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