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                         $hookResult = $this->runHooks( get_class( $this ) . "Raw" );
 185                         if ( $hookResult ) {
 186                                 die( $hookResult );
 187                         }
 188
 189                         echo $this->getHTML();
 190                         die(1);
 191                 }
 192         }
 193
 194         /**
 195          * Output a report about the exception and takes care of formatting.
 196          * It will be either HTML or plain text based on isCommandLine().
 197          */
 198         function report() {
 199                 $log = $this->getLogMessage();
 200
 201                 if ( $log ) {
 202                         wfDebugLog( 'exception', $log );
 203                 }
 204
 205                 if ( self::isCommandLine() ) {
 206                         MWExceptionHandler::printError( $this->getText() );
 207                 } else {
 208                         $this->reportHTML();
 209                 }
 210         }
 211
 212         /**
 213          * @static
 214          * @return bool
 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
 228         /**
 229          * @return string
 230          */
 231         function getHTML() {
 232                 return $this->getMessage();
 233         }
 234
 235         /**
 236          * @return string
 237          */
 238         function getText() {
 239                 return $this->getMessage();
 240         }
 241 }
 242
 243 /**
 244  * An error page which can definitely be safely rendered using the OutputPage
 245  * @ingroup Exception
 246  */
 247 class ErrorPageError extends MWException {
 248         public $title, $msg, $params;
 249
 250         /**
 251          * Note: these arguments are keys into wfMsg(), not text!
 252          */
 253         function __construct( $title, $msg, $params = null ) {
 254                 $this->title = $title;
 255                 $this->msg = $msg;
 256                 $this->params = $params;
 257
 258                 if( $msg instanceof Message ){
 259                         parent::__construct( $msg );
 260                 } else {
 261                         parent::__construct( wfMsg( $msg ) );
 262                 }
 263         }
 264
 265         function report() {
 266                 global $wgOut;
 267
 268                 $wgOut->showErrorPage( $this->title, $this->msg, $this->params );
 269                 $wgOut->output();
 270         }
 271 }
 272
 273 /**
 274  * Show an error when a user tries to do something they do not have the necessary
 275  * permissions for.
 276  * @ingroup Exception
 277  */
 278 class PermissionsError extends ErrorPageError {
 279         public $permission, $errors;
 280
 281         function __construct( $permission, $errors = array() ) {
 282                 global $wgLang;
 283
 284                 $this->permission = $permission;
 285
 286                 if ( !count( $errors ) ) {
 287                         $groups = array_map(
 288                                 array( 'User', 'makeGroupLinkWiki' ),
 289                                 User::getGroupsWithPermission( $this->permission )
 290                         );
 291
 292                         if ( $groups ) {
 293                                 $errors[] = array( 'badaccess-groups', $wgLang->commaList( $groups ), count( $groups ) );
 294                         } else {
 295                                 $errors[] = array( 'badaccess-group0' );
 296                         }
 297                 }
 298
 299                 $this->errors = $errors;
 300         }
 301
 302         function report() {
 303                 global $wgOut;
 304
 305                 $wgOut->showPermissionsErrorPage( $this->errors, $this->permission );
 306                 $wgOut->output();
 307         }
 308 }
 309
 310 /**
 311  * Show an error when the wiki is locked/read-only and the user tries to do
 312  * something that requires write access
 313  * @ingroup Exception
 314  */
 315 class ReadOnlyError extends ErrorPageError {
 316         public function __construct(){
 317                 parent::__construct(
 318                         'readonly',
 319                         'readonlytext',
 320                         wfReadOnlyReason()
 321                 );
 322         }
 323 }
 324
 325 /**
 326  * Show an error when the user hits a rate limit
 327  * @ingroup Exception
 328  */
 329 class ThrottledError extends ErrorPageError {
 330         public function __construct(){
 331                 parent::__construct(
 332                         'actionthrottled',
 333                         'actionthrottledtext'
 334                 );
 335         }
 336
 337         public function report(){
 338                 global $wgOut;
 339                 $wgOut->setStatusCode( 503 );
 340                 return parent::report();
 341         }
 342 }
 343
 344 /**
 345  * Show an error when the user tries to do something whilst blocked
 346  * @ingroup Exception
 347  */
 348 class UserBlockedError extends ErrorPageError {
 349         public function __construct( Block $block ){
 350                 global $wgLang, $wgRequest;
 351
 352                 $blocker = $block->getBlocker();
 353                 if ( $blocker instanceof User ) { // local user
 354                         $blockerUserpage = $block->getBlocker()->getUserPage();
 355                         $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
 356                 } else { // foreign user
 357                         $link = $blocker;
 358                 }
 359
 360                 $reason = $block->mReason;
 361                 if( $reason == '' ) {
 362                         $reason = wfMsg( 'blockednoreason' );
 363                 }
 364
 365                 /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
 366                  * This could be a username, an IP range, or a single IP. */
 367                 $intended = $block->getTarget();
 368
 369                 parent::__construct(
 370                         'blockedtitle',
 371                         $block->mAuto ? 'autoblockedtext' : 'blockedtext',
 372                         array(
 373                                 $link,
 374                                 $reason,
 375                                 $wgRequest->getIP(),
 376                                 $block->getByName(),
 377                                 $block->getId(),
 378                                 $wgLang->formatExpiry( $block->mExpiry ),
 379                                 $intended,
 380                                 $wgLang->timeanddate( wfTimestamp( TS_MW, $block->mTimestamp ), true )
 381                         )
 382                 );
 383         }
 384 }
 385
 386 /**
 387  * Show an error that looks like an HTTP server error.
 388  * Replacement for wfHttpError().
 389  *
 390  * @ingroup Exception
 391  */
 392 class HttpError extends MWException {
 393         private $httpCode, $header, $content;
 394
 395         /**
 396          * Constructor
 397          *
 398          * @param $httpCode Integer: HTTP status code to send to the client
 399          * @param $content String|Message: content of the message
 400          * @param $header String|Message: content of the header (\<title\> and \<h1\>)
 401          */
 402         public function __construct( $httpCode, $content, $header = null ){
 403                 parent::__construct( $content );
 404                 $this->httpCode = (int)$httpCode;
 405                 $this->header = $header;
 406                 $this->content = $content;
 407         }
 408
 409         public function reportHTML() {
 410                 $httpMessage = HttpStatus::getMessage( $this->httpCode );
 411
 412                 header( "Status: {$this->httpCode} {$httpMessage}" );
 413                 header( 'Content-type: text/html; charset=utf-8' );
 414
 415                 if ( $this->header === null ) {
 416                         $header = $httpMessage;
 417                 } elseif ( $this->header instanceof Message ) {
 418                         $header = $this->header->escaped();
 419                 } else {
 420                         $header = htmlspecialchars( $this->header );
 421                 }
 422
 423                 if ( $this->content instanceof Message ) {
 424                         $content = $this->content->escaped();
 425                 } else {
 426                         $content = htmlspecialchars( $this->content );
 427                 }
 428
 429                 print "<!DOCTYPE HTML PUBLIC \"-//IETF//DTD HTML 2.0//EN\">\n".
 430                         "<html><head><title>$header</title></head>\n" .
 431                         "<body><h1>$header</h1><p>$content</p></body></html>\n";
 432         }
 433 }
 434
 435 /**
 436  * Handler class for MWExceptions
 437  * @ingroup Exception
 438  */
 439 class MWExceptionHandler {
 440         /**
 441          * Install an exception handler for MediaWiki exception types.
 442          */
 443         public static function installHandler() {
 444                 set_exception_handler( array( 'MWExceptionHandler', 'handle' ) );
 445         }
 446
 447         /**
 448          * Report an exception to the user
 449          */
 450         protected static function report( Exception $e ) {
 451                 global $wgShowExceptionDetails;
 452
 453                 $cmdLine = MWException::isCommandLine();
 454
 455                 if ( $e instanceof MWException ) {
 456                         try {
 457                                 // Try and show the exception prettily, with the normal skin infrastructure
 458                                 $e->report();
 459                         } catch ( Exception $e2 ) {
 460                                 // Exception occurred from within exception handler
 461                                 // Show a simpler error message for the original exception,
 462                                 // don't try to invoke report()
 463                                 $message = "MediaWiki internal error.\n\n";
 464
 465                                 if ( $wgShowExceptionDetails ) {
 466                                         $message .= 'Original exception: ' . $e->__toString() . "\n\n" .
 467                                                 'Exception caught inside exception handler: ' . $e2->__toString();
 468                                 } else {
 469                                         $message .= "Exception caught inside exception handler.\n\n" .
 470                                                 "Set \$wgShowExceptionDetails = true; at the bottom of LocalSettings.php " .
 471                                                 "to show detailed debugging information.";
 472                                 }
 473
 474                                 $message .= "\n";
 475
 476                                 if ( $cmdLine ) {
 477                                         self::printError( $message );
 478                                 } else {
 479                                         self::escapeEchoAndDie( $message );
 480                                 }
 481                         }
 482                 } else {
 483                         $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 484                                 $e->__toString() . "\n";
 485
 486                         if ( $wgShowExceptionDetails ) {
 487                                 $message .= "\n" . $e->getTraceAsString() . "\n";
 488                         }
 489
 490                         if ( $cmdLine ) {
 491                                 self::printError( $message );
 492                         } else {
 493                                 self::escapeEchoAndDie( $message );
 494                         }
 495                 }
 496         }
 497
 498         /**
 499          * Print a message, if possible to STDERR.
 500          * Use this in command line mode only (see isCommandLine)
 501          * @param $message String Failure text
 502          */
 503         public static function printError( $message ) {
 504                 # NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 505                 #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 506                 if ( defined( 'STDERR' ) ) {
 507                         fwrite( STDERR, $message );
 508                 } else {
 509                         echo( $message );
 510                 }
 511         }
 512
 513         /**
 514          * Print a message after escaping it and converting newlines to <br>
 515          * Use this for non-command line failures
 516          * @param $message String Failure text
 517          */
 518         private static function escapeEchoAndDie( $message ) {
 519                 echo nl2br( htmlspecialchars( $message ) ) . "\n";
 520                 die(1);
 521         }
 522
 523         /**
 524          * Exception handler which simulates the appropriate catch() handling:
 525          *
 526          *   try {
 527          *       ...
 528          *   } catch ( MWException $e ) {
 529          *       $e->report();
 530          *   } catch ( Exception $e ) {
 531          *       echo $e->__toString();
 532          *   }
 533          */
 534         public static function handle( $e ) {
 535                 global $wgFullyInitialised;
 536
 537                 self::report( $e );
 538
 539                 // Final cleanup
 540                 if ( $wgFullyInitialised ) {
 541                         try {
 542                                 wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 543                         } catch ( Exception $e ) {}
 544                 }
 545
 546                 // Exit value should be nonzero for the benefit of shell jobs
 547                 exit( 1 );
 548         }
 549 }