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 queries.
  34  *
  35  * @ingroup API
  36  */
  37 abstract class ApiQueryBase extends ApiBase {
  38
  39         private $mQueryModule, $mDb, $tables, $where, $fields, $options, $join_conds;
  40
  41         public function __construct($query, $moduleName, $paramPrefix = '') {
  42                 parent :: __construct($query->getMain(), $moduleName, $paramPrefix);
  43                 $this->mQueryModule = $query;
  44                 $this->mDb = null;
  45                 $this->resetQueryParams();
  46         }
  47
  48         /**
  49          * Blank the internal arrays with query parameters
  50          */
  51         protected function resetQueryParams() {
  52                 $this->tables = array ();
  53                 $this->where = array ();
  54                 $this->fields = array ();
  55                 $this->options = array ();
  56                 $this->join_conds = array ();
  57         }
  58
  59         /**
  60          * Add a set of tables to the internal array
  61          * @param mixed $tables Table name or array of table names
  62          * @param mixed $alias Table alias, or null for no alias. Cannot be used with multiple tables
  63          */
  64         protected function addTables($tables, $alias = null) {
  65                 if (is_array($tables)) {
  66                         if (!is_null($alias))
  67                                 ApiBase :: dieDebug(__METHOD__, 'Multiple table aliases not supported');
  68                         $this->tables = array_merge($this->tables, $tables);
  69                 } else {
  70                         if (!is_null($alias))
  71                                 $tables = $this->getAliasedName($tables, $alias);
  72                         $this->tables[] = $tables;
  73                 }
  74         }
  75
  76         /**
  77          * Get the SQL for a table name with alias
  78          * @param string $table Table name
  79          * @param string $alias Alias
  80          * @return string SQL
  81          */
  82         protected function getAliasedName($table, $alias) {
  83                 return $this->getDB()->tableName($table) . ' ' . $alias;
  84         }
  85
  86         /**
  87          * Add a set of JOIN conditions to the internal array
  88          *
  89          * JOIN conditions are formatted as array( tablename => array(jointype, conditions)
  90          * e.g. array('page' => array('LEFT JOIN', 'page_id=rev_page'))
  91          * @param array $join_conds JOIN conditions
  92          */
  93         protected function addJoinConds($join_conds) {
  94                 if(!is_array($join_conds))
  95                         ApiBase::dieDebug(__METHOD__, 'Join conditions have to be arrays');
  96                 $this->join_conds = array_merge($this->join_conds, $join_conds);
  97         }
  98
  99         /**
 100          * Add a set of fields to select to the internal array
 101          * @param mixed $value Field name or array of field names
 102          */
 103         protected function addFields($value) {
 104                 if (is_array($value))
 105                         $this->fields = array_merge($this->fields, $value);
 106                 else
 107                         $this->fields[] = $value;
 108         }
 109
 110         /**
 111          * Same as addFields(), but add the fields only if a condition is met
 112          * @param mixed $value See addFields()
 113          * @param bool $condition If false, do nothing
 114          * @return bool $condition
 115          */
 116         protected function addFieldsIf($value, $condition) {
 117                 if ($condition) {
 118                         $this->addFields($value);
 119                         return true;
 120                 }
 121                 return false;
 122         }
 123
 124         /**
 125          * Add a set of WHERE clauses to the internal array.
 126          * Clauses can be formatted as 'foo=bar' or array('foo' => 'bar'),
 127          * the latter only works if the value is a constant (i.e. not another field)
 128          *
 129          * For example, array('foo=bar', 'baz' => 3, 'bla' => 'foo') translates
 130          * to "foo=bar AND baz='3' AND bla='foo'"
 131          * @param mixed $value String or array
 132          */
 133         protected function addWhere($value) {
 134                 if (is_array($value))
 135                         $this->where = array_merge($this->where, $value);
 136                 else
 137                         $this->where[] = $value;
 138         }
 139
 140         /**
 141          * Same as addWhere(), but add the WHERE clauses only if a condition is met
 142          * @param mixed $value See addWhere()
 143          * @param bool $condition If false, do nothing
 144          * @return bool $condition
 145          */
 146         protected function addWhereIf($value, $condition) {
 147                 if ($condition) {
 148                         $this->addWhere($value);
 149                         return true;
 150                 }
 151                 return false;
 152         }
 153
 154         /**
 155          * Equivalent to addWhere(array($field => $value))
 156          * @param string $field Field name
 157          * @param string $value Value; ignored if nul;
 158          */
 159         protected function addWhereFld($field, $value) {
 160                 if (!is_null($value))
 161                         $this->where[$field] = $value;
 162         }
 163
 164         /**
 165          * Add a WHERE clause corresponding to a range, and an ORDER BY
 166          * clause to sort in the right direction
 167          * @param string $field Field name
 168          * @param string $dir If 'newer', sort in ascending order, otherwise sort in descending order
 169          * @param string $start Value to start the list at. If $dir == 'newer' this is the lower boundary, otherwise it's the upper boundary
 170          * @param string $end Value to end the list at. If $dir == 'newer' this is the upper boundary, otherwise it's the lower boundary
 171          */
 172         protected function addWhereRange($field, $dir, $start, $end) {
 173                 $isDirNewer = ($dir === 'newer');
 174                 $after = ($isDirNewer ? '>=' : '<=');
 175                 $before = ($isDirNewer ? '<=' : '>=');
 176                 $db = $this->getDB();
 177
 178                 if (!is_null($start))
 179                         $this->addWhere($field . $after . $db->addQuotes($start));
 180
 181                 if (!is_null($end))
 182                         $this->addWhere($field . $before . $db->addQuotes($end));
 183
 184                 $order = $field . ($isDirNewer ? '' : ' DESC');
 185                 if (!isset($this->options['ORDER BY']))
 186                         $this->addOption('ORDER BY', $order);
 187                 else
 188                         $this->addOption('ORDER BY', $this->options['ORDER BY'] . ', ' . $order);
 189         }
 190
 191         /**
 192          * Add an option such as LIMIT or USE INDEX
 193          * @param string $name Option name
 194          * @param string $value Option value
 195          */
 196         protected function addOption($name, $value = null) {
 197                 if (is_null($value))
 198                         $this->options[] = $name;
 199                 else
 200                         $this->options[$name] = $value;
 201         }
 202
 203         /**
 204          * Execute a SELECT query based on the values in the internal arrays
 205          * @param string $method Function the query should be attributed to. You should usually use __METHOD__ here
 206          * @return ResultWrapper
 207          */
 208         protected function select($method) {
 209
 210                 // getDB has its own profileDBIn/Out calls
 211                 $db = $this->getDB();
 212
 213                 $this->profileDBIn();
 214                 $res = $db->select($this->tables, $this->fields, $this->where, $method, $this->options, $this->join_conds);
 215                 $this->profileDBOut();
 216
 217                 return $res;
 218         }
 219
 220         /**
 221          * Estimate the row count for the SELECT query that would be run if we
 222          * called select() right now, and check if it's acceptable.
 223          * @return bool true if acceptable, false otherwise
 224          */
 225         protected function checkRowCount() {
 226                 $db = $this->getDB();
 227                 $this->profileDBIn();
 228                 $rowcount = $db->estimateRowCount($this->tables, $this->fields, $this->where, __METHOD__, $this->options);
 229                 $this->profileDBOut();
 230
 231                 global $wgAPIMaxDBRows;
 232                 if($rowcount > $wgAPIMaxDBRows)
 233                         return false;
 234                 return true;
 235         }
 236
 237         /**
 238          * Add information (title and namespace) about a Title object to a result array
 239          * @param array $arr Result array à la ApiResult
 240          * @param Title $title Title object
 241          * @param string $prefix Module prefix
 242          */
 243         public static function addTitleInfo(&$arr, $title, $prefix='') {
 244                 $arr[$prefix . 'ns'] = intval($title->getNamespace());
 245                 $arr[$prefix . 'title'] = $title->getPrefixedText();
 246         }
 247
 248         /**
 249          * Override this method to request extra fields from the pageSet
 250          * using $pageSet->requestField('fieldName')
 251          * @param ApiPageSet $pageSet
 252          */
 253         public function requestExtraData($pageSet) {
 254         }
 255
 256         /**
 257          * Get the main Query module
 258          * @return ApiQuery
 259          */
 260         public function getQuery() {
 261                 return $this->mQueryModule;
 262         }
 263
 264         /**
 265          * Add a sub-element under the page element with the given page ID
 266          * @param int $pageId Page ID
 267          * @param array $data Data array à la ApiResult
 268          */
 269         protected function addPageSubItems($pageId, $data) {
 270                 $result = $this->getResult();
 271                 $result->setIndexedTagName($data, $this->getModulePrefix());
 272                 $result->addValue(array ('query', 'pages', intval($pageId)),
 273                         $this->getModuleName(),
 274                         $data);
 275         }
 276
 277         /**
 278          * Set a query-continue value
 279          * @param $paramName Parameter name
 280          * @param $paramValue Parameter value
 281          */
 282         protected function setContinueEnumParameter($paramName, $paramValue) {
 283
 284                 $paramName = $this->encodeParamName($paramName);
 285                 $msg = array( $paramName => $paramValue );
 286                 $this->getResult()->addValue('query-continue', $this->getModuleName(), $msg);
 287         }
 288
 289         /**
 290          * Get the Query database connection (readonly)
 291          * @return Database
 292          */
 293         protected function getDB() {
 294                 if (is_null($this->mDb))
 295                         $this->mDb = $this->getQuery()->getDB();
 296                 return $this->mDb;
 297         }
 298
 299         /**
 300          * Selects the query database connection with the given name.
 301          * If no such connection has been requested before, it will be created.
 302          * Subsequent calls with the same $name will return the same connection
 303          * as the first, regardless of $db or $groups new values.
 304          * @param string $name Name to assign to the database connection
 305          * @param int $db One of the DB_* constants
 306          * @param array $groups Query groups
 307          * @return Database
 308          */
 309         public function selectNamedDB($name, $db, $groups) {
 310                 $this->mDb = $this->getQuery()->getNamedDB($name, $db, $groups);
 311         }
 312
 313         /**
 314          * Get the PageSet object to work on
 315          * @return ApiPageSet
 316          */
 317         protected function getPageSet() {
 318                 return $this->getQuery()->getPageSet();
 319         }
 320
 321         /**
 322          * Convert a title to a DB key
 323          * @param string $title Page title with spaces
 324          * @return string Page title with underscores
 325          */
 326         public function titleToKey($title) {
 327                 global $wgContLang, $wgCapitalLinks;
 328                 if($wgCaptialLinks)
 329                         $title = $wgContLang->ucfirst($title);
 330                 return str_replace(' ', '_', $title);
 331         }
 332
 333         /**
 334          * The inverse of titleToKey()
 335          * @param string $key Page title with underscores
 336          * @return string Page title with spaces
 337          */
 338         public function keyToTitle($key) {
 339                 return str_replace('_', ' ', $key);
 340         }
 341
 342         /**
 343          * Get version string for use in the API help output
 344          * @return string
 345          */
 346         public static function getBaseVersion() {
 347                 return __CLASS__ . ': $Id$';
 348         }
 349 }
 350
 351 /**
 352  * @ingroup API
 353  */
 354 abstract class ApiQueryGeneratorBase extends ApiQueryBase {
 355
 356         private $mIsGenerator;
 357
 358         public function __construct($query, $moduleName, $paramPrefix = '') {
 359                 parent :: __construct($query, $moduleName, $paramPrefix);
 360                 $this->mIsGenerator = false;
 361         }
 362
 363         /**
 364          * Switch this module to generator mode. By default, generator mode is
 365          * switched off and the module acts like a normal query module.
 366          */
 367         public function setGeneratorMode() {
 368                 $this->mIsGenerator = true;
 369         }
 370
 371         /**
 372          * Overrides base class to prepend 'g' to every generator parameter
 373          */
 374         public function encodeParamName($paramName) {
 375                 if ($this->mIsGenerator)
 376                         return 'g' . parent :: encodeParamName($paramName);
 377                 else
 378                         return parent :: encodeParamName($paramName);
 379         }
 380
 381         /**
 382          * Execute this module as a generator
 383          * @param $resultPageSet PageSet: All output should be appended to this object
 384          */
 385         public abstract function executeGenerator($resultPageSet);
 386 }