includes/JobQueue.php

   1 <?php
   2
   3 if ( !defined( 'MEDIAWIKI' ) ) {
   4         die( "This file is part of MediaWiki, it is not a valid entry point\n" );
   5 }
   6
   7 require_once('UserMailer.php');
   8
   9 /**
  10  * Class to both describe a background job and handle jobs.
  11  */
  12 abstract class Job {
  13         var $command,
  14                 $title,
  15                 $params,
  16                 $id,
  17                 $removeDuplicates,
  18                 $error;
  19
  20         /*-------------------------------------------------------------------------
  21          * Abstract functions
  22          *------------------------------------------------------------------------*/
  23
  24         /**
  25          * Run the job
  26          * @return boolean success
  27          */
  28         abstract function run();
  29
  30         /*-------------------------------------------------------------------------
  31          * Static functions
  32          *------------------------------------------------------------------------*/
  33
  34         /**
  35          * @deprecated use LinksUpdate::queueRecursiveJobs()
  36          */
  37         /**
  38          * static function queueLinksJobs( $titles ) {}
  39          */
  40
  41         /**
  42          * Pop a job of a certain type.  This tries less hard than pop() to
  43          * actually find a job; it may be adversely affected by concurrent job
  44          * runners.
  45          */
  46         static function pop_type($type) {
  47                 wfProfilein( __METHOD__ );
  48
  49                 $dbw = wfGetDB( DB_MASTER );
  50
  51
  52                 $row = $dbw->selectRow( 'job', '*', array( 'job_cmd' => $type ), __METHOD__,
  53                                 array( 'LIMIT' => 1 ));
  54
  55                 if ($row === false) {
  56                         wfProfileOut( __METHOD__ );
  57                         return false;
  58                 }
  59
  60                 /* Ensure we "own" this row */
  61                 $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
  62                 $affected = $dbw->affectedRows();
  63
  64                 if ($affected == 0) {
  65                         wfProfileOut( __METHOD__ );
  66                         return false;
  67                 }
  68
  69                 $namespace = $row->job_namespace;
  70                 $dbkey = $row->job_title;
  71                 $title = Title::makeTitleSafe( $namespace, $dbkey );
  72                 $job = Job::factory( $row->job_cmd, $title, Job::extractBlob( $row->job_params ), $row->job_id );
  73
  74                 $dbw->delete( 'job', $job->insertFields(), __METHOD__ );
  75                 $dbw->immediateCommit();
  76
  77                 wfProfileOut( __METHOD__ );
  78                 return $job;
  79         }
  80
  81         /**
  82          * Pop a job off the front of the queue
  83          * @static
  84          * @param $offset Number of jobs to skip
  85          * @return Job or false if there's no jobs
  86          */
  87         static function pop($offset=0) {
  88                 wfProfileIn( __METHOD__ );
  89
  90                 $dbr = wfGetDB( DB_SLAVE );
  91
  92                 /* Get a job from the slave, start with an offset,
  93                         scan full set afterwards, avoid hitting purged rows
  94
  95                         NB: If random fetch previously was used, offset
  96                                 will always be ahead of few entries
  97                 */
  98
  99                 $row = $dbr->selectRow( 'job', '*', "job_id >= ${offset}", __METHOD__,
 100                         array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ));
 101
 102                 // Refetching without offset is needed as some of job IDs could have had delayed commits
 103                 // and have lower IDs than jobs already executed, blame concurrency :)
 104                 //
 105                 if ( $row === false) {
 106                         if ($offset!=0)
 107                                 $row = $dbr->selectRow( 'job', '*', '', __METHOD__,
 108                                         array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ));
 109
 110                         if ($row === false ) {
 111                                 wfProfileOut( __METHOD__ );
 112                                 return false;
 113                         }
 114                 }
 115                 $offset = $row->job_id;
 116
 117                 // Try to delete it from the master
 118                 $dbw = wfGetDB( DB_MASTER );
 119                 $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
 120                 $affected = $dbw->affectedRows();
 121                 $dbw->immediateCommit();
 122
 123                 if ( !$affected ) {
 124                         // Failed, someone else beat us to it
 125                         // Try getting a random row
 126                         $row = $dbw->selectRow( 'job', array( 'MIN(job_id) as minjob',
 127                                 'MAX(job_id) as maxjob' ), "job_id >= $offset", __METHOD__ );
 128                         if ( $row === false || is_null( $row->minjob ) || is_null( $row->maxjob ) ) {
 129                                 // No jobs to get
 130                                 wfProfileOut( __METHOD__ );
 131                                 return false;
 132                         }
 133                         // Get the random row
 134                         $row = $dbw->selectRow( 'job', '*',
 135                                 'job_id >= ' . mt_rand( $row->minjob, $row->maxjob ),   __METHOD__ );
 136                         if ( $row === false ) {
 137                                 // Random job gone before we got the chance to select it
 138                                 // Give up
 139                                 wfProfileOut( __METHOD__ );
 140                                 return false;
 141                         }
 142                         // Delete the random row
 143                         $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
 144                         $affected = $dbw->affectedRows();
 145                         $dbw->immediateCommit();
 146
 147                         if ( !$affected ) {
 148                                 // Random job gone before we exclusively deleted it
 149                                 // Give up
 150                                 wfProfileOut( __METHOD__ );
 151                                 return false;
 152                         }
 153                 }
 154
 155                 // If execution got to here, there's a row in $row that has been deleted from the database
 156                 // by this thread. Hence the concurrent pop was successful.
 157                 $namespace = $row->job_namespace;
 158                 $dbkey = $row->job_title;
 159                 $title = Title::makeTitleSafe( $namespace, $dbkey );
 160                 $job = Job::factory( $row->job_cmd, $title, Job::extractBlob( $row->job_params ), $row->job_id );
 161
 162                 // Remove any duplicates it may have later in the queue
 163                 $dbw->delete( 'job', $job->insertFields(), __METHOD__ );
 164
 165                 wfProfileOut( __METHOD__ );
 166                 return $job;
 167         }
 168
 169         /**
 170          * Create an object of a subclass
 171          */
 172         static function factory( $command, $title, $params = false, $id = 0 ) {
 173                 switch ( $command ) {
 174                         case 'refreshLinks':
 175                                 return new RefreshLinksJob( $title, $params, $id );
 176                         case 'htmlCacheUpdate':
 177                         case 'html_cache_update': # BC
 178                                 return new HTMLCacheUpdateJob( $title, $params['table'], $params['start'], $params['end'], $id );
 179                         case 'sendMail':
 180                                 return new EmaillingJob( $params );
 181                         case 'enotifNotify':
 182                                 return new EnotifNotifyJob( $title, $params );
 183                 }
 184                 // OK, check if this is a custom job
 185                 global $wgCustomJobs;
 186                 wfLoadAllExtensions(); // This may be for an extension
 187
 188                 if( isset($wgCustomJobs[$command]) ) {
 189                         $class = $wgCustomJobs[$command];
 190                         return new $class($title, $params, $id);
 191                 } else {
 192                         throw new MWException( "Invalid job command \"$command\"" );
 193                 }
 194         }
 195
 196         static function makeBlob( $params ) {
 197                 if ( $params !== false ) {
 198                         return serialize( $params );
 199                 } else {
 200                         return '';
 201                 }
 202         }
 203
 204         static function extractBlob( $blob ) {
 205                 if ( (string)$blob !== '' ) {
 206                         return unserialize( $blob );
 207                 } else {
 208                         return false;
 209                 }
 210         }
 211
 212         /**
 213          * Batch-insert a group of jobs into the queue.
 214          * This will be wrapped in a transaction with a forced commit.
 215          *
 216          * This may add duplicate at insert time, but they will be
 217          * removed later on, when the first one is popped.
 218          *
 219          * @param $jobs array of Job objects
 220          */
 221         static function batchInsert( $jobs ) {
 222                 if( count( $jobs ) ) {
 223                         $dbw = wfGetDB( DB_MASTER );
 224                         $dbw->begin();
 225                         foreach( $jobs as $job ) {
 226                                 $rows[] = $job->insertFields();
 227                         }
 228                         $dbw->insert( 'job', $rows, __METHOD__, 'IGNORE' );
 229                         $dbw->commit();
 230                 }
 231         }
 232
 233         /*-------------------------------------------------------------------------
 234          * Non-static functions
 235          *------------------------------------------------------------------------*/
 236
 237         function __construct( $command, $title, $params = false, $id = 0 ) {
 238                 $this->command = $command;
 239                 $this->title = $title;
 240                 $this->params = $params;
 241                 $this->id = $id;
 242
 243                 // A bit of premature generalisation
 244                 // Oh well, the whole class is premature generalisation really
 245                 $this->removeDuplicates = true;
 246         }
 247
 248         /**
 249          * Insert a single job into the queue.
 250          */
 251         function insert() {
 252                 $fields = $this->insertFields();
 253
 254                 $dbw = wfGetDB( DB_MASTER );
 255
 256                 if ( $this->removeDuplicates ) {
 257                         $res = $dbw->select( 'job', array( '1' ), $fields, __METHOD__ );
 258                         if ( $dbw->numRows( $res ) ) {
 259                                 return;
 260                         }
 261                 }
 262                 $fields['job_id'] = $dbw->nextSequenceValue( 'job_job_id_seq' );
 263                 $dbw->insert( 'job', $fields, __METHOD__ );
 264         }
 265
 266         protected function insertFields() {
 267                 return array(
 268                         'job_cmd' => $this->command,
 269                         'job_namespace' => $this->title->getNamespace(),
 270                         'job_title' => $this->title->getDBkey(),
 271                         'job_params' => Job::makeBlob( $this->params )
 272                 );
 273         }
 274
 275         function toString() {
 276                 $paramString = '';
 277                 if ( $this->params ) {
 278                         foreach ( $this->params as $key => $value ) {
 279                                 if ( $paramString != '' ) {
 280                                         $paramString .= ' ';
 281                                 }
 282                                 $paramString .= "$key=$value";
 283                         }
 284                 }
 285
 286                 if ( is_object( $this->title ) ) {
 287                         $s = "{$this->command} " . $this->title->getPrefixedDBkey();
 288                         if ( $paramString !== '' ) {
 289                                 $s .= ' ' . $paramString;
 290                         }
 291                         return $s;
 292                 } else {
 293                         return "{$this->command} $paramString";
 294                 }
 295         }
 296
 297         function getLastError() {
 298                 return $this->error;
 299         }
 300 }
 301
 302
 303 /**
 304  * Background job to update links for a given title.
 305  */
 306 class RefreshLinksJob extends Job {
 307         function __construct( $title, $params = '', $id = 0 ) {
 308                 parent::__construct( 'refreshLinks', $title, $params, $id );
 309         }
 310
 311         /**
 312          * Run a refreshLinks job
 313          * @return boolean success
 314          */
 315         function run() {
 316                 global $wgParser;
 317                 wfProfileIn( __METHOD__ );
 318
 319                 $linkCache =& LinkCache::singleton();
 320                 $linkCache->clear();
 321
 322                 if ( is_null( $this->title ) ) {
 323                         $this->error = "refreshLinks: Invalid title";
 324                         wfProfileOut( __METHOD__ );
 325                         return false;
 326                 }
 327
 328                 $revision = Revision::newFromTitle( $this->title );
 329                 if ( !$revision ) {
 330                         $this->error = 'refreshLinks: Article not found "' . $this->title->getPrefixedDBkey() . '"';
 331                         wfProfileOut( __METHOD__ );
 332                         return false;
 333                 }
 334
 335                 wfProfileIn( __METHOD__.'-parse' );
 336                 $options = new ParserOptions;
 337                 $parserOutput = $wgParser->parse( $revision->getText(), $this->title, $options, true, true, $revision->getId() );
 338                 wfProfileOut( __METHOD__.'-parse' );
 339                 wfProfileIn( __METHOD__.'-update' );
 340                 $update = new LinksUpdate( $this->title, $parserOutput, false );
 341                 $update->doUpdate();
 342                 wfProfileOut( __METHOD__.'-update' );
 343                 wfProfileOut( __METHOD__ );
 344                 return true;
 345         }
 346 }
 347
 348 class EmaillingJob extends Job {
 349         function __construct($params) {
 350                 parent::__construct('sendMail', Title::newMainPage(), $params);
 351         }
 352
 353         function run() {
 354                 userMailer($this->params['to'], $this->params['from'], $this->params['subj'],
 355                                 $this->params['body'], $this->params['replyto']);
 356         }
 357 }
 358
 359 class EnotifNotifyJob extends Job {
 360         function __construct($title, $params) {
 361                 parent::__construct('enotifNotify', $title, $params);
 362         }
 363
 364         function run() {
 365                 $enotif = new EmailNotification();
 366                 $enotif->actuallyNotifyOnPageChange( User::newFromName($this->params['editor'], false),
 367                                 $this->title, $this->params['timestamp'],
 368                                 $this->params['summary'], $this->params['minorEdit'],
 369                                 $this->params['oldid']);
 370         }
 371 }
 372
 373
 374 ?>