includes/api/ApiQueryBase.php

   1 <?php
   2 /**
   3  * API for MediaWiki 1.8+
   4  *
   5  * Created on Sep 7, 2006
   6  *
   7  * Copyright © 2006 Yuri Astrakhan <Firstname><Lastname>@gmail.com
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  22  * http://www.gnu.org/copyleft/gpl.html
  23  *
  24  * @file
  25  */
  26
  27 if ( !defined( 'MEDIAWIKI' ) ) {
  28         // Eclipse helper - will be ignored in production
  29         require_once( 'ApiBase.php' );
  30 }
  31
  32 /**
  33  * This is a base class for all Query modules.
  34  * It provides some common functionality such as constructing various SQL
  35  * queries.
  36  *
  37  * @ingroup API
  38  */
  39 abstract class ApiQueryBase extends ApiBase {
  40
  41         private $mQueryModule, $mDb, $tables, $where, $fields, $options, $join_conds;
  42
  43         public function __construct( ApiQuery $query, $moduleName, $paramPrefix = '' ) {
  44                 parent::__construct( $query->getMain(), $moduleName, $paramPrefix );
  45                 $this->mQueryModule = $query;
  46                 $this->mDb = null;
  47                 $this->resetQueryParams();
  48         }
  49
  50         /**
  51          * Get the cache mode for the data generated by this module. Override
  52          * this in the module subclass. For possible return values and other
  53          * details about cache modes, see ApiMain::setCacheMode()
  54          *
  55          * Public caching will only be allowed if *all* the modules that supply
  56          * data for a given request return a cache mode of public.
  57          */
  58         public function getCacheMode( $params ) {
  59                 return 'private';
  60         }
  61
  62         /**
  63          * Blank the internal arrays with query parameters
  64          */
  65         protected function resetQueryParams() {
  66                 $this->tables = array();
  67                 $this->where = array();
  68                 $this->fields = array();
  69                 $this->options = array();
  70                 $this->join_conds = array();
  71         }
  72
  73         /**
  74          * Add a set of tables to the internal array
  75          * @param $tables mixed Table name or array of table names
  76          * @param $alias mixed Table alias, or null for no alias. Cannot be
  77          *  used with multiple tables
  78          */
  79         protected function addTables( $tables, $alias = null ) {
  80                 if ( is_array( $tables ) ) {
  81                         if ( !is_null( $alias ) ) {
  82                                 ApiBase::dieDebug( __METHOD__, 'Multiple table aliases not supported' );
  83                         }
  84                         $this->tables = array_merge( $this->tables, $tables );
  85                 } else {
  86                         if ( !is_null( $alias ) ) {
  87                                 $tables = $this->getAliasedName( $tables, $alias );
  88                         }
  89                         $this->tables[] = $tables;
  90                 }
  91         }
  92
  93         /**
  94          * Get the SQL for a table name with alias
  95          * @param $table string Table name
  96          * @param $alias string Alias
  97          * @return string SQL
  98          */
  99         protected function getAliasedName( $table, $alias ) {
 100                 return $this->getDB()->tableName( $table ) . ' ' . $alias;
 101         }
 102
 103         /**
 104          * Add a set of JOIN conditions to the internal array
 105          *
 106          * JOIN conditions are formatted as array( tablename => array(jointype,
 107          * conditions) e.g. array('page' => array('LEFT JOIN',
 108          * 'page_id=rev_page')) . conditions may be a string or an
 109          * addWhere()-style array
 110          * @param $join_conds array JOIN conditions
 111          */
 112         protected function addJoinConds( $join_conds ) {
 113                 if ( !is_array( $join_conds ) ) {
 114                         ApiBase::dieDebug( __METHOD__, 'Join conditions have to be arrays' );
 115                 }
 116                 $this->join_conds = array_merge( $this->join_conds, $join_conds );
 117         }
 118
 119         /**
 120          * Add a set of fields to select to the internal array
 121          * @param $value mixed Field name or array of field names
 122          */
 123         protected function addFields( $value ) {
 124                 if ( is_array( $value ) ) {
 125                         $this->fields = array_merge( $this->fields, $value );
 126                 } else {
 127                         $this->fields[] = $value;
 128                 }
 129         }
 130
 131         /**
 132          * Same as addFields(), but add the fields only if a condition is met
 133          * @param $value mixed See addFields()
 134          * @param $condition bool If false, do nothing
 135          * @return bool $condition
 136          */
 137         protected function addFieldsIf( $value, $condition ) {
 138                 if ( $condition ) {
 139                         $this->addFields( $value );
 140                         return true;
 141                 }
 142                 return false;
 143         }
 144
 145         /**
 146          * Add a set of WHERE clauses to the internal array.
 147          * Clauses can be formatted as 'foo=bar' or array('foo' => 'bar'),
 148          * the latter only works if the value is a constant (i.e. not another field)
 149          *
 150          * If $value is an empty array, this function does nothing.
 151          *
 152          * For example, array('foo=bar', 'baz' => 3, 'bla' => 'foo') translates
 153          * to "foo=bar AND baz='3' AND bla='foo'"
 154          * @param $value mixed String or array
 155          */
 156         protected function addWhere( $value ) {
 157                 if ( is_array( $value ) ) {
 158                         // Sanity check: don't insert empty arrays,
 159                         // Database::makeList() chokes on them
 160                         if ( count( $value ) ) {
 161                                 $this->where = array_merge( $this->where, $value );
 162                         }
 163                 } else {
 164                         $this->where[] = $value;
 165                 }
 166         }
 167
 168         /**
 169          * Same as addWhere(), but add the WHERE clauses only if a condition is met
 170          * @param $value mixed See addWhere()
 171          * @param $condition boolIf false, do nothing
 172          * @return bool $condition
 173          */
 174         protected function addWhereIf( $value, $condition ) {
 175                 if ( $condition ) {
 176                         $this->addWhere( $value );
 177                         return true;
 178                 }
 179                 return false;
 180         }
 181
 182         /**
 183          * Equivalent to addWhere(array($field => $value))
 184          * @param $field string Field name
 185          * @param $value string Value; ignored if null or empty array;
 186          */
 187         protected function addWhereFld( $field, $value ) {
 188                 // Use count() to its full documented capabilities to simultaneously
 189                 // test for null, empty array or empty countable object
 190                 if ( count( $value ) ) {
 191                         $this->where[$field] = $value;
 192                 }
 193         }
 194
 195         /**
 196          * Add a WHERE clause corresponding to a range, and an ORDER BY
 197          * clause to sort in the right direction
 198          * @param $field string Field name
 199          * @param $dir string If 'newer', sort in ascending order, otherwise
 200          *  sort in descending order
 201          * @param $start string Value to start the list at. If $dir == 'newer'
 202          *  this is the lower boundary, otherwise it's the upper boundary
 203          * @param $end string Value to end the list at. If $dir == 'newer' this
 204          *  is the upper boundary, otherwise it's the lower boundary
 205          * @param $sort bool If false, don't add an ORDER BY clause
 206          */
 207         protected function addWhereRange( $field, $dir, $start, $end, $sort = true ) {
 208                 $isDirNewer = ( $dir === 'newer' );
 209                 $after = ( $isDirNewer ? '>=' : '<=' );
 210                 $before = ( $isDirNewer ? '<=' : '>=' );
 211                 $db = $this->getDB();
 212
 213                 if ( !is_null( $start ) ) {
 214                         $this->addWhere( $field . $after . $db->addQuotes( $start ) );
 215                 }
 216
 217                 if ( !is_null( $end ) ) {
 218                         $this->addWhere( $field . $before . $db->addQuotes( $end ) );
 219                 }
 220
 221                 if ( $sort ) {
 222                         $order = $field . ( $isDirNewer ? '' : ' DESC' );
 223                         if ( !isset( $this->options['ORDER BY'] ) ) {
 224                                 $this->addOption( 'ORDER BY', $order );
 225                         } else {
 226                                 $this->addOption( 'ORDER BY', $this->options['ORDER BY'] . ', ' . $order );
 227                         }
 228                 }
 229         }
 230
 231         /**
 232          * Add an option such as LIMIT or USE INDEX. If an option was set
 233          * before, the old value will be overwritten
 234          * @param $name string Option name
 235          * @param $value string Option value
 236          */
 237         protected function addOption( $name, $value = null ) {
 238                 if ( is_null( $value ) ) {
 239                         $this->options[] = $name;
 240                 } else {
 241                         $this->options[$name] = $value;
 242                 }
 243         }
 244
 245         /**
 246          * Execute a SELECT query based on the values in the internal arrays
 247          * @param $method string Function the query should be attributed to.
 248          *  You should usually use __METHOD__ here
 249          * @return ResultWrapper
 250          */
 251         protected function select( $method ) {
 252                 // getDB has its own profileDBIn/Out calls
 253                 $db = $this->getDB();
 254
 255                 $this->profileDBIn();
 256                 $res = $db->select( $this->tables, $this->fields, $this->where, $method, $this->options, $this->join_conds );
 257                 $this->profileDBOut();
 258
 259                 return $res;
 260         }
 261
 262         /**
 263          * Estimate the row count for the SELECT query that would be run if we
 264          * called select() right now, and check if it's acceptable.
 265          * @return bool true if acceptable, false otherwise
 266          */
 267         protected function checkRowCount() {
 268                 $db = $this->getDB();
 269                 $this->profileDBIn();
 270                 $rowcount = $db->estimateRowCount( $this->tables, $this->fields, $this->where, __METHOD__, $this->options );
 271                 $this->profileDBOut();
 272
 273                 global $wgAPIMaxDBRows;
 274                 if ( $rowcount > $wgAPIMaxDBRows ) {
 275                         return false;
 276                 }
 277                 return true;
 278         }
 279
 280         /**
 281          * Add information (title and namespace) about a Title object to a
 282          * result array
 283          * @param $arr array Result array à la ApiResult
 284          * @param $title Title
 285          * @param $prefix string Module prefix
 286          */
 287         public static function addTitleInfo( &$arr, $title, $prefix = '' ) {
 288                 $arr[$prefix . 'ns'] = intval( $title->getNamespace() );
 289                 $arr[$prefix . 'title'] = $title->getPrefixedText();
 290         }
 291
 292         /**
 293          * Override this method to request extra fields from the pageSet
 294          * using $pageSet->requestField('fieldName')
 295          * @param $pageSet ApiPageSet
 296          */
 297         public function requestExtraData( $pageSet ) {
 298         }
 299
 300         /**
 301          * Get the main Query module
 302          * @return ApiQuery
 303          */
 304         public function getQuery() {
 305                 return $this->mQueryModule;
 306         }
 307
 308         /**
 309          * Add a sub-element under the page element with the given page ID
 310          * @param $pageId int Page ID
 311          * @param $data array Data array à la ApiResult
 312          * @return bool Whether the element fit in the result
 313          */
 314         protected function addPageSubItems( $pageId, $data ) {
 315                 $result = $this->getResult();
 316                 $result->setIndexedTagName( $data, $this->getModulePrefix() );
 317                 return $result->addValue( array( 'query', 'pages', intval( $pageId ) ),
 318                         $this->getModuleName(),
 319                         $data );
 320         }
 321
 322         /**
 323          * Same as addPageSubItems(), but one element of $data at a time
 324          * @param $pageId int Page ID
 325          * @param $item array Data array à la ApiResult
 326          * @param $elemname string XML element name. If null, getModuleName()
 327          *  is used
 328          * @return bool Whether the element fit in the result
 329          */
 330         protected function addPageSubItem( $pageId, $item, $elemname = null ) {
 331                 if ( is_null( $elemname ) ) {
 332                         $elemname = $this->getModulePrefix();
 333                 }
 334                 $result = $this->getResult();
 335                 $fit = $result->addValue( array( 'query', 'pages', $pageId,
 336                                          $this->getModuleName() ), null, $item );
 337                 if ( !$fit ) {
 338                         return false;
 339                 }
 340                 $result->setIndexedTagName_internal( array( 'query', 'pages', $pageId,
 341                                 $this->getModuleName() ), $elemname );
 342                 return true;
 343         }
 344
 345         /**
 346          * Set a query-continue value
 347          * @param $paramName string Parameter name
 348          * @param $paramValue string Parameter value
 349          */
 350         protected function setContinueEnumParameter( $paramName, $paramValue ) {
 351                 $paramName = $this->encodeParamName( $paramName );
 352                 $msg = array( $paramName => $paramValue );
 353                 $this->getResult()->disableSizeCheck();
 354                 $this->getResult()->addValue( 'query-continue', $this->getModuleName(), $msg );
 355                 $this->getResult()->enableSizeCheck();
 356         }
 357
 358         /**
 359          * Get the Query database connection (read-only)
 360          * @return Database
 361          */
 362         protected function getDB() {
 363                 if ( is_null( $this->mDb ) ) {
 364                         $apiQuery = $this->getQuery();
 365                         $this->mDb = $apiQuery->getDB();
 366                 }
 367                 return $this->mDb;
 368         }
 369
 370         /**
 371          * Selects the query database connection with the given name.
 372          * See ApiQuery::getNamedDB() for more information
 373          * @param $name string Name to assign to the database connection
 374          * @param $db int One of the DB_* constants
 375          * @param $groups array Query groups
 376          * @return Database
 377          */
 378         public function selectNamedDB( $name, $db, $groups ) {
 379                 $this->mDb = $this->getQuery()->getNamedDB( $name, $db, $groups );
 380         }
 381
 382         /**
 383          * Get the PageSet object to work on
 384          * @return ApiPageSet
 385          */
 386         protected function getPageSet() {
 387                 return $this->getQuery()->getPageSet();
 388         }
 389
 390         /**
 391          * Convert a title to a DB key
 392          * @param $title string Page title with spaces
 393          * @return string Page title with underscores
 394          */
 395         public function titleToKey( $title ) {
 396                 // Don't throw an error if we got an empty string
 397                 if ( trim( $title ) == '' ) {
 398                         return '';
 399                 }
 400                 $t = Title::newFromText( $title );
 401                 if ( !$t ) {
 402                         $this->dieUsageMsg( array( 'invalidtitle', $title ) );
 403                 }
 404                 return $t->getPrefixedDbKey();
 405         }
 406
 407         /**
 408          * The inverse of titleToKey()
 409          * @param $key string Page title with underscores
 410          * @return string Page title with spaces
 411          */
 412         public function keyToTitle( $key ) {
 413                 // Don't throw an error if we got an empty string
 414                 if ( trim( $key ) == '' ) {
 415                         return '';
 416                 }
 417                 $t = Title::newFromDbKey( $key );
 418                 // This really shouldn't happen but we gotta check anyway
 419                 if ( !$t ) {
 420                         $this->dieUsageMsg( array( 'invalidtitle', $key ) );
 421                 }
 422                 return $t->getPrefixedText();
 423         }
 424
 425         /**
 426          * An alternative to titleToKey() that doesn't trim trailing spaces
 427          * @param $titlePart string Title part with spaces
 428          * @return string Title part with underscores
 429          */
 430         public function titlePartToKey( $titlePart ) {
 431                 return substr( $this->titleToKey( $titlePart . 'x' ), 0, - 1 );
 432         }
 433
 434         /**
 435          * An alternative to keyToTitle() that doesn't trim trailing spaces
 436          * @param $keyPart string Key part with spaces
 437          * @return string Key part with underscores
 438          */
 439         public function keyPartToTitle( $keyPart ) {
 440                 return substr( $this->keyToTitle( $keyPart . 'x' ), 0, - 1 );
 441         }
 442
 443         public function getPossibleErrors() {
 444                 return array_merge( parent::getPossibleErrors(), array(
 445                         array( 'invalidtitle', 'title' ),
 446                         array( 'invalidtitle', 'key' ),
 447                 ) );
 448         }
 449
 450         /**
 451          * Get version string for use in the API help output
 452          * @return string
 453          */
 454         public static function getBaseVersion() {
 455                 return __CLASS__ . ': $Id$';
 456         }
 457 }
 458
 459 /**
 460  * @ingroup API
 461  */
 462 abstract class ApiQueryGeneratorBase extends ApiQueryBase {
 463
 464         private $mIsGenerator;
 465
 466         public function __construct( $query, $moduleName, $paramPrefix = '' ) {
 467                 parent::__construct( $query, $moduleName, $paramPrefix );
 468                 $this->mIsGenerator = false;
 469         }
 470
 471         /**
 472          * Switch this module to generator mode. By default, generator mode is
 473          * switched off and the module acts like a normal query module.
 474          */
 475         public function setGeneratorMode() {
 476                 $this->mIsGenerator = true;
 477         }
 478
 479         /**
 480          * Overrides base class to prepend 'g' to every generator parameter
 481          * @param $paramName string Parameter name
 482          * @return string Prefixed parameter name
 483          */
 484         public function encodeParamName( $paramName ) {
 485                 if ( $this->mIsGenerator ) {
 486                         return 'g' . parent::encodeParamName( $paramName );
 487                 } else {
 488                         return parent::encodeParamName( $paramName );
 489                 }
 490         }
 491
 492         /**
 493          * Execute this module as a generator
 494          * @param $resultPageSet ApiPageSet: All output should be appended to
 495          *  this object
 496          */
 497         public abstract function executeGenerator( $resultPageSet );
 498 }