includes/api/ApiQueryBacklinksprop.php

   1 <?php
   2 /**
   3  * API module to handle links table back-queries
   4  *
   5  * Copyright © 2014 Wikimedia Foundation and contributors
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @file
  23  * @since 1.24
  24  */
  25
  26 /**
  27  * This implements prop=redirects, prop=linkshere, prop=catmembers,
  28  * prop=transcludedin, and prop=fileusage
  29  *
  30  * @ingroup API
  31  * @since 1.24
  32  */
  33 class ApiQueryBacklinksprop extends ApiQueryGeneratorBase {
  34
  35         // Data for the various modules implemented by this class
  36         private static $settings = [
  37                 'redirects' => [
  38                         'code' => 'rd',
  39                         'prefix' => 'rd',
  40                         'linktable' => 'redirect',
  41                         'props' => [
  42                                 'fragment',
  43                         ],
  44                         'showredirects' => false,
  45                         'show' => [
  46                                 'fragment',
  47                                 '!fragment',
  48                         ],
  49                 ],
  50                 'linkshere' => [
  51                         'code' => 'lh',
  52                         'prefix' => 'pl',
  53                         'linktable' => 'pagelinks',
  54                         'indexes' => [ 'pl_namespace', 'pl_backlinks_namespace' ],
  55                         'from_namespace' => true,
  56                         'showredirects' => true,
  57                 ],
  58                 'transcludedin' => [
  59                         'code' => 'ti',
  60                         'prefix' => 'tl',
  61                         'linktable' => 'templatelinks',
  62                         'indexes' => [ 'tl_namespace', 'tl_backlinks_namespace' ],
  63                         'from_namespace' => true,
  64                         'showredirects' => true,
  65                 ],
  66                 'fileusage' => [
  67                         'code' => 'fu',
  68                         'prefix' => 'il',
  69                         'linktable' => 'imagelinks',
  70                         'indexes' => [ 'il_to', 'il_backlinks_namespace' ],
  71                         'from_namespace' => true,
  72                         'to_namespace' => NS_FILE,
  73                         'exampletitle' => 'File:Example.jpg',
  74                         'showredirects' => true,
  75                 ],
  76         ];
  77
  78         public function __construct( ApiQuery $query, $moduleName ) {
  79                 parent::__construct( $query, $moduleName, self::$settings[$moduleName]['code'] );
  80         }
  81
  82         public function execute() {
  83                 $this->run();
  84         }
  85
  86         public function executeGenerator( $resultPageSet ) {
  87                 $this->run( $resultPageSet );
  88         }
  89
  90         /**
  91          * @param ApiPageSet|null $resultPageSet
  92          */
  93         private function run( ApiPageSet $resultPageSet = null ) {
  94                 $settings = self::$settings[$this->getModuleName()];
  95
  96                 $db = $this->getDB();
  97                 $params = $this->extractRequestParams();
  98                 $prop = array_flip( $params['prop'] );
  99                 $emptyString = $db->addQuotes( '' );
 100
 101                 $pageSet = $this->getPageSet();
 102                 $titles = $pageSet->getGoodAndMissingTitles();
 103                 $map = $pageSet->getGoodAndMissingTitlesByNamespace();
 104
 105                 // Add in special pages, they can theoretically have backlinks too.
 106                 // (although currently they only do for prop=redirects)
 107                 foreach ( $pageSet->getSpecialTitles() as $id => $title ) {
 108                         $titles[] = $title;
 109                         $map[$title->getNamespace()][$title->getDBkey()] = $id;
 110                 }
 111
 112                 // Determine our fields to query on
 113                 $p = $settings['prefix'];
 114                 $hasNS = !isset( $settings['to_namespace'] );
 115                 if ( $hasNS ) {
 116                         $bl_namespace = "{$p}_namespace";
 117                         $bl_title = "{$p}_title";
 118                 } else {
 119                         $bl_namespace = $settings['to_namespace'];
 120                         $bl_title = "{$p}_to";
 121
 122                         $titles = array_filter( $titles, function ( $t ) use ( $bl_namespace ) {
 123                                 return $t->getNamespace() === $bl_namespace;
 124                         } );
 125                         $map = array_intersect_key( $map, [ $bl_namespace => true ] );
 126                 }
 127                 $bl_from = "{$p}_from";
 128
 129                 if ( !$titles ) {
 130                         return; // nothing to do
 131                 }
 132                 if ( $params['namespace'] !== null && count( $params['namespace'] ) === 0 ) {
 133                         return; // nothing to do
 134                 }
 135
 136                 // Figure out what we're sorting by, and add associated WHERE clauses.
 137                 // MySQL's query planner screws up if we include a field in ORDER BY
 138                 // when it's constant in WHERE, so we have to test that for each field.
 139                 $sortby = [];
 140                 if ( $hasNS && count( $map ) > 1 ) {
 141                         $sortby[$bl_namespace] = 'ns';
 142                 }
 143                 $theTitle = null;
 144                 foreach ( $map as $nsTitles ) {
 145                         reset( $nsTitles );
 146                         $key = key( $nsTitles );
 147                         if ( $theTitle === null ) {
 148                                 $theTitle = $key;
 149                         }
 150                         if ( count( $nsTitles ) > 1 || $key !== $theTitle ) {
 151                                 $sortby[$bl_title] = 'title';
 152                                 break;
 153                         }
 154                 }
 155                 $miser_ns = null;
 156                 if ( $params['namespace'] !== null ) {
 157                         if ( empty( $settings['from_namespace'] ) ) {
 158                                 if ( $this->getConfig()->get( 'MiserMode' ) ) {
 159                                         $miser_ns = $params['namespace'];
 160                                 } else {
 161                                         $this->addWhereFld( 'page_namespace', $params['namespace'] );
 162                                 }
 163                         } else {
 164                                 $this->addWhereFld( "{$p}_from_namespace", $params['namespace'] );
 165                                 if ( !empty( $settings['from_namespace'] )
 166                                         && $params['namespace'] !== null && count( $params['namespace'] ) > 1
 167                                 ) {
 168                                         $sortby["{$p}_from_namespace"] = 'int';
 169                                 }
 170                         }
 171                 }
 172                 $sortby[$bl_from] = 'int';
 173
 174                 // Now use the $sortby to figure out the continuation
 175                 if ( !is_null( $params['continue'] ) ) {
 176                         $cont = explode( '|', $params['continue'] );
 177                         $this->dieContinueUsageIf( count( $cont ) != count( $sortby ) );
 178                         $where = '';
 179                         $i = count( $sortby ) - 1;
 180                         foreach ( array_reverse( $sortby, true ) as $field => $type ) {
 181                                 $v = $cont[$i];
 182                                 switch ( $type ) {
 183                                         case 'ns':
 184                                         case 'int':
 185                                                 $v = (int)$v;
 186                                                 $this->dieContinueUsageIf( $v != $cont[$i] );
 187                                                 break;
 188                                         default:
 189                                                 $v = $db->addQuotes( $v );
 190                                                 break;
 191                                 }
 192
 193                                 if ( $where === '' ) {
 194                                         $where = "$field >= $v";
 195                                 } else {
 196                                         $where = "$field > $v OR ($field = $v AND ($where))";
 197                                 }
 198
 199                                 $i--;
 200                         }
 201                         $this->addWhere( $where );
 202                 }
 203
 204                 // Populate the rest of the query
 205                 $this->addTables( [ $settings['linktable'], 'page' ] );
 206                 $this->addWhere( "$bl_from = page_id" );
 207
 208                 if ( $this->getModuleName() === 'redirects' ) {
 209                         $this->addWhere( "rd_interwiki = $emptyString OR rd_interwiki IS NULL" );
 210                 }
 211
 212                 $this->addFields( array_keys( $sortby ) );
 213                 $this->addFields( [ 'bl_namespace' => $bl_namespace, 'bl_title' => $bl_title ] );
 214                 if ( is_null( $resultPageSet ) ) {
 215                         $fld_pageid = isset( $prop['pageid'] );
 216                         $fld_title = isset( $prop['title'] );
 217                         $fld_redirect = isset( $prop['redirect'] );
 218
 219                         $this->addFieldsIf( 'page_id', $fld_pageid );
 220                         $this->addFieldsIf( [ 'page_title', 'page_namespace' ], $fld_title );
 221                         $this->addFieldsIf( 'page_is_redirect', $fld_redirect );
 222
 223                         // prop=redirects
 224                         $fld_fragment = isset( $prop['fragment'] );
 225                         $this->addFieldsIf( 'rd_fragment', $fld_fragment );
 226                 } else {
 227                         $this->addFields( $resultPageSet->getPageTableFields() );
 228                 }
 229
 230                 $this->addFieldsIf( 'page_namespace', $miser_ns !== null );
 231
 232                 if ( $hasNS ) {
 233                         // Can't use LinkBatch because it throws away Special titles.
 234                         // And we already have the needed data structure anyway.
 235                         $this->addWhere( $db->makeWhereFrom2d( $map, $bl_namespace, $bl_title ) );
 236                 } else {
 237                         $where = [];
 238                         foreach ( $titles as $t ) {
 239                                 if ( $t->getNamespace() == $bl_namespace ) {
 240                                         $where[] = "$bl_title = " . $db->addQuotes( $t->getDBkey() );
 241                                 }
 242                         }
 243                         $this->addWhere( $db->makeList( $where, LIST_OR ) );
 244                 }
 245
 246                 if ( $params['show'] !== null ) {
 247                         // prop=redirects only
 248                         $show = array_flip( $params['show'] );
 249                         if ( isset( $show['fragment'] ) && isset( $show['!fragment'] ) ||
 250                                 isset( $show['redirect'] ) && isset( $show['!redirect'] )
 251                         ) {
 252                                 $this->dieWithError( 'apierror-show' );
 253                         }
 254                         $this->addWhereIf( "rd_fragment != $emptyString", isset( $show['fragment'] ) );
 255                         $this->addWhereIf(
 256                                 "rd_fragment = $emptyString OR rd_fragment IS NULL",
 257                                 isset( $show['!fragment'] )
 258                         );
 259                         $this->addWhereIf( [ 'page_is_redirect' => 1 ], isset( $show['redirect'] ) );
 260                         $this->addWhereIf( [ 'page_is_redirect' => 0 ], isset( $show['!redirect'] ) );
 261                 }
 262
 263                 // Override any ORDER BY from above with what we calculated earlier.
 264                 $this->addOption( 'ORDER BY', array_keys( $sortby ) );
 265
 266                 // MySQL's optimizer chokes if we have too many values in "$bl_title IN
 267                 // (...)" and chooses the wrong index, so specify the correct index to
 268                 // use for the query. See T139056 for details.
 269                 if ( !empty( $settings['indexes'] ) ) {
 270                         list( $idxNoFromNS, $idxWithFromNS ) = $settings['indexes'];
 271                         if ( $params['namespace'] !== null && !empty( $settings['from_namespace'] ) ) {
 272                                 $this->addOption( 'USE INDEX', [ $settings['linktable'] => $idxWithFromNS ] );
 273                         } else {
 274                                 $this->addOption( 'USE INDEX', [ $settings['linktable'] => $idxNoFromNS ] );
 275                         }
 276                 }
 277
 278                 // MySQL (or at least 5.5.5-10.0.23-MariaDB) chooses a really bad query
 279                 // plan if it thinks there will be more matching rows in the linktable
 280                 // than are in page. Use STRAIGHT_JOIN here to force it to use the
 281                 // intended, fast plan. See T145079 for details.
 282                 $this->addOption( 'STRAIGHT_JOIN' );
 283
 284                 $this->addOption( 'LIMIT', $params['limit'] + 1 );
 285
 286                 $res = $this->select( __METHOD__ );
 287
 288                 if ( is_null( $resultPageSet ) ) {
 289                         if ( $fld_title ) {
 290                                 $this->executeGenderCacheFromResultWrapper( $res, __METHOD__ );
 291                         }
 292
 293                         $count = 0;
 294                         foreach ( $res as $row ) {
 295                                 if ( ++$count > $params['limit'] ) {
 296                                         // We've reached the one extra which shows that
 297                                         // there are additional pages to be had. Stop here...
 298                                         $this->setContinue( $row, $sortby );
 299                                         break;
 300                                 }
 301
 302                                 if ( $miser_ns !== null && !in_array( $row->page_namespace, $miser_ns ) ) {
 303                                         // Miser mode namespace check
 304                                         continue;
 305                                 }
 306
 307                                 // Get the ID of the current page
 308                                 $id = $map[$row->bl_namespace][$row->bl_title];
 309
 310                                 $vals = [];
 311                                 if ( $fld_pageid ) {
 312                                         $vals['pageid'] = (int)$row->page_id;
 313                                 }
 314                                 if ( $fld_title ) {
 315                                         ApiQueryBase::addTitleInfo( $vals,
 316                                                 Title::makeTitle( $row->page_namespace, $row->page_title )
 317                                         );
 318                                 }
 319                                 if ( $fld_fragment && $row->rd_fragment !== null && $row->rd_fragment !== '' ) {
 320                                         $vals['fragment'] = $row->rd_fragment;
 321                                 }
 322                                 if ( $fld_redirect ) {
 323                                         $vals['redirect'] = (bool)$row->page_is_redirect;
 324                                 }
 325                                 $fit = $this->addPageSubItem( $id, $vals );
 326                                 if ( !$fit ) {
 327                                         $this->setContinue( $row, $sortby );
 328                                         break;
 329                                 }
 330                         }
 331                 } else {
 332                         $titles = [];
 333                         $count = 0;
 334                         foreach ( $res as $row ) {
 335                                 if ( ++$count > $params['limit'] ) {
 336                                         // We've reached the one extra which shows that
 337                                         // there are additional pages to be had. Stop here...
 338                                         $this->setContinue( $row, $sortby );
 339                                         break;
 340                                 }
 341
 342                                 if ( $miser_ns !== null && !in_array( $row->page_namespace, $miser_ns ) ) {
 343                                         // Miser mode namespace check
 344                                         continue;
 345                                 }
 346
 347                                 $titles[] = Title::makeTitle( $row->page_namespace, $row->page_title );
 348                         }
 349                         $resultPageSet->populateFromTitles( $titles );
 350                 }
 351         }
 352
 353         private function setContinue( $row, $sortby ) {
 354                 $cont = [];
 355                 foreach ( $sortby as $field => $v ) {
 356                         $cont[] = $row->$field;
 357                 }
 358                 $this->setContinueEnumParameter( 'continue', implode( '|', $cont ) );
 359         }
 360
 361         public function getCacheMode( $params ) {
 362                 return 'public';
 363         }
 364
 365         public function getAllowedParams() {
 366                 $settings = self::$settings[$this->getModuleName()];
 367
 368                 $ret = [
 369                         'prop' => [
 370                                 ApiBase::PARAM_TYPE => [
 371                                         'pageid',
 372                                         'title',
 373                                 ],
 374                                 ApiBase::PARAM_ISMULTI => true,
 375                                 ApiBase::PARAM_DFLT => 'pageid|title',
 376                                 ApiBase::PARAM_HELP_MSG_PER_VALUE => [],
 377                         ],
 378                         'namespace' => [
 379                                 ApiBase::PARAM_ISMULTI => true,
 380                                 ApiBase::PARAM_TYPE => 'namespace',
 381                         ],
 382                         'show' => null, // Will be filled/removed below
 383                         'limit' => [
 384                                 ApiBase::PARAM_DFLT => 10,
 385                                 ApiBase::PARAM_TYPE => 'limit',
 386                                 ApiBase::PARAM_MIN => 1,
 387                                 ApiBase::PARAM_MAX => ApiBase::LIMIT_BIG1,
 388                                 ApiBase::PARAM_MAX2 => ApiBase::LIMIT_BIG2
 389                         ],
 390                         'continue' => [
 391                                 ApiBase::PARAM_HELP_MSG => 'api-help-param-continue',
 392                         ],
 393                 ];
 394
 395                 if ( empty( $settings['from_namespace'] ) && $this->getConfig()->get( 'MiserMode' ) ) {
 396                         $ret['namespace'][ApiBase::PARAM_HELP_MSG_APPEND] = [
 397                                 'api-help-param-limited-in-miser-mode',
 398                         ];
 399                 }
 400
 401                 if ( !empty( $settings['showredirects'] ) ) {
 402                         $ret['prop'][ApiBase::PARAM_TYPE][] = 'redirect';
 403                         $ret['prop'][ApiBase::PARAM_DFLT] .= '|redirect';
 404                 }
 405                 if ( isset( $settings['props'] ) ) {
 406                         $ret['prop'][ApiBase::PARAM_TYPE] = array_merge(
 407                                 $ret['prop'][ApiBase::PARAM_TYPE], $settings['props']
 408                         );
 409                 }
 410
 411                 $show = [];
 412                 if ( !empty( $settings['showredirects'] ) ) {
 413                         $show[] = 'redirect';
 414                         $show[] = '!redirect';
 415                 }
 416                 if ( isset( $settings['show'] ) ) {
 417                         $show = array_merge( $show, $settings['show'] );
 418                 }
 419                 if ( $show ) {
 420                         $ret['show'] = [
 421                                 ApiBase::PARAM_TYPE => $show,
 422                                 ApiBase::PARAM_ISMULTI => true,
 423                         ];
 424                 } else {
 425                         unset( $ret['show'] );
 426                 }
 427
 428                 return $ret;
 429         }
 430
 431         protected function getExamplesMessages() {
 432                 $settings = self::$settings[$this->getModuleName()];
 433                 $name = $this->getModuleName();
 434                 $path = $this->getModulePath();
 435                 $title = $settings['exampletitle'] ?? 'Main Page';
 436                 $etitle = rawurlencode( $title );
 437
 438                 return [
 439                         "action=query&prop={$name}&titles={$etitle}"
 440                                 => "apihelp-$path-example-simple",
 441                         "action=query&generator={$name}&titles={$etitle}&prop=info"
 442                                 => "apihelp-$path-example-generator",
 443                 ];
 444         }
 445
 446         public function getHelpUrls() {
 447                 $name = ucfirst( $this->getModuleName() );
 448                 return "https://www.mediawiki.org/wiki/Special:MyLanguage/API:{$name}";
 449         }
 450 }