includes/api/ApiBase.php

   1 <?php
   2
   3 /*
   4  * Created on Sep 5, 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 /**
  27  * This abstract class implements many basic API functions, and is the base of all API classes.
  28  * The class functions are divided into several areas of functionality:
  29  *
  30  * Module parameters: Derived classes can define getAllowedParams() to specify which parameters to expect,
  31  *      how to parse and validate them.
  32  *
  33  * Profiling: various methods to allow keeping tabs on various tasks and their time costs
  34  *
  35  * Self-documentation: code to allow api to document its own state.
  36  *
  37  * @addtogroup API
  38  */
  39 abstract class ApiBase {
  40
  41         // These constants allow modules to specify exactly how to treat incomming parameters.
  42
  43         const PARAM_DFLT = 0;
  44         const PARAM_ISMULTI = 1;
  45         const PARAM_TYPE = 2;
  46         const PARAM_MAX = 3;
  47         const PARAM_MAX2 = 4;
  48         const PARAM_MIN = 5;
  49
  50         const LIMIT_BIG1 = 500; // Fast query, std user limit
  51         const LIMIT_BIG2 = 5000; // Fast query, bot/sysop limit
  52         const LIMIT_SML1 = 50; // Slow query, std user limit
  53         const LIMIT_SML2 = 500; // Slow query, bot/sysop limit
  54
  55         private $mMainModule, $mModuleName, $mModulePrefix;
  56
  57         /**
  58         * Constructor
  59         */
  60         public function __construct($mainModule, $moduleName, $modulePrefix = '') {
  61                 $this->mMainModule = $mainModule;
  62                 $this->mModuleName = $moduleName;
  63                 $this->mModulePrefix = $modulePrefix;
  64         }
  65
  66         /**
  67          * Executes this module
  68          */
  69         public abstract function execute();
  70
  71         /**
  72          * Get the name of the module being executed by this instance
  73          */
  74         public function getModuleName() {
  75                 return $this->mModuleName;
  76         }
  77
  78         /**
  79          * Get parameter prefix (usually two letters or an empty string).
  80          */
  81         public function getModulePrefix() {
  82                 return $this->mModulePrefix;
  83         }
  84
  85         /**
  86          * Get the name of the module as shown in the profiler log
  87          */
  88         public function getModuleProfileName($db = false) {
  89                 if ($db)
  90                         return 'API:' . $this->mModuleName . '-DB';
  91                 else
  92                         return 'API:' . $this->mModuleName;
  93         }
  94
  95         /**
  96          * Get main module
  97          */
  98         public function getMain() {
  99                 return $this->mMainModule;
 100         }
 101
 102         /**
 103          * If this module's $this is the same as $this->mMainModule, its the root, otherwise no
 104          */
 105         public function isMain() {
 106                 return $this === $this->mMainModule;
 107         }
 108
 109         /**
 110          * Get result object
 111          */
 112         public function getResult() {
 113                 // Main module has getResult() method overriden
 114                 // Safety - avoid infinite loop:
 115                 if ($this->isMain())
 116                         ApiBase :: dieDebug(__METHOD__, 'base method was called on main module. ');
 117                 return $this->getMain()->getResult();
 118         }
 119
 120         /**
 121          * Get the result data array
 122          */
 123         public function & getResultData() {
 124                 return $this->getResult()->getData();
 125         }
 126
 127         /**
 128          * Set warning section for this module. Users should monitor this section to notice any changes in API.
 129          */
 130         public function setWarning($warning) {
 131                 $msg = array();
 132                 ApiResult :: setContent($msg, $warning);
 133                 $this->getResult()->addValue('warnings', $this->getModuleName(), $msg);
 134         }
 135
 136         /**
 137          * If the module may only be used with a certain format module,
 138          * it should override this method to return an instance of that formatter.
 139          * A value of null means the default format will be used.
 140          */
 141         public function getCustomPrinter() {
 142                 return null;
 143         }
 144
 145         /**
 146          * Generates help message for this module, or false if there is no description
 147          */
 148         public function makeHelpMsg() {
 149
 150                 static $lnPrfx = "\n  ";
 151
 152                 $msg = $this->getDescription();
 153
 154                 if ($msg !== false) {
 155
 156                         if (!is_array($msg))
 157                                 $msg = array (
 158                                         $msg
 159                                 );
 160                         $msg = $lnPrfx . implode($lnPrfx, $msg) . "\n";
 161
 162                         // Parameters
 163                         $paramsMsg = $this->makeHelpMsgParameters();
 164                         if ($paramsMsg !== false) {
 165                                 $msg .= "Parameters:\n$paramsMsg";
 166                         }
 167
 168                         // Examples
 169                         $examples = $this->getExamples();
 170                         if ($examples !== false) {
 171                                 if (!is_array($examples))
 172                                         $examples = array (
 173                                                 $examples
 174                                         );
 175                                 $msg .= 'Example' . (count($examples) > 1 ? 's' : '') . ":\n  ";
 176                                 $msg .= implode($lnPrfx, $examples) . "\n";
 177                         }
 178
 179                         if ($this->getMain()->getShowVersions()) {
 180                                 $versions = $this->getVersion();
 181                                 $pattern = '(\$.*) ([0-9a-z_]+\.php) (.*\$)';
 182                                 $replacement = '\\0' . "\n    " . 'http://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/includes/api/\\2';
 183
 184                                 if (is_array($versions)) {
 185                                         foreach ($versions as &$v)
 186                                                 $v = eregi_replace($pattern, $replacement, $v);
 187                                         $versions = implode("\n  ", $versions);
 188                                 }
 189                                 else
 190                                         $versions = eregi_replace($pattern, $replacement, $versions);
 191
 192                                 $msg .= "Version:\n  $versions\n";
 193                         }
 194                 }
 195
 196                 return $msg;
 197         }
 198
 199         public function makeHelpMsgParameters() {
 200                 $params = $this->getAllowedParams();
 201                 if ($params !== false) {
 202
 203                         $paramsDescription = $this->getParamDescription();
 204                         $msg = '';
 205                         $paramPrefix = "\n" . str_repeat(' ', 19);
 206                         foreach ($params as $paramName => $paramSettings) {
 207                                 $desc = isset ($paramsDescription[$paramName]) ? $paramsDescription[$paramName] : '';
 208                                 if (is_array($desc))
 209                                         $desc = implode($paramPrefix, $desc);
 210
 211                                 @ $type = $paramSettings[self :: PARAM_TYPE];
 212                                 if (isset ($type)) {
 213                                         if (isset ($paramSettings[self :: PARAM_ISMULTI]))
 214                                                 $prompt = 'Values (separate with \'|\'): ';
 215                                         else
 216                                                 $prompt = 'One value: ';
 217
 218                                         if (is_array($type)) {
 219                                                 $choices = array();
 220                                                 $nothingPrompt = false;
 221                                                 foreach ($type as $t)
 222                                                         if ($t=='')
 223                                                                 $nothingPrompt = 'Can be empty, or ';
 224                                                         else
 225                                                                 $choices[] =  $t;
 226                                                 $desc .= $paramPrefix . $nothingPrompt . $prompt . implode(', ', $choices);
 227                                         } else {
 228                                                 switch ($type) {
 229                                                         case 'namespace':
 230                                                                 // Special handling because namespaces are type-limited, yet they are not given
 231                                                                 $desc .= $paramPrefix . $prompt . implode(', ', ApiBase :: getValidNamespaces());
 232                                                                 break;
 233                                                         case 'limit':
 234                                                                 $desc .= $paramPrefix . "No more than {$paramSettings[self :: PARAM_MAX]} ({$paramSettings[self :: PARAM_MAX2]} for bots) allowed.";
 235                                                                 break;
 236                                                         case 'integer':
 237                                                                 $hasMin = isset($paramSettings[self :: PARAM_MIN]);
 238                                                                 $hasMax = isset($paramSettings[self :: PARAM_MAX]);
 239                                                                 if ($hasMin || $hasMax) {
 240                                                                         if (!$hasMax)
 241                                                                                 $intRangeStr = "The value must be no less than {$paramSettings[self :: PARAM_MIN]}";
 242                                                                         elseif (!$hasMin)
 243                                                                                 $intRangeStr = "The value must be no more than {$paramSettings[self :: PARAM_MAX]}";
 244                                                                         else
 245                                                                                 $intRangeStr = "The value must be between {$paramSettings[self :: PARAM_MIN]} and {$paramSettings[self :: PARAM_MAX]}";
 246
 247                                                                         $desc .= $paramPrefix . $intRangeStr;
 248                                                                 }
 249                                                                 break;
 250                                                 }
 251                                         }
 252                                 }
 253
 254                                 $default = is_array($paramSettings) ? (isset ($paramSettings[self :: PARAM_DFLT]) ? $paramSettings[self :: PARAM_DFLT] : null) : $paramSettings;
 255                                 if (!is_null($default) && $default !== false)
 256                                         $desc .= $paramPrefix . "Default: $default";
 257
 258                                 $msg .= sprintf("  %-14s - %s\n", $this->encodeParamName($paramName), $desc);
 259                         }
 260                         return $msg;
 261
 262                 } else
 263                         return false;
 264         }
 265
 266         /**
 267          * Returns the description string for this module
 268          */
 269         protected function getDescription() {
 270                 return false;
 271         }
 272
 273         /**
 274          * Returns usage examples for this module. Return null if no examples are available.
 275          */
 276         protected function getExamples() {
 277                 return false;
 278         }
 279
 280         /**
 281          * Returns an array of allowed parameters (keys) => default value for that parameter
 282          */
 283         protected function getAllowedParams() {
 284                 return false;
 285         }
 286
 287         /**
 288          * Returns the description string for the given parameter.
 289          */
 290         protected function getParamDescription() {
 291                 return false;
 292         }
 293
 294         /**
 295          * This method mangles parameter name based on the prefix supplied to the constructor.
 296          * Override this method to change parameter name during runtime
 297          */
 298         public function encodeParamName($paramName) {
 299                 return $this->mModulePrefix . $paramName;
 300         }
 301
 302         /**
 303         * Using getAllowedParams(), makes an array of the values provided by the user,
 304         * with key being the name of the variable, and value - validated value from user or default.
 305         * This method can be used to generate local variables using extract().
 306         */
 307         public function extractRequestParams() {
 308                 $params = $this->getAllowedParams();
 309                 $results = array ();
 310
 311                 foreach ($params as $paramName => $paramSettings)
 312                         $results[$paramName] = $this->getParameterFromSettings($paramName, $paramSettings);
 313
 314                 return $results;
 315         }
 316
 317         /**
 318          * Get a value for the given parameter
 319          */
 320         protected function getParameter($paramName) {
 321                 $params = $this->getAllowedParams();
 322                 $paramSettings = $params[$paramName];
 323                 return $this->getParameterFromSettings($paramName, $paramSettings);
 324         }
 325
 326         public static function getValidNamespaces() {
 327                 static $mValidNamespaces = null;
 328                 if (is_null($mValidNamespaces)) {
 329
 330                         global $wgContLang;
 331                         $mValidNamespaces = array ();
 332                         foreach (array_keys($wgContLang->getNamespaces()) as $ns) {
 333                                 if ($ns >= 0)
 334                                         $mValidNamespaces[] = $ns;
 335                         }
 336                 }
 337                 return $mValidNamespaces;
 338         }
 339
 340         /**
 341          * Using the settings determine the value for the given parameter
 342          * @param $paramName String: parameter name
 343          * @param $paramSettings Mixed: default value or an array of settings using PARAM_* constants.
 344          */
 345         protected function getParameterFromSettings($paramName, $paramSettings) {
 346
 347                 // Some classes may decide to change parameter names
 348                 $encParamName = $this->encodeParamName($paramName);
 349
 350                 if (!is_array($paramSettings)) {
 351                         $default = $paramSettings;
 352                         $multi = false;
 353                         $type = gettype($paramSettings);
 354                 } else {
 355                         $default = isset ($paramSettings[self :: PARAM_DFLT]) ? $paramSettings[self :: PARAM_DFLT] : null;
 356                         $multi = isset ($paramSettings[self :: PARAM_ISMULTI]) ? $paramSettings[self :: PARAM_ISMULTI] : false;
 357                         $type = isset ($paramSettings[self :: PARAM_TYPE]) ? $paramSettings[self :: PARAM_TYPE] : null;
 358
 359                         // When type is not given, and no choices, the type is the same as $default
 360                         if (!isset ($type)) {
 361                                 if (isset ($default))
 362                                         $type = gettype($default);
 363                                 else
 364                                         $type = 'NULL'; // allow everything
 365                         }
 366                 }
 367
 368                 if ($type == 'boolean') {
 369                         if (isset ($default) && $default !== false) {
 370                                 // Having a default value of anything other than 'false' is pointless
 371                                 ApiBase :: dieDebug(__METHOD__, "Boolean param $encParamName's default is set to '$default'");
 372                         }
 373
 374                         $value = $this->getMain()->getRequest()->getCheck($encParamName);
 375                 } else {
 376                         $value = $this->getMain()->getRequest()->getVal($encParamName, $default);
 377
 378                         if (isset ($value) && $type == 'namespace')
 379                                 $type = ApiBase :: getValidNamespaces();
 380                 }
 381
 382                 if (isset ($value) && ($multi || is_array($type)))
 383                         $value = $this->parseMultiValue($encParamName, $value, $multi, is_array($type) ? $type : null);
 384
 385                 // More validation only when choices were not given
 386                 // choices were validated in parseMultiValue()
 387                 if (isset ($value)) {
 388                         if (!is_array($type)) {
 389                                 switch ($type) {
 390                                         case 'NULL' : // nothing to do
 391                                                 break;
 392                                         case 'string' : // nothing to do
 393                                                 break;
 394                                         case 'integer' : // Force everything using intval() and optionally validate limits
 395
 396                                                 $value = is_array($value) ? array_map('intval', $value) : intval($value);
 397                                                 $min = isset ($paramSettings[self :: PARAM_MIN]) ? $paramSettings[self :: PARAM_MIN] : null;
 398                                                 $max = isset ($paramSettings[self :: PARAM_MAX]) ? $paramSettings[self :: PARAM_MAX] : null;
 399
 400                                                 if (!is_null($min) || !is_null($max)) {
 401                                                         $values = is_array($value) ? $value : array($value);
 402                                                         foreach ($values as $v) {
 403                                                                 $this->validateLimit($paramName, $v, $min, $max);
 404                                                         }
 405                                                 }
 406                                                 break;
 407                                         case 'limit' :
 408                                                 if (!isset ($paramSettings[self :: PARAM_MAX]) || !isset ($paramSettings[self :: PARAM_MAX2]))
 409                                                         ApiBase :: dieDebug(__METHOD__, "MAX1 or MAX2 are not defined for the limit $encParamName");
 410                                                 if ($multi)
 411                                                         ApiBase :: dieDebug(__METHOD__, "Multi-values not supported for $encParamName");
 412                                                 $min = isset ($paramSettings[self :: PARAM_MIN]) ? $paramSettings[self :: PARAM_MIN] : 0;
 413                                                 if( $value == 'max' ) {
 414                                                         $value = $this->getMain()->canApiHighLimits() ? $paramSettings[self :: PARAM_MAX2] : $paramSettings[self :: PARAM_MAX];
 415                                                         $this->getResult()->addValue( 'limits', 'limit', $value );
 416                                                 }
 417                                                 else {
 418                                                         $value = intval($value);
 419                                                 }
 420                                                 $this->validateLimit($paramName, $value, $min, $paramSettings[self :: PARAM_MAX], $paramSettings[self :: PARAM_MAX2]);
 421                                                 break;
 422                                         case 'boolean' :
 423                                                 if ($multi)
 424                                                         ApiBase :: dieDebug(__METHOD__, "Multi-values not supported for $encParamName");
 425                                                 break;
 426                                         case 'timestamp' :
 427                                                 if ($multi)
 428                                                         ApiBase :: dieDebug(__METHOD__, "Multi-values not supported for $encParamName");
 429                                                 $value = wfTimestamp(TS_UNIX, $value);
 430                                                 if ($value === 0)
 431                                                         $this->dieUsage("Invalid value '$value' for timestamp parameter $encParamName", "badtimestamp_{$encParamName}");
 432                                                 $value = wfTimestamp(TS_MW, $value);
 433                                                 break;
 434                                         case 'user' :
 435                                                 $title = Title::makeTitleSafe( NS_USER, $value );
 436                                                 if ( is_null( $title ) )
 437                                                         $this->dieUsage("Invalid value for user parameter $encParamName", "baduser_{$encParamName}");
 438                                                 $value = $title->getText();
 439                                                 break;
 440                                         default :
 441                                                 ApiBase :: dieDebug(__METHOD__, "Param $encParamName's type is unknown - $type");
 442                                 }
 443                         }
 444
 445                         // There should never be any duplicate values in a list
 446                         if (is_array($value))
 447                                 $value = array_unique($value);
 448                 }
 449
 450                 return $value;
 451         }
 452
 453         /**
 454         * Return an array of values that were given in a 'a|b|c' notation,
 455         * after it optionally validates them against the list allowed values.
 456         *
 457         * @param valueName - The name of the parameter (for error reporting)
 458         * @param value - The value being parsed
 459         * @param allowMultiple - Can $value contain more than one value separated by '|'?
 460         * @param allowedValues - An array of values to check against. If null, all values are accepted.
 461         * @return (allowMultiple ? an_array_of_values : a_single_value)
 462         */
 463         protected function parseMultiValue($valueName, $value, $allowMultiple, $allowedValues) {
 464                 $valuesList = explode('|', $value);
 465                 if (!$allowMultiple && count($valuesList) != 1) {
 466                         $possibleValues = is_array($allowedValues) ? "of '" . implode("', '", $allowedValues) . "'" : '';
 467                         $this->dieUsage("Only one $possibleValues is allowed for parameter '$valueName'", "multival_$valueName");
 468                 }
 469                 if (is_array($allowedValues)) {
 470                         $unknownValues = array_diff($valuesList, $allowedValues);
 471                         if ($unknownValues) {
 472                                 $this->dieUsage('Unrecognised value' . (count($unknownValues) > 1 ? "s" : "") . " for parameter '$valueName'", "unknown_$valueName");
 473                         }
 474                 }
 475
 476                 return $allowMultiple ? $valuesList : $valuesList[0];
 477         }
 478
 479         /**
 480         * Validate the value against the minimum and user/bot maximum limits. Prints usage info on failure.
 481         */
 482         function validateLimit($paramName, $value, $min, $max, $botMax = null) {
 483                 if (!is_null($min) && $value < $min) {
 484                         $this->dieUsage($this->encodeParamName($paramName) . " may not be less than $min (set to $value)", $paramName);
 485                 }
 486
 487                 // Minimum is always validated, whereas maximum is checked only if not running in internal call mode
 488                 if ($this->getMain()->isInternalMode())
 489                         return;
 490
 491                 // Optimization: do not check user's bot status unless really needed -- skips db query
 492                 // assumes $botMax >= $max
 493                 if (!is_null($max) && $value > $max) {
 494                         if (!is_null($botMax) && $this->getMain()->canApiHighLimits()) {
 495                                 if ($value > $botMax) {
 496                                         $this->dieUsage($this->encodeParamName($paramName) . " may not be over $botMax (set to $value) for bots or sysops", $paramName);
 497                                 }
 498                         } else {
 499                                 $this->dieUsage($this->encodeParamName($paramName) . " may not be over $max (set to $value) for users", $paramName);
 500                         }
 501                 }
 502         }
 503
 504         /**
 505          * Call main module's error handler
 506          */
 507         public function dieUsage($description, $errorCode, $httpRespCode = 0) {
 508                 throw new UsageException($description, $this->encodeParamName($errorCode), $httpRespCode);
 509         }
 510
 511         /**
 512          * Internal code errors should be reported with this method
 513          */
 514         protected static function dieDebug($method, $message) {
 515                 wfDebugDieBacktrace("Internal error in $method: $message");
 516         }
 517
 518         /**
 519          * Indicates if API needs to check maxlag
 520          */
 521         public function shouldCheckMaxlag() {
 522                 return true;
 523         }
 524
 525         /**
 526          * Indicates if this module requires edit mode
 527          */
 528         public function isEditMode() {
 529                 return false;
 530         }
 531
 532
 533         /**
 534          * Profiling: total module execution time
 535          */
 536         private $mTimeIn = 0, $mModuleTime = 0;
 537
 538         /**
 539          * Start module profiling
 540          */
 541         public function profileIn() {
 542                 if ($this->mTimeIn !== 0)
 543                         ApiBase :: dieDebug(__METHOD__, 'called twice without calling profileOut()');
 544                 $this->mTimeIn = microtime(true);
 545                 wfProfileIn($this->getModuleProfileName());
 546         }
 547
 548         /**
 549          * End module profiling
 550          */
 551         public function profileOut() {
 552                 if ($this->mTimeIn === 0)
 553                         ApiBase :: dieDebug(__METHOD__, 'called without calling profileIn() first');
 554                 if ($this->mDBTimeIn !== 0)
 555                         ApiBase :: dieDebug(__METHOD__, 'must be called after database profiling is done with profileDBOut()');
 556
 557                 $this->mModuleTime += microtime(true) - $this->mTimeIn;
 558                 $this->mTimeIn = 0;
 559                 wfProfileOut($this->getModuleProfileName());
 560         }
 561
 562         /**
 563          * When modules crash, sometimes it is needed to do a profileOut() regardless
 564          * of the profiling state the module was in. This method does such cleanup.
 565          */
 566         public function safeProfileOut() {
 567                 if ($this->mTimeIn !== 0) {
 568                         if ($this->mDBTimeIn !== 0)
 569                                 $this->profileDBOut();
 570                         $this->profileOut();
 571                 }
 572         }
 573
 574         /**
 575          * Total time the module was executed
 576          */
 577         public function getProfileTime() {
 578                 if ($this->mTimeIn !== 0)
 579                         ApiBase :: dieDebug(__METHOD__, 'called without calling profileOut() first');
 580                 return $this->mModuleTime;
 581         }
 582
 583         /**
 584          * Profiling: database execution time
 585          */
 586         private $mDBTimeIn = 0, $mDBTime = 0;
 587
 588         /**
 589          * Start module profiling
 590          */
 591         public function profileDBIn() {
 592                 if ($this->mTimeIn === 0)
 593                         ApiBase :: dieDebug(__METHOD__, 'must be called while profiling the entire module with profileIn()');
 594                 if ($this->mDBTimeIn !== 0)
 595                         ApiBase :: dieDebug(__METHOD__, 'called twice without calling profileDBOut()');
 596                 $this->mDBTimeIn = microtime(true);
 597                 wfProfileIn($this->getModuleProfileName(true));
 598         }
 599
 600         /**
 601          * End database profiling
 602          */
 603         public function profileDBOut() {
 604                 if ($this->mTimeIn === 0)
 605                         ApiBase :: dieDebug(__METHOD__, 'must be called while profiling the entire module with profileIn()');
 606                 if ($this->mDBTimeIn === 0)
 607                         ApiBase :: dieDebug(__METHOD__, 'called without calling profileDBIn() first');
 608
 609                 $time = microtime(true) - $this->mDBTimeIn;
 610                 $this->mDBTimeIn = 0;
 611
 612                 $this->mDBTime += $time;
 613                 $this->getMain()->mDBTime += $time;
 614                 wfProfileOut($this->getModuleProfileName(true));
 615         }
 616
 617         /**
 618          * Total time the module used the database
 619          */
 620         public function getProfileDBTime() {
 621                 if ($this->mDBTimeIn !== 0)
 622                         ApiBase :: dieDebug(__METHOD__, 'called without calling profileDBOut() first');
 623                 return $this->mDBTime;
 624         }
 625
 626         public static function debugPrint($value, $name = 'unknown', $backtrace = false) {
 627                 print "\n\n<pre><b>Debuging value '$name':</b>\n\n";
 628                 var_export($value);
 629                 if ($backtrace)
 630                         print "\n" . wfBacktrace();
 631                 print "\n</pre>\n";
 632         }
 633
 634         public abstract function getVersion();
 635
 636         public static function getBaseVersion() {
 637                 return __CLASS__ . ': $Id$';
 638         }
 639 }
 640