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 <FirstnameLastname@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  * @addtogroup API
  33  */
  34 class ApiQueryBacklinks extends ApiQueryGeneratorBase {
  35
  36         private $rootTitle, $contRedirs, $contLevel, $contTitle, $contID;
  37
  38         // output element name, database column field prefix, database table
  39         private $backlinksSettings = array (
  40                 'backlinks' => array (
  41                         'code' => 'bl',
  42                         'prefix' => 'pl',
  43                         'linktbl' => 'pagelinks'
  44                 ),
  45                 'embeddedin' => array (
  46                         'code' => 'ei',
  47                         'prefix' => 'tl',
  48                         'linktbl' => 'templatelinks'
  49                 ),
  50                 'imageusage' => array (
  51                         'code' => 'iu',
  52                         'prefix' => 'il',
  53                         'linktbl' => 'imagelinks'
  54                 )
  55         );
  56
  57         public function __construct($query, $moduleName) {
  58                 $code = $prefix = $linktbl = null;
  59                 extract($this->backlinksSettings[$moduleName]);
  60
  61                 parent :: __construct($query, $moduleName, $code);
  62                 $this->bl_ns = $prefix . '_namespace';
  63                 $this->bl_from = $prefix . '_from';
  64                 $this->bl_tables = array (
  65                         $linktbl,
  66                         'page'
  67                 );
  68                 $this->bl_code = $code;
  69
  70                 $this->hasNS = $moduleName !== 'imageusage';
  71                 if ($this->hasNS) {
  72                         $this->bl_title = $prefix . '_title';
  73                         $this->bl_sort = "{$this->bl_ns}, {$this->bl_title}, {$this->bl_from}";
  74                         $this->bl_fields = array (
  75                                 $this->bl_ns,
  76                                 $this->bl_title
  77                         );
  78                 } else {
  79                         $this->bl_title = $prefix . '_to';
  80                         $this->bl_sort = "{$this->bl_title}, {$this->bl_from}";
  81                         $this->bl_fields = array (
  82                                 $this->bl_title
  83                         );
  84                 }
  85         }
  86
  87         public function execute() {
  88                 $this->run();
  89         }
  90
  91         public function executeGenerator($resultPageSet) {
  92                 $this->run($resultPageSet);
  93         }
  94
  95         private function run($resultPageSet = null) {
  96                 $continue = $namespace = $redirect = $limit = null;
  97                 extract($this->extractRequestParams());
  98
  99                 if ($redirect)
 100                         ApiBase :: dieDebug(__METHOD__, 'Redirect has not been implemented', 'notimplemented');
 101
 102                 $this->processContinue($continue, $redirect);
 103
 104                 $this->addFields($this->bl_fields);
 105                 if (is_null($resultPageSet))
 106                         $this->addFields(array (
 107                                 'page_id',
 108                                 'page_namespace',
 109                                 'page_title'
 110                         ));
 111                 else
 112                         $this->addFields($resultPageSet->getPageTableFields()); // will include page_id
 113
 114                 $this->addTables($this->bl_tables);
 115                 $this->addWhere($this->bl_from . '=page_id');
 116
 117                 if ($this->hasNS)
 118                         $this->addWhereFld($this->bl_ns, $this->rootTitle->getNamespace());
 119                 $this->addWhereFld($this->bl_title, $this->rootTitle->getDBkey());
 120                 $this->addWhereFld('page_namespace', $namespace);
 121                 $this->addOption('LIMIT', $limit +1);
 122                 $this->addOption('ORDER BY', $this->bl_sort);
 123
 124                 if ($redirect)
 125                         $this->addWhereFld('page_is_redirect', 0);
 126
 127                 $db = $this->getDB();
 128                 if (!is_null($continue)) {
 129                         $plfrm = intval($this->contID);
 130                         if ($this->contLevel == 0) {
 131                                 // For the first level, there is only one target title, so no need for complex filtering
 132                                 $this->addWhere($this->bl_from . '>=' . $plfrm);
 133                         } else {
 134                                 $ns = $this->contTitle->getNamespace();
 135                                 $t = $db->addQuotes($this->contTitle->getDBkey());
 136                                 $whereWithoutNS = "{$this->bl_title}>$t OR ({$this->bl_title}=$t AND {$this->bl_from}>=$plfrm))";
 137
 138                                 if ($this->hasNS)
 139                                         $this->addWhere("{$this->bl_ns}>$ns OR ({$this->bl_ns}=$ns AND ($whereWithoutNS)");
 140                                 else
 141                                         $this->addWhere($whereWithoutNS);
 142                         }
 143                 }
 144
 145                 $res = $this->select(__METHOD__);
 146
 147                 $count = 0;
 148                 $data = array ();
 149                 while ($row = $db->fetchObject($res)) {
 150                         if (++ $count > $limit) {
 151                                 // We've reached the one extra which shows that there are additional pages to be had. Stop here...
 152                                 if ($redirect) {
 153                                         $ns = $row-> {
 154                                                 $this->bl_ns };
 155                                         $t = $row-> {
 156                                                 $this->bl_title };
 157                                         $continue = $this->getContinueRedirStr(false, 0, $ns, $t, $row->page_id);
 158                                 } else
 159                                         $continue = $this->getContinueStr($row->page_id);
 160                                 $this->setContinueEnumParameter('continue', $continue);
 161                                 break;
 162                         }
 163
 164                         if (is_null($resultPageSet)) {
 165                                 $vals = $this->addRowInfo('page', $row);
 166                                 if ($vals)
 167                                         $data[intval($row->page_id)] = $vals;
 168                         } else {
 169                                 $resultPageSet->processDbRow($row);
 170                         }
 171                 }
 172                 $db->freeResult($res);
 173
 174                 if (is_null($resultPageSet)) {
 175                         $result = $this->getResult();
 176                         $result->setIndexedTagName($data, $this->bl_code);
 177                         $result->addValue('query', $this->getModuleName(), $data);
 178                 }
 179         }
 180
 181         protected function processContinue($continue, $redirect) {
 182                 $pageSet = $this->getPageSet();
 183                 $count = $pageSet->getTitleCount();
 184                 if (!is_null($continue)) {
 185                         if ($count !== 0)
 186                                 $this->dieUsage("When continuing the {$this->getModuleName()} query, no other titles may be provided", 'titles_on_continue');
 187                         $this->parseContinueParam($continue, $redirect);
 188
 189                         // Skip all completed links
 190
 191                 } else {
 192                         if ($count !== 1)
 193                                 $this->dieUsage("The {$this->getModuleName()} query requires one title to start", 'bad_title_count');
 194                         $this->rootTitle = current($pageSet->getTitles()); // only one title there
 195                 }
 196
 197                 // only image titles are allowed for the root
 198                 if (!$this->hasNS && $this->rootTitle->getNamespace() !== NS_IMAGE)
 199                         $this->dieUsage("The title for {$this->getModuleName()} query must be an image", 'bad_image_title');
 200         }
 201
 202         protected function parseContinueParam($continue, $redirect) {
 203                 $continueList = explode('|', $continue);
 204                 if ($redirect) {
 205                         //
 206                         // expected redirect-mode parameter:
 207                         // ns|db_key|step|level|ns|db_key|id
 208                         // ns+db_key -- the root title
 209                         // step = 1 or 2 - which step to continue from - 1-titles, 2-redirects
 210                         // level -- how many levels to follow before starting enumerating.
 211                         // if level > 0 -- ns+title to continue from, otherwise skip these
 212                         // id = last page_id to continue from
 213                         //
 214                         if (count($continueList) > 4) {
 215                                 $rootNs = intval($continueList[0]);
 216                                 if (($rootNs !== 0 || $continueList[0] === '0') && !empty ($continueList[1])) {
 217                                         $this->rootTitle = Title :: makeTitleSafe($rootNs, $continueList[1]);
 218                                         if ($this->rootTitle && $this->rootTitle->userCanRead()) {
 219
 220                                                 $step = intval($continueList[2]);
 221                                                 if ($step === 1 || $step === 2) {
 222                                                         $this->contRedirs = ($step === 2);
 223
 224                                                         $level = intval($continueList[3]);
 225                                                         if ($level !== 0 || $continueList[3] === '0') {
 226                                                                 $this->contLevel = $level;
 227
 228                                                                 if ($level === 0) {
 229                                                                         if (count($continueList) === 5) {
 230                                                                                 $contID = intval($continueList[4]);
 231                                                                                 if ($contID !== 0 || $continueList[4] === '0') {
 232                                                                                         $this->contID = $contID;
 233                                                                                         return; // done
 234                                                                                 }
 235                                                                         }
 236                                                                 } else {
 237                                                                         if (count($continueList) === 7) {
 238                                                                                 $contNs = intval($continueList[4]);
 239                                                                                 if (($contNs !== 0 || $continueList[4] === '0') && !empty ($continueList[5])) {
 240                                                                                         $this->contTitle = Title :: makeTitleSafe($contNs, $continueList[5]);
 241
 242                                                                                         $contID = intval($continueList[6]);
 243                                                                                         if ($contID !== 0 || $continueList[6] === '0') {
 244                                                                                                 $this->contID = $contID;
 245                                                                                                 return; // done
 246                                                                                         }
 247                                                                                 }
 248                                                                         }
 249                                                                 }
 250                                                         }
 251                                                 }
 252                                         }
 253                                 }
 254                         }
 255                 } else {
 256                         //
 257                         // expected non-redirect-mode parameter:
 258                         // ns|db_key|id
 259                         // ns+db_key -- the root title
 260                         // id = last page_id to continue from
 261                         //
 262                         if (count($continueList) === 3) {
 263                                 $rootNs = intval($continueList[0]);
 264                                 if (($rootNs !== 0 || $continueList[0] === '0') && !empty ($continueList[1])) {
 265                                         $this->rootTitle = Title :: makeTitleSafe($rootNs, $continueList[1]);
 266                                         if ($this->rootTitle && $this->rootTitle->userCanRead()) {
 267
 268                                                 $contID = intval($continueList[2]);
 269                                                 if ($contID !== 0) {
 270                                                         $this->contID = $contID;
 271                                                         return; // done
 272                                                 }
 273                                         }
 274                                 }
 275                         }
 276                 }
 277
 278                 $this->dieUsage("Invalid continue param. You should pass the original value returned by the previous query", "_badcontinue");
 279         }
 280
 281         protected function getContinueStr($lastPageID) {
 282                 return $this->rootTitle->getNamespace() .
 283                 '|' . $this->rootTitle->getDBkey() .
 284                 '|' . $lastPageID;
 285         }
 286
 287         protected function getContinueRedirStr($isRedirPhase, $level, $ns, $title, $lastPageID) {
 288                 return $this->rootTitle->getNamespace() .
 289                 '|' . $this->rootTitle->getDBkey() .
 290                 '|' . ($isRedirPhase ? 1 : 2) .
 291                 '|' . $level .
 292                  ($level > 0 ? ('|' . $ns . '|' . $title) : '') .
 293                 '|' . $lastPageID;
 294         }
 295
 296         protected function getAllowedParams() {
 297
 298                 return array (
 299                         'continue' => null,
 300                         'namespace' => array (
 301                                 ApiBase :: PARAM_ISMULTI => true,
 302                                 ApiBase :: PARAM_TYPE => 'namespace'
 303                         ),
 304                         'redirect' => false,
 305                         'limit' => array (
 306                                 ApiBase :: PARAM_DFLT => 10,
 307                                 ApiBase :: PARAM_TYPE => 'limit',
 308                                 ApiBase :: PARAM_MIN => 1,
 309                                 ApiBase :: PARAM_MAX1 => ApiBase :: LIMIT_BIG1,
 310                                 ApiBase :: PARAM_MAX2 => ApiBase :: LIMIT_BIG2
 311                         )
 312                 );
 313         }
 314
 315         protected function getParamDescription() {
 316                 return array (
 317                         'continue' => 'When more results are available, use this to continue.',
 318                         'namespace' => 'The namespace to enumerate.',
 319                         'redirect' => 'If linking page is a redirect, find all pages that link to that redirect (not implemented)',
 320                         'limit' => 'How many total pages to return.'
 321                 );
 322         }
 323
 324         protected function getDescription() {
 325                 switch ($this->getModuleName()) {
 326                         case 'backlinks' :
 327                                 return 'Find all pages that link to the given page';
 328                         case 'embeddedin' :
 329                                 return 'Find all pages that embed (transclude) the given title';
 330                         case 'imageusage' :
 331                                 return 'Find all pages that use the given image title.';
 332                         default :
 333                                 ApiBase :: dieDebug(__METHOD__, 'Unknown module name');
 334                 }
 335         }
 336
 337         protected function getExamples() {
 338                 static $examples = array (
 339                         'backlinks' => array (
 340                                 "api.php?action=query&list=backlinks&titles=Main%20Page",
 341                                 "api.php?action=query&generator=backlinks&titles=Main%20Page&prop=info"
 342                         ),
 343                         'embeddedin' => array (
 344                                 "api.php?action=query&list=embeddedin&titles=Template:Stub",
 345                                 "api.php?action=query&generator=embeddedin&titles=Template:Stub&prop=info"
 346                         ),
 347                         'imageusage' => array (
 348                                 "api.php?action=query&list=imageusage&titles=Image:Albert%20Einstein%20Head.jpg",
 349                                 "api.php?action=query&generator=imageusage&titles=Image:Albert%20Einstein%20Head.jpg&prop=info"
 350                         )
 351                 );
 352
 353                 return $examples[$this->getModuleName()];
 354         }
 355
 356         public function getVersion() {
 357                 return __CLASS__ . ': $Id$';
 358         }
 359 }
 360 ?>