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