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