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          * Get a message from i18n
  80          *
  81          * @param $key String: message name
  82          * @param $fallback String: default message if the message cache can't be
  83          *                  called by the exception
  84          * The function also has other parameters that are arguments for the message
  85          * @return String message with arguments replaced
  86          */
  87         function msg( $key, $fallback /*[, params...] */ ) {
  88                 $args = array_slice( func_get_args(), 2 );
  89
  90                 if ( $this->useMessageCache() ) {
  91                         return wfMsgNoTrans( $key, $args );
  92                 } else {
  93                         return wfMsgReplaceArgs( $fallback, $args );
  94                 }
  95         }
  96
  97         /**
  98          * If $wgShowExceptionDetails is true, return a HTML message with a
  99          * backtrace to the error, otherwise show a message to ask to set it to true
 100          * to show that information.
 101          *
 102          * @return String html to output
 103          */
 104         function getHTML() {
 105                 global $wgShowExceptionDetails;
 106
 107                 if ( $wgShowExceptionDetails ) {
 108                         return '<p>' . nl2br( htmlspecialchars( $this->getMessage() ) ) .
 109                                 '</p><p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
 110                                 "</p>\n";
 111                 } else {
 112                         return "<p>Set <b><tt>\$wgShowExceptionDetails = true;</tt></b> " .
 113                                 "at the bottom of LocalSettings.php to show detailed " .
 114                                 "debugging information.</p>";
 115                 }
 116         }
 117
 118         /**
 119          * If $wgShowExceptionDetails is true, return a text message with a
 120          * backtrace to the error.
 121          */
 122         function getText() {
 123                 global $wgShowExceptionDetails;
 124
 125                 if ( $wgShowExceptionDetails ) {
 126                         return $this->getMessage() .
 127                                 "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
 128                 } else {
 129                         return "Set \$wgShowExceptionDetails = true; " .
 130                                 "in LocalSettings.php to show detailed debugging information.\n";
 131                 }
 132         }
 133
 134         /**
 135          * Return titles of this error page
 136          * @return String
 137          */
 138         function getPageTitle() {
 139                 global $wgSitename;
 140                 return $this->msg( 'internalerror', "$wgSitename error" );
 141         }
 142
 143         /**
 144          * Return the requested URL and point to file and line number from which the
 145          * exception occured
 146          *
 147          * @return String
 148          */
 149         function getLogMessage() {
 150                 global $wgRequest;
 151
 152                 $file = $this->getFile();
 153                 $line = $this->getLine();
 154                 $message = $this->getMessage();
 155
 156                 if ( isset( $wgRequest ) && !$wgRequest instanceof FauxRequest ) {
 157                         $url = $wgRequest->getRequestURL();
 158                         if ( !$url ) {
 159                                 $url = '[no URL]';
 160                         }
 161                 } else {
 162                         $url = '[no req]';
 163                 }
 164
 165                 return "$url   Exception from line $line of $file: $message";
 166         }
 167
 168         /** Output the exception report using HTML */
 169         function reportHTML() {
 170                 global $wgOut;
 171                 if ( $this->useOutputPage() ) {
 172                         $wgOut->setPageTitle( $this->getPageTitle() );
 173                         $wgOut->setRobotPolicy( "noindex,nofollow" );
 174                         $wgOut->setArticleRelated( false );
 175                         $wgOut->enableClientCache( false );
 176                         $wgOut->redirect( '' );
 177                         $wgOut->clearHTML();
 178
 179                         $hookResult = $this->runHooks( get_class( $this ) );
 180                         if ( $hookResult ) {
 181                                 $wgOut->addHTML( $hookResult );
 182                         } else {
 183                                 $wgOut->addHTML( $this->getHTML() );
 184                         }
 185
 186                         $wgOut->output();
 187                 } else {
 188                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 189                         if ( $hookResult ) {
 190                                 die( $hookResult );
 191                         }
 192
 193                         echo $this->getHTML();
 194                         die(1);
 195                 }
 196         }
 197
 198         /**
 199          * Output a report about the exception and takes care of formatting.
 200          * It will be either HTML or plain text based on isCommandLine().
 201          */
 202         function report() {
 203                 $log = $this->getLogMessage();
 204
 205                 if ( $log ) {
 206                         wfDebugLog( 'exception', $log );
 207                 }
 208
 209                 if ( self::isCommandLine() ) {
 210                         MWExceptionHandler::printError( $this->getText() );
 211                 } else {
 212                         $this->reportHTML();
 213                 }
 214         }
 215
 216         static function isCommandLine() {
 217                 return !empty( $GLOBALS['wgCommandLineMode'] );
 218         }
 219 }
 220
 221 /**
 222  * Exception class which takes an HTML error message, and does not
 223  * produce a backtrace. Replacement for OutputPage::fatalError().
 224  * @ingroup Exception
 225  */
 226 class FatalError extends MWException {
 227         function getHTML() {
 228                 return $this->getMessage();
 229         }
 230
 231         function getText() {
 232                 return $this->getMessage();
 233         }
 234 }
 235
 236 /**
 237  * An error page which can definitely be safely rendered using the OutputPage
 238  * @ingroup Exception
 239  */
 240 class ErrorPageError extends MWException {
 241         public $title, $msg, $params;
 242
 243         /**
 244          * Note: these arguments are keys into wfMsg(), not text!
 245          */
 246         function __construct( $title, $msg, $params = null ) {
 247                 $this->title = $title;
 248                 $this->msg = $msg;
 249                 $this->params = $params;
 250
 251                 if( $msg instanceof Message ){
 252                         parent::__construct( $msg );
 253                 } else {
 254                         parent::__construct( wfMsg( $msg ) );
 255                 }
 256         }
 257
 258         function report() {
 259                 global $wgOut;
 260
 261                 $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
 262                 $wgOut->output();
 263         }
 264 }
 265
 266 /**
 267  * Show an error when a user tries to do something they do not have the necessary
 268  * permissions for.
 269  * @ingroup Exception
 270  */
 271 class PermissionsError extends ErrorPageError {
 272         public $permission;
 273
 274         function __construct( $permission ) {
 275                 global $wgLang;
 276
 277                 $this->permission = $permission;
 278
 279                 $groups = array_map(
 280                         array( 'User', 'makeGroupLinkWiki' ),
 281                         User::getGroupsWithPermission( $this->permission )
 282                 );
 283
 284                 if( $groups ) {
 285                         parent::__construct(
 286                                 'badaccess',
 287                                 'badaccess-groups',
 288                                 array(
 289                                         $wgLang->commaList( $groups ),
 290                                         count( $groups )
 291                                 )
 292                         );
 293                 } else {
 294                         parent::__construct(
 295                                 'badaccess',
 296                                 'badaccess-group0'
 297                         );
 298                 }
 299         }
 300 }
 301
 302 /**
 303  * Show an error when the wiki is locked/read-only and the user tries to do
 304  * something that requires write access
 305  * @ingroup Exception
 306  */
 307 class ReadOnlyError extends ErrorPageError {
 308         public function __construct(){
 309                 parent::__construct(
 310                         'readonly',
 311                         'readonlytext',
 312                         wfReadOnlyReason()
 313                 );
 314         }
 315 }
 316
 317 /**
 318  * Show an error when the user hits a rate limit
 319  * @ingroup Exception
 320  */
 321 class ThrottledError extends ErrorPageError {
 322         public function __construct(){
 323                 parent::__construct(
 324                         'actionthrottled',
 325                         'actionthrottledtext'
 326                 );
 327         }
 328         public function report(){
 329                 global $wgOut;
 330                 $wgOut->setStatusCode( 503 );
 331                 return parent::report();
 332         }
 333 }
 334
 335 /**
 336  * Show an error when the user tries to do something whilst blocked
 337  * @ingroup Exception
 338  */
 339 class UserBlockedError extends ErrorPageError {
 340         public function __construct( Block $block ){
 341                 global $wgLang, $wgRequest;
 342
 343                 $blockerUserpage = $block->getBlocker()->getUserPage();
 344                 $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 345
 346                 $reason = $block->mReason;
 347                 if( $reason == '' ) {
 348                         $reason = wfMsg( 'blockednoreason' );
 349                 }
 350
 351                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 352                  * This could be a username, an IP range, or a single IP. */
 353                 $intended = $block->getTarget();
 354
 355                 parent::__construct(
 356                         'blockedtitle',
 357                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 358                         array(
 359                                 $link,
 360                                 $reason,
 361                                 $wgRequest->getIP(),
 362                                 $block->getBlocker()->getName(),
 363                                 $block->getId(),
 364                                 $wgLang->formatExpiry( $block->mExpiry ),
 365                                 $intended,
 366                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 367                         )
 368                 );
 369         }
 370 }
 371
 372 /**
 373  * Show an error that looks like an HTTP server error.
 374  * Replacement for wfHttpError().
 375  *
 376  * @ingroup Exception
 377  */
 378 class HttpError extends MWException {
 379         private $httpCode, $header, $content;
 380
 381         /**
 382          * Constructor
 383          *
 384          * @param $httpCode Integer: HTTP status code to send to the client
 385          * @param $content String|Message: content of the message
 386          * @param $header String|Message: content of the header (\<title\> and \<h1\>)
 387          */
 388         public function __construct( $httpCode, $content, $header = null ){
 389                 parent::__construct( $content );
 390                 $this->httpCode = (int)$httpCode;
 391                 $this->header = $header;
 392                 $this->content = $content;
 393         }
 394
 395         public function reportHTML() {
 396                 $httpMessage = HttpStatus::getMessage( $this->httpCode );
 397
 398                 header( "Status: {$this->httpCode} {$httpMessage}" );
 399                 header( 'Content-type: text/html; charset=utf-8' );
 400
 401                 if ( $this->header === null ) {
 402                         $header = $httpMessage;
 403                 } elseif ( $this->header instanceof Message ) {
 404                         $header = $this->header->escaped();
 405                 } else {
 406                         $header = htmlspecialchars( $this->header );
 407                 }
 408
 409                 if ( $this->content instanceof Message ) {
 410                         $content = $this->content->escaped();
 411                 } else {
 412                         $content = htmlspecialchars( $this->content );
 413                 }
 414
 415                 print "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n".
 416                         "<html><head><title>$header</title></head>\n" .
 417                         "<body><h1>$header</h1><p>$content</p></body></html>\n";
 418         }
 419 }
 420
 421 /**
 422  * Handler class for MWExceptions
 423  * @ingroup Exception
 424  */
 425 class MWExceptionHandler {
 426         /**
 427          * Install an exception handler for MediaWiki exception types.
 428          */
 429         public static function installHandler() {
 430                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 431         }
 432
 433         /**
 434          * Report an exception to the user
 435          */
 436         protected static function report( Exception $e ) {
 437                 global $wgShowExceptionDetails;
 438
 439                 $cmdLine = MWException::isCommandLine();
 440
 441                 if ( $e instanceof MWException ) {
 442                         try {
 443                                 // Try and show the exception prettily, with the normal skin infrastructure
 444                                 $e->report();
 445                         } catch ( Exception $e2 ) {
 446                                 // Exception occurred from within exception handler
 447                                 // Show a simpler error message for the original exception,
 448                                 // don't try to invoke report()
 449                                 $message = "MediaWiki internal error.\n\n";
 450
 451                                 if ( $wgShowExceptionDetails ) {
 452                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 453                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 454                                 } else {
 455                                         $message .= "Exception caught inside exception handler.\n\n" .
 456                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 457                                                 "to show detailed debugging information.";
 458                                 }
 459
 460                                 $message .= "\n";
 461
 462                                 if ( $cmdLine ) {
 463                                         self::printError( $message );
 464                                 } else {
 465                                         self::escapeEchoAndDie( $message );
 466                                 }
 467                         }
 468                 } else {
 469                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 470                                 $e->__toString() . "\n";
 471
 472                         if ( $wgShowExceptionDetails ) {
 473                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 474                         }
 475
 476                         if ( $cmdLine ) {
 477                                 self::printError( $message );
 478                         } else {
 479                                 self::escapeEchoAndDie( $message );
 480                         }
 481                 }
 482         }
 483
 484         /**
 485          * Print a message, if possible to STDERR.
 486          * Use this in command line mode only (see isCommandLine)
 487          * @param $message String Failure text
 488          */
 489         public static function printError( $message ) {
 490                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 491                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 492                 if ( defined( 'STDERR' ) ) {
 493                         fwrite( STDERR, $message );
 494                 } else {
 495                         echo( $message );
 496                 }
 497         }
 498
 499         /**
 500          * Print a message after escaping it and converting newlines to <br>
 501          * Use this for non-command line failures
 502          * @param $message String Failure text
 503          */
 504         private static function escapeEchoAndDie( $message ) {
 505                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 506                 die(1);
 507         }
 508
 509         /**
 510          * Exception handler which simulates the appropriate catch() handling:
 511          *
 512          *   try {
 513          *       ...
 514          *   } catch ( MWException $e ) {
 515          *       $e->report();
 516          *   } catch ( Exception $e ) {
 517          *       echo $e->__toString();
 518          *   }
 519          */
 520         public static function handle( $e ) {
 521                 global $wgFullyInitialised;
 522
 523                 self::report( $e );
 524
 525                 // Final cleanup
 526                 if ( $wgFullyInitialised ) {
 527                         try {
 528                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 529                         } catch ( Exception $e ) {}
 530                 }
 531
 532                 // Exit value should be nonzero for the benefit of shell jobs
 533                 exit( 1 );
 534         }
 535 }