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  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 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  * @addtogroup API
  38  */
  39 class ApiQueryBacklinks extends ApiQueryGeneratorBase {
  40
  41         private $rootTitle, $contRedirs, $contLevel, $contTitle, $contID;
  42
  43         // output element name, database column field prefix, database table
  44         private $backlinksSettings = array (
  45                 'backlinks' => array (
  46                         'code' => 'bl',
  47                         'prefix' => 'pl',
  48                         'linktbl' => 'pagelinks'
  49                 ),
  50                 'embeddedin' => array (
  51                         'code' => 'ei',
  52                         'prefix' => 'tl',
  53                         'linktbl' => 'templatelinks'
  54                 ),
  55                 'imageusage' => array (
  56                         'code' => 'iu',
  57                         'prefix' => 'il',
  58                         'linktbl' => 'imagelinks'
  59                 )
  60         );
  61
  62         public function __construct($query, $moduleName) {
  63                 $code = $prefix = $linktbl = null;
  64                 extract($this->backlinksSettings[$moduleName]);
  65
  66                 parent :: __construct($query, $moduleName, $code);
  67                 $this->bl_ns = $prefix . '_namespace';
  68                 $this->bl_from = $prefix . '_from';
  69                 $this->bl_tables = array (
  70                         $linktbl,
  71                         'page'
  72                 );
  73                 $this->bl_code = $code;
  74
  75                 $this->hasNS = $moduleName !== 'imageusage';
  76                 if ($this->hasNS) {
  77                         $this->bl_title = $prefix . '_title';
  78                         $this->bl_sort = "{$this->bl_ns}, {$this->bl_title}, {$this->bl_from}";
  79                         $this->bl_fields = array (
  80                                 $this->bl_ns,
  81                                 $this->bl_title
  82                         );
  83                 } else {
  84                         $this->bl_title = $prefix . '_to';
  85                         $this->bl_sort = "{$this->bl_title}, {$this->bl_from}";
  86                         $this->bl_fields = array (
  87                                 $this->bl_title
  88                         );
  89                 }
  90         }
  91
  92         public function execute() {
  93                 $this->run();
  94         }
  95
  96         public function executeGenerator($resultPageSet) {
  97                 $this->run($resultPageSet);
  98         }
  99
 100         private function run($resultPageSet = null) {
 101                 $continue = $namespace = $redirect = $limit = null;
 102                 extract($this->extractRequestParams());
 103
 104                 if ($redirect)
 105                         ApiBase :: dieDebug(__METHOD__, 'Redirect has not been implemented', 'notimplemented');
 106
 107                 $this->processContinue($continue, $redirect);
 108
 109                 $this->addFields($this->bl_fields);
 110                 if (is_null($resultPageSet))
 111                         $this->addFields(array (
 112                                 'page_id',
 113                                 'page_namespace',
 114                                 'page_title'
 115                         ));
 116                 else
 117                         $this->addFields($resultPageSet->getPageTableFields()); // will include page_id
 118
 119                 $this->addTables($this->bl_tables);
 120                 $this->addWhere($this->bl_from . '=page_id');
 121
 122                 if ($this->hasNS)
 123                         $this->addWhereFld($this->bl_ns, $this->rootTitle->getNamespace());
 124                 $this->addWhereFld($this->bl_title, $this->rootTitle->getDBkey());
 125                 $this->addWhereFld('page_namespace', $namespace);
 126                 $this->addOption('LIMIT', $limit +1);
 127                 $this->addOption('ORDER BY', $this->bl_sort);
 128
 129                 if ($redirect)
 130                         $this->addWhereFld('page_is_redirect', 0);
 131
 132                 $db = $this->getDB();
 133                 if (!is_null($continue)) {
 134                         $plfrm = intval($this->contID);
 135                         if ($this->contLevel == 0) {
 136                                 // For the first level, there is only one target title, so no need for complex filtering
 137                                 $this->addWhere($this->bl_from . '>=' . $plfrm);
 138                         } else {
 139                                 $ns = $this->contTitle->getNamespace();
 140                                 $t = $db->addQuotes($this->contTitle->getDBkey());
 141                                 $whereWithoutNS = "{$this->bl_title}>$t OR ({$this->bl_title}=$t AND {$this->bl_from}>=$plfrm))";
 142
 143                                 if ($this->hasNS)
 144                                         $this->addWhere("{$this->bl_ns}>$ns OR ({$this->bl_ns}=$ns AND ($whereWithoutNS)");
 145                                 else
 146                                         $this->addWhere($whereWithoutNS);
 147                         }
 148                 }
 149
 150                 $res = $this->select(__METHOD__);
 151
 152                 $count = 0;
 153                 $data = array ();
 154                 while ($row = $db->fetchObject($res)) {
 155                         if (++ $count > $limit) {
 156                                 // We've reached the one extra which shows that there are additional pages to be had. Stop here...
 157                                 if ($redirect) {
 158                                         $ns = $row-> { $this->bl_ns };
 159                                         $t = $row-> { $this->bl_title };
 160                                         $continue = $this->getContinueRedirStr(false, 0, $ns, $t, $row->page_id);
 161                                 } else
 162                                         $continue = $this->getContinueStr($row->page_id);
 163                                 $this->setContinueEnumParameter('continue', $continue);
 164                                 break;
 165                         }
 166
 167                         if (is_null($resultPageSet)) {
 168                                 $vals = $this->extractRowInfo($row);
 169                                 if ($vals)
 170                                         $data[] = $vals;
 171                         } else {
 172                                 $resultPageSet->processDbRow($row);
 173                         }
 174                 }
 175                 $db->freeResult($res);
 176
 177                 if (is_null($resultPageSet) && !empty($data)) {
 178                         $result = $this->getResult();
 179                         $result->setIndexedTagName($data, $this->bl_code);
 180                         $result->addValue('query', $this->getModuleName(), $data);
 181                 }
 182         }
 183
 184         private function extractRowInfo($row) {
 185
 186                 $title = Title :: makeTitle($row->page_namespace, $row->page_title);
 187                 if (!$title->userCanRead())
 188                         return false;
 189
 190                 $vals = array();
 191                 $vals['pageid'] = intval($row->page_id);
 192                 ApiQueryBase :: addTitleInfo($vals, $title);
 193
 194                 return $vals;
 195         }
 196
 197         protected function processContinue($continue, $redirect) {
 198                 $pageSet = $this->getPageSet();
 199                 $count = $pageSet->getTitleCount();
 200                 if (!is_null($continue)) {
 201                         if ($count !== 0)
 202                                 $this->dieUsage("When continuing the {$this->getModuleName()} query, no other titles may be provided", 'titles_on_continue');
 203                         $this->parseContinueParam($continue, $redirect);
 204
 205                         // Skip all completed links
 206
 207                 } else {
 208                         if ($count !== 1)
 209                                 $this->dieUsage("The {$this->getModuleName()} query requires one title to start", 'bad_title_count');
 210                         $this->rootTitle = current($pageSet->getTitles()); // only one title there
 211                 }
 212
 213                 // only image titles are allowed for the root
 214                 if (!$this->hasNS && $this->rootTitle->getNamespace() !== NS_IMAGE)
 215                         $this->dieUsage("The title for {$this->getModuleName()} query must be an image", 'bad_image_title');
 216         }
 217
 218         protected function parseContinueParam($continue, $redirect) {
 219                 $continueList = explode('|', $continue);
 220                 if ($redirect) {
 221                         //
 222                         // expected redirect-mode parameter:
 223                         // ns|db_key|step|level|ns|db_key|id
 224                         // ns+db_key -- the root title
 225                         // step = 1 or 2 - which step to continue from - 1-titles, 2-redirects
 226                         // level -- how many levels to follow before starting enumerating.
 227                         // if level > 0 -- ns+title to continue from, otherwise skip these
 228                         // id = last page_id to continue from
 229                         //
 230                         if (count($continueList) > 4) {
 231                                 $rootNs = intval($continueList[0]);
 232                                 if (($rootNs !== 0 || $continueList[0] === '0') && !empty ($continueList[1])) {
 233                                         $this->rootTitle = Title :: makeTitleSafe($rootNs, $continueList[1]);
 234                                         if ($this->rootTitle && $this->rootTitle->userCanRead()) {
 235
 236                                                 $step = intval($continueList[2]);
 237                                                 if ($step === 1 || $step === 2) {
 238                                                         $this->contRedirs = ($step === 2);
 239
 240                                                         $level = intval($continueList[3]);
 241                                                         if ($level !== 0 || $continueList[3] === '0') {
 242                                                                 $this->contLevel = $level;
 243
 244                                                                 if ($level === 0) {
 245                                                                         if (count($continueList) === 5) {
 246                                                                                 $contID = intval($continueList[4]);
 247                                                                                 if ($contID !== 0 || $continueList[4] === '0') {
 248                                                                                         $this->contID = $contID;
 249                                                                                         return; // done
 250                                                                                 }
 251                                                                         }
 252                                                                 } else {
 253                                                                         if (count($continueList) === 7) {
 254                                                                                 $contNs = intval($continueList[4]);
 255                                                                                 if (($contNs !== 0 || $continueList[4] === '0') && !empty ($continueList[5])) {
 256                                                                                         $this->contTitle = Title :: makeTitleSafe($contNs, $continueList[5]);
 257
 258                                                                                         $contID = intval($continueList[6]);
 259                                                                                         if ($contID !== 0 || $continueList[6] === '0') {
 260                                                                                                 $this->contID = $contID;
 261                                                                                                 return; // done
 262                                                                                         }
 263                                                                                 }
 264                                                                         }
 265                                                                 }
 266                                                         }
 267                                                 }
 268                                         }
 269                                 }
 270                         }
 271                 } else {
 272                         //
 273                         // expected non-redirect-mode parameter:
 274                         // ns|db_key|id
 275                         // ns+db_key -- the root title
 276                         // id = last page_id to continue from
 277                         //
 278                         if (count($continueList) === 3) {
 279                                 $rootNs = intval($continueList[0]);
 280                                 if (($rootNs !== 0 || $continueList[0] === '0') && !empty ($continueList[1])) {
 281                                         $this->rootTitle = Title :: makeTitleSafe($rootNs, $continueList[1]);
 282                                         if ($this->rootTitle && $this->rootTitle->userCanRead()) {
 283
 284                                                 $contID = intval($continueList[2]);
 285                                                 if ($contID !== 0) {
 286                                                         $this->contID = $contID;
 287                                                         return; // done
 288                                                 }
 289                                         }
 290                                 }
 291                         }
 292                 }
 293
 294                 $this->dieUsage("Invalid continue param. You should pass the original value returned by the previous query", "_badcontinue");
 295         }
 296
 297         protected function getContinueStr($lastPageID) {
 298                 return $this->rootTitle->getNamespace() .
 299                 '|' . $this->rootTitle->getDBkey() .
 300                 '|' . $lastPageID;
 301         }
 302
 303         protected function getContinueRedirStr($isRedirPhase, $level, $ns, $title, $lastPageID) {
 304                 return $this->rootTitle->getNamespace() .
 305                 '|' . $this->rootTitle->getDBkey() .
 306                 '|' . ($isRedirPhase ? 1 : 2) .
 307                 '|' . $level .
 308                  ($level > 0 ? ('|' . $ns . '|' . $title) : '') .
 309                 '|' . $lastPageID;
 310         }
 311
 312         protected function getAllowedParams() {
 313
 314                 return array (
 315                         'continue' => null,
 316                         'namespace' => array (
 317                                 ApiBase :: PARAM_ISMULTI => true,
 318                                 ApiBase :: PARAM_TYPE => 'namespace'
 319                         ),
 320                         'redirect' => false,
 321                         'limit' => array (
 322                                 ApiBase :: PARAM_DFLT => 10,
 323                                 ApiBase :: PARAM_TYPE => 'limit',
 324                                 ApiBase :: PARAM_MIN => 1,
 325                                 ApiBase :: PARAM_MAX => ApiBase :: LIMIT_BIG1,
 326                                 ApiBase :: PARAM_MAX2 => ApiBase :: LIMIT_BIG2
 327                         )
 328                 );
 329         }
 330
 331         protected function getParamDescription() {
 332                 return array (
 333                         'continue' => 'When more results are available, use this to continue.',
 334                         'namespace' => 'The namespace to enumerate.',
 335                         'redirect' => 'If linking page is a redirect, find all pages that link to that redirect (not implemented)',
 336                         'limit' => 'How many total pages to return.'
 337                 );
 338         }
 339
 340         protected function getDescription() {
 341                 switch ($this->getModuleName()) {
 342                         case 'backlinks' :
 343                                 return 'Find all pages that link to the given page';
 344                         case 'embeddedin' :
 345                                 return 'Find all pages that embed (transclude) the given title';
 346                         case 'imageusage' :
 347                                 return 'Find all pages that use the given image title.';
 348                         default :
 349                                 ApiBase :: dieDebug(__METHOD__, 'Unknown module name');
 350                 }
 351         }
 352
 353         protected function getExamples() {
 354                 static $examples = array (
 355                         'backlinks' => array (
 356                                 "api.php?action=query&list=backlinks&titles=Main%20Page",
 357                                 "api.php?action=query&generator=backlinks&titles=Main%20Page&prop=info"
 358                         ),
 359                         'embeddedin' => array (
 360                                 "api.php?action=query&list=embeddedin&titles=Template:Stub",
 361                                 "api.php?action=query&generator=embeddedin&titles=Template:Stub&prop=info"
 362                         ),
 363                         'imageusage' => array (
 364                                 "api.php?action=query&list=imageusage&titles=Image:Albert%20Einstein%20Head.jpg",
 365                                 "api.php?action=query&generator=imageusage&titles=Image:Albert%20Einstein%20Head.jpg&prop=info"
 366                         )
 367                 );
 368
 369                 return $examples[$this->getModuleName()];
 370         }
 371
 372         public function getVersion() {
 373                 return __CLASS__ . ': $Id$';
 374         }
 375 }
 376