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