includes/api/ApiQueryBase.php

   1 <?php
   2
   3 /**
   4  * Created on Sep 7, 2006
   5  *
   6  * API for MediaWiki 1.8+
   7  *
   8  * Copyright © 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  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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( 'ApiBase.php' );
  29 }
  30
  31 /**
  32  * This is a base class for all Query modules.
  33  * It provides some common functionality such as constructing various SQL
  34  * queries.
  35  *
  36  * @ingroup API
  37  */
  38 abstract class ApiQueryBase extends ApiBase {
  39
  40         private $mQueryModule, $mDb, $tables, $where, $fields, $options, $join_conds;
  41
  42         public function __construct( $query, $moduleName, $paramPrefix = '' ) {
  43                 parent::__construct( $query->getMain(), $moduleName, $paramPrefix );
  44                 $this->mQueryModule = $query;
  45                 $this->mDb = null;
  46                 $this->resetQueryParams();
  47         }
  48
  49         /**
  50          * Get the cache mode for the data generated by this module. Override this
  51          * in the module subclass.
  52          *
  53          * Public caching will only be allowed if *all* the modules that supply
  54          * data for a given request return a cache mode of public.
  55          */
  56         public function getCacheMode( $params ) {
  57                 return 'private';
  58         }
  59
  60         /**
  61          * Blank the internal arrays with query parameters
  62          */
  63         protected function resetQueryParams() {
  64                 $this->tables = array();
  65                 $this->where = array();
  66                 $this->fields = array();
  67                 $this->options = array();
  68                 $this->join_conds = array();
  69         }
  70
  71         /**
  72          * Add a set of tables to the internal array
  73          * @param $tables mixed Table name or array of table names
  74          * @param $alias mixed Table alias, or null for no alias. Cannot be
  75          *  used with multiple tables
  76          */
  77         protected function addTables( $tables, $alias = null ) {
  78                 if ( is_array( $tables ) ) {
  79                         if ( !is_null( $alias ) ) {
  80                                 ApiBase::dieDebug( __METHOD__, 'Multiple table aliases not supported' );
  81                         }
  82                         $this->tables = array_merge( $this->tables, $tables );
  83                 } else {
  84                         if ( !is_null( $alias ) ) {
  85                                 $tables = $this->getAliasedName( $tables, $alias );
  86                         }
  87                         $this->tables[] = $tables;
  88                 }
  89         }
  90
  91         /**
  92          * Get the SQL for a table name with alias
  93          * @param $table string Table name
  94          * @param $alias string Alias
  95          * @return string SQL
  96          */
  97         protected function getAliasedName( $table, $alias ) {
  98                 return $this->getDB()->tableName( $table ) . ' ' . $alias;
  99         }
 100
 101         /**
 102          * Add a set of JOIN conditions to the internal array
 103          *
 104          * JOIN conditions are formatted as array( tablename => array(jointype,
 105          * conditions) e.g. array('page' => array('LEFT JOIN',
 106          * 'page_id=rev_page')) . conditions may be a string or an
 107          * addWhere()-style array
 108          * @param $join_conds array JOIN conditions
 109          */
 110         protected function addJoinConds( $join_conds ) {
 111                 if ( !is_array( $join_conds ) ) {
 112                         ApiBase::dieDebug( __METHOD__, 'Join conditions have to be arrays' );
 113                 }
 114                 $this->join_conds = array_merge( $this->join_conds, $join_conds );
 115         }
 116
 117         /**
 118          * Add a set of fields to select to the internal array
 119          * @param $value mixed Field name or array of field names
 120          */
 121         protected function addFields( $value ) {
 122                 if ( is_array( $value ) ) {
 123                         $this->fields = array_merge( $this->fields, $value );
 124                 } else {
 125                         $this->fields[] = $value;
 126                 }
 127         }
 128
 129         /**
 130          * Same as addFields(), but add the fields only if a condition is met
 131          * @param $value mixed See addFields()
 132          * @param $condition bool If false, do nothing
 133          * @return bool $condition
 134          */
 135         protected function addFieldsIf( $value, $condition ) {
 136                 if ( $condition ) {
 137                         $this->addFields( $value );
 138                         return true;
 139                 }
 140                 return false;
 141         }
 142
 143         /**
 144          * Add a set of WHERE clauses to the internal array.
 145          * Clauses can be formatted as 'foo=bar' or array('foo' => 'bar'),
 146          * the latter only works if the value is a constant (i.e. not another field)
 147          *
 148          * If $value is an empty array, this function does nothing.
 149          *
 150          * For example, array('foo=bar', 'baz' => 3, 'bla' => 'foo') translates
 151          * to "foo=bar AND baz='3' AND bla='foo'"
 152          * @param $value mixed String or array
 153          */
 154         protected function addWhere( $value ) {
 155                 if ( is_array( $value ) ) {
 156                         // Sanity check: don't insert empty arrays,
 157                         // Database::makeList() chokes on them
 158                         if ( count( $value ) ) {
 159                                 $this->where = array_merge( $this->where, $value );
 160                         }
 161                 } else {
 162                         $this->where[] = $value;
 163                 }
 164         }
 165
 166         /**
 167          * Same as addWhere(), but add the WHERE clauses only if a condition is met
 168          * @param $value mixed See addWhere()
 169          * @param $condition boolIf false, do nothing
 170          * @return bool $condition
 171          */
 172         protected function addWhereIf( $value, $condition ) {
 173                 if ( $condition ) {
 174                         $this->addWhere( $value );
 175                         return true;
 176                 }
 177                 return false;
 178         }
 179
 180         /**
 181          * Equivalent to addWhere(array($field => $value))
 182          * @param $field string Field name
 183          * @param $value string Value; ignored if null or empty array;
 184          */
 185         protected function addWhereFld( $field, $value ) {
 186                 // Use count() to its full documented capabilities to simultaneously
 187                 // test for null, empty array or empty countable object
 188                 if ( count( $value ) ) {
 189                         $this->where[$field] = $value;
 190                 }
 191         }
 192
 193         /**
 194          * Add a WHERE clause corresponding to a range, and an ORDER BY
 195          * clause to sort in the right direction
 196          * @param $field string Field name
 197          * @param $dir string If 'newer', sort in ascending order, otherwise
 198          *  sort in descending order
 199          * @param $start string Value to start the list at. If $dir == 'newer'
 200          *  this is the lower boundary, otherwise it's the upper boundary
 201          * @param $end string Value to end the list at. If $dir == 'newer' this
 202          *  is the upper boundary, otherwise it's the lower boundary
 203          * @param $sort bool If false, don't add an ORDER BY clause
 204          */
 205         protected function addWhereRange( $field, $dir, $start, $end, $sort = true ) {
 206                 $isDirNewer = ( $dir === 'newer' );
 207                 $after = ( $isDirNewer ? '>=' : '<=' );
 208                 $before = ( $isDirNewer ? '<=' : '>=' );
 209                 $db = $this->getDB();
 210
 211                 if ( !is_null( $start ) ) {
 212                         $this->addWhere( $field . $after . $db->addQuotes( $start ) );
 213                 }
 214
 215                 if ( !is_null( $end ) ) {
 216                         $this->addWhere( $field . $before . $db->addQuotes( $end ) );
 217                 }
 218
 219                 if ( $sort ) {
 220                         $order = $field . ( $isDirNewer ? '' : ' DESC' );
 221                         if ( !isset( $this->options['ORDER BY'] ) ) {
 222                                 $this->addOption( 'ORDER BY', $order );
 223                         } else {
 224                                 $this->addOption( 'ORDER BY', $this->options['ORDER BY'] . ', ' . $order );
 225                         }
 226                 }
 227         }
 228
 229         /**
 230          * Add an option such as LIMIT or USE INDEX. If an option was set
 231          * before, the old value will be overwritten
 232          * @param $name string Option name
 233          * @param $value string Option value
 234          */
 235         protected function addOption( $name, $value = null ) {
 236                 if ( is_null( $value ) ) {
 237                         $this->options[] = $name;
 238                 } else {
 239                         $this->options[$name] = $value;
 240                 }
 241         }
 242
 243         /**
 244          * Execute a SELECT query based on the values in the internal arrays
 245          * @param $method string Function the query should be attributed to.
 246          *  You should usually use __METHOD__ here
 247          * @return ResultWrapper
 248          */
 249         protected function select( $method ) {
 250                 // getDB has its own profileDBIn/Out calls
 251                 $db = $this->getDB();
 252
 253                 $this->profileDBIn();
 254                 $res = $db->select( $this->tables, $this->fields, $this->where, $method, $this->options, $this->join_conds );
 255                 $this->profileDBOut();
 256
 257                 return $res;
 258         }
 259
 260         /**
 261          * Estimate the row count for the SELECT query that would be run if we
 262          * called select() right now, and check if it's acceptable.
 263          * @return bool true if acceptable, false otherwise
 264          */
 265         protected function checkRowCount() {
 266                 $db = $this->getDB();
 267                 $this->profileDBIn();
 268                 $rowcount = $db->estimateRowCount( $this->tables, $this->fields, $this->where, __METHOD__, $this->options );
 269                 $this->profileDBOut();
 270
 271                 global $wgAPIMaxDBRows;
 272                 if ( $rowcount > $wgAPIMaxDBRows ) {
 273                         return false;
 274                 }
 275                 return true;
 276         }
 277
 278         /**
 279          * Add information (title and namespace) about a Title object to a
 280          * result array
 281          * @param $arr array Result array à la ApiResult
 282          * @param $title Title
 283          * @param $prefix string Module prefix
 284          */
 285         public static function addTitleInfo( &$arr, $title, $prefix = '' ) {
 286                 $arr[$prefix . 'ns'] = intval( $title->getNamespace() );
 287                 $arr[$prefix . 'title'] = $title->getPrefixedText();
 288         }
 289
 290         /**
 291          * Override this method to request extra fields from the pageSet
 292          * using $pageSet->requestField('fieldName')
 293          * @param $pageSet ApiPageSet
 294          */
 295         public function requestExtraData( $pageSet ) {
 296         }
 297
 298         /**
 299          * Get the main Query module
 300          * @return ApiQuery
 301          */
 302         public function getQuery() {
 303                 return $this->mQueryModule;
 304         }
 305
 306         /**
 307          * Add a sub-element under the page element with the given page ID
 308          * @param $pageId int Page ID
 309          * @param $data array Data array à la ApiResult
 310          * @return bool Whether the element fit in the result
 311          */
 312         protected function addPageSubItems( $pageId, $data ) {
 313                 $result = $this->getResult();
 314                 $result->setIndexedTagName( $data, $this->getModulePrefix() );
 315                 return $result->addValue( array( 'query', 'pages', intval( $pageId ) ),
 316                         $this->getModuleName(),
 317                         $data );
 318         }
 319
 320         /**
 321          * Same as addPageSubItems(), but one element of $data at a time
 322          * @param $pageId int Page ID
 323          * @param $item array Data array à la ApiResult
 324          * @param $elemname string XML element name. If null, getModuleName()
 325          *  is used
 326          * @return bool Whether the element fit in the result
 327          */
 328         protected function addPageSubItem( $pageId, $item, $elemname = null ) {
 329                 if ( is_null( $elemname ) ) {
 330                         $elemname = $this->getModulePrefix();
 331                 }
 332                 $result = $this->getResult();
 333                 $fit = $result->addValue( array( 'query', 'pages', $pageId,
 334                                          $this->getModuleName() ), null, $item );
 335                 if ( !$fit ) {
 336                         return false;
 337                 }
 338                 $result->setIndexedTagName_internal( array( 'query', 'pages', $pageId,
 339                                 $this->getModuleName() ), $elemname );
 340                 return true;
 341         }
 342
 343         /**
 344          * Set a query-continue value
 345          * @param $paramName string Parameter name
 346          * @param $paramValue string Parameter value
 347          */
 348         protected function setContinueEnumParameter( $paramName, $paramValue ) {
 349                 $paramName = $this->encodeParamName( $paramName );
 350                 $msg = array( $paramName => $paramValue );
 351                 $this->getResult()->disableSizeCheck();
 352                 $this->getResult()->addValue( 'query-continue', $this->getModuleName(), $msg );
 353                 $this->getResult()->enableSizeCheck();
 354         }
 355
 356         /**
 357          * Get the Query database connection (read-only)
 358          * @return Database
 359          */
 360         protected function getDB() {
 361                 if ( is_null( $this->mDb ) ) {
 362                         $this->mDb = $this->getQuery()->getDB();
 363                 }
 364                 return $this->mDb;
 365         }
 366
 367         /**
 368          * Selects the query database connection with the given name.
 369          * See ApiQuery::getNamedDB() for more information
 370          * @param $name string Name to assign to the database connection
 371          * @param $db int One of the DB_* constants
 372          * @param $groups array Query groups
 373          * @return Database
 374          */
 375         public function selectNamedDB( $name, $db, $groups ) {
 376                 $this->mDb = $this->getQuery()->getNamedDB( $name, $db, $groups );
 377         }
 378
 379         /**
 380          * Get the PageSet object to work on
 381          * @return ApiPageSet
 382          */
 383         protected function getPageSet() {
 384                 return $this->getQuery()->getPageSet();
 385         }
 386
 387         /**
 388          * Convert a title to a DB key
 389          * @param $title string Page title with spaces
 390          * @return string Page title with underscores
 391          */
 392         public function titleToKey( $title ) {
 393                 // Don't throw an error if we got an empty string
 394                 if ( trim( $title ) == '' ) {
 395                         return '';
 396                 }
 397                 $t = Title::newFromText( $title );
 398                 if ( !$t ) {
 399                         $this->dieUsageMsg( array( 'invalidtitle', $title ) );
 400                 }
 401                 return $t->getPrefixedDbKey();
 402         }
 403
 404         /**
 405          * The inverse of titleToKey()
 406          * @param $key string Page title with underscores
 407          * @return string Page title with spaces
 408          */
 409         public function keyToTitle( $key ) {
 410                 // Don't throw an error if we got an empty string
 411                 if ( trim( $key ) == '' ) {
 412                         return '';
 413                 }
 414                 $t = Title::newFromDbKey( $key );
 415                 // This really shouldn't happen but we gotta check anyway
 416                 if ( !$t ) {
 417                         $this->dieUsageMsg( array( 'invalidtitle', $key ) );
 418                 }
 419                 return $t->getPrefixedText();
 420         }
 421
 422         /**
 423          * An alternative to titleToKey() that doesn't trim trailing spaces
 424          * @param $titlePart string Title part with spaces
 425          * @return string Title part with underscores
 426          */
 427         public function titlePartToKey( $titlePart ) {
 428                 return substr( $this->titleToKey( $titlePart . 'x' ), 0, - 1 );
 429         }
 430
 431         /**
 432          * An alternative to keyToTitle() that doesn't trim trailing spaces
 433          * @param $keyPart string Key part with spaces
 434          * @return string Key part with underscores
 435          */
 436         public function keyPartToTitle( $keyPart ) {
 437                 return substr( $this->keyToTitle( $keyPart . 'x' ), 0, - 1 );
 438         }
 439
 440         public function getPossibleErrors() {
 441                 return array_merge( parent::getPossibleErrors(), array(
 442                         array( 'invalidtitle', 'title' ),
 443                         array( 'invalidtitle', 'key' ),
 444                 ) );
 445         }
 446
 447         /**
 448          * Get version string for use in the API help output
 449          * @return string
 450          */
 451         public static function getBaseVersion() {
 452                 return __CLASS__ . ': $Id$';
 453         }
 454 }
 455
 456 /**
 457  * @ingroup API
 458  */
 459 abstract class ApiQueryGeneratorBase extends ApiQueryBase {
 460
 461         private $mIsGenerator;
 462
 463         public function __construct( $query, $moduleName, $paramPrefix = '' ) {
 464                 parent::__construct( $query, $moduleName, $paramPrefix );
 465                 $this->mIsGenerator = false;
 466         }
 467
 468         /**
 469          * Switch this module to generator mode. By default, generator mode is
 470          * switched off and the module acts like a normal query module.
 471          */
 472         public function setGeneratorMode() {
 473                 $this->mIsGenerator = true;
 474         }
 475
 476         /**
 477          * Overrides base class to prepend 'g' to every generator parameter
 478          * @param $paramName string Parameter name
 479          * @return string Prefixed parameter name
 480          */
 481         public function encodeParamName( $paramName ) {
 482                 if ( $this->mIsGenerator ) {
 483                         return 'g' . parent::encodeParamName( $paramName );
 484                 } else {
 485                         return parent::encodeParamName( $paramName );
 486                 }
 487         }
 488
 489         /**
 490          * Execute this module as a generator
 491          * @param $resultPageSet ApiPageSet: All output should be appended to
 492          *  this object
 493          */
 494         public abstract function executeGenerator( $resultPageSet );
 495 }