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                 $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
 274                 $wgOut->output();
 275         }
 276 }
 277
 278 /**
 279  * Show an error page on a badtitle.
 280  * Similar to ErrorPage, but emit a 400 HTTP error code to let mobile
 281  * browser it is not really a valid content.
 282  */
 283 class BadTitleError extends ErrorPageError {
 284
 285         /**
 286          * @param $msg string A message key (default: 'badtitletext')
 287          * @param $params Array parameter to wfMsg()
 288          */
 289         function __construct( $msg = 'badtitletext', $params = null ) {
 290                 parent::__construct( 'badtitle', $msg, $params );
 291         }
 292
 293         /**
 294          * Just like ErrorPageError::report() but additionally set
 295          * a 400 HTTP status code (bug 33646).
 296          */
 297         function report() {
 298                 global $wgOut;
 299
 300                 // bug 33646: a badtitle error page need to return an error code
 301                 // to let mobile browser now that it is not a normal page.
 302                 $wgOut->setStatusCode( 400 );
 303                 parent::report();
 304         }
 305
 306 }
 307
 308 /**
 309  * Show an error when a user tries to do something they do not have the necessary
 310  * permissions for.
 311  * @ingroup Exception
 312  */
 313 class PermissionsError extends ErrorPageError {
 314         public $permission, $errors;
 315
 316         function __construct( $permission, $errors = array() ) {
 317                 global $wgLang;
 318
 319                 $this->permission = $permission;
 320
 321                 if ( !count( $errors ) ) {
 322                         $groups = array_map(
 323                                 array( 'User', 'makeGroupLinkWiki' ),
 324                                 User::getGroupsWithPermission( $this->permission )
 325                         );
 326
 327                         if ( $groups ) {
 328                                 $errors[] = array( 'badaccess-groups', $wgLang->commaList( $groups ), count( $groups ) );
 329                         } else {
 330                                 $errors[] = array( 'badaccess-group0' );
 331                         }
 332                 }
 333
 334                 $this->errors = $errors;
 335         }
 336
 337         function report() {
 338                 global $wgOut;
 339
 340                 $wgOut->showPermissionsErrorPage( $this->errors, $this->permission );
 341                 $wgOut->output();
 342         }
 343 }
 344
 345 /**
 346  * Show an error when the wiki is locked/read-only and the user tries to do
 347  * something that requires write access
 348  * @ingroup Exception
 349  */
 350 class ReadOnlyError extends ErrorPageError {
 351         public function __construct(){
 352                 parent::__construct(
 353                         'readonly',
 354                         'readonlytext',
 355                         wfReadOnlyReason()
 356                 );
 357         }
 358 }
 359
 360 /**
 361  * Show an error when the user hits a rate limit
 362  * @ingroup Exception
 363  */
 364 class ThrottledError extends ErrorPageError {
 365         public function __construct(){
 366                 parent::__construct(
 367                         'actionthrottled',
 368                         'actionthrottledtext'
 369                 );
 370         }
 371
 372         public function report(){
 373                 global $wgOut;
 374                 $wgOut->setStatusCode( 503 );
 375                 parent::report();
 376         }
 377 }
 378
 379 /**
 380  * Show an error when the user tries to do something whilst blocked
 381  * @ingroup Exception
 382  */
 383 class UserBlockedError extends ErrorPageError {
 384         public function __construct( Block $block ){
 385                 global $wgLang, $wgRequest;
 386
 387                 $blocker = $block->getBlocker();
 388                 if ( $blocker instanceof User ) { // local user
 389                         $blockerUserpage = $block->getBlocker()->getUserPage();
 390                         $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 391                 } else { // foreign user
 392                         $link = $blocker;
 393                 }
 394
 395                 $reason = $block->mReason;
 396                 if( $reason == '' ) {
 397                         $reason = wfMsg( 'blockednoreason' );
 398                 }
 399
 400                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 401                  * This could be a username, an IP range, or a single IP. */
 402                 $intended = $block->getTarget();
 403
 404                 parent::__construct(
 405                         'blockedtitle',
 406                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 407                         array(
 408                                 $link,
 409                                 $reason,
 410                                 $wgRequest->getIP(),
 411                                 $block->getByName(),
 412                                 $block->getId(),
 413                                 $wgLang->formatExpiry( $block->mExpiry ),
 414                                 $intended,
 415                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 416                         )
 417                 );
 418         }
 419 }
 420
 421 /**
 422  * Show an error that looks like an HTTP server error.
 423  * Replacement for wfHttpError().
 424  *
 425  * @ingroup Exception
 426  */
 427 class HttpError extends MWException {
 428         private $httpCode, $header, $content;
 429
 430         /**
 431          * Constructor
 432          *
 433          * @param $httpCode Integer: HTTP status code to send to the client
 434          * @param $content String|Message: content of the message
 435          * @param $header String|Message: content of the header (\<title\> and \<h1\>)
 436          */
 437         public function __construct( $httpCode, $content, $header = null ){
 438                 parent::__construct( $content );
 439                 $this->httpCode = (int)$httpCode;
 440                 $this->header = $header;
 441                 $this->content = $content;
 442         }
 443
 444         public function reportHTML() {
 445                 $httpMessage = HttpStatus::getMessage( $this->httpCode );
 446
 447                 header( "Status: {$this->httpCode} {$httpMessage}" );
 448                 header( 'Content-type: text/html; charset=utf-8' );
 449
 450                 if ( $this->header === null ) {
 451                         $header = $httpMessage;
 452                 } elseif ( $this->header instanceof Message ) {
 453                         $header = $this->header->escaped();
 454                 } else {
 455                         $header = htmlspecialchars( $this->header );
 456                 }
 457
 458                 if ( $this->content instanceof Message ) {
 459                         $content = $this->content->escaped();
 460                 } else {
 461                         $content = htmlspecialchars( $this->content );
 462                 }
 463
 464                 print "<!DOCTYPE html>\n".
 465                         "<html><head><title>$header</title></head>\n" .
 466                         "<body><h1>$header</h1><p>$content</p></body></html>\n";
 467         }
 468 }
 469
 470 /**
 471  * Handler class for MWExceptions
 472  * @ingroup Exception
 473  */
 474 class MWExceptionHandler {
 475         /**
 476          * Install an exception handler for MediaWiki exception types.
 477          */
 478         public static function installHandler() {
 479                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 480         }
 481
 482         /**
 483          * Report an exception to the user
 484          */
 485         protected static function report( Exception $e ) {
 486                 global $wgShowExceptionDetails;
 487
 488                 $cmdLine = MWException::isCommandLine();
 489
 490                 if ( $e instanceof MWException ) {
 491                         try {
 492                                 // Try and show the exception prettily, with the normal skin infrastructure
 493                                 $e->report();
 494                         } catch ( Exception $e2 ) {
 495                                 // Exception occurred from within exception handler
 496                                 // Show a simpler error message for the original exception,
 497                                 // don't try to invoke report()
 498                                 $message = "MediaWiki internal error.\n\n";
 499
 500                                 if ( $wgShowExceptionDetails ) {
 501                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 502                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 503                                 } else {
 504                                         $message .= "Exception caught inside exception handler.\n\n" .
 505                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 506                                                 "to show detailed debugging information.";
 507                                 }
 508
 509                                 $message .= "\n";
 510
 511                                 if ( $cmdLine ) {
 512                                         self::printError( $message );
 513                                 } else {
 514                                         self::escapeEchoAndDie( $message );
 515                                 }
 516                         }
 517                 } else {
 518                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 519                                 $e->__toString() . "\n";
 520
 521                         if ( $wgShowExceptionDetails ) {
 522                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 523                         }
 524
 525                         if ( $cmdLine ) {
 526                                 self::printError( $message );
 527                         } else {
 528                                 self::escapeEchoAndDie( $message );
 529                         }
 530                 }
 531         }
 532
 533         /**
 534          * Print a message, if possible to STDERR.
 535          * Use this in command line mode only (see isCommandLine)
 536          * @param $message String Failure text
 537          */
 538         public static function printError( $message ) {
 539                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 540                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 541                 if ( defined( 'STDERR' ) ) {
 542                         fwrite( STDERR, $message );
 543                 } else {
 544                         echo( $message );
 545                 }
 546         }
 547
 548         /**
 549          * Print a message after escaping it and converting newlines to <br>
 550          * Use this for non-command line failures
 551          * @param $message String Failure text
 552          */
 553         private static function escapeEchoAndDie( $message ) {
 554                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 555                 die(1);
 556         }
 557
 558         /**
 559          * Exception handler which simulates the appropriate catch() handling:
 560          *
 561          *   try {
 562          *       ...
 563          *   } catch ( MWException $e ) {
 564          *       $e->report();
 565          *   } catch ( Exception $e ) {
 566          *       echo $e->__toString();
 567          *   }
 568          */
 569         public static function handle( $e ) {
 570                 global $wgFullyInitialised;
 571
 572                 self::report( $e );
 573
 574                 // Final cleanup
 575                 if ( $wgFullyInitialised ) {
 576                         try {
 577                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 578                         } catch ( Exception $e ) {}
 579                 }
 580
 581                 // Exit value should be nonzero for the benefit of shell jobs
 582                 exit( 1 );
 583         }
 584 }