includes/api/ApiMain.php

   1 <?php
   2
   3 /*
   4  * Created on Sep 4, 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 the main API class, used for both external and internal processing.
  33  * When executed, it will create the requested formatter object,
  34  * instantiate and execute an object associated with the needed action,
  35  * and use formatter to print results.
  36  * In case of an exception, an error message will be printed using the same formatter.
  37  *
  38  * To use API from another application, run it using FauxRequest object, in which
  39  * case any internal exceptions will not be handled but passed up to the caller.
  40  * After successful execution, use getResult() for the resulting data.
  41  *
  42  * @addtogroup API
  43  */
  44 class ApiMain extends ApiBase {
  45
  46         /**
  47          * When no format parameter is given, this format will be used
  48          */
  49         const API_DEFAULT_FORMAT = 'xmlfm';
  50
  51         /**
  52          * List of available modules: action name => module class
  53          */
  54         private static $Modules = array (
  55                 'login' => 'ApiLogin',
  56                 'query' => 'ApiQuery',
  57                 'expandtemplates' => 'ApiExpandTemplates',
  58                 'render' => 'ApiRender',
  59                 'opensearch' => 'ApiOpenSearch',
  60                 'feedwatchlist' => 'ApiFeedWatchlist',
  61                 'help' => 'ApiHelp',
  62         );
  63
  64         /**
  65          * List of available formats: format name => format class
  66          */
  67         private static $Formats = array (
  68                 'json' => 'ApiFormatJson',
  69                 'jsonfm' => 'ApiFormatJson',
  70                 'php' => 'ApiFormatPhp',
  71                 'phpfm' => 'ApiFormatPhp',
  72                 'wddx' => 'ApiFormatWddx',
  73                 'wddxfm' => 'ApiFormatWddx',
  74                 'xml' => 'ApiFormatXml',
  75                 'xmlfm' => 'ApiFormatXml',
  76                 'yaml' => 'ApiFormatYaml',
  77                 'yamlfm' => 'ApiFormatYaml',
  78                 'rawfm' => 'ApiFormatJson'
  79         );
  80
  81         private $mPrinter, $mModules, $mModuleNames, $mFormats, $mFormatNames;
  82         private $mResult, $mAction, $mShowVersions, $mEnableWrite, $mRequest, $mInternalMode, $mSquidMaxage;
  83
  84         /**
  85         * Constructs an instance of ApiMain that utilizes the module and format specified by $request.
  86         *
  87         * @param $request object - if this is an instance of FauxRequest, errors are thrown and no printing occurs
  88         * @param $enableWrite bool should be set to true if the api may modify data
  89         */
  90         public function __construct($request, $enableWrite = false) {
  91
  92                 $this->mInternalMode = ($request instanceof FauxRequest);
  93
  94                 // Special handling for the main module: $parent === $this
  95                 parent :: __construct($this, $this->mInternalMode ? 'main_int' : 'main');
  96
  97                 if (!$this->mInternalMode) {
  98
  99                         // Impose module restrictions.
 100                         // If the current user cannot read,
 101                         // Remove all modules other than login
 102                         global $wgUser;
 103                         if (!$wgUser->isAllowed('read')) {
 104                                 self::$Modules = array(
 105                                         'login' => self::$Modules['login'],
 106                                         'help' => self::$Modules['help']
 107                                         );
 108                         }
 109                 }
 110
 111                 global $wgAPIModules; // extension modules
 112                 $this->mModules = $wgAPIModules + self :: $Modules;
 113
 114                 $this->mModuleNames = array_keys($this->mModules); // todo: optimize
 115                 $this->mFormats = self :: $Formats;
 116                 $this->mFormatNames = array_keys($this->mFormats); // todo: optimize
 117
 118                 $this->mResult = new ApiResult($this);
 119                 $this->mShowVersions = false;
 120                 $this->mEnableWrite = $enableWrite;
 121
 122                 $this->mRequest = & $request;
 123
 124                 $this->mSquidMaxage = 0;
 125         }
 126
 127         /**
 128          * Return true if the API was started by other PHP code using FauxRequest
 129          */
 130         public function isInternalMode() {
 131                 return $this->mInternalMode;
 132         }
 133
 134         /**
 135          * Return the request object that contains client's request
 136          */
 137         public function getRequest() {
 138                 return $this->mRequest;
 139         }
 140
 141         /**
 142          * Get the ApiResult object asscosiated with current request
 143          */
 144         public function getResult() {
 145                 return $this->mResult;
 146         }
 147
 148         /**
 149          * This method will simply cause an error if the write mode was disabled for this api.
 150          */
 151         public function requestWriteMode() {
 152                 if (!$this->mEnableWrite)
 153                         $this->dieUsage('Editing of this site is disabled. Make sure the $wgEnableWriteAPI=true; ' .
 154                         'statement is included in the site\'s LocalSettings.php file', 'readonly');
 155         }
 156
 157         /**
 158          * Set how long the response should be cached.
 159          */
 160         public function setCacheMaxAge($maxage) {
 161                 $this->mSquidMaxage = $maxage;
 162         }
 163
 164         /**
 165          * Create an instance of an output formatter by its name
 166          */
 167         public function createPrinterByName($format) {
 168                 return new $this->mFormats[$format] ($this, $format);
 169         }
 170
 171         /**
 172          * Execute api request. Any errors will be handled if the API was called by the remote client.
 173          */
 174         public function execute() {
 175                 $this->profileIn();
 176                 if ($this->mInternalMode)
 177                         $this->executeAction();
 178                 else
 179                         $this->executeActionWithErrorHandling();
 180                 $this->profileOut();
 181         }
 182
 183         /**
 184          * Execute an action, and in case of an error, erase whatever partial results
 185          * have been accumulated, and replace it with an error message and a help screen.
 186          */
 187         protected function executeActionWithErrorHandling() {
 188
 189                 // In case an error occurs during data output,
 190                 // clear the output buffer and print just the error information
 191                 ob_start();
 192
 193                 try {
 194                         $this->executeAction();
 195                 } catch (Exception $e) {
 196                         //
 197                         // Handle any kind of exception by outputing properly formatted error message.
 198                         // If this fails, an unhandled exception should be thrown so that global error
 199                         // handler will process and log it.
 200                         //
 201
 202                         $errCode = $this->substituteResultWithError($e);
 203
 204                         // Error results should not be cached
 205                         $this->setCacheMaxAge(0);
 206
 207                         $headerStr = 'MediaWiki-API-Error: ' . $errCode;
 208                         if ($e->getCode() === 0)
 209                                 header($headerStr, true);
 210                         else
 211                                 header($headerStr, true, $e->getCode());
 212
 213                         // Reset and print just the error message
 214                         ob_clean();
 215
 216                         // If the error occured during printing, do a printer->profileOut()
 217                         $this->mPrinter->safeProfileOut();
 218                         $this->printResult(true);
 219                 }
 220
 221                 // Set the cache expiration at the last moment, as any errors may change the expiration.
 222                 // if $this->mSquidMaxage == 0, the expiry time is set to the first second of unix epoch
 223                 $expires = $this->mSquidMaxage == 0 ? 1 : time() + $this->mSquidMaxage;
 224                 header('Expires: ' . wfTimestamp(TS_RFC2822, $expires));
 225                 header('Cache-Control: s-maxage=' . $this->mSquidMaxage . ', must-revalidate, max-age=0');
 226
 227                 if($this->mPrinter->getIsHtml())
 228                         echo wfReportTime();
 229
 230                 ob_end_flush();
 231         }
 232
 233         /**
 234          * Replace the result data with the information about an exception.
 235          * Returns the error code
 236          */
 237         protected function substituteResultWithError($e) {
 238
 239                         // Printer may not be initialized if the extractRequestParams() fails for the main module
 240                         if (!isset ($this->mPrinter)) {
 241                                 // The printer has not been created yet. Try to manually get formatter value.
 242                                 $value = $this->getRequest()->getVal('format', self::API_DEFAULT_FORMAT);
 243                                 if (!in_array($value, $this->mFormatNames))
 244                                         $value = self::API_DEFAULT_FORMAT;
 245
 246                                 $this->mPrinter = $this->createPrinterByName($value);
 247                                 if ($this->mPrinter->getNeedsRawData())
 248                                         $this->getResult()->setRawMode();
 249                         }
 250
 251                         if ($e instanceof UsageException) {
 252                                 //
 253                                 // User entered incorrect parameters - print usage screen
 254                                 //
 255                                 $errMessage = array (
 256                                 'code' => $e->getCodeString(),
 257                                 'info' => $e->getMessage());
 258
 259                                 // Only print the help message when this is for the developer, not runtime
 260                                 if ($this->mPrinter->getIsHtml() || $this->mAction == 'help')
 261                                         ApiResult :: setContent($errMessage, $this->makeHelpMsg());
 262
 263                         } else {
 264                                 //
 265                                 // Something is seriously wrong
 266                                 //
 267                                 $errMessage = array (
 268                                         'code' => 'internal_api_error_'. get_class($e),
 269                                         'info' => "Exception Caught: {$e->getMessage()}"
 270                                 );
 271                                 ApiResult :: setContent($errMessage, "\n\n{$e->getTraceAsString()}\n\n");
 272                         }
 273
 274                         $this->getResult()->reset();
 275                         $this->getResult()->addValue(null, 'error', $errMessage);
 276
 277                 return $errMessage['code'];
 278         }
 279
 280         /**
 281          * Execute the actual module, without any error handling
 282          */
 283         protected function executeAction() {
 284
 285                 $params = $this->extractRequestParams();
 286
 287                 $this->mShowVersions = $params['version'];
 288                 $this->mAction = $params['action'];
 289
 290                 // Instantiate the module requested by the user
 291                 $module = new $this->mModules[$this->mAction] ($this, $this->mAction);
 292
 293                 if( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
 294                         // Check for maxlag
 295                         global $wgLoadBalancer, $wgShowHostnames;
 296                         $maxLag = $params['maxlag'];
 297                         list( $host, $lag ) = $wgLoadBalancer->getMaxLag();
 298                         if ( $lag > $maxLag ) {
 299                                 if( $wgShowHostnames ) {
 300                                         ApiBase :: dieUsage( "Waiting for $host: $lag seconds lagged", 'maxlag' );
 301                                 } else {
 302                                         ApiBase :: dieUsage( "Waiting for a database server: $lag seconds lagged", 'maxlag' );
 303                                 }
 304                                 return;
 305                         }
 306                 }
 307
 308                 if (!$this->mInternalMode) {
 309
 310                         // See if custom printer is used
 311                         $this->mPrinter = $module->getCustomPrinter();
 312                         if (is_null($this->mPrinter)) {
 313                                 // Create an appropriate printer
 314                                 $this->mPrinter = $this->createPrinterByName($params['format']);
 315                         }
 316
 317                         if ($this->mPrinter->getNeedsRawData())
 318                                 $this->getResult()->setRawMode();
 319                 }
 320
 321                 // Execute
 322                 $module->profileIn();
 323                 $module->execute();
 324                 $module->profileOut();
 325
 326                 if (!$this->mInternalMode) {
 327                         // Print result data
 328                         $this->printResult(false);
 329                 }
 330         }
 331
 332         /**
 333          * Print results using the current printer
 334          */
 335         protected function printResult($isError) {
 336                 $printer = $this->mPrinter;
 337                 $printer->profileIn();
 338
 339                 /* If the help message is requested in the default (xmlfm) format,
 340                  * tell the printer not to escape ampersands so that our links do
 341                  * not break. */
 342                 $params = $this->extractRequestParams();
 343                 $printer->setUnescapeAmps ( ( $this->mAction == 'help' || $isError )
 344                                 && $params['format'] == ApiMain::API_DEFAULT_FORMAT );
 345
 346                 $printer->initPrinter($isError);
 347
 348                 $printer->execute();
 349                 $printer->closePrinter();
 350                 $printer->profileOut();
 351         }
 352
 353         /**
 354          * See ApiBase for description.
 355          */
 356         protected function getAllowedParams() {
 357                 return array (
 358                         'format' => array (
 359                                 ApiBase :: PARAM_DFLT => ApiMain :: API_DEFAULT_FORMAT,
 360                                 ApiBase :: PARAM_TYPE => $this->mFormatNames
 361                         ),
 362                         'action' => array (
 363                                 ApiBase :: PARAM_DFLT => 'help',
 364                                 ApiBase :: PARAM_TYPE => $this->mModuleNames
 365                         ),
 366                         'version' => false,
 367                         'maxlag'  => array (
 368                                 ApiBase :: PARAM_TYPE => 'integer'
 369                         ),
 370                 );
 371         }
 372
 373         /**
 374          * See ApiBase for description.
 375          */
 376         protected function getParamDescription() {
 377                 return array (
 378                         'format' => 'The format of the output',
 379                         'action' => 'What action you would like to perform',
 380                         'version' => 'When showing help, include version for each module',
 381                         'maxlag' => 'Maximum lag'
 382                 );
 383         }
 384
 385         /**
 386          * See ApiBase for description.
 387          */
 388         protected function getDescription() {
 389                 return array (
 390                         '',
 391                         '',
 392                         '******************************************************************',
 393                         '**                                                              **',
 394                         '**  This is an auto-generated MediaWiki API documentation page  **',
 395                         '**                                                              **',
 396                         '**                  Documentation and Examples:                 **',
 397                         '**               http://www.mediawiki.org/wiki/API              **',
 398                         '**                                                              **',
 399                         '******************************************************************',
 400                         '',
 401                         'Status:          All features shown on this page should be working, but the API',
 402                         '                 is still in active development, and  may change at any time.',
 403                         '                 Make sure to monitor our mailing list for any updates.',
 404                         '',
 405                         'Documentation:   http://www.mediawiki.org/wiki/API',
 406                         'Mailing list:    http://lists.wikimedia.org/mailman/listinfo/mediawiki-api',
 407                         'Bugs & Requests: http://bugzilla.wikimedia.org/buglist.cgi?component=API&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&order=bugs.delta_ts',
 408                         '',
 409                         '',
 410                         '',
 411                         '',
 412                         '',
 413                 );
 414         }
 415
 416         /**
 417          * Returns an array of strings with credits for the API
 418          */
 419         protected function getCredits() {
 420                 return array(
 421                         'This API is being implemented by Yuri Astrakhan [[User:Yurik]] / <Firstname><Lastname>@gmail.com',
 422                         'Please leave your comments and suggestions at http://www.mediawiki.org/wiki/API'
 423                 );
 424         }
 425
 426         /**
 427          * Override the parent to generate help messages for all available modules.
 428          */
 429         public function makeHelpMsg() {
 430
 431                 // Use parent to make default message for the main module
 432                 $msg = parent :: makeHelpMsg();
 433
 434                 $astriks = str_repeat('*** ', 10);
 435                 $msg .= "\n\n$astriks Modules  $astriks\n\n";
 436                 foreach( $this->mModules as $moduleName => $unused ) {
 437                         $module = new $this->mModules[$moduleName] ($this, $moduleName);
 438                         $msg .= self::makeHelpMsgHeader($module, 'action');
 439                         $msg2 = $module->makeHelpMsg();
 440                         if ($msg2 !== false)
 441                                 $msg .= $msg2;
 442                         $msg .= "\n";
 443                 }
 444
 445                 $msg .= "\n$astriks Formats  $astriks\n\n";
 446                 foreach( $this->mFormats as $formatName => $unused ) {
 447                         $module = $this->createPrinterByName($formatName);
 448                         $msg .= self::makeHelpMsgHeader($module, 'format');
 449                         $msg2 = $module->makeHelpMsg();
 450                         if ($msg2 !== false)
 451                                 $msg .= $msg2;
 452                         $msg .= "\n";
 453                 }
 454
 455                 $msg .= "\n*** Credits: ***\n   " . implode("\n   ", $this->getCredits()) . "\n";
 456
 457
 458                 return $msg;
 459         }
 460
 461         public static function makeHelpMsgHeader($module, $paramName) {
 462                 $modulePrefix = $module->getModulePrefix();
 463                 if (!empty($modulePrefix))
 464                         $modulePrefix = "($modulePrefix) ";
 465
 466                 return "* $paramName={$module->getModuleName()} $modulePrefix*";
 467         }
 468
 469         private $mIsBot = null;
 470         private $mIsSysop = null;
 471         private $mCanApiHighLimits = null;
 472
 473         /**
 474          * Returns true if the currently logged in user is a bot, false otherwise
 475          * OBSOLETE, use canApiHighLimits() instead
 476          */
 477         public function isBot() {
 478                 if (!isset ($this->mIsBot)) {
 479                         global $wgUser;
 480                         $this->mIsBot = $wgUser->isAllowed('bot');
 481                 }
 482                 return $this->mIsBot;
 483         }
 484
 485         /**
 486          * Similar to isBot(), this method returns true if the logged in user is
 487          * a sysop, and false if not.
 488          * OBSOLETE, use canApiHighLimits() instead
 489          */
 490         public function isSysop() {
 491                 if (!isset ($this->mIsSysop)) {
 492                         global $wgUser;
 493                         $this->mIsSysop = in_array( 'sysop', $wgUser->getGroups());
 494                 }
 495
 496                 return $this->mIsSysop;
 497         }
 498
 499         public function canApiHighLimits() {
 500                 if (!isset($this->mCanApiHighLimits)) {
 501                         global $wgUser;
 502                         $this->mCanApiHighLimits = $wgUser->isAllowed('apihighlimits');
 503                 }
 504
 505                 return $this->mCanApiHighLimits;
 506         }
 507
 508         public function getShowVersions() {
 509                 return $this->mShowVersions;
 510         }
 511
 512         /**
 513          * Returns the version information of this file, plus it includes
 514          * the versions for all files that are not callable proper API modules
 515          */
 516         public function getVersion() {
 517                 $vers = array ();
 518                 $vers[] = 'MediaWiki ' . SpecialVersion::getVersion();
 519                 $vers[] = __CLASS__ . ': $Id$';
 520                 $vers[] = ApiBase :: getBaseVersion();
 521                 $vers[] = ApiFormatBase :: getBaseVersion();
 522                 $vers[] = ApiQueryBase :: getBaseVersion();
 523                 $vers[] = ApiFormatFeedWrapper :: getVersion(); // not accessible with format=xxx
 524                 return $vers;
 525         }
 526
 527         /**
 528          * Add or overwrite a module in this ApiMain instance. Intended for use by extending
 529          * classes who wish to add their own modules to their lexicon or override the
 530          * behavior of inherent ones.
 531          *
 532          * @access protected
 533          * @param $mdlName String The identifier for this module.
 534          * @param $mdlClass String The class where this module is implemented.
 535          */
 536         protected function addModule( $mdlName, $mdlClass ) {
 537                 $this->mModules[$mdlName] = $mdlClass;
 538         }
 539
 540         /**
 541          * Add or overwrite an output format for this ApiMain. Intended for use by extending
 542          * classes who wish to add to or modify current formatters.
 543          *
 544          * @access protected
 545          * @param $fmtName The identifier for this format.
 546          * @param $fmtClass The class implementing this format.
 547          */
 548         protected function addFormat( $fmtName, $fmtClass ) {
 549                 $this->mFormats[$fmtName] = $fmtClass;
 550         }
 551 }
 552
 553 /**
 554  * This exception will be thrown when dieUsage is called to stop module execution.
 555  * The exception handling code will print a help screen explaining how this API may be used.
 556  *
 557  * @addtogroup API
 558  */
 559 class UsageException extends Exception {
 560
 561         private $mCodestr;
 562
 563         public function __construct($message, $codestr, $code = 0) {
 564                 parent :: __construct($message, $code);
 565                 $this->mCodestr = $codestr;
 566         }
 567         public function getCodeString() {
 568                 return $this->mCodestr;
 569         }
 570         public function __toString() {
 571                 return "{$this->getCodeString()}: {$this->getMessage()}";
 572         }
 573 }
 574
 575