCategories, $oldCategories ) );
222 $categoryDeletes = array_values( array_diff( $oldCategories, $newCategories ) );
223
224 return [ $categoryInserts, $categoryDeletes ];
225 }
226
234 private function getCategoriesAtRev( WikiPage $page, Revision $rev, $parseTimestamp ) {
235 $renderer = MediaWikiServices::getInstance()->getRevisionRenderer();
236 $options = $page->makeParserOptions( 'canonical' );
237 $options->setTimestamp( $parseTimestamp );
238
239 // This could possibly use the parser cache if it checked the revision ID,
240 // but that's more complicated than it's worth.
241 $output = $renderer->getRenderedRevision( $rev->getRevisionRecord(), $options )
242 ->getRevisionParserOutput();
243
244 // array keys will cast numeric category names to ints
245 // so we need to cast them back to strings to avoid breaking things!
246 return array_map( 'strval', array_keys( $output->getCategories() ) );
247 }
248
249 public function getDeduplicationInfo() {
250 $info = parent::getDeduplicationInfo();
251 unset( $info['params']['revTimestamp'] ); // first job wins
252
253 return $info;
254 }
255}
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
wfTimestamp( $outputtype=TS_UNIX, $ts=0)
Get a timestamp string in one of various formats.
Job to add recent change entries mentioning category membership changes.
getExplicitCategoriesChanges(WikiPage $page, Revision $newRev, Revision $oldRev=null)
__construct(Title $title, array $params)
getDeduplicationInfo()
Subclasses may need to override this to make duplication detection work.
notifyUpdatesForRevision(LBFactory $lbFactory, WikiPage $page, Revision $newRev)
getCategoriesAtRev(WikiPage $page, Revision $rev, $parseTimestamp)
Class to both describe a background job and handle jobs.
Definition Job.php:30
Title $title
Definition Job.php:41
setLastError( $error)
Definition Job.php:384
MediaWikiServices is the service locator for the application scope of MediaWiki.
static newFromRow( $row)
Definition Revision.php:218
static getQueryInfo( $options=[])
Return the tables, fields, and join conditions to be selected to create a new revision object.
Definition Revision.php:521
static newFromId( $id, $flags=0)
Load a page revision from a given revision ID number.
Definition Revision.php:114
Represents a title within MediaWiki.
Definition Title.php:39
Class representing a MediaWiki article and history.
Definition WikiPage.php:44
makeParserOptions( $context)
Get parser options suitable for rendering the primary article wikitext.
getTitle()
Get the title object of the article.
Definition WikiPage.php:276
An interface for generating database load balancers.
Definition LBFactory.php:39
commitAndWaitForReplication( $fname, $ticket, array $opts=[])
Convenience method for safely running commitMasterChanges()/waitForReplication()
$res
Definition database.txt:21
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global list
Definition deferred.txt:11
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
const NS_CATEGORY
Definition Defines.php:78
null means default in associative array with keys and values unescaped Should be merged with default with a value of false meaning to suppress the attribute in associative array with keys and values unescaped & $options
Definition hooks.txt:2050
namespace and then decline to actually register it file or subcat img or subcat $title
Definition hooks.txt:994
static configuration should be added through ResourceLoaderGetConfigVars instead can be used to get the real title e g db for database replication lag or jobqueue for job queue size converted to pseudo seconds It is possible to add more fields and they will be returned to the user in the API response after the basic globals have been set but before ordinary actions take place $output
Definition hooks.txt:2317
presenting them properly to the user as errors is done by the caller return true use this to change the list i e etc $rev
Definition hooks.txt:1818
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition injection.txt:37
The wiki should then use memcached to cache various data To use multiple just add more items to the array To increase the weight of a make its entry a array("192.168.0.1:11211", 2))
$newRev
const DB_REPLICA
Definition defines.php:25
const DB_MASTER
Definition defines.php:26
$params