wiki.techinc.nl/includes/api/ApiQueryAllCategories.php
Roan Kattouw 2df33ff098 * API: BREAKING CHANGE: (bug 11430) Return fewer results than the limit in some cases to prevent running out of memory
* This means queries could possibly return fewer results than the limit and still set a query-continue
* Add iicontinue, rvcontinue, cicontinue, incontinue, amfrom to faciliate query-continue for these modules
* Implemented by blocking additions to the ApiResult object if they would make it too large
** Important things like query-continue values and warnings are exempt from this check
** RSS feeds and exported XML are also exempted (size-checking them would be too messy)
** Result size is checked against $wgAPIMaxResultSize, which defaults to 8 MB

For those who really care, per-file details follow:

ApiResult.php:
* Introduced ApiResult::$mSize which keeps track of the result size.
* Introduced ApiResult::size() which calculates an array's size
  (which is the sum of the strlen()s of its elements).
* ApiResult::addValue() now checks that the result size stays below
  $wgAPIMaxResultSize. If the item won't fit, it won't be added and addValue()
  will return false. Callers should check the return value and set a
  query-continue if it's false.
* Closed the back door that is ApiResult::getData(): callers can't manipulate
  the data array directly anymore so they can't bypass the result size limit.
* Added ApiResult::setIndexedTagName_internal() which will call
  setIndexedTagName() on an array already in the result. This is needed for the
  'new' order of adding results, which means addValue()ing one result at a time
  until you hit the limit or run out, then calling this function to set the tag
  name.
* Added ApiResult::disableSizeCheck() and enableSizeCheck() which disable and
  enable size checking in addValue(). This is used for stuff like query-continue
  elements and warnings which shouldn't count towards the result size.
* Added ApiResult::unsetValue() which removes an element from the result and
  decreases $mSize.

ApiBase.php:
* Like ApiResult::getData(), ApiBase::getResultData() no longer returns a
  reference.
* Use ApiResult::disableSizeCheck() in ApiBase::setWarning()

ApiQueryBase.php:
* Added ApiQueryBase::addPageSubItem(), which adds page subitems one item
  at a time.
* addPageSubItem() and addPageSubItems() now return whether the subitem
  fit in the result.
* Use ApiResult::disableSizeCheck() in setContinueEnumParameter()

ApiMain.php:
* Use ApiResult::disableSizeCheck() in ApiMain::substituteResultWithError()
* Use getParameter() rather than $mRequest to obtain requestid

DefaultSettings.php:
* Added $wgAPIMaxResultSize, with a default value of 8 MB

ApiQuery*.php:
* Added results one at a time, and set a query-continue if the result is full.

ApiQueryLangLinks.php and friends:
* Migrated from addPageSubItems() to addPageSubItem(). This eliminates the
  need for $lastId.

ApiQueryAllLinks.php, ApiQueryWatchlist.php, ApiQueryAllimages.php, ApiQuerySearch.php:
* Renamed $data to something more appropriate ($pageids, $ids or $titles)

ApiQuerySiteinfo.php:
* Abuse siprop as a query-continue parameter and set it to all props that
  couldn't be processed.

ApiQueryRandom.php:
* Doesn't do continuations, because the result is supposed to be random.
* Be smart enough to not run the second query if the results of the first
  didn't fit.

ApiQueryImageInfo.php, ApiQueryRevisions.php, ApiQueryCategoryInfo.php, ApiQueryInfo.php:
* Added continue parameter which basically skips the first so many items

ApiQueryBacklinks.php:
* Throw the result in a big array first and addValue() that one element at a time if necessary
** This is necessary because the results aren't retrieved in order
* Introduced $this->pageMap to map namespace and title to page ID
* Rewritten extractRowInfo() and extractRedirRowInfo() a little
* Declared all private member variables explicitly

ApiQueryDeletedrevs.php:
* Use a pagemap just like in Backlinks
* Introduce fake page IDs and keep track of them so we know where to add what
** This doesn't change the output format, because the fake page IDs start at 0 and are consecutive

ApiQueryAllmessages.php:
* Add amfrom to facilitate query-continue

ApiQueryUsers.php:
* Rewrite: put the getOtherUsersInfo() code in execute()
2009-02-05 14:30:59 +00:00

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<?php
/*
* Created on December 12, 2007
*
* API for MediaWiki 1.8+
*
* Copyright (C) 2007 Roan Kattouw <Firstname>.<Lastname>@home.nl
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
* http://www.gnu.org/copyleft/gpl.html
*/
if (!defined('MEDIAWIKI')) {
// Eclipse helper - will be ignored in production
require_once ('ApiQueryBase.php');
}
/**
* Query module to enumerate all categories, even the ones that don't have
* category pages.
*
* @ingroup API
*/
class ApiQueryAllCategories extends ApiQueryGeneratorBase {
public function __construct($query, $moduleName) {
parent :: __construct($query, $moduleName, 'ac');
}
public function execute() {
$this->run();
}
public function executeGenerator($resultPageSet) {
$this->run($resultPageSet);
}
private function run($resultPageSet = null) {
$db = $this->getDB();
$params = $this->extractRequestParams();
$this->addTables('category');
$this->addFields('cat_title');
$dir = ($params['dir'] == 'descending' ? 'older' : 'newer');
$from = (is_null($params['from']) ? null : $this->titlePartToKey($params['from']));
$this->addWhereRange('cat_title', $dir, $from, null);
if (isset ($params['prefix']))
$this->addWhere("cat_title LIKE '" . $db->escapeLike($this->titlePartToKey($params['prefix'])) . "%'");
$this->addOption('LIMIT', $params['limit']+1);
$this->addOption('ORDER BY', 'cat_title' . ($params['dir'] == 'descending' ? ' DESC' : ''));
$prop = array_flip($params['prop']);
$this->addFieldsIf( array( 'cat_pages', 'cat_subcats', 'cat_files' ), isset($prop['size']) );
if(isset($prop['hidden']))
{
$this->addTables(array('page', 'page_props'));
$this->addJoinConds(array(
'page' => array('LEFT JOIN', array(
'page_namespace' => NS_CATEGORY,
'page_title=cat_title')),
'page_props' => array('LEFT JOIN', array(
'pp_page=page_id',
'pp_propname' => 'hiddencat')),
));
$this->addFields('pp_propname AS cat_hidden');
}
$res = $this->select(__METHOD__);
$pages = array();
$categories = array();
$result = $this->getResult();
$count = 0;
while ($row = $db->fetchObject($res)) {
if (++ $count > $params['limit']) {
// We've reached the one extra which shows that there are additional cats to be had. Stop here...
// TODO: Security issue - if the user has no right to view next title, it will still be shown
$this->setContinueEnumParameter('from', $this->keyToTitle($row->cat_title));
break;
}
// Normalize titles
$titleObj = Title::makeTitle(NS_CATEGORY, $row->cat_title);
if(!is_null($resultPageSet))
$pages[] = $titleObj->getPrefixedText();
else {
$item = array();
$result->setContent( $item, $titleObj->getText() );
if( isset( $prop['size'] ) ) {
$item['size'] = $row->cat_pages;
$item['pages'] = $row->cat_pages - $row->cat_subcats - $row->cat_files;
$item['files'] = $row->cat_files;
$item['subcats'] = $row->cat_subcats;
}
if( isset( $prop['hidden'] ) && $row->cat_hidden )
$item['hidden'] = '';
$fit = $result->addValue(array('query', $this->getModuleName()), null, $item);
if(!$fit)
{
$this->setContinueEnumParameter('from', $this->keyToTitle($row->cat_title));
break;
}
}
}
$db->freeResult($res);
if (is_null($resultPageSet)) {
$result->setIndexedTagName_internal(array('query', $this->getModuleName()), 'c');
} else {
$resultPageSet->populateFromTitles($pages);
}
}
public function getAllowedParams() {
return array (
'from' => null,
'prefix' => null,
'dir' => array(
ApiBase :: PARAM_DFLT => 'ascending',
ApiBase :: PARAM_TYPE => array(
'ascending',
'descending'
),
),
'limit' => array (
ApiBase :: PARAM_DFLT => 10,
ApiBase :: PARAM_TYPE => 'limit',
ApiBase :: PARAM_MIN => 1,
ApiBase :: PARAM_MAX => ApiBase :: LIMIT_BIG1,
ApiBase :: PARAM_MAX2 => ApiBase :: LIMIT_BIG2
),
'prop' => array (
ApiBase :: PARAM_TYPE => array( 'size', 'hidden' ),
ApiBase :: PARAM_DFLT => '',
ApiBase :: PARAM_ISMULTI => true
),
);
}
public function getParamDescription() {
return array (
'from' => 'The category to start enumerating from.',
'prefix' => 'Search for all category titles that begin with this value.',
'dir' => 'Direction to sort in.',
'limit' => 'How many categories to return.',
'prop' => 'Which properties to get',
);
}
public function getDescription() {
return 'Enumerate all categories';
}
protected function getExamples() {
return array (
'api.php?action=query&list=allcategories&acprop=size',
'api.php?action=query&generator=allcategories&gacprefix=List&prop=info',
);
}
public function getVersion() {
return __CLASS__ . ': $Id$';
}
}