includes/api/ApiQueryBase.php

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