includes/api/ApiMain.php

   1 <?php
   2 /**
   3  *
   4  *
   5  * Created on Sep 4, 2006
   6  *
   7  * Copyright © 2006 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  22  * http://www.gnu.org/copyleft/gpl.html
  23  *
  24  * @file
  25  * @defgroup API API
  26  */
  27
  28 /**
  29  * This is the main API class, used for both external and internal processing.
  30  * When executed, it will create the requested formatter object,
  31  * instantiate and execute an object associated with the needed action,
  32  * and use formatter to print results.
  33  * In case of an exception, an error message will be printed using the same formatter.
  34  *
  35  * To use API from another application, run it using FauxRequest object, in which
  36  * case any internal exceptions will not be handled but passed up to the caller.
  37  * After successful execution, use getResult() for the resulting data.
  38  *
  39  * @ingroup API
  40  */
  41 class ApiMain extends ApiBase {
  42
  43         /**
  44          * When no format parameter is given, this format will be used
  45          */
  46         const API_DEFAULT_FORMAT = 'xmlfm';
  47
  48         /**
  49          * List of available modules: action name => module class
  50          */
  51         private static $Modules = array(
  52                 'login' => 'ApiLogin',
  53                 'logout' => 'ApiLogout',
  54                 'query' => 'ApiQuery',
  55                 'expandtemplates' => 'ApiExpandTemplates',
  56                 'parse' => 'ApiParse',
  57                 'opensearch' => 'ApiOpenSearch',
  58                 'feedcontributions' => 'ApiFeedContributions',
  59                 'feedwatchlist' => 'ApiFeedWatchlist',
  60                 'help' => 'ApiHelp',
  61                 'paraminfo' => 'ApiParamInfo',
  62                 'rsd' => 'ApiRsd',
  63                 'compare' => 'ApiComparePages',
  64                 'tokens' => 'ApiTokens',
  65
  66                 // Write modules
  67                 'purge' => 'ApiPurge',
  68                 'setnotificationtimestamp' => 'ApiSetNotificationTimestamp',
  69                 'rollback' => 'ApiRollback',
  70                 'delete' => 'ApiDelete',
  71                 'undelete' => 'ApiUndelete',
  72                 'protect' => 'ApiProtect',
  73                 'block' => 'ApiBlock',
  74                 'unblock' => 'ApiUnblock',
  75                 'move' => 'ApiMove',
  76                 'edit' => 'ApiEditPage',
  77                 'upload' => 'ApiUpload',
  78                 'filerevert' => 'ApiFileRevert',
  79                 'emailuser' => 'ApiEmailUser',
  80                 'watch' => 'ApiWatch',
  81                 'patrol' => 'ApiPatrol',
  82                 'import' => 'ApiImport',
  83                 'userrights' => 'ApiUserrights',
  84                 'options' => 'ApiOptions',
  85         );
  86
  87         /**
  88          * List of available formats: format name => format class
  89          */
  90         private static $Formats = array(
  91                 'json' => 'ApiFormatJson',
  92                 'jsonfm' => 'ApiFormatJson',
  93                 'php' => 'ApiFormatPhp',
  94                 'phpfm' => 'ApiFormatPhp',
  95                 'wddx' => 'ApiFormatWddx',
  96                 'wddxfm' => 'ApiFormatWddx',
  97                 'xml' => 'ApiFormatXml',
  98                 'xmlfm' => 'ApiFormatXml',
  99                 'yaml' => 'ApiFormatYaml',
 100                 'yamlfm' => 'ApiFormatYaml',
 101                 'rawfm' => 'ApiFormatJson',
 102                 'txt' => 'ApiFormatTxt',
 103                 'txtfm' => 'ApiFormatTxt',
 104                 'dbg' => 'ApiFormatDbg',
 105                 'dbgfm' => 'ApiFormatDbg',
 106                 'dump' => 'ApiFormatDump',
 107                 'dumpfm' => 'ApiFormatDump',
 108                 'none' => 'ApiFormatNone',
 109         );
 110
 111         /**
 112          * List of user roles that are specifically relevant to the API.
 113          * array( 'right' => array ( 'msg'    => 'Some message with a $1',
 114          *                           'params' => array ( $someVarToSubst ) ),
 115          *                          );
 116          */
 117         private static $mRights = array(
 118                 'writeapi' => array(
 119                         'msg' => 'Use of the write API',
 120                         'params' => array()
 121                 ),
 122                 'apihighlimits' => array(
 123                         'msg' => 'Use higher limits in API queries (Slow queries: $1 results; Fast queries: $2 results). The limits for slow queries also apply to multivalue parameters.',
 124                         'params' => array( ApiBase::LIMIT_SML2, ApiBase::LIMIT_BIG2 )
 125                 )
 126         );
 127
 128         /**
 129          * @var ApiFormatBase
 130          */
 131         private $mPrinter;
 132
 133         private $mModules, $mModuleNames, $mFormats, $mFormatNames;
 134         private $mResult, $mAction, $mShowVersions, $mEnableWrite;
 135         private $mInternalMode, $mSquidMaxage, $mModule;
 136
 137         private $mCacheMode = 'private';
 138         private $mCacheControl = array();
 139         private $mParamsUsed = array();
 140
 141         /**
 142          * Constructs an instance of ApiMain that utilizes the module and format specified by $request.
 143          *
 144          * @param $context IContextSource|WebRequest - if this is an instance of FauxRequest, errors are thrown and no printing occurs
 145          * @param $enableWrite bool should be set to true if the api may modify data
 146          */
 147         public function __construct( $context = null, $enableWrite = false ) {
 148                 if ( $context === null ) {
 149                         $context = RequestContext::getMain();
 150                 } elseif ( $context instanceof WebRequest ) {
 151                         // BC for pre-1.19
 152                         $request = $context;
 153                         $context = RequestContext::getMain();
 154                 }
 155                 // We set a derivative context so we can change stuff later
 156                 $this->setContext( new DerivativeContext( $context ) );
 157
 158                 if ( isset( $request ) ) {
 159                         $this->getContext()->setRequest( $request );
 160                 }
 161
 162                 $this->mInternalMode = ( $this->getRequest() instanceof FauxRequest );
 163
 164                 // Special handling for the main module: $parent === $this
 165                 parent::__construct( $this, $this->mInternalMode ? 'main_int' : 'main' );
 166
 167                 if ( !$this->mInternalMode ) {
 168                         // Impose module restrictions.
 169                         // If the current user cannot read,
 170                         // Remove all modules other than login
 171                         global $wgUser;
 172
 173                         if ( $this->getVal( 'callback' ) !== null ) {
 174                                 // JSON callback allows cross-site reads.
 175                                 // For safety, strip user credentials.
 176                                 wfDebug( "API: stripping user credentials for JSON callback\n" );
 177                                 $wgUser = new User();
 178                                 $this->getContext()->setUser( $wgUser );
 179                         }
 180                 }
 181
 182                 global $wgAPIModules; // extension modules
 183                 $this->mModules = $wgAPIModules + self::$Modules;
 184
 185                 $this->mModuleNames = array_keys( $this->mModules );
 186                 $this->mFormats = self::$Formats;
 187                 $this->mFormatNames = array_keys( $this->mFormats );
 188
 189                 $this->mResult = new ApiResult( $this );
 190                 $this->mShowVersions = false;
 191                 $this->mEnableWrite = $enableWrite;
 192
 193                 $this->mSquidMaxage = - 1; // flag for executeActionWithErrorHandling()
 194                 $this->mCommit = false;
 195         }
 196
 197         /**
 198          * Return true if the API was started by other PHP code using FauxRequest
 199          * @return bool
 200          */
 201         public function isInternalMode() {
 202                 return $this->mInternalMode;
 203         }
 204
 205         /**
 206          * Get the ApiResult object associated with current request
 207          *
 208          * @return ApiResult
 209          */
 210         public function getResult() {
 211                 return $this->mResult;
 212         }
 213
 214         /**
 215          * Get the API module object. Only works after executeAction()
 216          *
 217          * @return ApiBase
 218          */
 219         public function getModule() {
 220                 return $this->mModule;
 221         }
 222
 223         /**
 224          * Get the result formatter object. Only works after setupExecuteAction()
 225          *
 226          * @return ApiFormatBase
 227          */
 228         public function getPrinter() {
 229                 return $this->mPrinter;
 230         }
 231
 232         /**
 233          * Set how long the response should be cached.
 234          *
 235          * @param $maxage
 236          */
 237         public function setCacheMaxAge( $maxage ) {
 238                 $this->setCacheControl( array(
 239                         'max-age' => $maxage,
 240                         's-maxage' => $maxage
 241                 ) );
 242         }
 243
 244         /**
 245          * Set the type of caching headers which will be sent.
 246          *
 247          * @param $mode String One of:
 248          *    - 'public':     Cache this object in public caches, if the maxage or smaxage
 249          *         parameter is set, or if setCacheMaxAge() was called. If a maximum age is
 250          *         not provided by any of these means, the object will be private.
 251          *    - 'private':    Cache this object only in private client-side caches.
 252          *    - 'anon-public-user-private': Make this object cacheable for logged-out
 253          *         users, but private for logged-in users. IMPORTANT: If this is set, it must be
 254          *         set consistently for a given URL, it cannot be set differently depending on
 255          *         things like the contents of the database, or whether the user is logged in.
 256          *
 257          *  If the wiki does not allow anonymous users to read it, the mode set here
 258          *  will be ignored, and private caching headers will always be sent. In other words,
 259          *  the "public" mode is equivalent to saying that the data sent is as public as a page
 260          *  view.
 261          *
 262          *  For user-dependent data, the private mode should generally be used. The
 263          *  anon-public-user-private mode should only be used where there is a particularly
 264          *  good performance reason for caching the anonymous response, but where the
 265          *  response to logged-in users may differ, or may contain private data.
 266          *
 267          *  If this function is never called, then the default will be the private mode.
 268          */
 269         public function setCacheMode( $mode ) {
 270                 if ( !in_array( $mode, array( 'private', 'public', 'anon-public-user-private' ) ) ) {
 271                         wfDebug( __METHOD__ . ": unrecognised cache mode \"$mode\"\n" );
 272                         // Ignore for forwards-compatibility
 273                         return;
 274                 }
 275
 276                 if ( !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) ) {
 277                         // Private wiki, only private headers
 278                         if ( $mode !== 'private' ) {
 279                                 wfDebug( __METHOD__ . ": ignoring request for $mode cache mode, private wiki\n" );
 280                                 return;
 281                         }
 282                 }
 283
 284                 wfDebug( __METHOD__ . ": setting cache mode $mode\n" );
 285                 $this->mCacheMode = $mode;
 286         }
 287
 288         /**
 289          * @deprecated since 1.17 Private caching is now the default, so there is usually no
 290          * need to call this function. If there is a need, you can use
 291          * $this->setCacheMode('private')
 292          */
 293         public function setCachePrivate() {
 294                 wfDeprecated( __METHOD__, '1.17' );
 295                 $this->setCacheMode( 'private' );
 296         }
 297
 298         /**
 299          * Set directives (key/value pairs) for the Cache-Control header.
 300          * Boolean values will be formatted as such, by including or omitting
 301          * without an equals sign.
 302          *
 303          * Cache control values set here will only be used if the cache mode is not
 304          * private, see setCacheMode().
 305          *
 306          * @param $directives array
 307          */
 308         public function setCacheControl( $directives ) {
 309                 $this->mCacheControl = $directives + $this->mCacheControl;
 310         }
 311
 312         /**
 313          * Make sure Vary: Cookie and friends are set. Use this when the output of a request
 314          * may be cached for anons but may not be cached for logged-in users.
 315          *
 316          * WARNING: This function must be called CONSISTENTLY for a given URL. This means that a
 317          * given URL must either always or never call this function; if it sometimes does and
 318          * sometimes doesn't, stuff will break.
 319          *
 320          * @deprecated since 1.17 Use setCacheMode( 'anon-public-user-private' )
 321          */
 322         public function setVaryCookie() {
 323                 wfDeprecated( __METHOD__, '1.17' );
 324                 $this->setCacheMode( 'anon-public-user-private' );
 325         }
 326
 327         /**
 328          * Create an instance of an output formatter by its name
 329          *
 330          * @param $format string
 331          *
 332          * @return ApiFormatBase
 333          */
 334         public function createPrinterByName( $format ) {
 335                 if ( !isset( $this->mFormats[$format] ) ) {
 336                         $this->dieUsage( "Unrecognized format: {$format}", 'unknown_format' );
 337                 }
 338                 return new $this->mFormats[$format] ( $this, $format );
 339         }
 340
 341         /**
 342          * Execute api request. Any errors will be handled if the API was called by the remote client.
 343          */
 344         public function execute() {
 345                 $this->profileIn();
 346                 if ( $this->mInternalMode ) {
 347                         $this->executeAction();
 348                 } else {
 349                         $this->executeActionWithErrorHandling();
 350                 }
 351
 352                 $this->profileOut();
 353         }
 354
 355         /**
 356          * Execute an action, and in case of an error, erase whatever partial results
 357          * have been accumulated, and replace it with an error message and a help screen.
 358          */
 359         protected function executeActionWithErrorHandling() {
 360                 // Verify the CORS header before executing the action
 361                 if ( !$this->handleCORS() ) {
 362                         // handleCORS() has sent a 403, abort
 363                         return;
 364                 }
 365
 366                 // In case an error occurs during data output,
 367                 // clear the output buffer and print just the error information
 368                 ob_start();
 369
 370                 $t = microtime( true );
 371                 try {
 372                         $this->executeAction();
 373                 } catch ( Exception $e ) {
 374                         // Allow extra cleanup and logging
 375                         wfRunHooks( 'ApiMain::onException', array( $this, $e ) );
 376
 377                         // Log it
 378                         if ( !( $e instanceof UsageException ) ) {
 379                                 global $wgLogExceptionBacktrace;
 380                                 if ( $wgLogExceptionBacktrace ) {
 381                                         wfDebugLog( 'exception', $e->getLogMessage() . "\n" . $e->getTraceAsString() . "\n" );
 382                                 } else {
 383                                         wfDebugLog( 'exception', $e->getLogMessage() );
 384                                 }
 385                         }
 386
 387                         // Handle any kind of exception by outputing properly formatted error message.
 388                         // If this fails, an unhandled exception should be thrown so that global error
 389                         // handler will process and log it.
 390
 391                         $errCode = $this->substituteResultWithError( $e );
 392
 393                         // Error results should not be cached
 394                         $this->setCacheMode( 'private' );
 395
 396                         $response = $this->getRequest()->response();
 397                         $headerStr = 'MediaWiki-API-Error: ' . $errCode;
 398                         if ( $e->getCode() === 0 ) {
 399                                 $response->header( $headerStr );
 400                         } else {
 401                                 $response->header( $headerStr, true, $e->getCode() );
 402                         }
 403
 404                         // Reset and print just the error message
 405                         ob_clean();
 406
 407                         // If the error occurred during printing, do a printer->profileOut()
 408                         $this->mPrinter->safeProfileOut();
 409                         $this->printResult( true );
 410                 }
 411
 412                 // Log the request whether or not there was an error
 413                 $this->logRequest( microtime( true ) - $t);
 414
 415                 // Send cache headers after any code which might generate an error, to
 416                 // avoid sending public cache headers for errors.
 417                 $this->sendCacheHeaders();
 418
 419                 if ( $this->mPrinter->getIsHtml() && !$this->mPrinter->isDisabled() ) {
 420                         echo wfReportTime();
 421                 }
 422
 423                 ob_end_flush();
 424         }
 425
 426         /**
 427          * Check the &origin= query parameter against the Origin: HTTP header and respond appropriately.
 428          *
 429          * If no origin parameter is present, nothing happens.
 430          * If an origin parameter is present but doesn't match the Origin header, a 403 status code
 431          * is set and false is returned.
 432          * If the parameter and the header do match, the header is checked against $wgCrossSiteAJAXdomains
 433          * and $wgCrossSiteAJAXdomainExceptions, and if the origin qualifies, the appropriate CORS
 434          * headers are set.
 435          *
 436          * @return bool False if the caller should abort (403 case), true otherwise (all other cases)
 437          */
 438         protected function handleCORS() {
 439                 global $wgCrossSiteAJAXdomains, $wgCrossSiteAJAXdomainExceptions;
 440
 441                 $originParam = $this->getParameter( 'origin' ); // defaults to null
 442                 if ( $originParam === null ) {
 443                         // No origin parameter, nothing to do
 444                         return true;
 445                 }
 446
 447                 $request = $this->getRequest();
 448                 $response = $request->response();
 449                 // Origin: header is a space-separated list of origins, check all of them
 450                 $originHeader = $request->getHeader( 'Origin' );
 451                 if ( $originHeader === false ) {
 452                         $origins = array();
 453                 } else {
 454                         $origins = explode( ' ', $originHeader );
 455                 }
 456                 if ( !in_array( $originParam, $origins ) ) {
 457                         // origin parameter set but incorrect
 458                         // Send a 403 response
 459                         $message = HttpStatus::getMessage( 403 );
 460                         $response->header( "HTTP/1.1 403 $message", true, 403 );
 461                         $response->header( 'Cache-Control: no-cache' );
 462                         echo "'origin' parameter does not match Origin header\n";
 463                         return false;
 464                 }
 465                 if ( self::matchOrigin( $originParam, $wgCrossSiteAJAXdomains, $wgCrossSiteAJAXdomainExceptions ) ) {
 466                         $response->header( "Access-Control-Allow-Origin: $originParam" );
 467                         $response->header( 'Access-Control-Allow-Credentials: true' );
 468                         $this->getOutput()->addVaryHeader( 'Origin' );
 469                 }
 470                 return true;
 471         }
 472
 473         /**
 474          * Attempt to match an Origin header against a set of rules and a set of exceptions
 475          * @param $value string Origin header
 476          * @param $rules array Set of wildcard rules
 477          * @param $exceptions array Set of wildcard rules
 478          * @return bool True if $value matches a rule in $rules and doesn't match any rules in $exceptions, false otherwise
 479          */
 480         protected static function matchOrigin( $value, $rules, $exceptions ) {
 481                 foreach ( $rules as $rule ) {
 482                         if ( preg_match( self::wildcardToRegex( $rule ), $value ) ) {
 483                                 // Rule matches, check exceptions
 484                                 foreach ( $exceptions as $exc ) {
 485                                         if ( preg_match( self::wildcardToRegex( $exc ), $value ) ) {
 486                                                 return false;
 487                                         }
 488                                 }
 489                                 return true;
 490                         }
 491                 }
 492                 return false;
 493         }
 494
 495         /**
 496          * Helper function to convert wildcard string into a regex
 497          * '*' => '.*?'
 498          * '?' => '.'
 499          *
 500          * @param $wildcard string String with wildcards
 501          * @return string Regular expression
 502          */
 503         protected static function wildcardToRegex( $wildcard ) {
 504                 $wildcard = preg_quote( $wildcard, '/' );
 505                 $wildcard = str_replace(
 506                         array( '\*', '\?' ),
 507                         array( '.*?', '.' ),
 508                         $wildcard
 509                 );
 510                 return "/https?:\/\/$wildcard/";
 511         }
 512
 513         protected function sendCacheHeaders() {
 514                 global $wgUseXVO, $wgVaryOnXFP;
 515                 $response = $this->getRequest()->response();
 516                 $out = $this->getOutput();
 517
 518                 if ( $wgVaryOnXFP ) {
 519                         $out->addVaryHeader( 'X-Forwarded-Proto' );
 520                 }
 521
 522                 if ( $this->mCacheMode == 'private' ) {
 523                         $response->header( 'Cache-Control: private' );
 524                         return;
 525                 }
 526
 527                 if ( $this->mCacheMode == 'anon-public-user-private' ) {
 528                         $out->addVaryHeader( 'Cookie' );
 529                         $response->header( $out->getVaryHeader() );
 530                         if ( $wgUseXVO ) {
 531                                 $response->header( $out->getXVO() );
 532                                 if ( $out->haveCacheVaryCookies() ) {
 533                                         // Logged in, mark this request private
 534                                         $response->header( 'Cache-Control: private' );
 535                                         return;
 536                                 }
 537                                 // Logged out, send normal public headers below
 538                         } elseif ( session_id() != '' ) {
 539                                 // Logged in or otherwise has session (e.g. anonymous users who have edited)
 540                                 // Mark request private
 541                                 $response->header( 'Cache-Control: private' );
 542                                 return;
 543                         } // else no XVO and anonymous, send public headers below
 544                 }
 545
 546                 // Send public headers
 547                 $response->header( $out->getVaryHeader() );
 548                 if ( $wgUseXVO ) {
 549                         $response->header( $out->getXVO() );
 550                 }
 551
 552                 // If nobody called setCacheMaxAge(), use the (s)maxage parameters
 553                 if ( !isset( $this->mCacheControl['s-maxage'] ) ) {
 554                         $this->mCacheControl['s-maxage'] = $this->getParameter( 'smaxage' );
 555                 }
 556                 if ( !isset( $this->mCacheControl['max-age'] ) ) {
 557                         $this->mCacheControl['max-age'] = $this->getParameter( 'maxage' );
 558                 }
 559
 560                 if ( !$this->mCacheControl['s-maxage'] && !$this->mCacheControl['max-age'] ) {
 561                         // Public cache not requested
 562                         // Sending a Vary header in this case is harmless, and protects us
 563                         // against conditional calls of setCacheMaxAge().
 564                         $response->header( 'Cache-Control: private' );
 565                         return;
 566                 }
 567
 568                 $this->mCacheControl['public'] = true;
 569
 570                 // Send an Expires header
 571                 $maxAge = min( $this->mCacheControl['s-maxage'], $this->mCacheControl['max-age'] );
 572                 $expiryUnixTime = ( $maxAge == 0 ? 1 : time() + $maxAge );
 573                 $response->header( 'Expires: ' . wfTimestamp( TS_RFC2822, $expiryUnixTime ) );
 574
 575                 // Construct the Cache-Control header
 576                 $ccHeader = '';
 577                 $separator = '';
 578                 foreach ( $this->mCacheControl as $name => $value ) {
 579                         if ( is_bool( $value ) ) {
 580                                 if ( $value ) {
 581                                         $ccHeader .= $separator . $name;
 582                                         $separator = ', ';
 583                                 }
 584                         } else {
 585                                 $ccHeader .= $separator . "$name=$value";
 586                                 $separator = ', ';
 587                         }
 588                 }
 589
 590                 $response->header( "Cache-Control: $ccHeader" );
 591         }
 592
 593         /**
 594          * Replace the result data with the information about an exception.
 595          * Returns the error code
 596          * @param $e Exception
 597          * @return string
 598          */
 599         protected function substituteResultWithError( $e ) {
 600                 global $wgShowHostnames;
 601
 602                 $result = $this->getResult();
 603                 // Printer may not be initialized if the extractRequestParams() fails for the main module
 604                 if ( !isset ( $this->mPrinter ) ) {
 605                         // The printer has not been created yet. Try to manually get formatter value.
 606                         $value = $this->getRequest()->getVal( 'format', self::API_DEFAULT_FORMAT );
 607                         if ( !in_array( $value, $this->mFormatNames ) ) {
 608                                 $value = self::API_DEFAULT_FORMAT;
 609                         }
 610
 611                         $this->mPrinter = $this->createPrinterByName( $value );
 612                         if ( $this->mPrinter->getNeedsRawData() ) {
 613                                 $result->setRawMode();
 614                         }
 615                 }
 616
 617                 if ( $e instanceof UsageException ) {
 618                         // User entered incorrect parameters - print usage screen
 619                         $errMessage = $e->getMessageArray();
 620
 621                         // Only print the help message when this is for the developer, not runtime
 622                         if ( $this->mPrinter->getWantsHelp() || $this->mAction == 'help' ) {
 623                                 ApiResult::setContent( $errMessage, $this->makeHelpMsg() );
 624                         }
 625
 626                 } else {
 627                         global $wgShowSQLErrors, $wgShowExceptionDetails;
 628                         // Something is seriously wrong
 629                         if ( ( $e instanceof DBQueryError ) && !$wgShowSQLErrors ) {
 630                                 $info = 'Database query error';
 631                         } else {
 632                                 $info = "Exception Caught: {$e->getMessage()}";
 633                         }
 634
 635                         $errMessage = array(
 636                                 'code' => 'internal_api_error_' . get_class( $e ),
 637                                 'info' => $info,
 638                         );
 639                         ApiResult::setContent( $errMessage, $wgShowExceptionDetails ? "\n\n{$e->getTraceAsString()}\n\n" : '' );
 640                 }
 641
 642                 $result->reset();
 643                 $result->disableSizeCheck();
 644                 // Re-add the id
 645                 $requestid = $this->getParameter( 'requestid' );
 646                 if ( !is_null( $requestid ) ) {
 647                         $result->addValue( null, 'requestid', $requestid );
 648                 }
 649
 650                 if ( $wgShowHostnames ) {
 651                         // servedby is especially useful when debugging errors
 652                         $result->addValue( null, 'servedby', wfHostName() );
 653                 }
 654
 655                 $result->addValue( null, 'error', $errMessage );
 656
 657                 return $errMessage['code'];
 658         }
 659
 660         /**
 661          * Set up for the execution.
 662          * @return array
 663          */
 664         protected function setupExecuteAction() {
 665                 global $wgShowHostnames;
 666
 667                 // First add the id to the top element
 668                 $result = $this->getResult();
 669                 $requestid = $this->getParameter( 'requestid' );
 670                 if ( !is_null( $requestid ) ) {
 671                         $result->addValue( null, 'requestid', $requestid );
 672                 }
 673
 674                 if ( $wgShowHostnames ) {
 675                         $servedby = $this->getParameter( 'servedby' );
 676                         if ( $servedby ) {
 677                                 $result->addValue( null, 'servedby', wfHostName() );
 678                         }
 679                 }
 680
 681                 $params = $this->extractRequestParams();
 682
 683                 $this->mShowVersions = $params['version'];
 684                 $this->mAction = $params['action'];
 685
 686                 if ( !is_string( $this->mAction ) ) {
 687                         $this->dieUsage( 'The API requires a valid action parameter', 'unknown_action' );
 688                 }
 689
 690                 return $params;
 691         }
 692
 693         /**
 694          * Set up the module for response
 695          * @return ApiBase The module that will handle this action
 696          */
 697         protected function setupModule() {
 698                 // Instantiate the module requested by the user
 699                 $module = new $this->mModules[$this->mAction] ( $this, $this->mAction );
 700                 $this->mModule = $module;
 701
 702                 $moduleParams = $module->extractRequestParams();
 703
 704                 // Die if token required, but not provided (unless there is a gettoken parameter)
 705                 if ( isset( $moduleParams['gettoken'] ) ) {
 706                         $gettoken = $moduleParams['gettoken'];
 707                 } else {
 708                         $gettoken = false;
 709                 }
 710
 711                 $salt = $module->getTokenSalt();
 712                 if ( $salt !== false && !$gettoken ) {
 713                         if ( !isset( $moduleParams['token'] ) ) {
 714                                 $this->dieUsageMsg( array( 'missingparam', 'token' ) );
 715                         } else {
 716                                 if ( !$this->getUser()->matchEditToken( $moduleParams['token'], $salt, $this->getContext()->getRequest() ) ) {
 717                                         $this->dieUsageMsg( 'sessionfailure' );
 718                                 }
 719                         }
 720                 }
 721                 return $module;
 722         }
 723
 724         /**
 725          * Check the max lag if necessary
 726          * @param $module ApiBase object: Api module being used
 727          * @param $params Array an array containing the request parameters.
 728          * @return boolean True on success, false should exit immediately
 729          */
 730         protected function checkMaxLag( $module, $params ) {
 731                 if ( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
 732                         // Check for maxlag
 733                         global $wgShowHostnames;
 734                         $maxLag = $params['maxlag'];
 735                         list( $host, $lag ) = wfGetLB()->getMaxLag();
 736                         if ( $lag > $maxLag ) {
 737                                 $response = $this->getRequest()->response();
 738
 739                                 $response->header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
 740                                 $response->header( 'X-Database-Lag: ' . intval( $lag ) );
 741
 742                                 if ( $wgShowHostnames ) {
 743                                         $this->dieUsage( "Waiting for $host: $lag seconds lagged", 'maxlag' );
 744                                 } else {
 745                                         $this->dieUsage( "Waiting for a database server: $lag seconds lagged", 'maxlag' );
 746                                 }
 747                                 return false;
 748                         }
 749                 }
 750                 return true;
 751         }
 752
 753         /**
 754          * Check for sufficient permissions to execute
 755          * @param $module ApiBase An Api module
 756          */
 757         protected function checkExecutePermissions( $module ) {
 758                 $user = $this->getUser();
 759                 if ( $module->isReadMode() && !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) &&
 760                         !$user->isAllowed( 'read' ) )
 761                 {
 762                         $this->dieUsageMsg( 'readrequired' );
 763                 }
 764                 if ( $module->isWriteMode() ) {
 765                         if ( !$this->mEnableWrite ) {
 766                                 $this->dieUsageMsg( 'writedisabled' );
 767                         }
 768                         if ( !$user->isAllowed( 'writeapi' ) ) {
 769                                 $this->dieUsageMsg( 'writerequired' );
 770                         }
 771                         if ( wfReadOnly() ) {
 772                                 $this->dieReadOnly();
 773                         }
 774                 }
 775
 776                 // Allow extensions to stop execution for arbitrary reasons.
 777                 $message = false;
 778                 if( !wfRunHooks( 'ApiCheckCanExecute', array( $module, $user, &$message ) ) ) {
 779                         $this->dieUsageMsg( $message );
 780                 }
 781         }
 782
 783         /**
 784          * Check POST for external response and setup result printer
 785          * @param $module ApiBase An Api module
 786          * @param $params Array an array with the request parameters
 787          */
 788         protected function setupExternalResponse( $module, $params ) {
 789                 // Ignore mustBePosted() for internal calls
 790                 if ( $module->mustBePosted() && !$this->getRequest()->wasPosted() ) {
 791                         $this->dieUsageMsg( array( 'mustbeposted', $this->mAction ) );
 792                 }
 793
 794                 // See if custom printer is used
 795                 $this->mPrinter = $module->getCustomPrinter();
 796                 if ( is_null( $this->mPrinter ) ) {
 797                         // Create an appropriate printer
 798                         $this->mPrinter = $this->createPrinterByName( $params['format'] );
 799                 }
 800
 801                 if ( $this->mPrinter->getNeedsRawData() ) {
 802                         $this->getResult()->setRawMode();
 803                 }
 804         }
 805
 806         /**
 807          * Execute the actual module, without any error handling
 808          */
 809         protected function executeAction() {
 810                 $params = $this->setupExecuteAction();
 811                 $module = $this->setupModule();
 812
 813                 $this->checkExecutePermissions( $module );
 814
 815                 if ( !$this->checkMaxLag( $module, $params ) ) {
 816                         return;
 817                 }
 818
 819                 if ( !$this->mInternalMode ) {
 820                         $this->setupExternalResponse( $module, $params );
 821                 }
 822
 823                 // Execute
 824                 $module->profileIn();
 825                 $module->execute();
 826                 wfRunHooks( 'APIAfterExecute', array( &$module ) );
 827                 $module->profileOut();
 828
 829                 if ( !$this->mInternalMode ) {
 830                         // Report unused params
 831                         $this->reportUnusedParams();
 832
 833                         //append Debug information
 834                         MWDebug::appendDebugInfoToApiResult( $this->getContext(), $this->getResult() );
 835
 836                         // Print result data
 837                         $this->printResult( false );
 838                 }
 839         }
 840
 841         /**
 842          * Log the preceding request
 843          * @param $time Time in seconds
 844          */
 845         protected function logRequest( $time ) {
 846                 $request = $this->getRequest();
 847                 $milliseconds = $time === null ? '?' : round( $time * 1000 );
 848                 $s = 'API' .
 849                         ' ' . $request->getMethod() .
 850                         ' ' . wfUrlencode( str_replace( ' ', '_', $this->getUser()->getName() ) ) .
 851                         ' ' . $request->getIP() .
 852                         ' T=' . $milliseconds .'ms';
 853                 foreach ( $this->getParamsUsed() as $name ) {
 854                         $value = $request->getVal( $name );
 855                         if ( $value === null ) {
 856                                 continue;
 857                         }
 858                         $s .= ' ' . $name . '=';
 859                         if ( strlen( $value ) > 256 ) {
 860                                 $encValue = $this->encodeRequestLogValue( substr( $value, 0, 256 ) );
 861                                 $s .= $encValue . '[...]';
 862                         } else {
 863                                 $s .= $this->encodeRequestLogValue( $value );
 864                         }
 865                 }
 866                 $s .= "\n";
 867                 wfDebugLog( 'api', $s, false );
 868         }
 869
 870         /**
 871          * Encode a value in a format suitable for a space-separated log line.
 872          */
 873         protected function encodeRequestLogValue( $s ) {
 874                 static $table;
 875                 if ( !$table ) {
 876                         $chars = ';@$!*(),/:';
 877                         for ( $i = 0; $i < strlen( $chars ); $i++ ) {
 878                                 $table[ rawurlencode( $chars[$i] ) ] = $chars[$i];
 879                         }
 880                 }
 881                 return strtr( rawurlencode( $s ), $table );
 882         }
 883
 884         /**
 885          * Get the request parameters used in the course of the preceding execute() request
 886          */
 887         protected function getParamsUsed() {
 888                 return array_keys( $this->mParamsUsed );
 889         }
 890
 891         /**
 892          * Get a request value, and register the fact that it was used, for logging.
 893          */
 894         public function getVal( $name, $default = null ) {
 895                 $this->mParamsUsed[$name] = true;
 896                 return $this->getRequest()->getVal( $name, $default );
 897         }
 898
 899         /**
 900          * Get a boolean request value, and register the fact that the parameter
 901          * was used, for logging.
 902          */
 903         public function getCheck( $name ) {
 904                 $this->mParamsUsed[$name] = true;
 905                 return $this->getRequest()->getCheck( $name );
 906         }
 907
 908         /**
 909          * Report unused parameters, so the client gets a hint in case it gave us parameters we don't know,
 910          * for example in case of spelling mistakes or a missing 'g' prefix for generators.
 911          */
 912         protected function reportUnusedParams() {
 913                 $paramsUsed = $this->getParamsUsed();
 914                 $allParams = $this->getRequest()->getValueNames();
 915
 916                 $unusedParams = array_diff( $allParams, $paramsUsed );
 917                 if( count( $unusedParams ) ) {
 918                         $s = count( $unusedParams ) > 1 ? 's' : '';
 919                         $this->setWarning( "Unrecognized parameter$s: '" . implode( $unusedParams, "', '" ) . "'" );
 920                 }
 921         }
 922
 923         /**
 924          * Print results using the current printer
 925          *
 926          * @param $isError bool
 927          */
 928         protected function printResult( $isError ) {
 929                 $this->getResult()->cleanUpUTF8();
 930                 $printer = $this->mPrinter;
 931                 $printer->profileIn();
 932
 933                 /**
 934                  * If the help message is requested in the default (xmlfm) format,
 935                  * tell the printer not to escape ampersands so that our links do
 936                  * not break.
 937                  */
 938                 $printer->setUnescapeAmps( ( $this->mAction == 'help' || $isError )
 939                                 && $printer->getFormat() == 'XML' && $printer->getIsHtml() );
 940
 941                 $printer->initPrinter( $isError );
 942
 943                 $printer->execute();
 944                 $printer->closePrinter();
 945                 $printer->profileOut();
 946         }
 947
 948         /**
 949          * @return bool
 950          */
 951         public function isReadMode() {
 952                 return false;
 953         }
 954
 955         /**
 956          * See ApiBase for description.
 957          *
 958          * @return array
 959          */
 960         public function getAllowedParams() {
 961                 return array(
 962                         'format' => array(
 963                                 ApiBase::PARAM_DFLT => ApiMain::API_DEFAULT_FORMAT,
 964                                 ApiBase::PARAM_TYPE => $this->mFormatNames
 965                         ),
 966                         'action' => array(
 967                                 ApiBase::PARAM_DFLT => 'help',
 968                                 ApiBase::PARAM_TYPE => $this->mModuleNames
 969                         ),
 970                         'version' => false,
 971                         'maxlag'  => array(
 972                                 ApiBase::PARAM_TYPE => 'integer'
 973                         ),
 974                         'smaxage' => array(
 975                                 ApiBase::PARAM_TYPE => 'integer',
 976                                 ApiBase::PARAM_DFLT => 0
 977                         ),
 978                         'maxage' => array(
 979                                 ApiBase::PARAM_TYPE => 'integer',
 980                                 ApiBase::PARAM_DFLT => 0
 981                         ),
 982                         'requestid' => null,
 983                         'servedby'  => false,
 984                         'origin' => null,
 985                 );
 986         }
 987
 988         /**
 989          * See ApiBase for description.
 990          *
 991          * @return array
 992          */
 993         public function getParamDescription() {
 994                 return array(
 995                         'format' => 'The format of the output',
 996                         'action' => 'What action you would like to perform. See below for module help',
 997                         'version' => 'When showing help, include version for each module',
 998                         'maxlag' => array(
 999                                 'Maximum lag can be used when MediaWiki is installed on a database replicated cluster.',
1000                                 'To save actions causing any more site replication lag, this parameter can make the client',
1001                                 'wait until the replication lag is less than the specified value.',
1002                                 'In case of a replag error, error code "maxlag" is returned, with the message like',
1003                                 '"Waiting for $host: $lag seconds lagged\n".',
1004                                 'See https://www.mediawiki.org/wiki/Manual:Maxlag_parameter for more information',
1005                         ),
1006                         'smaxage' => 'Set the s-maxage header to this many seconds. Errors are never cached',
1007                         'maxage' => 'Set the max-age header to this many seconds. Errors are never cached',
1008                         'requestid' => 'Request ID to distinguish requests. This will just be output back to you',
1009                         'servedby' => 'Include the hostname that served the request in the results. Unconditionally shown on error',
1010                         'origin' => array(
1011                                 'When accessing the API using a cross-domain AJAX request (CORS), set this to the originating domain.',
1012                                 'This must match one of the origins in the Origin: header exactly, so it has to be set to something like http://en.wikipedia.org or https://meta.wikimedia.org .',
1013                                 'If this parameter does not match the Origin: header, a 403 response will be returned.',
1014                                 'If this parameter matches the Origin: header and the origin is whitelisted, an Access-Control-Allow-Origin header will be set.',
1015                         ),
1016                 );
1017         }
1018
1019         /**
1020          * See ApiBase for description.
1021          *
1022          * @return array
1023          */
1024         public function getDescription() {
1025                 return array(
1026                         '',
1027                         '',
1028                         '**********************************************************************************************************',
1029                         '**                                                                                                      **',
1030                         '**                      This is an auto-generated MediaWiki API documentation page                      **',
1031                         '**                                                                                                      **',
1032                         '**                                     Documentation and Examples:                                      **',
1033                         '**                                  https://www.mediawiki.org/wiki/API                                  **',
1034                         '**                                                                                                      **',
1035                         '**********************************************************************************************************',
1036                         '',
1037                         'Status:                All features shown on this page should be working, but the API',
1038                         '                       is still in active development, and may change at any time.',
1039                         '                       Make sure to monitor our mailing list for any updates',
1040                         '',
1041                         'Erroneous requests:    When erroneous requests are sent to the API, a HTTP header will be sent',
1042                         '                       with the key "MediaWiki-API-Error" and then both the value of the',
1043                         '                       header and the error code sent back will be set to the same value',
1044                         '',
1045                         '                       In the case of an invalid action being passed, these will have a value',
1046                         '                       of "unknown_action"',
1047                         '',
1048                         '                       For more information see https://www.mediawiki.org/wiki/API:Errors_and_warnings',
1049                         '',
1050                         'Documentation:         https://www.mediawiki.org/wiki/API:Main_page',
1051                         'FAQ                    https://www.mediawiki.org/wiki/API:FAQ',
1052                         'Mailing list:          https://lists.wikimedia.org/mailman/listinfo/mediawiki-api',
1053                         'Api Announcements:     https://lists.wikimedia.org/mailman/listinfo/mediawiki-api-announce',
1054                         'Bugs & Requests:       https://bugzilla.wikimedia.org/buglist.cgi?component=API&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&order=bugs.delta_ts',
1055                         '',
1056                         '',
1057                         '',
1058                         '',
1059                         '',
1060                 );
1061         }
1062
1063         /**
1064          * @return array
1065          */
1066         public function getPossibleErrors() {
1067                 return array_merge( parent::getPossibleErrors(), array(
1068                         array( 'readonlytext' ),
1069                         array( 'code' => 'unknown_format', 'info' => 'Unrecognized format: format' ),
1070                         array( 'code' => 'unknown_action', 'info' => 'The API requires a valid action parameter' ),
1071                         array( 'code' => 'maxlag', 'info' => 'Waiting for host: x seconds lagged' ),
1072                         array( 'code' => 'maxlag', 'info' => 'Waiting for a database server: x seconds lagged' ),
1073                 ) );
1074         }
1075
1076         /**
1077          * Returns an array of strings with credits for the API
1078          * @return array
1079          */
1080         protected function getCredits() {
1081                 return array(
1082                         'API developers:',
1083                         '    Roan Kattouw "<Firstname>.<Lastname>@gmail.com" (lead developer Sep 2007-present)',
1084                         '    Victor Vasiliev - vasilvv at gee mail dot com',
1085                         '    Bryan Tong Minh - bryan . tongminh @ gmail . com',
1086                         '    Sam Reed - sam @ reedyboy . net',
1087                         '    Yuri Astrakhan "<Firstname><Lastname>@gmail.com" (creator, lead developer Sep 2006-Sep 2007)',
1088                         '',
1089                         'Please send your comments, suggestions and questions to mediawiki-api@lists.wikimedia.org',
1090                         'or file a bug report at https://bugzilla.wikimedia.org/'
1091                 );
1092         }
1093
1094         /**
1095          * Sets whether the pretty-printer should format *bold* and $italics$
1096          *
1097          * @param $help bool
1098          */
1099         public function setHelp( $help = true ) {
1100                 $this->mPrinter->setHelp( $help );
1101         }
1102
1103         /**
1104          * Override the parent to generate help messages for all available modules.
1105          *
1106          * @return string
1107          */
1108         public function makeHelpMsg() {
1109                 global $wgMemc, $wgAPICacheHelpTimeout;
1110                 $this->setHelp();
1111                 // Get help text from cache if present
1112                 $key = wfMemcKey( 'apihelp', $this->getModuleName(),
1113                         SpecialVersion::getVersion( 'nodb' ) .
1114                         $this->getShowVersions() );
1115                 if ( $wgAPICacheHelpTimeout > 0 ) {
1116                         $cached = $wgMemc->get( $key );
1117                         if ( $cached ) {
1118                                 return $cached;
1119                         }
1120                 }
1121                 $retval = $this->reallyMakeHelpMsg();
1122                 if ( $wgAPICacheHelpTimeout > 0 ) {
1123                         $wgMemc->set( $key, $retval, $wgAPICacheHelpTimeout );
1124                 }
1125                 return $retval;
1126         }
1127
1128         /**
1129          * @return mixed|string
1130          */
1131         public function reallyMakeHelpMsg() {
1132                 $this->setHelp();
1133
1134                 // Use parent to make default message for the main module
1135                 $msg = parent::makeHelpMsg();
1136
1137                 $astriks = str_repeat( '*** ', 14 );
1138                 $msg .= "\n\n$astriks Modules  $astriks\n\n";
1139                 foreach ( array_keys( $this->mModules ) as $moduleName ) {
1140                         $module = new $this->mModules[$moduleName] ( $this, $moduleName );
1141                         $msg .= self::makeHelpMsgHeader( $module, 'action' );
1142                         $msg2 = $module->makeHelpMsg();
1143                         if ( $msg2 !== false ) {
1144                                 $msg .= $msg2;
1145                         }
1146                         $msg .= "\n";
1147                 }
1148
1149                 $msg .= "\n$astriks Permissions $astriks\n\n";
1150                 foreach ( self::$mRights as $right => $rightMsg ) {
1151                         $groups = User::getGroupsWithPermission( $right );
1152                         $msg .= "* " . $right . " *\n  " . wfMsgReplaceArgs( $rightMsg[ 'msg' ], $rightMsg[ 'params' ] ) .
1153                                                 "\nGranted to:\n  " . str_replace( '*', 'all', implode( ', ', $groups ) ) . "\n\n";
1154
1155                 }
1156
1157                 $msg .= "\n$astriks Formats  $astriks\n\n";
1158                 foreach ( array_keys( $this->mFormats ) as $formatName ) {
1159                         $module = $this->createPrinterByName( $formatName );
1160                         $msg .= self::makeHelpMsgHeader( $module, 'format' );
1161                         $msg2 = $module->makeHelpMsg();
1162                         if ( $msg2 !== false ) {
1163                                 $msg .= $msg2;
1164                         }
1165                         $msg .= "\n";
1166                 }
1167
1168                 $msg .= "\n*** Credits: ***\n   " . implode( "\n   ", $this->getCredits() ) . "\n";
1169
1170                 return $msg;
1171         }
1172
1173         /**
1174          * @param $module ApiBase
1175          * @param $paramName String What type of request is this? e.g. action, query, list, prop, meta, format
1176          * @return string
1177          */
1178         public static function makeHelpMsgHeader( $module, $paramName ) {
1179                 $modulePrefix = $module->getModulePrefix();
1180                 if ( strval( $modulePrefix ) !== '' ) {
1181                         $modulePrefix = "($modulePrefix) ";
1182                 }
1183
1184                 return "* $paramName={$module->getModuleName()} $modulePrefix*";
1185         }
1186
1187         private $mCanApiHighLimits = null;
1188
1189         /**
1190          * Check whether the current user is allowed to use high limits
1191          * @return bool
1192          */
1193         public function canApiHighLimits() {
1194                 if ( !isset( $this->mCanApiHighLimits ) ) {
1195                         $this->mCanApiHighLimits = $this->getUser()->isAllowed( 'apihighlimits' );
1196                 }
1197
1198                 return $this->mCanApiHighLimits;
1199         }
1200
1201         /**
1202          * Check whether the user wants us to show version information in the API help
1203          * @return bool
1204          */
1205         public function getShowVersions() {
1206                 return $this->mShowVersions;
1207         }
1208
1209         /**
1210          * Returns the version information of this file, plus it includes
1211          * the versions for all files that are not callable proper API modules
1212          *
1213          * @return array
1214          */
1215         public function getVersion() {
1216                 $vers = array();
1217                 $vers[] = 'MediaWiki: ' . SpecialVersion::getVersion() . "\n    https://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/";
1218                 $vers[] = __CLASS__ . ': $Id$';
1219                 $vers[] = ApiBase::getBaseVersion();
1220                 $vers[] = ApiFormatBase::getBaseVersion();
1221                 $vers[] = ApiQueryBase::getBaseVersion();
1222                 return $vers;
1223         }
1224
1225         /**
1226          * Add or overwrite a module in this ApiMain instance. Intended for use by extending
1227          * classes who wish to add their own modules to their lexicon or override the
1228          * behavior of inherent ones.
1229          *
1230          * @param $mdlName String The identifier for this module.
1231          * @param $mdlClass String The class where this module is implemented.
1232          */
1233         protected function addModule( $mdlName, $mdlClass ) {
1234                 $this->mModules[$mdlName] = $mdlClass;
1235         }
1236
1237         /**
1238          * Add or overwrite an output format for this ApiMain. Intended for use by extending
1239          * classes who wish to add to or modify current formatters.
1240          *
1241          * @param $fmtName string The identifier for this format.
1242          * @param $fmtClass ApiFormatBase The class implementing this format.
1243          */
1244         protected function addFormat( $fmtName, $fmtClass ) {
1245                 $this->mFormats[$fmtName] = $fmtClass;
1246         }
1247
1248         /**
1249          * Get the array mapping module names to class names
1250          * @return array
1251          */
1252         function getModules() {
1253                 return $this->mModules;
1254         }
1255
1256         /**
1257          * Returns the list of supported formats in form ( 'format' => 'ClassName' )
1258          *
1259          * @since 1.18
1260          * @return array
1261          */
1262         public function getFormats() {
1263                 return $this->mFormats;
1264         }
1265 }
1266
1267 /**
1268  * This exception will be thrown when dieUsage is called to stop module execution.
1269  * The exception handling code will print a help screen explaining how this API may be used.
1270  *
1271  * @ingroup API
1272  */
1273 class UsageException extends MWException {
1274
1275         private $mCodestr;
1276
1277         /**
1278          * @var null|array
1279          */
1280         private $mExtraData;
1281
1282         /**
1283          * @param $message string
1284          * @param $codestr string
1285          * @param $code int
1286          * @param $extradata array|null
1287          */
1288         public function __construct( $message, $codestr, $code = 0, $extradata = null ) {
1289                 parent::__construct( $message, $code );
1290                 $this->mCodestr = $codestr;
1291                 $this->mExtraData = $extradata;
1292         }
1293
1294         /**
1295          * @return string
1296          */
1297         public function getCodeString() {
1298                 return $this->mCodestr;
1299         }
1300
1301         /**
1302          * @return array
1303          */
1304         public function getMessageArray() {
1305                 $result = array(
1306                         'code' => $this->mCodestr,
1307                         'info' => $this->getMessage()
1308                 );
1309                 if ( is_array( $this->mExtraData ) ) {
1310                         $result = array_merge( $result, $this->mExtraData );
1311                 }
1312                 return $result;
1313         }
1314
1315         /**
1316          * @return string
1317          */
1318         public function __toString() {
1319                 return "{$this->getCodeString()}: {$this->getMessage()}";
1320         }
1321 }