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 $params, $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                 $this->params = $this->extractRequestParams();
 102
 103                 $redirect = $this->params['redirect'];
 104                 if ($redirect)
 105                         ApiBase :: dieDebug(__METHOD__, 'Redirect has not been implemented', 'notimplemented');
 106
 107                 $this->processContinue();
 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', $this->params['namespace']);
 126
 127                 $limit = $this->params['limit'];
 128                 $this->addOption('LIMIT', $limit +1);
 129                 $this->addOption('ORDER BY', $this->bl_sort);
 130
 131                 if ($redirect)
 132                         $this->addWhereFld('page_is_redirect', 0);
 133
 134                 $db = $this->getDB();
 135                 if (!is_null($this->params['continue'])) {
 136                         $plfrm = intval($this->contID);
 137                         if ($this->contLevel == 0) {
 138                                 // For the first level, there is only one target title, so no need for complex filtering
 139                                 $this->addWhere($this->bl_from . '>=' . $plfrm);
 140                         } else {
 141                                 $ns = $this->contTitle->getNamespace();
 142                                 $t = $db->addQuotes($this->contTitle->getDBkey());
 143                                 $whereWithoutNS = "{$this->bl_title}>$t OR ({$this->bl_title}=$t AND {$this->bl_from}>=$plfrm))";
 144
 145                                 if ($this->hasNS)
 146                                         $this->addWhere("{$this->bl_ns}>$ns OR ({$this->bl_ns}=$ns AND ($whereWithoutNS)");
 147                                 else
 148                                         $this->addWhere($whereWithoutNS);
 149                         }
 150                 }
 151
 152                 $res = $this->select(__METHOD__);
 153
 154                 $count = 0;
 155                 $data = array ();
 156                 while ($row = $db->fetchObject($res)) {
 157                         if (++ $count > $limit) {
 158                                 // We've reached the one extra which shows that there are additional pages to be had. Stop here...
 159                                 if ($redirect) {
 160                                         $ns = $row-> { $this->bl_ns };
 161                                         $t = $row-> { $this->bl_title };
 162                                         $continue = $this->getContinueRedirStr(false, 0, $ns, $t, $row->page_id);
 163                                 } else
 164                                         $continue = $this->getContinueStr($row->page_id);
 165                                 // TODO: Security issue - if the user has no right to view next title, it will still be shown
 166                                 $this->setContinueEnumParameter('continue', $continue);
 167                                 break;
 168                         }
 169
 170                         if (is_null($resultPageSet)) {
 171                                 $vals = $this->extractRowInfo($row);
 172                                 if ($vals)
 173                                         $data[] = $vals;
 174                         } else {
 175                                 $resultPageSet->processDbRow($row);
 176                         }
 177                 }
 178                 $db->freeResult($res);
 179
 180                 if (is_null($resultPageSet) && !empty($data)) {
 181                         $result = $this->getResult();
 182                         $result->setIndexedTagName($data, $this->bl_code);
 183                         $result->addValue('query', $this->getModuleName(), $data);
 184                 }
 185         }
 186
 187         private function extractRowInfo($row) {
 188
 189                 $vals = array();
 190                 $vals['pageid'] = intval($row->page_id);
 191                 ApiQueryBase :: addTitleInfo($vals, Title :: makeTitle($row->page_namespace, $row->page_title));
 192
 193                 return $vals;
 194         }
 195
 196         protected function processContinue() {
 197                 $pageSet = $this->getPageSet();
 198                 $count = $pageSet->getTitleCount();
 199
 200                 if (!is_null($this->params['continue'])) {
 201                         $this->parseContinueParam();
 202
 203                         // Skip all completed links
 204
 205                 } else {
 206                         $title = $this->params['title'];
 207                         if (!is_null($title)) {
 208                                 $this->rootTitle = Title :: newFromText($title);
 209                         } else {  // This case is obsolete. Will support this for a while
 210                                 if ($count !== 1)
 211                                         $this->dieUsage("The {$this->getModuleName()} query requires one title to start", 'bad_title_count');
 212                                 $this->rootTitle = current($pageSet->getTitles()); // only one title there
 213                                 $this->setWarning('Using titles parameter is obsolete for this list. Use ' . $this->encodeParamName('title') . ' instead.');
 214                         }
 215                 }
 216
 217                 // only image titles are allowed for the root
 218                 if (!$this->hasNS && $this->rootTitle->getNamespace() !== NS_IMAGE)
 219                         $this->dieUsage("The title for {$this->getModuleName()} query must be an image", 'bad_image_title');
 220         }
 221
 222         protected function parseContinueParam() {
 223                 $continueList = explode('|', $this->params['continue']);
 224                 if ($this->params['redirect']) {
 225                         //
 226                         // expected redirect-mode parameter:
 227                         // ns|db_key|step|level|ns|db_key|id
 228                         // ns+db_key -- the root title
 229                         // step = 1 or 2 - which step to continue from - 1-titles, 2-redirects
 230                         // level -- how many levels to follow before starting enumerating.
 231                         // if level > 0 -- ns+title to continue from, otherwise skip these
 232                         // id = last page_id to continue from
 233                         //
 234                         if (count($continueList) > 4) {
 235                                 $rootNs = intval($continueList[0]);
 236                                 if (($rootNs !== 0 || $continueList[0] === '0') && !empty ($continueList[1])) {
 237                                         $this->rootTitle = Title :: makeTitleSafe($rootNs, $continueList[1]);
 238                                         if ($this->rootTitle) {
 239
 240                                                 $step = intval($continueList[2]);
 241                                                 if ($step === 1 || $step === 2) {
 242                                                         $this->contRedirs = ($step === 2);
 243
 244                                                         $level = intval($continueList[3]);
 245                                                         if ($level !== 0 || $continueList[3] === '0') {
 246                                                                 $this->contLevel = $level;
 247
 248                                                                 if ($level === 0) {
 249                                                                         if (count($continueList) === 5) {
 250                                                                                 $contID = intval($continueList[4]);
 251                                                                                 if ($contID !== 0 || $continueList[4] === '0') {
 252                                                                                         $this->contID = $contID;
 253                                                                                         return; // done
 254                                                                                 }
 255                                                                         }
 256                                                                 } else {
 257                                                                         if (count($continueList) === 7) {
 258                                                                                 $contNs = intval($continueList[4]);
 259                                                                                 if (($contNs !== 0 || $continueList[4] === '0') && !empty ($continueList[5])) {
 260                                                                                         $this->contTitle = Title :: makeTitleSafe($contNs, $continueList[5]);
 261
 262                                                                                         $contID = intval($continueList[6]);
 263                                                                                         if ($contID !== 0 || $continueList[6] === '0') {
 264                                                                                                 $this->contID = $contID;
 265                                                                                                 return; // done
 266                                                                                         }
 267                                                                                 }
 268                                                                         }
 269                                                                 }
 270                                                         }
 271                                                 }
 272                                         }
 273                                 }
 274                         }
 275                 } else {
 276                         //
 277                         // expected non-redirect-mode parameter:
 278                         // ns|db_key|id
 279                         // ns+db_key -- the root title
 280                         // id = last page_id to continue from
 281                         //
 282                         if (count($continueList) === 3) {
 283                                 $rootNs = intval($continueList[0]);
 284                                 if (($rootNs !== 0 || $continueList[0] === '0') && !empty ($continueList[1])) {
 285                                         $this->rootTitle = Title :: makeTitleSafe($rootNs, $continueList[1]);
 286                                         if ($this->rootTitle) {
 287
 288                                                 $contID = intval($continueList[2]);
 289                                                 if ($contID !== 0) {
 290                                                         $this->contID = $contID;
 291                                                         return; // done
 292                                                 }
 293                                         }
 294                                 }
 295                         }
 296                 }
 297
 298                 $this->dieUsage("Invalid continue param. You should pass the original value returned by the previous query", "_badcontinue");
 299         }
 300
 301         protected function getContinueStr($lastPageID) {
 302                 return $this->rootTitle->getNamespace() .
 303                 '|' . $this->rootTitle->getDBkey() .
 304                 '|' . $lastPageID;
 305         }
 306
 307         protected function getContinueRedirStr($isRedirPhase, $level, $ns, $title, $lastPageID) {
 308                 return $this->rootTitle->getNamespace() .
 309                 '|' . $this->rootTitle->getDBkey() .
 310                 '|' . ($isRedirPhase ? 1 : 2) .
 311                 '|' . $level .
 312                  ($level > 0 ? ('|' . $ns . '|' . $title) : '') .
 313                 '|' . $lastPageID;
 314         }
 315
 316         protected function getAllowedParams() {
 317
 318                 return array (
 319                         'title' => null,
 320                         'continue' => null,
 321                         'namespace' => array (
 322                                 ApiBase :: PARAM_ISMULTI => true,
 323                                 ApiBase :: PARAM_TYPE => 'namespace'
 324                         ),
 325                         'redirect' => false,
 326                         'limit' => array (
 327                                 ApiBase :: PARAM_DFLT => 10,
 328                                 ApiBase :: PARAM_TYPE => 'limit',
 329                                 ApiBase :: PARAM_MIN => 1,
 330                                 ApiBase :: PARAM_MAX => ApiBase :: LIMIT_BIG1,
 331                                 ApiBase :: PARAM_MAX2 => ApiBase :: LIMIT_BIG2
 332                         )
 333                 );
 334         }
 335
 336         protected function getParamDescription() {
 337                 return array (
 338                         'title' => 'Title to search. If null, titles= parameter will be used instead, but will be obsolete soon.',
 339                         'continue' => 'When more results are available, use this to continue.',
 340                         'namespace' => 'The namespace to enumerate.',
 341                         'redirect' => 'If linking page is a redirect, find all pages that link to that redirect (not implemented)',
 342                         'limit' => 'How many total pages to return.'
 343                 );
 344         }
 345
 346         protected function getDescription() {
 347                 switch ($this->getModuleName()) {
 348                         case 'backlinks' :
 349                                 return 'Find all pages that link to the given page';
 350                         case 'embeddedin' :
 351                                 return 'Find all pages that embed (transclude) the given title';
 352                         case 'imageusage' :
 353                                 return 'Find all pages that use the given image title.';
 354                         default :
 355                                 ApiBase :: dieDebug(__METHOD__, 'Unknown module name');
 356                 }
 357         }
 358
 359         protected function getExamples() {
 360                 static $examples = array (
 361                         'backlinks' => array (
 362                                 "api.php?action=query&list=backlinks&bltitle=Main%20Page",
 363                                 "api.php?action=query&generator=backlinks&gbltitle=Main%20Page&prop=info"
 364                         ),
 365                         'embeddedin' => array (
 366                                 "api.php?action=query&list=embeddedin&eititle=Template:Stub",
 367                                 "api.php?action=query&generator=embeddedin&geititle=Template:Stub&prop=info"
 368                         ),
 369                         'imageusage' => array (
 370                                 "api.php?action=query&list=imageusage&iutitle=Image:Albert%20Einstein%20Head.jpg",
 371                                 "api.php?action=query&generator=imageusage&giutitle=Image:Albert%20Einstein%20Head.jpg&prop=info"
 372                         )
 373                 );
 374
 375                 return $examples[$this->getModuleName()];
 376         }
 377
 378         public function getVersion() {
 379                 return __CLASS__ . ': $Id$';
 380         }
 381 }
 382