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                 'rollback' => 'ApiRollback',
  69                 'delete' => 'ApiDelete',
  70                 'undelete' => 'ApiUndelete',
  71                 'protect' => 'ApiProtect',
  72                 'block' => 'ApiBlock',
  73                 'unblock' => 'ApiUnblock',
  74                 'move' => 'ApiMove',
  75                 'edit' => 'ApiEditPage',
  76                 'upload' => 'ApiUpload',
  77                 'filerevert' => 'ApiFileRevert',
  78                 'emailuser' => 'ApiEmailUser',
  79                 'watch' => 'ApiWatch',
  80                 'patrol' => 'ApiPatrol',
  81                 'import' => 'ApiImport',
  82                 'userrights' => 'ApiUserrights',
  83         );
  84
  85         /**
  86          * List of available formats: format name => format class
  87          */
  88         private static $Formats = array(
  89                 'json' => 'ApiFormatJson',
  90                 'jsonfm' => 'ApiFormatJson',
  91                 'php' => 'ApiFormatPhp',
  92                 'phpfm' => 'ApiFormatPhp',
  93                 'wddx' => 'ApiFormatWddx',
  94                 'wddxfm' => 'ApiFormatWddx',
  95                 'xml' => 'ApiFormatXml',
  96                 'xmlfm' => 'ApiFormatXml',
  97                 'yaml' => 'ApiFormatYaml',
  98                 'yamlfm' => 'ApiFormatYaml',
  99                 'rawfm' => 'ApiFormatJson',
 100                 'txt' => 'ApiFormatTxt',
 101                 'txtfm' => 'ApiFormatTxt',
 102                 'dbg' => 'ApiFormatDbg',
 103                 'dbgfm' => 'ApiFormatDbg',
 104                 'dump' => 'ApiFormatDump',
 105                 'dumpfm' => 'ApiFormatDump',
 106                 'none' => 'ApiFormatNone',
 107         );
 108
 109         /**
 110          * List of user roles that are specifically relevant to the API.
 111          * array( 'right' => array ( 'msg'    => 'Some message with a $1',
 112          *                           'params' => array ( $someVarToSubst ) ),
 113          *                          );
 114          */
 115         private static $mRights = array(
 116                 'writeapi' => array(
 117                         'msg' => 'Use of the write API',
 118                         'params' => array()
 119                 ),
 120                 'apihighlimits' => array(
 121                         '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.',
 122                         'params' => array( ApiBase::LIMIT_SML2, ApiBase::LIMIT_BIG2 )
 123                 )
 124         );
 125
 126         /**
 127          * @var ApiFormatBase
 128          */
 129         private $mPrinter;
 130
 131         private $mModules, $mModuleNames, $mFormats, $mFormatNames;
 132         private $mResult, $mAction, $mShowVersions, $mEnableWrite;
 133         private $mInternalMode, $mSquidMaxage, $mModule;
 134
 135         private $mCacheMode = 'private';
 136         private $mCacheControl = array();
 137
 138         /**
 139          * Constructs an instance of ApiMain that utilizes the module and format specified by $request.
 140          *
 141          * @param $context IContextSource|WebRequest - if this is an instance of FauxRequest, errors are thrown and no printing occurs
 142          * @param $enableWrite bool should be set to true if the api may modify data
 143          */
 144         public function __construct( $context = null, $enableWrite = false ) {
 145                 if ( $context === null ) {
 146                         $context = RequestContext::getMain();
 147                 } elseif ( $context instanceof WebRequest ) {
 148                         // BC for pre-1.19
 149                         $request = $context;
 150                         $context = RequestContext::getMain();
 151                 }
 152                 // We set a derivative context so we can change stuff later
 153                 $this->setContext( new DerivativeContext( $context ) );
 154
 155                 if ( isset( $request ) ) {
 156                         $this->getContext()->setRequest( $request );
 157                 }
 158
 159                 $this->mInternalMode = ( $this->getRequest() instanceof FauxRequest );
 160
 161                 // Special handling for the main module: $parent === $this
 162                 parent::__construct( $this, $this->mInternalMode ? 'main_int' : 'main' );
 163
 164                 if ( !$this->mInternalMode ) {
 165                         // Impose module restrictions.
 166                         // If the current user cannot read,
 167                         // Remove all modules other than login
 168                         global $wgUser;
 169
 170                         if ( $this->getRequest()->getVal( 'callback' ) !== null ) {
 171                                 // JSON callback allows cross-site reads.
 172                                 // For safety, strip user credentials.
 173                                 wfDebug( "API: stripping user credentials for JSON callback\n" );
 174                                 $wgUser = new User();
 175                                 $this->getContext()->setUser( $wgUser );
 176                         }
 177                 }
 178
 179                 global $wgAPIModules; // extension modules
 180                 $this->mModules = $wgAPIModules + self::$Modules;
 181
 182                 $this->mModuleNames = array_keys( $this->mModules );
 183                 $this->mFormats = self::$Formats;
 184                 $this->mFormatNames = array_keys( $this->mFormats );
 185
 186                 $this->mResult = new ApiResult( $this );
 187                 $this->mShowVersions = false;
 188                 $this->mEnableWrite = $enableWrite;
 189
 190                 $this->mSquidMaxage = - 1; // flag for executeActionWithErrorHandling()
 191                 $this->mCommit = false;
 192         }
 193
 194         /**
 195          * Return true if the API was started by other PHP code using FauxRequest
 196          * @return bool
 197          */
 198         public function isInternalMode() {
 199                 return $this->mInternalMode;
 200         }
 201
 202         /**
 203          * Get the ApiResult object associated with current request
 204          *
 205          * @return ApiResult
 206          */
 207         public function getResult() {
 208                 return $this->mResult;
 209         }
 210
 211         /**
 212          * Get the API module object. Only works after executeAction()
 213          *
 214          * @return ApiBase
 215          */
 216         public function getModule() {
 217                 return $this->mModule;
 218         }
 219
 220         /**
 221          * Get the result formatter object. Only works after setupExecuteAction()
 222          *
 223          * @return ApiFormatBase
 224          */
 225         public function getPrinter() {
 226                 return $this->mPrinter;
 227         }
 228
 229         /**
 230          * Set how long the response should be cached.
 231          *
 232          * @param $maxage
 233          */
 234         public function setCacheMaxAge( $maxage ) {
 235                 $this->setCacheControl( array(
 236                         'max-age' => $maxage,
 237                         's-maxage' => $maxage
 238                 ) );
 239         }
 240
 241         /**
 242          * Set the type of caching headers which will be sent.
 243          *
 244          * @param $mode String One of:
 245          *    - 'public':     Cache this object in public caches, if the maxage or smaxage
 246          *         parameter is set, or if setCacheMaxAge() was called. If a maximum age is
 247          *         not provided by any of these means, the object will be private.
 248          *    - 'private':    Cache this object only in private client-side caches.
 249          *    - 'anon-public-user-private': Make this object cacheable for logged-out
 250          *         users, but private for logged-in users. IMPORTANT: If this is set, it must be
 251          *         set consistently for a given URL, it cannot be set differently depending on
 252          *         things like the contents of the database, or whether the user is logged in.
 253          *
 254          *  If the wiki does not allow anonymous users to read it, the mode set here
 255          *  will be ignored, and private caching headers will always be sent. In other words,
 256          *  the "public" mode is equivalent to saying that the data sent is as public as a page
 257          *  view.
 258          *
 259          *  For user-dependent data, the private mode should generally be used. The
 260          *  anon-public-user-private mode should only be used where there is a particularly
 261          *  good performance reason for caching the anonymous response, but where the
 262          *  response to logged-in users may differ, or may contain private data.
 263          *
 264          *  If this function is never called, then the default will be the private mode.
 265          */
 266         public function setCacheMode( $mode ) {
 267                 if ( !in_array( $mode, array( 'private', 'public', 'anon-public-user-private' ) ) ) {
 268                         wfDebug( __METHOD__ . ": unrecognised cache mode \"$mode\"\n" );
 269                         // Ignore for forwards-compatibility
 270                         return;
 271                 }
 272
 273                 if ( !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) ) {
 274                         // Private wiki, only private headers
 275                         if ( $mode !== 'private' ) {
 276                                 wfDebug( __METHOD__ . ": ignoring request for $mode cache mode, private wiki\n" );
 277                                 return;
 278                         }
 279                 }
 280
 281                 wfDebug( __METHOD__ . ": setting cache mode $mode\n" );
 282                 $this->mCacheMode = $mode;
 283         }
 284
 285         /**
 286          * @deprecated since 1.17 Private caching is now the default, so there is usually no
 287          * need to call this function. If there is a need, you can use
 288          * $this->setCacheMode('private')
 289          */
 290         public function setCachePrivate() {
 291                 wfDeprecated( __METHOD__, '1.17' );
 292                 $this->setCacheMode( 'private' );
 293         }
 294
 295         /**
 296          * Set directives (key/value pairs) for the Cache-Control header.
 297          * Boolean values will be formatted as such, by including or omitting
 298          * without an equals sign.
 299          *
 300          * Cache control values set here will only be used if the cache mode is not
 301          * private, see setCacheMode().
 302          *
 303          * @param $directives array
 304          */
 305         public function setCacheControl( $directives ) {
 306                 $this->mCacheControl = $directives + $this->mCacheControl;
 307         }
 308
 309         /**
 310          * Make sure Vary: Cookie and friends are set. Use this when the output of a request
 311          * may be cached for anons but may not be cached for logged-in users.
 312          *
 313          * WARNING: This function must be called CONSISTENTLY for a given URL. This means that a
 314          * given URL must either always or never call this function; if it sometimes does and
 315          * sometimes doesn't, stuff will break.
 316          *
 317          * @deprecated since 1.17 Use setCacheMode( 'anon-public-user-private' )
 318          */
 319         public function setVaryCookie() {
 320                 wfDeprecated( __METHOD__, '1.17' );
 321                 $this->setCacheMode( 'anon-public-user-private' );
 322         }
 323
 324         /**
 325          * Create an instance of an output formatter by its name
 326          *
 327          * @param $format string
 328          *
 329          * @return ApiFormatBase
 330          */
 331         public function createPrinterByName( $format ) {
 332                 if ( !isset( $this->mFormats[$format] ) ) {
 333                         $this->dieUsage( "Unrecognized format: {$format}", 'unknown_format' );
 334                 }
 335                 return new $this->mFormats[$format] ( $this, $format );
 336         }
 337
 338         /**
 339          * Execute api request. Any errors will be handled if the API was called by the remote client.
 340          */
 341         public function execute() {
 342                 $this->profileIn();
 343                 if ( $this->mInternalMode ) {
 344                         $this->executeAction();
 345                 } else {
 346                         $this->executeActionWithErrorHandling();
 347                 }
 348
 349                 $this->profileOut();
 350         }
 351
 352         /**
 353          * Execute an action, and in case of an error, erase whatever partial results
 354          * have been accumulated, and replace it with an error message and a help screen.
 355          */
 356         protected function executeActionWithErrorHandling() {
 357                 // In case an error occurs during data output,
 358                 // clear the output buffer and print just the error information
 359                 ob_start();
 360
 361                 try {
 362                         $this->executeAction();
 363                 } catch ( Exception $e ) {
 364                         // Log it
 365                         if ( $e instanceof MWException ) {
 366                                 wfDebugLog( 'exception', $e->getLogMessage() );
 367                         }
 368
 369                         // Handle any kind of exception by outputing properly formatted error message.
 370                         // If this fails, an unhandled exception should be thrown so that global error
 371                         // handler will process and log it.
 372
 373                         $errCode = $this->substituteResultWithError( $e );
 374
 375                         // Error results should not be cached
 376                         $this->setCacheMode( 'private' );
 377
 378                         $response = $this->getRequest()->response();
 379                         $headerStr = 'MediaWiki-API-Error: ' . $errCode;
 380                         if ( $e->getCode() === 0 ) {
 381                                 $response->header( $headerStr );
 382                         } else {
 383                                 $response->header( $headerStr, true, $e->getCode() );
 384                         }
 385
 386                         // Reset and print just the error message
 387                         ob_clean();
 388
 389                         // If the error occured during printing, do a printer->profileOut()
 390                         $this->mPrinter->safeProfileOut();
 391                         $this->printResult( true );
 392                 }
 393
 394                 // Send cache headers after any code which might generate an error, to
 395                 // avoid sending public cache headers for errors.
 396                 $this->sendCacheHeaders();
 397
 398                 if ( $this->mPrinter->getIsHtml() && !$this->mPrinter->isDisabled() ) {
 399                         echo wfReportTime();
 400                 }
 401
 402                 ob_end_flush();
 403         }
 404
 405         protected function sendCacheHeaders() {
 406                 global $wgUseXVO, $wgVaryOnXFP;
 407                 $response = $this->getRequest()->response();
 408
 409                 if ( $this->mCacheMode == 'private' ) {
 410                         $response->header( 'Cache-Control: private' );
 411                         return;
 412                 }
 413
 414                 if ( $this->mCacheMode == 'anon-public-user-private' ) {
 415                         $xfp = $wgVaryOnXFP ? ', X-Forwarded-Proto' : '';
 416                         $response->header( 'Vary: Accept-Encoding, Cookie' . $xfp );
 417                         if ( $wgUseXVO ) {
 418                                 $out = $this->getOutput();
 419                                 if ( $wgVaryOnXFP ) {
 420                                         $out->addVaryHeader( 'X-Forwarded-Proto' );
 421                                 }
 422                                 $response->header( $out->getXVO() );
 423                                 if ( $out->haveCacheVaryCookies() ) {
 424                                         // Logged in, mark this request private
 425                                         $response->header( 'Cache-Control: private' );
 426                                         return;
 427                                 }
 428                                 // Logged out, send normal public headers below
 429                         } elseif ( session_id() != '' ) {
 430                                 // Logged in or otherwise has session (e.g. anonymous users who have edited)
 431                                 // Mark request private
 432                                 $response->header( 'Cache-Control: private' );
 433                                 return;
 434                         } // else no XVO and anonymous, send public headers below
 435                 }
 436
 437                 // Send public headers
 438                 if ( $wgVaryOnXFP ) {
 439                         $response->header( 'Vary: Accept-Encoding, X-Forwarded-Proto' );
 440                         if ( $wgUseXVO ) {
 441                                 // Bleeeeegh. Our header setting system sucks
 442                                 $response->header( 'X-Vary-Options: Accept-Encoding;list-contains=gzip, X-Forwarded-Proto' );
 443                         }
 444                 }
 445
 446                 // If nobody called setCacheMaxAge(), use the (s)maxage parameters
 447                 if ( !isset( $this->mCacheControl['s-maxage'] ) ) {
 448                         $this->mCacheControl['s-maxage'] = $this->getParameter( 'smaxage' );
 449                 }
 450                 if ( !isset( $this->mCacheControl['max-age'] ) ) {
 451                         $this->mCacheControl['max-age'] = $this->getParameter( 'maxage' );
 452                 }
 453
 454                 if ( !$this->mCacheControl['s-maxage'] && !$this->mCacheControl['max-age'] ) {
 455                         // Public cache not requested
 456                         // Sending a Vary header in this case is harmless, and protects us
 457                         // against conditional calls of setCacheMaxAge().
 458                         $response->header( 'Cache-Control: private' );
 459                         return;
 460                 }
 461
 462                 $this->mCacheControl['public'] = true;
 463
 464                 // Send an Expires header
 465                 $maxAge = min( $this->mCacheControl['s-maxage'], $this->mCacheControl['max-age'] );
 466                 $expiryUnixTime = ( $maxAge == 0 ? 1 : time() + $maxAge );
 467                 $response->header( 'Expires: ' . wfTimestamp( TS_RFC2822, $expiryUnixTime ) );
 468
 469                 // Construct the Cache-Control header
 470                 $ccHeader = '';
 471                 $separator = '';
 472                 foreach ( $this->mCacheControl as $name => $value ) {
 473                         if ( is_bool( $value ) ) {
 474                                 if ( $value ) {
 475                                         $ccHeader .= $separator . $name;
 476                                         $separator = ', ';
 477                                 }
 478                         } else {
 479                                 $ccHeader .= $separator . "$name=$value";
 480                                 $separator = ', ';
 481                         }
 482                 }
 483
 484                 $response->header( "Cache-Control: $ccHeader" );
 485         }
 486
 487         /**
 488          * Replace the result data with the information about an exception.
 489          * Returns the error code
 490          * @param $e Exception
 491          * @return string
 492          */
 493         protected function substituteResultWithError( $e ) {
 494                 global $wgShowHostnames;
 495
 496                 $result = $this->getResult();
 497                 // Printer may not be initialized if the extractRequestParams() fails for the main module
 498                 if ( !isset ( $this->mPrinter ) ) {
 499                         // The printer has not been created yet. Try to manually get formatter value.
 500                         $value = $this->getRequest()->getVal( 'format', self::API_DEFAULT_FORMAT );
 501                         if ( !in_array( $value, $this->mFormatNames ) ) {
 502                                 $value = self::API_DEFAULT_FORMAT;
 503                         }
 504
 505                         $this->mPrinter = $this->createPrinterByName( $value );
 506                         if ( $this->mPrinter->getNeedsRawData() ) {
 507                                 $result->setRawMode();
 508                         }
 509                 }
 510
 511                 if ( $e instanceof UsageException ) {
 512                         // User entered incorrect parameters - print usage screen
 513                         $errMessage = $e->getMessageArray();
 514
 515                         // Only print the help message when this is for the developer, not runtime
 516                         if ( $this->mPrinter->getWantsHelp() || $this->mAction == 'help' ) {
 517                                 ApiResult::setContent( $errMessage, $this->makeHelpMsg() );
 518                         }
 519
 520                 } else {
 521                         global $wgShowSQLErrors, $wgShowExceptionDetails;
 522                         // Something is seriously wrong
 523                         if ( ( $e instanceof DBQueryError ) && !$wgShowSQLErrors ) {
 524                                 $info = 'Database query error';
 525                         } else {
 526                                 $info = "Exception Caught: {$e->getMessage()}";
 527                         }
 528
 529                         $errMessage = array(
 530                                 'code' => 'internal_api_error_' . get_class( $e ),
 531                                 'info' => $info,
 532                         );
 533                         ApiResult::setContent( $errMessage, $wgShowExceptionDetails ? "\n\n{$e->getTraceAsString()}\n\n" : '' );
 534                 }
 535
 536                 $result->reset();
 537                 $result->disableSizeCheck();
 538                 // Re-add the id
 539                 $requestid = $this->getParameter( 'requestid' );
 540                 if ( !is_null( $requestid ) ) {
 541                         $result->addValue( null, 'requestid', $requestid );
 542                 }
 543
 544                 if ( $wgShowHostnames ) {
 545                         // servedby is especially useful when debugging errors
 546                         $result->addValue( null, 'servedby', wfHostName() );
 547                 }
 548
 549                 $result->addValue( null, 'error', $errMessage );
 550
 551                 return $errMessage['code'];
 552         }
 553
 554         /**
 555          * Set up for the execution.
 556          * @return array
 557          */
 558         protected function setupExecuteAction() {
 559                 global $wgShowHostnames;
 560
 561                 // First add the id to the top element
 562                 $result = $this->getResult();
 563                 $requestid = $this->getParameter( 'requestid' );
 564                 if ( !is_null( $requestid ) ) {
 565                         $result->addValue( null, 'requestid', $requestid );
 566                 }
 567
 568                 if ( $wgShowHostnames ) {
 569                         $servedby = $this->getParameter( 'servedby' );
 570                         if ( $servedby ) {
 571                                 $result->addValue( null, 'servedby', wfHostName() );
 572                         }
 573                 }
 574
 575                 $params = $this->extractRequestParams();
 576
 577                 $this->mShowVersions = $params['version'];
 578                 $this->mAction = $params['action'];
 579
 580                 if ( !is_string( $this->mAction ) ) {
 581                         $this->dieUsage( 'The API requires a valid action parameter', 'unknown_action' );
 582                 }
 583
 584                 return $params;
 585         }
 586
 587         /**
 588          * Set up the module for response
 589          * @return ApiBase The module that will handle this action
 590          */
 591         protected function setupModule() {
 592                 // Instantiate the module requested by the user
 593                 $module = new $this->mModules[$this->mAction] ( $this, $this->mAction );
 594                 $this->mModule = $module;
 595
 596                 $moduleParams = $module->extractRequestParams();
 597
 598                 // Die if token required, but not provided (unless there is a gettoken parameter)
 599                 if ( isset( $moduleParams['gettoken'] ) ) {
 600                         $gettoken = $moduleParams['gettoken'];
 601                 } else {
 602                         $gettoken = false;
 603                 }
 604
 605                 $salt = $module->getTokenSalt();
 606                 if ( $salt !== false && !$gettoken ) {
 607                         if ( !isset( $moduleParams['token'] ) ) {
 608                                 $this->dieUsageMsg( array( 'missingparam', 'token' ) );
 609                         } else {
 610                                 if ( !$this->getUser()->matchEditToken( $moduleParams['token'], $salt ) ) {
 611                                         $this->dieUsageMsg( 'sessionfailure' );
 612                                 }
 613                         }
 614                 }
 615                 return $module;
 616         }
 617
 618         /**
 619          * Check the max lag if necessary
 620          * @param $module ApiBase object: Api module being used
 621          * @param $params Array an array containing the request parameters.
 622          * @return boolean True on success, false should exit immediately
 623          */
 624         protected function checkMaxLag( $module, $params ) {
 625                 if ( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
 626                         // Check for maxlag
 627                         global $wgShowHostnames;
 628                         $maxLag = $params['maxlag'];
 629                         list( $host, $lag ) = wfGetLB()->getMaxLag();
 630                         if ( $lag > $maxLag ) {
 631                                 $response = $this->getRequest()->response();
 632
 633                                 $response->header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
 634                                 $response->header( 'X-Database-Lag: ' . intval( $lag ) );
 635
 636                                 if ( $wgShowHostnames ) {
 637                                         $this->dieUsage( "Waiting for $host: $lag seconds lagged", 'maxlag' );
 638                                 } else {
 639                                         $this->dieUsage( "Waiting for a database server: $lag seconds lagged", 'maxlag' );
 640                                 }
 641                                 return false;
 642                         }
 643                 }
 644                 return true;
 645         }
 646
 647         /**
 648          * Check for sufficient permissions to execute
 649          * @param $module ApiBase An Api module
 650          */
 651         protected function checkExecutePermissions( $module ) {
 652                 $user = $this->getUser();
 653                 if ( $module->isReadMode() && !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) &&
 654                         !$user->isAllowed( 'read' ) )
 655                 {
 656                         $this->dieUsageMsg( 'readrequired' );
 657                 }
 658                 if ( $module->isWriteMode() ) {
 659                         if ( !$this->mEnableWrite ) {
 660                                 $this->dieUsageMsg( 'writedisabled' );
 661                         }
 662                         if ( !$user->isAllowed( 'writeapi' ) ) {
 663                                 $this->dieUsageMsg( 'writerequired' );
 664                         }
 665                         if ( wfReadOnly() ) {
 666                                 $this->dieReadOnly();
 667                         }
 668                 }
 669         }
 670
 671         /**
 672          * Check POST for external response and setup result printer
 673          * @param $module ApiBase An Api module
 674          * @param $params Array an array with the request parameters
 675          */
 676         protected function setupExternalResponse( $module, $params ) {
 677                 // Ignore mustBePosted() for internal calls
 678                 if ( $module->mustBePosted() && !$this->getRequest()->wasPosted() ) {
 679                         $this->dieUsageMsg( array( 'mustbeposted', $this->mAction ) );
 680                 }
 681
 682                 // See if custom printer is used
 683                 $this->mPrinter = $module->getCustomPrinter();
 684                 if ( is_null( $this->mPrinter ) ) {
 685                         // Create an appropriate printer
 686                         $this->mPrinter = $this->createPrinterByName( $params['format'] );
 687                 }
 688
 689                 if ( $this->mPrinter->getNeedsRawData() ) {
 690                         $this->getResult()->setRawMode();
 691                 }
 692         }
 693
 694         /**
 695          * Execute the actual module, without any error handling
 696          */
 697         protected function executeAction() {
 698                 $params = $this->setupExecuteAction();
 699                 $module = $this->setupModule();
 700
 701                 $this->checkExecutePermissions( $module );
 702
 703                 if ( !$this->checkMaxLag( $module, $params ) ) {
 704                         return;
 705                 }
 706
 707                 if ( !$this->mInternalMode ) {
 708                         $this->setupExternalResponse( $module, $params );
 709                 }
 710
 711                 // Execute
 712                 $module->profileIn();
 713                 $module->execute();
 714                 wfRunHooks( 'APIAfterExecute', array( &$module ) );
 715                 $module->profileOut();
 716
 717                 if ( !$this->mInternalMode ) {
 718                         // Print result data
 719                         $this->printResult( false );
 720                 }
 721         }
 722
 723         /**
 724          * Print results using the current printer
 725          *
 726          * @param $isError bool
 727          */
 728         protected function printResult( $isError ) {
 729                 $this->getResult()->cleanUpUTF8();
 730                 $printer = $this->mPrinter;
 731                 $printer->profileIn();
 732
 733                 /**
 734                  * If the help message is requested in the default (xmlfm) format,
 735                  * tell the printer not to escape ampersands so that our links do
 736                  * not break.
 737                  */
 738                 $printer->setUnescapeAmps( ( $this->mAction == 'help' || $isError )
 739                                 && $printer->getFormat() == 'XML' && $printer->getIsHtml() );
 740
 741                 $printer->initPrinter( $isError );
 742
 743                 $printer->execute();
 744                 $printer->closePrinter();
 745                 $printer->profileOut();
 746         }
 747
 748         /**
 749          * @return bool
 750          */
 751         public function isReadMode() {
 752                 return false;
 753         }
 754
 755         /**
 756          * See ApiBase for description.
 757          *
 758          * @return array
 759          */
 760         public function getAllowedParams() {
 761                 return array(
 762                         'format' => array(
 763                                 ApiBase::PARAM_DFLT => ApiMain::API_DEFAULT_FORMAT,
 764                                 ApiBase::PARAM_TYPE => $this->mFormatNames
 765                         ),
 766                         'action' => array(
 767                                 ApiBase::PARAM_DFLT => 'help',
 768                                 ApiBase::PARAM_TYPE => $this->mModuleNames
 769                         ),
 770                         'version' => false,
 771                         'maxlag'  => array(
 772                                 ApiBase::PARAM_TYPE => 'integer'
 773                         ),
 774                         'smaxage' => array(
 775                                 ApiBase::PARAM_TYPE => 'integer',
 776                                 ApiBase::PARAM_DFLT => 0
 777                         ),
 778                         'maxage' => array(
 779                                 ApiBase::PARAM_TYPE => 'integer',
 780                                 ApiBase::PARAM_DFLT => 0
 781                         ),
 782                         'requestid' => null,
 783                         'servedby'  => false,
 784                 );
 785         }
 786
 787         /**
 788          * See ApiBase for description.
 789          *
 790          * @return array
 791          */
 792         public function getParamDescription() {
 793                 return array(
 794                         'format' => 'The format of the output',
 795                         'action' => 'What action you would like to perform. See below for module help',
 796                         'version' => 'When showing help, include version for each module',
 797                         'maxlag' => array(
 798                                 'Maximum lag can be used when MediaWiki is installed on a database replicated cluster.',
 799                                 'To save actions causing any more site replication lag, this parameter can make the client',
 800                                 'wait until the replication lag is less than the specified value.',
 801                                 'In case of a replag error, a HTTP 503 error is returned, with the message like',
 802                                 '"Waiting for $host: $lag seconds lagged\n".',
 803                                 'See https://www.mediawiki.org/wiki/Manual:Maxlag_parameter for more information',
 804                         ),
 805                         'smaxage' => 'Set the s-maxage header to this many seconds. Errors are never cached',
 806                         'maxage' => 'Set the max-age header to this many seconds. Errors are never cached',
 807                         'requestid' => 'Request ID to distinguish requests. This will just be output back to you',
 808                         'servedby' => 'Include the hostname that served the request in the results. Unconditionally shown on error',
 809                 );
 810         }
 811
 812         /**
 813          * See ApiBase for description.
 814          *
 815          * @return array
 816          */
 817         public function getDescription() {
 818                 return array(
 819                         '',
 820                         '',
 821                         '**********************************************************************************************************',
 822                         '**                                                                                                      **',
 823                         '**                      This is an auto-generated MediaWiki API documentation page                      **',
 824                         '**                                                                                                      **',
 825                         '**                                     Documentation and Examples:                                      **',
 826                         '**                                  https://www.mediawiki.org/wiki/API                                  **',
 827                         '**                                                                                                      **',
 828                         '**********************************************************************************************************',
 829                         '',
 830                         'Status:                All features shown on this page should be working, but the API',
 831                         '                       is still in active development, and may change at any time.',
 832                         '                       Make sure to monitor our mailing list for any updates',
 833                         '',
 834                         'Erroneous requests:    When erroneous requests are sent to the API, a HTTP header will be sent',
 835                         '                       with the key "MediaWiki-API-Error" and then both the value of the',
 836                         '                       header and the error code sent back will be set to the same value',
 837                         '',
 838                         '                       In the case of an invalid action being passed, these will have a value',
 839                         '                       of "unknown_action"',
 840                         '',
 841                         '                       For more information see https://www.mediawiki.org/wiki/API:Errors_and_warnings',
 842                         '',
 843                         'Documentation:         https://www.mediawiki.org/wiki/API:Main_page',
 844                         'FAQ                    https://www.mediawiki.org/wiki/API:FAQ',
 845                         'Mailing list:          https://lists.wikimedia.org/mailman/listinfo/mediawiki-api',
 846                         'Api Announcements:     https://lists.wikimedia.org/mailman/listinfo/mediawiki-api-announce',
 847                         'Bugs & Requests:       https://bugzilla.wikimedia.org/buglist.cgi?component=API&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&order=bugs.delta_ts',
 848                         '',
 849                         '',
 850                         '',
 851                         '',
 852                         '',
 853                 );
 854         }
 855
 856         /**
 857          * @return array
 858          */
 859         public function getPossibleErrors() {
 860                 return array_merge( parent::getPossibleErrors(), array(
 861                         array( 'readonlytext' ),
 862                         array( 'code' => 'unknown_format', 'info' => 'Unrecognized format: format' ),
 863                         array( 'code' => 'unknown_action', 'info' => 'The API requires a valid action parameter' ),
 864                         array( 'code' => 'maxlag', 'info' => 'Waiting for host: x seconds lagged' ),
 865                         array( 'code' => 'maxlag', 'info' => 'Waiting for a database server: x seconds lagged' ),
 866                 ) );
 867         }
 868
 869         /**
 870          * Returns an array of strings with credits for the API
 871          * @return array
 872          */
 873         protected function getCredits() {
 874                 return array(
 875                         'API developers:',
 876                         '    Roan Kattouw <Firstname>.<Lastname>@gmail.com (lead developer Sep 2007-present)',
 877                         '    Victor Vasiliev - vasilvv at gee mail dot com',
 878                         '    Bryan Tong Minh - bryan . tongminh @ gmail . com',
 879                         '    Sam Reed - sam @ reedyboy . net',
 880                         '    Yuri Astrakhan <Firstname><Lastname>@gmail.com (creator, lead developer Sep 2006-Sep 2007)',
 881                         '',
 882                         'Please send your comments, suggestions and questions to mediawiki-api@lists.wikimedia.org',
 883                         'or file a bug report at https://bugzilla.wikimedia.org/'
 884                 );
 885         }
 886
 887         /**
 888          * Sets whether the pretty-printer should format *bold* and $italics$
 889          *
 890          * @param $help bool
 891          */
 892         public function setHelp( $help = true ) {
 893                 $this->mPrinter->setHelp( $help );
 894         }
 895
 896         /**
 897          * Override the parent to generate help messages for all available modules.
 898          *
 899          * @return string
 900          */
 901         public function makeHelpMsg() {
 902                 global $wgMemc, $wgAPICacheHelpTimeout;
 903                 $this->setHelp();
 904                 // Get help text from cache if present
 905                 $key = wfMemcKey( 'apihelp', $this->getModuleName(),
 906                         SpecialVersion::getVersion( 'nodb' ) .
 907                         $this->getShowVersions() );
 908                 if ( $wgAPICacheHelpTimeout > 0 ) {
 909                         $cached = $wgMemc->get( $key );
 910                         if ( $cached ) {
 911                                 return $cached;
 912                         }
 913                 }
 914                 $retval = $this->reallyMakeHelpMsg();
 915                 if ( $wgAPICacheHelpTimeout > 0 ) {
 916                         $wgMemc->set( $key, $retval, $wgAPICacheHelpTimeout );
 917                 }
 918                 return $retval;
 919         }
 920
 921         /**
 922          * @return mixed|string
 923          */
 924         public function reallyMakeHelpMsg() {
 925                 $this->setHelp();
 926
 927                 // Use parent to make default message for the main module
 928                 $msg = parent::makeHelpMsg();
 929
 930                 $astriks = str_repeat( '*** ', 14 );
 931                 $msg .= "\n\n$astriks Modules  $astriks\n\n";
 932                 foreach ( array_keys( $this->mModules ) as $moduleName ) {
 933                         $module = new $this->mModules[$moduleName] ( $this, $moduleName );
 934                         $msg .= self::makeHelpMsgHeader( $module, 'action' );
 935                         $msg2 = $module->makeHelpMsg();
 936                         if ( $msg2 !== false ) {
 937                                 $msg .= $msg2;
 938                         }
 939                         $msg .= "\n";
 940                 }
 941
 942                 $msg .= "\n$astriks Permissions $astriks\n\n";
 943                 foreach ( self::$mRights as $right => $rightMsg ) {
 944                         $groups = User::getGroupsWithPermission( $right );
 945                         $msg .= "* " . $right . " *\n  " . wfMsgReplaceArgs( $rightMsg[ 'msg' ], $rightMsg[ 'params' ] ) .
 946                                                 "\nGranted to:\n  " . str_replace( '*', 'all', implode( ', ', $groups ) ) . "\n\n";
 947
 948                 }
 949
 950                 $msg .= "\n$astriks Formats  $astriks\n\n";
 951                 foreach ( array_keys( $this->mFormats ) as $formatName ) {
 952                         $module = $this->createPrinterByName( $formatName );
 953                         $msg .= self::makeHelpMsgHeader( $module, 'format' );
 954                         $msg2 = $module->makeHelpMsg();
 955                         if ( $msg2 !== false ) {
 956                                 $msg .= $msg2;
 957                         }
 958                         $msg .= "\n";
 959                 }
 960
 961                 $msg .= "\n*** Credits: ***\n   " . implode( "\n   ", $this->getCredits() ) . "\n";
 962
 963                 return $msg;
 964         }
 965
 966         /**
 967          * @param $module ApiBase
 968          * @param $paramName String What type of request is this? e.g. action, query, list, prop, meta, format
 969          * @return string
 970          */
 971         public static function makeHelpMsgHeader( $module, $paramName ) {
 972                 $modulePrefix = $module->getModulePrefix();
 973                 if ( strval( $modulePrefix ) !== '' ) {
 974                         $modulePrefix = "($modulePrefix) ";
 975                 }
 976
 977                 return "* $paramName={$module->getModuleName()} $modulePrefix*";
 978         }
 979
 980         private $mCanApiHighLimits = null;
 981
 982         /**
 983          * Check whether the current user is allowed to use high limits
 984          * @return bool
 985          */
 986         public function canApiHighLimits() {
 987                 if ( !isset( $this->mCanApiHighLimits ) ) {
 988                         $this->mCanApiHighLimits = $this->getUser()->isAllowed( 'apihighlimits' );
 989                 }
 990
 991                 return $this->mCanApiHighLimits;
 992         }
 993
 994         /**
 995          * Check whether the user wants us to show version information in the API help
 996          * @return bool
 997          */
 998         public function getShowVersions() {
 999                 return $this->mShowVersions;
1000         }
1001
1002         /**
1003          * Returns the version information of this file, plus it includes
1004          * the versions for all files that are not callable proper API modules
1005          *
1006          * @return array
1007          */
1008         public function getVersion() {
1009                 $vers = array();
1010                 $vers[] = 'MediaWiki: ' . SpecialVersion::getVersion() . "\n    https://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/";
1011                 $vers[] = __CLASS__ . ': $Id$';
1012                 $vers[] = ApiBase::getBaseVersion();
1013                 $vers[] = ApiFormatBase::getBaseVersion();
1014                 $vers[] = ApiQueryBase::getBaseVersion();
1015                 return $vers;
1016         }
1017
1018         /**
1019          * Add or overwrite a module in this ApiMain instance. Intended for use by extending
1020          * classes who wish to add their own modules to their lexicon or override the
1021          * behavior of inherent ones.
1022          *
1023          * @param $mdlName String The identifier for this module.
1024          * @param $mdlClass String The class where this module is implemented.
1025          */
1026         protected function addModule( $mdlName, $mdlClass ) {
1027                 $this->mModules[$mdlName] = $mdlClass;
1028         }
1029
1030         /**
1031          * Add or overwrite an output format for this ApiMain. Intended for use by extending
1032          * classes who wish to add to or modify current formatters.
1033          *
1034          * @param $fmtName string The identifier for this format.
1035          * @param $fmtClass ApiFormatBase The class implementing this format.
1036          */
1037         protected function addFormat( $fmtName, $fmtClass ) {
1038                 $this->mFormats[$fmtName] = $fmtClass;
1039         }
1040
1041         /**
1042          * Get the array mapping module names to class names
1043          * @return array
1044          */
1045         function getModules() {
1046                 return $this->mModules;
1047         }
1048
1049         /**
1050          * Returns the list of supported formats in form ( 'format' => 'ClassName' )
1051          *
1052          * @since 1.18
1053          * @return array
1054          */
1055         public function getFormats() {
1056                 return $this->mFormats;
1057         }
1058 }
1059
1060 /**
1061  * This exception will be thrown when dieUsage is called to stop module execution.
1062  * The exception handling code will print a help screen explaining how this API may be used.
1063  *
1064  * @ingroup API
1065  */
1066 class UsageException extends MWException {
1067
1068         private $mCodestr;
1069         private $mExtraData;
1070
1071         public function __construct( $message, $codestr, $code = 0, $extradata = null ) {
1072                 parent::__construct( $message, $code );
1073                 $this->mCodestr = $codestr;
1074                 $this->mExtraData = $extradata;
1075         }
1076
1077         /**
1078          * @return string
1079          */
1080         public function getCodeString() {
1081                 return $this->mCodestr;
1082         }
1083
1084         /**
1085          * @return array
1086          */
1087         public function getMessageArray() {
1088                 $result = array(
1089                         'code' => $this->mCodestr,
1090                         'info' => $this->getMessage()
1091                 );
1092                 if ( is_array( $this->mExtraData ) ) {
1093                         $result = array_merge( $result, $this->mExtraData );
1094                 }
1095                 return $result;
1096         }
1097
1098         /**
1099          * @return string
1100          */
1101         public function __toString() {
1102                 return "{$this->getCodeString()}: {$this->getMessage()}";
1103         }
1104 }