includes/api/ApiQueryBacklinks.php

   1 <?php
   2
   3 /*
   4  * Created on Oct 16, 2006
   5  *
   6  * API for MediaWiki 1.8+
   7  *
   8  * Copyright (C) 2006 Yuri Astrakhan <Firstname><Lastname>@gmail.com
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License along
  21  * with this program; if not, write to the Free Software Foundation, Inc.,
  22  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  23  * http://www.gnu.org/copyleft/gpl.html
  24  */
  25
  26 if ( !defined( 'MEDIAWIKI' ) ) {
  27         // Eclipse helper - will be ignored in production
  28         require_once( "ApiQueryBase.php" );
  29 }
  30
  31 /**
  32  * This is a three-in-one module to query:
  33  *   * backlinks  - links pointing to the given page,
  34  *   * embeddedin - what pages transclude the given page within themselves,
  35  *   * imageusage - what pages use the given image
  36  *
  37  * @ingroup API
  38  */
  39 class ApiQueryBacklinks extends ApiQueryGeneratorBase {
  40
  41         private $params, $rootTitle, $contID, $redirID, $redirect;
  42         private $bl_ns, $bl_from, $bl_table, $bl_code, $bl_title, $bl_sort, $bl_fields, $hasNS;
  43         private $pageMap, $resultArr;
  44
  45         // output element name, database column field prefix, database table
  46         private $backlinksSettings = array(
  47                 'backlinks' => array(
  48                         'code' => 'bl',
  49                         'prefix' => 'pl',
  50                         'linktbl' => 'pagelinks'
  51                 ),
  52                 'embeddedin' => array(
  53                         'code' => 'ei',
  54                         'prefix' => 'tl',
  55                         'linktbl' => 'templatelinks'
  56                 ),
  57                 'imageusage' => array(
  58                         'code' => 'iu',
  59                         'prefix' => 'il',
  60                         'linktbl' => 'imagelinks'
  61                 )
  62         );
  63
  64         public function __construct( $query, $moduleName ) {
  65                 extract( $this->backlinksSettings[$moduleName] );
  66                 $this->resultArr = array();
  67
  68                 parent::__construct( $query, $moduleName, $code );
  69                 $this->bl_ns = $prefix . '_namespace';
  70                 $this->bl_from = $prefix . '_from';
  71                 $this->bl_table = $linktbl;
  72                 $this->bl_code = $code;
  73
  74                 $this->hasNS = $moduleName !== 'imageusage';
  75                 if ( $this->hasNS ) {
  76                         $this->bl_title = $prefix . '_title';
  77                         $this->bl_sort = "{$this->bl_ns}, {$this->bl_title}, {$this->bl_from}";
  78                         $this->bl_fields = array(
  79                                 $this->bl_ns,
  80                                 $this->bl_title
  81                         );
  82                 } else {
  83                         $this->bl_title = $prefix . '_to';
  84                         $this->bl_sort = "{$this->bl_title}, {$this->bl_from}";
  85                         $this->bl_fields = array(
  86                                 $this->bl_title
  87                         );
  88                 }
  89         }
  90
  91         public function execute() {
  92                 $this->run();
  93         }
  94
  95         public function getCacheMode( $params ) {
  96                 return 'public';
  97         }
  98
  99         public function executeGenerator( $resultPageSet ) {
 100                 $this->run( $resultPageSet );
 101         }
 102
 103         private function prepareFirstQuery( $resultPageSet = null ) {
 104                 /* SELECT page_id, page_title, page_namespace, page_is_redirect
 105                  * FROM pagelinks, page WHERE pl_from=page_id
 106                  * AND pl_title='Foo' AND pl_namespace=0
 107                  * LIMIT 11 ORDER BY pl_from
 108                  */
 109                 $this->addTables( array( $this->bl_table, 'page' ) );
 110                 $this->addWhere( "{$this->bl_from}=page_id" );
 111                 if ( is_null( $resultPageSet ) ) {
 112                         $this->addFields( array( 'page_id', 'page_title', 'page_namespace' ) );
 113                 } else {
 114                         $this->addFields( $resultPageSet->getPageTableFields() );
 115                 }
 116
 117                 $this->addFields( 'page_is_redirect' );
 118                 $this->addWhereFld( $this->bl_title, $this->rootTitle->getDBkey() );
 119
 120                 if ( $this->hasNS ) {
 121                         $this->addWhereFld( $this->bl_ns, $this->rootTitle->getNamespace() );
 122                 }
 123                 $this->addWhereFld( 'page_namespace', $this->params['namespace'] );
 124
 125                 if ( !is_null( $this->contID ) ) {
 126                         $this->addWhere( "{$this->bl_from}>={$this->contID}" );
 127                 }
 128
 129                 if ( $this->params['filterredir'] == 'redirects' ) {
 130                         $this->addWhereFld( 'page_is_redirect', 1 );
 131                 } elseif ( $this->params['filterredir'] == 'nonredirects' && !$this->redirect ) {
 132                         // bug 22245 - Check for !redirect, as filtering nonredirects, when getting what links to them is contradictory
 133                         $this->addWhereFld( 'page_is_redirect', 0 );
 134                 }
 135
 136                 $this->addOption( 'LIMIT', $this->params['limit'] + 1 );
 137                 $this->addOption( 'ORDER BY', $this->bl_from );
 138                 $this->addOption( 'STRAIGHT_JOIN' );
 139         }
 140
 141         private function prepareSecondQuery( $resultPageSet = null ) {
 142                 /* SELECT page_id, page_title, page_namespace, page_is_redirect, pl_title, pl_namespace
 143                    FROM pagelinks, page WHERE pl_from=page_id
 144                    AND (pl_title='Foo' AND pl_namespace=0) OR (pl_title='Bar' AND pl_namespace=1)
 145                    ORDER BY pl_namespace, pl_title, pl_from LIMIT 11
 146                  */
 147                 $db = $this->getDB();
 148                 $this->addTables( array( 'page', $this->bl_table ) );
 149                 $this->addWhere( "{$this->bl_from}=page_id" );
 150
 151                 if ( is_null( $resultPageSet ) ) {
 152                         $this->addFields( array( 'page_id', 'page_title', 'page_namespace', 'page_is_redirect' ) );
 153                 } else {
 154                         $this->addFields( $resultPageSet->getPageTableFields() );
 155                 }
 156
 157                 $this->addFields( $this->bl_title );
 158                 if ( $this->hasNS ) {
 159                         $this->addFields( $this->bl_ns );
 160                 }
 161
 162                 // We can't use LinkBatch here because $this->hasNS may be false
 163                 $titleWhere = array();
 164                 foreach ( $this->redirTitles as $t ) {
 165                         $titleWhere[] = "{$this->bl_title} = " . $db->addQuotes( $t->getDBkey() ) .
 166                                         ( $this->hasNS ? " AND {$this->bl_ns} = '{$t->getNamespace()}'" : '' );
 167                 }
 168                 $this->addWhere( $db->makeList( $titleWhere, LIST_OR ) );
 169                 $this->addWhereFld( 'page_namespace', $this->params['namespace'] );
 170
 171                 if ( !is_null( $this->redirID ) ) {
 172                         $first = $this->redirTitles[0];
 173                         $title = $db->strencode( $first->getDBkey() );
 174                         $ns = $first->getNamespace();
 175                         $from = $this->redirID;
 176                         if ( $this->hasNS ) {
 177                                 $this->addWhere( "{$this->bl_ns} > $ns OR " .
 178                                                 "({$this->bl_ns} = $ns AND " .
 179                                                 "({$this->bl_title} > '$title' OR " .
 180                                                 "({$this->bl_title} = '$title' AND " .
 181                                                 "{$this->bl_from} >= $from)))" );
 182                         } else {
 183                                 $this->addWhere( "{$this->bl_title} > '$title' OR " .
 184                                                 "({$this->bl_title} = '$title' AND " .
 185                                                 "{$this->bl_from} >= $from)" );
 186                         }
 187                 }
 188                 if ( $this->params['filterredir'] == 'redirects' ) {
 189                         $this->addWhereFld( 'page_is_redirect', 1 );
 190                 } elseif ( $this->params['filterredir'] == 'nonredirects' ) {
 191                         $this->addWhereFld( 'page_is_redirect', 0 );
 192                 }
 193
 194                 $this->addOption( 'LIMIT', $this->params['limit'] + 1 );
 195                 $this->addOption( 'ORDER BY', $this->bl_sort );
 196                 $this->addOption( 'USE INDEX', array( 'page' => 'PRIMARY' ) );
 197         }
 198
 199         private function run( $resultPageSet = null ) {
 200                 $this->params = $this->extractRequestParams( false );
 201                 $this->redirect = isset( $this->params['redirect'] ) && $this->params['redirect'];
 202                 $userMax = ( $this->redirect ? ApiBase::LIMIT_BIG1 / 2 : ApiBase::LIMIT_BIG1 );
 203                 $botMax  = ( $this->redirect ? ApiBase::LIMIT_BIG2 / 2 : ApiBase::LIMIT_BIG2 );
 204                 if ( $this->params['limit'] == 'max' ) {
 205                         $this->params['limit'] = $this->getMain()->canApiHighLimits() ? $botMax : $userMax;
 206                         $this->getResult()->setParsedLimit( $this->getModuleName(), $this->params['limit'] );
 207                 }
 208
 209                 $this->processContinue();
 210                 $this->prepareFirstQuery( $resultPageSet );
 211
 212                 $res = $this->select( __METHOD__ . '::firstQuery' );
 213
 214                 $count = 0;
 215                 $this->pageMap = array(); // Maps ns and title to pageid
 216                 $this->continueStr = null;
 217                 $this->redirTitles = array();
 218                 foreach ( $res as $row ) {
 219                         if ( ++ $count > $this->params['limit'] ) {
 220                                 // We've reached the one extra which shows that there are additional pages to be had. Stop here...
 221                                 // Continue string preserved in case the redirect query doesn't pass the limit
 222                                 $this->continueStr = $this->getContinueStr( $row->page_id );
 223                                 break;
 224                         }
 225
 226                         if ( is_null( $resultPageSet ) ) {
 227                                 $this->extractRowInfo( $row );
 228                         } else {
 229                                 $this->pageMap[$row->page_namespace][$row->page_title] = $row->page_id;
 230                                 if ( $row->page_is_redirect ) {
 231                                         $this->redirTitles[] = Title::makeTitle( $row->page_namespace, $row->page_title );
 232                                 }
 233
 234                                 $resultPageSet->processDbRow( $row );
 235                         }
 236                 }
 237
 238                 if ( $this->redirect && count( $this->redirTitles ) ) {
 239                         $this->resetQueryParams();
 240                         $this->prepareSecondQuery( $resultPageSet );
 241                         $res = $this->select( __METHOD__ . '::secondQuery' );
 242                         $count = 0;
 243                         foreach ( $res as $row ) {
 244                                 if ( ++$count > $this->params['limit'] ) {
 245                                         // We've reached the one extra which shows that there are additional pages to be had. Stop here...
 246                                         // We need to keep the parent page of this redir in
 247                                         if ( $this->hasNS ) {
 248                                                 $parentID = $this->pageMap[$row-> { $this->bl_ns } ][$row-> { $this->bl_title } ];
 249                                         } else {
 250                                                 $parentID = $this->pageMap[NS_IMAGE][$row-> { $this->bl_title } ];
 251                                         }
 252                                         $this->continueStr = $this->getContinueRedirStr( $parentID, $row->page_id );
 253                                         break;
 254                                 }
 255
 256                                 if ( is_null( $resultPageSet ) ) {
 257                                         $this->extractRedirRowInfo( $row );
 258                                 } else {
 259                                         $resultPageSet->processDbRow( $row );
 260                                 }
 261                         }
 262                 }
 263                 if ( is_null( $resultPageSet ) ) {
 264                         // Try to add the result data in one go and pray that it fits
 265                         $fit = $this->getResult()->addValue( 'query', $this->getModuleName(), array_values( $this->resultArr ) );
 266                         if ( !$fit ) {
 267                                 // It didn't fit. Add elements one by one until the
 268                                 // result is full.
 269                                 foreach ( $this->resultArr as $pageID => $arr ) {
 270                                         // Add the basic entry without redirlinks first
 271                                         $fit = $this->getResult()->addValue(
 272                                                 array( 'query', $this->getModuleName() ),
 273                                                 null, array_diff_key( $arr, array( 'redirlinks' => '' ) ) );
 274                                         if ( !$fit ) {
 275                                                 $this->continueStr = $this->getContinueStr( $pageID );
 276                                                 break;
 277                                         }
 278
 279                                         $hasRedirs = false;
 280                                         foreach ( (array)@$arr['redirlinks'] as $key => $redir ) {
 281                                                 $fit = $this->getResult()->addValue(
 282                                                         array( 'query', $this->getModuleName(), $pageID, 'redirlinks' ),
 283                                                         $key, $redir );
 284                                                 if ( !$fit ) {
 285                                                         $this->continueStr = $this->getContinueRedirStr( $pageID, $redir['pageid'] );
 286                                                         break;
 287                                                 }
 288                                                 $hasRedirs = true;
 289                                         }
 290                                         if ( $hasRedirs ) {
 291                                                 $this->getResult()->setIndexedTagName_internal(
 292                                                         array( 'query', $this->getModuleName(), $pageID, 'redirlinks' ),
 293                                                         $this->bl_code );
 294                                         }
 295                                         if ( !$fit ) {
 296                                                 break;
 297                                         }
 298                                 }
 299                         }
 300
 301                         $this->getResult()->setIndexedTagName_internal(
 302                                 array( 'query', $this->getModuleName() ),
 303                                 $this->bl_code
 304                         );
 305                 }
 306                 if ( !is_null( $this->continueStr ) ) {
 307                         $this->setContinueEnumParameter( 'continue', $this->continueStr );
 308                 }
 309         }
 310
 311         private function extractRowInfo( $row ) {
 312                 $this->pageMap[$row->page_namespace][$row->page_title] = $row->page_id;
 313                 $t = Title::makeTitle( $row->page_namespace, $row->page_title );
 314                 $a = array( 'pageid' => intval( $row->page_id ) );
 315                 ApiQueryBase::addTitleInfo( $a, $t );
 316                 if ( $row->page_is_redirect ) {
 317                         $a['redirect'] = '';
 318                         $this->redirTitles[] = $t;
 319                 }
 320                 // Put all the results in an array first
 321                 $this->resultArr[$a['pageid']] = $a;
 322         }
 323
 324         private function extractRedirRowInfo( $row ) {
 325                 $a['pageid'] = intval( $row->page_id );
 326                 ApiQueryBase::addTitleInfo( $a, Title::makeTitle( $row->page_namespace, $row->page_title ) );
 327                 if ( $row->page_is_redirect ) {
 328                         $a['redirect'] = '';
 329                 }
 330                 $ns = $this->hasNS ? $row-> { $this->bl_ns } : NS_FILE;
 331                 $parentID = $this->pageMap[$ns][$row-> { $this->bl_title } ];
 332                 // Put all the results in an array first
 333                 $this->resultArr[$parentID]['redirlinks'][] = $a;
 334                 $this->getResult()->setIndexedTagName( $this->resultArr[$parentID]['redirlinks'], $this->bl_code );
 335         }
 336
 337         protected function processContinue() {
 338                 if ( !is_null( $this->params['continue'] ) ) {
 339                         $this->parseContinueParam();
 340                 } else {
 341                         if ( $this->params['title'] !== '' ) {
 342                                 $title = Title::newFromText( $this->params['title'] );
 343                                 if ( !$title ) {
 344                                         $this->dieUsageMsg( array( 'invalidtitle', $this->params['title'] ) );
 345                                 } else {
 346                                         $this->rootTitle = $title;
 347                                 }
 348                         }
 349                 }
 350
 351                 // only image titles are allowed for the root in imageinfo mode
 352                 if ( !$this->hasNS && $this->rootTitle->getNamespace() !== NS_FILE ) {
 353                         $this->dieUsage( "The title for {$this->getModuleName()} query must be an image", 'bad_image_title' );
 354                 }
 355         }
 356
 357         protected function parseContinueParam() {
 358                 $continueList = explode( '|', $this->params['continue'] );
 359                 // expected format:
 360                 // ns | key | id1 [| id2]
 361                 // ns+key: root title
 362                 // id1: first-level page ID to continue from
 363                 // id2: second-level page ID to continue from
 364
 365                 // null stuff out now so we know what's set and what isn't
 366                 $this->rootTitle = $this->contID = $this->redirID = null;
 367                 $rootNs = intval( $continueList[0] );
 368                 if ( $rootNs === 0 && $continueList[0] !== '0' ) {
 369                         // Illegal continue parameter
 370                         $this->dieUsage( 'Invalid continue param. You should pass the original value returned by the previous query', '_badcontinue' );
 371                 }
 372                 $this->rootTitle = Title::makeTitleSafe( $rootNs, $continueList[1] );
 373
 374                 if ( !$this->rootTitle ) {
 375                         $this->dieUsage( 'Invalid continue param. You should pass the original value returned by the previous query', '_badcontinue' );
 376                 }
 377                 $contID = intval( $continueList[2] );
 378
 379                 if ( $contID === 0 && $continueList[2] !== '0' ) {
 380                         $this->dieUsage( 'Invalid continue param. You should pass the original value returned by the previous query', '_badcontinue' );
 381                 }
 382                 $this->contID = $contID;
 383                 $redirID = intval( @$continueList[3] );
 384
 385                 if ( $redirID === 0 && @$continueList[3] !== '0' ) {
 386                         // This one isn't required
 387                         return;
 388                 }
 389                 $this->redirID = $redirID;
 390
 391         }
 392
 393         protected function getContinueStr( $lastPageID ) {
 394                 return $this->rootTitle->getNamespace() .
 395                 '|' . $this->rootTitle->getDBkey() .
 396                 '|' . $lastPageID;
 397         }
 398
 399         protected function getContinueRedirStr( $lastPageID, $lastRedirID ) {
 400                 return $this->getContinueStr( $lastPageID ) . '|' . $lastRedirID;
 401         }
 402
 403         public function getAllowedParams() {
 404                 $retval = array(
 405                         'title' => array(
 406                                 ApiBase::PARAM_TYPE => 'string',
 407                                 ApiBase::PARAM_REQUIRED => true
 408                         ),
 409                         'continue' => null,
 410                         'namespace' => array(
 411                                 ApiBase::PARAM_ISMULTI => true,
 412                                 ApiBase::PARAM_TYPE => 'namespace'
 413                         ),
 414                         'filterredir' => array(
 415                                 ApiBase::PARAM_DFLT => 'all',
 416                                 ApiBase::PARAM_TYPE => array(
 417                                         'all',
 418                                         'redirects',
 419                                         'nonredirects'
 420                                 )
 421                         ),
 422                         'limit' => array(
 423                                 ApiBase::PARAM_DFLT => 10,
 424                                 ApiBase::PARAM_TYPE => 'limit',
 425                                 ApiBase::PARAM_MIN => 1,
 426                                 ApiBase::PARAM_MAX => ApiBase::LIMIT_BIG1,
 427                                 ApiBase::PARAM_MAX2 => ApiBase::LIMIT_BIG2
 428                         )
 429                 );
 430                 if ( $this->getModuleName() == 'embeddedin' ) {
 431                         return $retval;
 432                 }
 433                 $retval['redirect'] = false;
 434                 return $retval;
 435         }
 436
 437         public function getParamDescription() {
 438                 $retval = array(
 439                         'title' => 'Title to search',
 440                         'continue' => 'When more results are available, use this to continue',
 441                         'namespace' => 'The namespace to enumerate',
 442                 );
 443                 if ( $this->getModuleName() != 'embeddedin' ) {
 444                         return array_merge( $retval, array(
 445                                 'redirect' => 'If linking page is a redirect, find all pages that link to that redirect as well. Maximum limit is halved.',
 446                                 'filterredir' => "How to filter for redirects. If set to nonredirects when {$this->bl_code}redirect is enabled, this is only applied to the second level",
 447                                 'limit' => "How many total pages to return. If {$this->bl_code}redirect is enabled, limit applies to each level separately (which means you may get up to 2 * limit results)."
 448                         ) );
 449                 }
 450                 return array_merge( $retval, array(
 451                         'filterredir' => 'How to filter for redirects',
 452                         'limit' => 'How many total pages to return'
 453                 ) );
 454         }
 455
 456         public function getDescription() {
 457                 switch ( $this->getModuleName() ) {
 458                         case 'backlinks':
 459                                 return 'Find all pages that link to the given page';
 460                         case 'embeddedin':
 461                                 return 'Find all pages that embed (transclude) the given title';
 462                         case 'imageusage':
 463                                 return 'Find all pages that use the given image title.';
 464                         default:
 465                                 ApiBase::dieDebug( __METHOD__, 'Unknown module name' );
 466                 }
 467         }
 468
 469         public function getPossibleErrors() {
 470                 return array_merge( parent::getPossibleErrors(), array(
 471                         array( 'invalidtitle', 'title' ),
 472                         array( 'code' => 'bad_image_title', 'info' => "The title for {$this->getModuleName()} query must be an image" ),
 473                         array( 'code' => '_badcontinue', 'info' => 'Invalid continue param. You should pass the original value returned by the previous query' ),
 474                 ) );
 475         }
 476
 477         protected function getExamples() {
 478                 static $examples = array(
 479                         'backlinks' => array(
 480                                 'api.php?action=query&list=backlinks&bltitle=Main%20Page',
 481                                 'api.php?action=query&generator=backlinks&gbltitle=Main%20Page&prop=info'
 482                         ),
 483                         'embeddedin' => array(
 484                                 'api.php?action=query&list=embeddedin&eititle=Template:Stub',
 485                                 'api.php?action=query&generator=embeddedin&geititle=Template:Stub&prop=info'
 486                         ),
 487                         'imageusage' => array(
 488                                 'api.php?action=query&list=imageusage&iutitle=File:Albert%20Einstein%20Head.jpg',
 489                                 'api.php?action=query&generator=imageusage&giutitle=File:Albert%20Einstein%20Head.jpg&prop=info'
 490                         )
 491                 );
 492
 493                 return $examples[$this->getModuleName()];
 494         }
 495
 496         public function getVersion() {
 497                 return __CLASS__ . ': $Id$';
 498         }
 499 }