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