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 ) ) {
 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                         header( $_SERVER['SERVER_PROTOCOL'] . ' 500 MediaWiki Error', true, 500 );
 186                         header( 'Content-type: text/html; charset=UTF-8' );
 187                         header( 'Cache-control: none' );
 188                         header( 'Pragma: nocache' );
 189
 190                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 191                         if ( $hookResult ) {
 192                                 die( $hookResult );
 193                         }
 194
 195                         echo "<html>
 196 <head>
 197 <meta http-equiv='Content-Type' content='text/html; charset=utf-8' />
 198 <title>" . $this->getPageTitle() . "</title>
 199 </head>
 200 <body>
 201 ";
 202                         echo $this->getHTML();
 203                         echo "\n</body></html>";
 204                         die(1);
 205                 }
 206         }
 207
 208         /**
 209          * Output a report about the exception and takes care of formatting.
 210          * It will be either HTML or plain text based on isCommandLine().
 211          */
 212         function report() {
 213                 $log = $this->getLogMessage();
 214
 215                 if ( $log ) {
 216                         wfDebugLog( 'exception', $log );
 217                 }
 218
 219                 if ( self::isCommandLine() ) {
 220                         MWExceptionHandler::printError( $this->getText() );
 221                 } else {
 222                         $this->reportHTML();
 223                 }
 224         }
 225
 226         static function isCommandLine() {
 227                 return !empty( $GLOBALS['wgCommandLineMode'] );
 228         }
 229 }
 230
 231 /**
 232  * Exception class which takes an HTML error message, and does not
 233  * produce a backtrace. Replacement for OutputPage::fatalError().
 234  * @ingroup Exception
 235  */
 236 class FatalError extends MWException {
 237         function getHTML() {
 238                 return $this->getMessage();
 239         }
 240
 241         function getText() {
 242                 return $this->getMessage();
 243         }
 244 }
 245
 246 /**
 247  * An error page which can definitely be safely rendered using the OutputPage
 248  * @ingroup Exception
 249  */
 250 class ErrorPageError extends MWException {
 251         public $title, $msg, $params;
 252
 253         /**
 254          * Note: these arguments are keys into wfMsg(), not text!
 255          */
 256         function __construct( $title, $msg, $params = null ) {
 257                 $this->title = $title;
 258                 $this->msg = $msg;
 259                 $this->params = $params;
 260
 261                 if( $msg instanceof Message ){
 262                         parent::__construct( $msg );
 263                 } else {
 264                         parent::__construct( wfMsg( $msg ) );
 265                 }
 266         }
 267
 268         function report() {
 269                 global $wgOut;
 270
 271                 if ( $wgOut->getTitle() ) {
 272                         $wgOut->debug( 'Original title: ' . $wgOut->getTitle()->getPrefixedText() . "\n" );
 273                 }
 274                 $wgOut->setPageTitle( wfMsg( $this->title ) );
 275                 $wgOut->setHTMLTitle( wfMsg( 'errorpagetitle' ) );
 276                 $wgOut->setRobotPolicy( 'noindex,nofollow' );
 277                 $wgOut->setArticleRelated( false );
 278                 $wgOut->enableClientCache( false );
 279                 $wgOut->mRedirect = '';
 280                 $wgOut->clearHTML();
 281
 282                 if( $this->msg instanceof Message ){
 283                         $wgOut->addHTML( $this->msg->parse() );
 284                 } else {
 285                         $wgOut->addWikiMsgArray( $this->msg, $this->params );
 286                 }
 287
 288                 $wgOut->returnToMain();
 289                 $wgOut->output();
 290         }
 291 }
 292
 293 /**
 294  * Show an error when a user tries to do something they do not have the necessary
 295  * permissions for.
 296  * @ingroup Exception
 297  */
 298 class PermissionsError extends ErrorPageError {
 299         public $permission;
 300
 301         function __construct( $permission ) {
 302                 global $wgLang;
 303
 304                 $this->permission = $permission;
 305
 306                 $groups = array_map(
 307                         array( 'User', 'makeGroupLinkWiki' ),
 308                         User::getGroupsWithPermission( $this->permission )
 309                 );
 310
 311                 if( $groups ) {
 312                         parent::__construct(
 313                                 'badaccess',
 314                                 'badaccess-groups',
 315                                 array(
 316                                         $wgLang->commaList( $groups ),
 317                                         count( $groups )
 318                                 )
 319                         );
 320                 } else {
 321                         parent::__construct(
 322                                 'badaccess',
 323                                 'badaccess-group0'
 324                         );
 325                 }
 326         }
 327 }
 328
 329 /**
 330  * Show an error when the wiki is locked/read-only and the user tries to do
 331  * something that requires write access
 332  * @ingroup Exception
 333  */
 334 class ReadOnlyError extends ErrorPageError {
 335         public function __construct(){
 336                 parent::__construct(
 337                         'readonly',
 338                         'readonlytext',
 339                         wfReadOnlyReason()
 340                 );
 341         }
 342 }
 343
 344 /**
 345  * Show an error when the user hits a rate limit
 346  * @ingroup Exception
 347  */
 348 class ThrottledError extends ErrorPageError {
 349         public function __construct(){
 350                 parent::__construct(
 351                         'actionthrottled',
 352                         'actionthrottledtext'
 353                 );
 354         }
 355         public function report(){
 356                 global $wgOut;
 357                 $wgOut->setStatusCode( 503 );
 358                 return parent::report();
 359         }
 360 }
 361
 362 /**
 363  * Show an error when the user tries to do something whilst blocked
 364  * @ingroup Exception
 365  */
 366 class UserBlockedError extends ErrorPageError {
 367         public function __construct( Block $block ){
 368                 global $wgLang;
 369
 370                 $blockerUserpage = $block->getBlocker()->getUserPage();
 371                 $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 372
 373                 $reason = $block->mReason;
 374                 if( $reason == '' ) {
 375                         $reason = wfMsg( 'blockednoreason' );
 376                 }
 377
 378                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 379                  * This could be a username, an IP range, or a single IP. */
 380                 $intended = $block->getTarget();
 381
 382                 parent::__construct(
 383                         'blockedtitle',
 384                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 385                         array(
 386                                 $link,
 387                                 $reason,
 388                                 wfGetIP(),
 389                                 $block->getBlocker()->getName(),
 390                                 $block->getId(),
 391                                 $wgLang->formatExpiry( $block->mExpiry ),
 392                                 $intended,
 393                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 394                         )
 395                 );
 396         }
 397 }
 398
 399 /**
 400  * Handler class for MWExceptions
 401  * @ingroup Exception
 402  */
 403 class MWExceptionHandler {
 404         /**
 405          * Install an exception handler for MediaWiki exception types.
 406          */
 407         public static function installHandler() {
 408                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 409         }
 410
 411         /**
 412          * Report an exception to the user
 413          */
 414         protected static function report( Exception $e ) {
 415                 global $wgShowExceptionDetails;
 416
 417                 $cmdLine = MWException::isCommandLine();
 418
 419                 if ( $e instanceof MWException ) {
 420                         try {
 421                                 // Try and show the exception prettily, with the normal skin infrastructure
 422                                 $e->report();
 423                         } catch ( Exception $e2 ) {
 424                                 // Exception occurred from within exception handler
 425                                 // Show a simpler error message for the original exception,
 426                                 // don't try to invoke report()
 427                                 $message = "MediaWiki internal error.\n\n";
 428
 429                                 if ( $wgShowExceptionDetails ) {
 430                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 431                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 432                                 } else {
 433                                         $message .= "Exception caught inside exception handler.\n\n" .
 434                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 435                                                 "to show detailed debugging information.";
 436                                 }
 437
 438                                 $message .= "\n";
 439
 440                                 if ( $cmdLine ) {
 441                                         self::printError( $message );
 442                                 } else {
 443                                         self::escapeEchoAndDie( $message );
 444                                 }
 445                         }
 446                 } else {
 447                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 448                                 $e->__toString() . "\n";
 449
 450                         if ( $wgShowExceptionDetails ) {
 451                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 452                         }
 453
 454                         if ( $cmdLine ) {
 455                                 self::printError( $message );
 456                         } else {
 457                                 self::escapeEchoAndDie( $message );
 458                         }
 459                 }
 460         }
 461
 462         /**
 463          * Print a message, if possible to STDERR.
 464          * Use this in command line mode only (see isCommandLine)
 465          * @param $message String Failure text
 466          */
 467         public static function printError( $message ) {
 468                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 469                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 470                 if ( defined( 'STDERR' ) ) {
 471                         fwrite( STDERR, $message );
 472                 } else {
 473                         echo( $message );
 474                 }
 475         }
 476
 477         /**
 478          * Print a message after escaping it and converting newlines to <br>
 479          * Use this for non-command line failures
 480          * @param $message String Failure text
 481          */
 482         private static function escapeEchoAndDie( $message ) {
 483                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 484                 die(1);
 485         }
 486
 487         /**
 488          * Exception handler which simulates the appropriate catch() handling:
 489          *
 490          *   try {
 491          *       ...
 492          *   } catch ( MWException $e ) {
 493          *       $e->report();
 494          *   } catch ( Exception $e ) {
 495          *       echo $e->__toString();
 496          *   }
 497          */
 498         public static function handle( $e ) {
 499                 global $wgFullyInitialised;
 500
 501                 self::report( $e );
 502
 503                 // Final cleanup
 504                 if ( $wgFullyInitialised ) {
 505                         try {
 506                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 507                         } catch ( Exception $e ) {}
 508                 }
 509
 510                 // Exit value should be nonzero for the benefit of shell jobs
 511                 exit( 1 );
 512         }
 513 }