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