includes/Exception.php

   1 <?php
   2 /**
   3  * Exception class and handler
   4  *
   5  * @file
   6  */
   7
   8 /**
   9  * @defgroup Exception Exception
  10  */
  11
  12 /**
  13  * MediaWiki exception
  14  *
  15  * @ingroup Exception
  16  */
  17 class MWException extends Exception {
  18         /**
  19          * Should the exception use $wgOut to output the error ?
  20          * @return bool
  21          */
  22         function useOutputPage() {
  23                 return $this->useMessageCache() &&
  24                         !empty( $GLOBALS['wgFullyInitialised'] ) &&
  25                         !empty( $GLOBALS['wgOut'] ) &&
  26                         !empty( $GLOBALS['wgTitle'] );
  27         }
  28
  29         /**
  30          * Can the extension use wfMsg() to get i18n messages ?
  31          * @return bool
  32          */
  33         function useMessageCache() {
  34                 global $wgLang;
  35
  36                 foreach ( $this->getTrace() as $frame ) {
  37                         if ( isset( $frame['class'] ) && $frame['class'] === 'LocalisationCache' ) {
  38                                 return false;
  39                         }
  40                 }
  41
  42                 return $wgLang instanceof Language;
  43         }
  44
  45         /**
  46          * Run hook to allow extensions to modify the text of the exception
  47          *
  48          * @param $name String: class name of the exception
  49          * @param $args Array: arguments to pass to the callback functions
  50          * @return Mixed: string to output or null if any hook has been called
  51          */
  52         function runHooks( $name, $args = array() ) {
  53                 global $wgExceptionHooks;
  54
  55                 if ( !isset( $wgExceptionHooks ) || !is_array( $wgExceptionHooks ) ) {
  56                         return; // Just silently ignore
  57                 }
  58
  59                 if ( !array_key_exists( $name, $wgExceptionHooks ) || !is_array( $wgExceptionHooks[ $name ] ) ) {
  60                         return;
  61                 }
  62
  63                 $hooks = $wgExceptionHooks[ $name ];
  64                 $callargs = array_merge( array( $this ), $args );
  65
  66                 foreach ( $hooks as $hook ) {
  67                         if ( is_string( $hook ) || ( is_array( $hook ) && count( $hook ) >= 2 && is_string( $hook[0] ) ) ) {    // 'function' or array( 'class', hook' )
  68                                 $result = call_user_func_array( $hook, $callargs );
  69                         } else {
  70                                 $result = null;
  71                         }
  72
  73                         if ( is_string( $result ) ) {
  74                                 return $result;
  75                         }
  76                 }
  77         }
  78
  79         /**
  80          * Get a message from i18n
  81          *
  82          * @param $key String: message name
  83          * @param $fallback String: default message if the message cache can't be
  84          *                  called by the exception
  85          * The function also has other parameters that are arguments for the message
  86          * @return String message with arguments replaced
  87          */
  88         function msg( $key, $fallback /*[, params...] */ ) {
  89                 $args = array_slice( func_get_args(), 2 );
  90
  91                 if ( $this->useMessageCache() ) {
  92                         return wfMsgNoTrans( $key, $args );
  93                 } else {
  94                         return wfMsgReplaceArgs( $fallback, $args );
  95                 }
  96         }
  97
  98         /**
  99          * If $wgShowExceptionDetails is true, return a HTML message with a
 100          * backtrace to the error, otherwise show a message to ask to set it to true
 101          * to show that information.
 102          *
 103          * @return String html to output
 104          */
 105         function getHTML() {
 106                 global $wgShowExceptionDetails;
 107
 108                 if ( $wgShowExceptionDetails ) {
 109                         return '<p>' . nl2br( htmlspecialchars( $this->getMessage() ) ) .
 110                                 '</p><p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
 111                                 "</p>\n";
 112                 } else {
 113                         return "<p>Set <b><tt>\$wgShowExceptionDetails = true;</tt></b> " .
 114                                 "at the bottom of LocalSettings.php to show detailed " .
 115                                 "debugging information.</p>";
 116                 }
 117         }
 118
 119         /**
 120          * If $wgShowExceptionDetails is true, return a text message with a
 121          * backtrace to the error.
 122          * @return string
 123          */
 124         function getText() {
 125                 global $wgShowExceptionDetails;
 126
 127                 if ( $wgShowExceptionDetails ) {
 128                         return $this->getMessage() .
 129                                 "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
 130                 } else {
 131                         return "Set \$wgShowExceptionDetails = true; " .
 132                                 "in LocalSettings.php to show detailed debugging information.\n";
 133                 }
 134         }
 135
 136         /**
 137          * Return titles of this error page
 138          * @return String
 139          */
 140         function getPageTitle() {
 141                 return $this->msg( 'internalerror', "Internal error" );
 142         }
 143
 144         /**
 145          * Return the requested URL and point to file and line number from which the
 146          * exception occured
 147          *
 148          * @return String
 149          */
 150         function getLogMessage() {
 151                 global $wgRequest;
 152
 153                 $file = $this->getFile();
 154                 $line = $this->getLine();
 155                 $message = $this->getMessage();
 156
 157                 if ( isset( $wgRequest ) && !$wgRequest instanceof FauxRequest ) {
 158                         $url = $wgRequest->getRequestURL();
 159                         if ( !$url ) {
 160                                 $url = '[no URL]';
 161                         }
 162                 } else {
 163                         $url = '[no req]';
 164                 }
 165
 166                 return "$url   Exception from line $line of $file: $message";
 167         }
 168
 169         /** Output the exception report using HTML */
 170         function reportHTML() {
 171                 global $wgOut;
 172                 if ( $this->useOutputPage() ) {
 173                         $wgOut->prepareErrorPage( $this->getPageTitle() );
 174
 175                         $hookResult = $this->runHooks( get_class( $this ) );
 176                         if ( $hookResult ) {
 177                                 $wgOut->addHTML( $hookResult );
 178                         } else {
 179                                 $wgOut->addHTML( $this->getHTML() );
 180                         }
 181
 182                         $wgOut->output();
 183                 } else {
 184                         header( "Content-Type: text/html; charset=utf-8" );
 185                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 186                         if ( $hookResult ) {
 187                                 die( $hookResult );
 188                         }
 189
 190                         echo $this->getHTML();
 191                         die(1);
 192                 }
 193         }
 194
 195         /**
 196          * Output a report about the exception and takes care of formatting.
 197          * It will be either HTML or plain text based on isCommandLine().
 198          */
 199         function report() {
 200                 $log = $this->getLogMessage();
 201
 202                 if ( $log ) {
 203                         wfDebugLog( 'exception', $log );
 204                 }
 205
 206                 if ( defined( 'MW_API' ) ) {
 207                         // Unhandled API exception, we can't be sure that format printer is alive
 208                         header( 'MediaWiki-API-Error: internal_api_error_' . get_class( $this ) );
 209                         wfHttpError(500, 'Internal Server Error', $this->getText() );
 210                 } elseif ( self::isCommandLine() ) {
 211                         MWExceptionHandler::printError( $this->getText() );
 212                 } else {
 213                         $this->reportHTML();
 214                 }
 215         }
 216
 217         /**
 218          * @static
 219          * @return bool
 220          */
 221         static function isCommandLine() {
 222                 return !empty( $GLOBALS['wgCommandLineMode'] );
 223         }
 224 }
 225
 226 /**
 227  * Exception class which takes an HTML error message, and does not
 228  * produce a backtrace. Replacement for OutputPage::fatalError().
 229  * @ingroup Exception
 230  */
 231 class FatalError extends MWException {
 232
 233         /**
 234          * @return string
 235          */
 236         function getHTML() {
 237                 return $this->getMessage();
 238         }
 239
 240         /**
 241          * @return string
 242          */
 243         function getText() {
 244                 return $this->getMessage();
 245         }
 246 }
 247
 248 /**
 249  * An error page which can definitely be safely rendered using the OutputPage
 250  * @ingroup Exception
 251  */
 252 class ErrorPageError extends MWException {
 253         public $title, $msg, $params;
 254
 255         /**
 256          * Note: these arguments are keys into wfMsg(), not text!
 257          */
 258         function __construct( $title, $msg, $params = null ) {
 259                 $this->title = $title;
 260                 $this->msg = $msg;
 261                 $this->params = $params;
 262
 263                 if( $msg instanceof Message ){
 264                         parent::__construct( $msg );
 265                 } else {
 266                         parent::__construct( wfMsg( $msg ) );
 267                 }
 268         }
 269
 270         function report() {
 271                 global $wgOut;
 272
 273
 274                 $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
 275                 $wgOut->output();
 276         }
 277 }
 278
 279 /**
 280  * Show an error page on a badtitle.
 281  * Similar to ErrorPage, but emit a 400 HTTP error code to let mobile
 282  * browser it is not really a valid content.
 283  */
 284 class BadTitleError extends ErrorPageError {
 285
 286         /**
 287          * @param $msg string A message key (default: 'badtitletext')
 288          * @param $params Array parameter to wfMsg()
 289          */
 290         function __construct( $msg = 'badtitletext', $params = null ) {
 291                 parent::__construct( 'badtitle', $msg, $params );
 292         }
 293
 294         /**
 295          * Just like ErrorPageError::report() but additionally set
 296          * a 400 HTTP status code (bug 33646).
 297          */
 298         function report() {
 299                 global $wgOut;
 300
 301                 // bug 33646: a badtitle error page need to return an error code
 302                 // to let mobile browser now that it is not a normal page.
 303                 $wgOut->setStatusCode( 400 );
 304                 parent::report();
 305         }
 306
 307 }
 308
 309 /**
 310  * Show an error when a user tries to do something they do not have the necessary
 311  * permissions for.
 312  * @ingroup Exception
 313  */
 314 class PermissionsError extends ErrorPageError {
 315         public $permission, $errors;
 316
 317         function __construct( $permission, $errors = array() ) {
 318                 global $wgLang;
 319
 320                 $this->permission = $permission;
 321
 322                 if ( !count( $errors ) ) {
 323                         $groups = array_map(
 324                                 array( 'User', 'makeGroupLinkWiki' ),
 325                                 User::getGroupsWithPermission( $this->permission )
 326                         );
 327
 328                         if ( $groups ) {
 329                                 $errors[] = array( 'badaccess-groups', $wgLang->commaList( $groups ), count( $groups ) );
 330                         } else {
 331                                 $errors[] = array( 'badaccess-group0' );
 332                         }
 333                 }
 334
 335                 $this->errors = $errors;
 336         }
 337
 338         function report() {
 339                 global $wgOut;
 340
 341                 $wgOut->showPermissionsErrorPage( $this->errors, $this->permission );
 342                 $wgOut->output();
 343         }
 344 }
 345
 346 /**
 347  * Show an error when the wiki is locked/read-only and the user tries to do
 348  * something that requires write access
 349  * @ingroup Exception
 350  */
 351 class ReadOnlyError extends ErrorPageError {
 352         public function __construct(){
 353                 parent::__construct(
 354                         'readonly',
 355                         'readonlytext',
 356                         wfReadOnlyReason()
 357                 );
 358         }
 359 }
 360
 361 /**
 362  * Show an error when the user hits a rate limit
 363  * @ingroup Exception
 364  */
 365 class ThrottledError extends ErrorPageError {
 366         public function __construct(){
 367                 parent::__construct(
 368                         'actionthrottled',
 369                         'actionthrottledtext'
 370                 );
 371         }
 372
 373         public function report(){
 374                 global $wgOut;
 375                 $wgOut->setStatusCode( 503 );
 376                 return parent::report();
 377         }
 378 }
 379
 380 /**
 381  * Show an error when the user tries to do something whilst blocked
 382  * @ingroup Exception
 383  */
 384 class UserBlockedError extends ErrorPageError {
 385         public function __construct( Block $block ){
 386                 global $wgLang, $wgRequest;
 387
 388                 $blocker = $block->getBlocker();
 389                 if ( $blocker instanceof User ) { // local user
 390                         $blockerUserpage = $block->getBlocker()->getUserPage();
 391                         $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 392                 } else { // foreign user
 393                         $link = $blocker;
 394                 }
 395
 396                 $reason = $block->mReason;
 397                 if( $reason == '' ) {
 398                         $reason = wfMsg( 'blockednoreason' );
 399                 }
 400
 401                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 402                  * This could be a username, an IP range, or a single IP. */
 403                 $intended = $block->getTarget();
 404
 405                 parent::__construct(
 406                         'blockedtitle',
 407                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 408                         array(
 409                                 $link,
 410                                 $reason,
 411                                 $wgRequest->getIP(),
 412                                 $block->getByName(),
 413                                 $block->getId(),
 414                                 $wgLang->formatExpiry( $block->mExpiry ),
 415                                 $intended,
 416                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 417                         )
 418                 );
 419         }
 420 }
 421
 422 /**
 423  * Show an error that looks like an HTTP server error.
 424  * Replacement for wfHttpError().
 425  *
 426  * @ingroup Exception
 427  */
 428 class HttpError extends MWException {
 429         private $httpCode, $header, $content;
 430
 431         /**
 432          * Constructor
 433          *
 434          * @param $httpCode Integer: HTTP status code to send to the client
 435          * @param $content String|Message: content of the message
 436          * @param $header String|Message: content of the header (\<title\> and \<h1\>)
 437          */
 438         public function __construct( $httpCode, $content, $header = null ){
 439                 parent::__construct( $content );
 440                 $this->httpCode = (int)$httpCode;
 441                 $this->header = $header;
 442                 $this->content = $content;
 443         }
 444
 445         public function reportHTML() {
 446                 $httpMessage = HttpStatus::getMessage( $this->httpCode );
 447
 448                 header( "Status: {$this->httpCode} {$httpMessage}" );
 449                 header( 'Content-type: text/html; charset=utf-8' );
 450
 451                 if ( $this->header === null ) {
 452                         $header = $httpMessage;
 453                 } elseif ( $this->header instanceof Message ) {
 454                         $header = $this->header->escaped();
 455                 } else {
 456                         $header = htmlspecialchars( $this->header );
 457                 }
 458
 459                 if ( $this->content instanceof Message ) {
 460                         $content = $this->content->escaped();
 461                 } else {
 462                         $content = htmlspecialchars( $this->content );
 463                 }
 464
 465                 print "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n".
 466                         "<html><head><title>$header</title></head>\n" .
 467                         "<body><h1>$header</h1><p>$content</p></body></html>\n";
 468         }
 469 }
 470
 471 /**
 472  * Handler class for MWExceptions
 473  * @ingroup Exception
 474  */
 475 class MWExceptionHandler {
 476         /**
 477          * Install an exception handler for MediaWiki exception types.
 478          */
 479         public static function installHandler() {
 480                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 481         }
 482
 483         /**
 484          * Report an exception to the user
 485          */
 486         protected static function report( Exception $e ) {
 487                 global $wgShowExceptionDetails;
 488
 489                 $cmdLine = MWException::isCommandLine();
 490
 491                 if ( $e instanceof MWException ) {
 492                         try {
 493                                 // Try and show the exception prettily, with the normal skin infrastructure
 494                                 $e->report();
 495                         } catch ( Exception $e2 ) {
 496                                 // Exception occurred from within exception handler
 497                                 // Show a simpler error message for the original exception,
 498                                 // don't try to invoke report()
 499                                 $message = "MediaWiki internal error.\n\n";
 500
 501                                 if ( $wgShowExceptionDetails ) {
 502                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 503                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 504                                 } else {
 505                                         $message .= "Exception caught inside exception handler.\n\n" .
 506                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 507                                                 "to show detailed debugging information.";
 508                                 }
 509
 510                                 $message .= "\n";
 511
 512                                 if ( $cmdLine ) {
 513                                         self::printError( $message );
 514                                 } else {
 515                                         self::escapeEchoAndDie( $message );
 516                                 }
 517                         }
 518                 } else {
 519                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 520                                 $e->__toString() . "\n";
 521
 522                         if ( $wgShowExceptionDetails ) {
 523                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 524                         }
 525
 526                         if ( $cmdLine ) {
 527                                 self::printError( $message );
 528                         } else {
 529                                 self::escapeEchoAndDie( $message );
 530                         }
 531                 }
 532         }
 533
 534         /**
 535          * Print a message, if possible to STDERR.
 536          * Use this in command line mode only (see isCommandLine)
 537          * @param $message String Failure text
 538          */
 539         public static function printError( $message ) {
 540                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 541                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 542                 if ( defined( 'STDERR' ) ) {
 543                         fwrite( STDERR, $message );
 544                 } else {
 545                         echo( $message );
 546                 }
 547         }
 548
 549         /**
 550          * Print a message after escaping it and converting newlines to <br>
 551          * Use this for non-command line failures
 552          * @param $message String Failure text
 553          */
 554         private static function escapeEchoAndDie( $message ) {
 555                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 556                 die(1);
 557         }
 558
 559         /**
 560          * Exception handler which simulates the appropriate catch() handling:
 561          *
 562          *   try {
 563          *       ...
 564          *   } catch ( MWException $e ) {
 565          *       $e->report();
 566          *   } catch ( Exception $e ) {
 567          *       echo $e->__toString();
 568          *   }
 569          */
 570         public static function handle( $e ) {
 571                 global $wgFullyInitialised;
 572
 573                 self::report( $e );
 574
 575                 // Final cleanup
 576                 if ( $wgFullyInitialised ) {
 577                         try {
 578                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 579                         } catch ( Exception $e ) {}
 580                 }
 581
 582                 // Exit value should be nonzero for the benefit of shell jobs
 583                 exit( 1 );
 584         }
 585 }