includes/Exception.php

   1 <?php
   2 /**
   3  * @defgroup Exception Exception
   4  */
   5
   6 /**
   7  * MediaWiki exception
   8  * @ingroup Exception
   9  */
  10 class MWException extends Exception {
  11
  12         /**
  13          * Should the exception use $wgOut to output the error ?
  14          * @return bool
  15          */
  16         function useOutputPage() {
  17                 return !empty( $GLOBALS['wgFullyInitialised'] ) &&
  18                         ( !empty( $GLOBALS['wgArticle'] ) || ( !empty( $GLOBALS['wgOut'] ) && !$GLOBALS['wgOut']->isArticle() ) ) &&
  19                         !empty( $GLOBALS['wgTitle'] );
  20         }
  21
  22         /**
  23          * Can the extension use wfMsg() to get i18n messages ?
  24          * @return bool
  25          */
  26         function useMessageCache() {
  27                 global $wgLang;
  28                 return is_object( $wgLang );
  29         }
  30
  31         /**
  32          * Run hook to allow extensions to modify the text of the exception
  33          *
  34          * @param String $name class name of the exception
  35          * @param Array $args arguments to pass to the callback functions
  36          * @return mixed string to output or null if any hook has been called
  37          */
  38         function runHooks( $name, $args = array() ) {
  39                 global $wgExceptionHooks;
  40                 if( !isset( $wgExceptionHooks ) || !is_array( $wgExceptionHooks ) )
  41                         return; // Just silently ignore
  42                 if( !array_key_exists( $name, $wgExceptionHooks ) || !is_array( $wgExceptionHooks[ $name ] ) )
  43                         return;
  44                 $hooks = $wgExceptionHooks[ $name ];
  45                 $callargs = array_merge( array( $this ), $args );
  46
  47                 foreach( $hooks as $hook ) {
  48                         if( is_string( $hook ) || ( is_array( $hook ) && count( $hook ) >= 2 && is_string( $hook[0] ) ) ) {     //'function' or array( 'class', hook' )
  49                                 $result = call_user_func_array( $hook, $callargs );
  50                         } else {
  51                                 $result = null;
  52                         }
  53                         if( is_string( $result ) )
  54                                 return $result;
  55                 }
  56         }
  57
  58         /**
  59          * Get a message from i18n
  60          *
  61          * @param String $key message name
  62          * @param String $fallback default message if the message cache can't be
  63          *                         called by the exception
  64          * The function also has other parameters that are arguments for the message
  65          * @return String message with arguments replaced
  66          */
  67         function msg( $key, $fallback /*[, params...] */ ) {
  68                 $args = array_slice( func_get_args(), 2 );
  69                 if ( $this->useMessageCache() ) {
  70                         return wfMsgReal( $key, $args );
  71                 } else {
  72                         return wfMsgReplaceArgs( $fallback, $args );
  73                 }
  74         }
  75
  76         /**
  77          * If $wgShowExceptionDetails is true, return a HTML message with a
  78          * backtrace to the error, otherwise show a message to ask to set it to true
  79          * to show that information.
  80          *
  81          * @return String html to output
  82          */
  83         function getHTML() {
  84                 global $wgShowExceptionDetails;
  85                 if( $wgShowExceptionDetails ) {
  86                         return '<p>' . nl2br( htmlspecialchars( $this->getMessage() ) ) .
  87                                 '</p><p>Backtrace:</p><p>' . nl2br( htmlspecialchars( $this->getTraceAsString() ) ) .
  88                                 "</p>\n";
  89                 } else {
  90                         return "<p>Set <b><tt>\$wgShowExceptionDetails = true;</tt></b> " .
  91                                 "at the bottom of LocalSettings.php to show detailed " .
  92                                 "debugging information.</p>";
  93                 }
  94         }
  95
  96         /**
  97          * If $wgShowExceptionDetails is true, return a text message with a
  98          * backtrace to the error.
  99          */
 100         function getText() {
 101                 global $wgShowExceptionDetails;
 102                 if( $wgShowExceptionDetails ) {
 103                         return $this->getMessage() .
 104                                 "\nBacktrace:\n" . $this->getTraceAsString() . "\n";
 105                 } else {
 106                         return "Set \$wgShowExceptionDetails = true; " .
 107                                 "in LocalSettings.php to show detailed debugging information.\n";
 108                 }
 109         }
 110
 111         /* Return titles of this error page */
 112         function getPageTitle() {
 113                 if ( $this->useMessageCache() ) {
 114                         return wfMsg( 'internalerror' );
 115                 } else {
 116                         global $wgSitename;
 117                         return "$wgSitename error";
 118                 }
 119         }
 120
 121         /**
 122          * Return the requested URL and point to file and line number from which the
 123          * exception occured
 124          *
 125          * @return string
 126          */
 127         function getLogMessage() {
 128                 global $wgRequest;
 129                 $file = $this->getFile();
 130                 $line = $this->getLine();
 131                 $message = $this->getMessage();
 132                 if ( isset( $wgRequest ) ) {
 133                         $url = $wgRequest->getRequestURL();
 134                         if ( !$url ) {
 135                                 $url = '[no URL]';
 136                         }
 137                 } else {
 138                         $url = '[no req]';
 139                 }
 140
 141                 return "$url   Exception from line $line of $file: $message";
 142         }
 143
 144         /** Output the exception report using HTML */
 145         function reportHTML() {
 146                 global $wgOut;
 147                 if ( $this->useOutputPage() ) {
 148                         $wgOut->setPageTitle( $this->getPageTitle() );
 149                         $wgOut->setRobotPolicy( "noindex,nofollow" );
 150                         $wgOut->setArticleRelated( false );
 151                         $wgOut->enableClientCache( false );
 152                         $wgOut->redirect( '' );
 153                         $wgOut->clearHTML();
 154                         if( $hookResult = $this->runHooks( get_class( $this ) ) ) {
 155                                 $wgOut->addHTML( $hookResult );
 156                         } else {
 157                                 $wgOut->addHTML( $this->getHTML() );
 158                         }
 159                         $wgOut->output();
 160                 } else {
 161                         if( $hookResult = $this->runHooks( get_class( $this ) . "Raw" ) ) {
 162                                 die( $hookResult );
 163                         }
 164                         if ( defined( 'MEDIAWIKI_INSTALL' ) || $this->htmlBodyOnly() ) {
 165                                 echo $this->getHTML();
 166                         } else {
 167                                 echo $this->htmlHeader();
 168                                 echo $this->getHTML();
 169                                 echo $this->htmlFooter();
 170                         }
 171                 }
 172         }
 173
 174         /**
 175          * Output a report about the exception and takes care of formatting.
 176          * It will be either HTML or plain text based on isCommandLine().
 177          */
 178         function report() {
 179                 $log = $this->getLogMessage();
 180                 if ( $log ) {
 181                         wfDebugLog( 'exception', $log );
 182                 }
 183                 if ( self::isCommandLine() ) {
 184                         wfPrintError( $this->getText() );
 185                 } else {
 186                         $this->reportHTML();
 187                 }
 188         }
 189
 190         /**
 191          * Send headers and output the beginning of the html page if not using
 192          * $wgOut to output the exception.
 193          */
 194         function htmlHeader() {
 195                 global $wgLogo, $wgSitename, $wgOutputEncoding;
 196
 197                 if ( !headers_sent() ) {
 198                         header( 'HTTP/1.0 500 Internal Server Error' );
 199                         header( 'Content-type: text/html; charset='.$wgOutputEncoding );
 200                         /* Don't cache error pages!  They cause no end of trouble... */
 201                         header( 'Cache-control: none' );
 202                         header( 'Pragma: nocache' );
 203                 }
 204                 $title = $this->getPageTitle();
 205                 return "<html>
 206                 <head>
 207                 <title>$title</title>
 208                 </head>
 209                 <body>
 210                 <h1><img src='$wgLogo' style='float:left;margin-right:1em' alt=''/>$title</h1>
 211                 ";
 212         }
 213
 214         /**
 215          * print the end of the html page if not using $wgOut.
 216          */
 217         function htmlFooter() {
 218                 return "</body></html>";
 219         }
 220
 221         /**
 222          * headers handled by subclass?
 223          */
 224         function htmlBodyOnly() {
 225                 return false;
 226         }
 227
 228         static function isCommandLine() {
 229                 return !empty( $GLOBALS['wgCommandLineMode'] ) && !defined( 'MEDIAWIKI_INSTALL' );
 230         }
 231 }
 232
 233 /**
 234  * Exception class which takes an HTML error message, and does not
 235  * produce a backtrace. Replacement for OutputPage::fatalError().
 236  * @ingroup Exception
 237  */
 238 class FatalError extends MWException {
 239         function getHTML() {
 240                 return $this->getMessage();
 241         }
 242
 243         function getText() {
 244                 return $this->getMessage();
 245         }
 246 }
 247
 248 /**
 249  * @ingroup Exception
 250  */
 251 class ErrorPageError extends MWException {
 252         public $title, $msg;
 253
 254         /**
 255          * Note: these arguments are keys into wfMsg(), not text!
 256          */
 257         function __construct( $title, $msg ) {
 258                 $this->title = $title;
 259                 $this->msg = $msg;
 260                 parent::__construct( wfMsg( $msg ) );
 261         }
 262
 263         function report() {
 264                 global $wgOut;
 265                 $wgOut->showErrorPage( $this->title, $this->msg );
 266                 $wgOut->output();
 267         }
 268 }
 269
 270 /**
 271  * Install an exception handler for MediaWiki exception types.
 272  */
 273 function wfInstallExceptionHandler() {
 274         set_exception_handler( 'wfExceptionHandler' );
 275 }
 276
 277 /**
 278  * Report an exception to the user
 279  */
 280 function wfReportException( Exception $e ) {
 281         $cmdLine = MWException::isCommandLine();
 282         if ( $e instanceof MWException ) {
 283                 try {
 284                         $e->report();
 285                 } catch ( Exception $e2 ) {
 286                         // Exception occurred from within exception handler
 287                         // Show a simpler error message for the original exception,
 288                         // don't try to invoke report()
 289                         $message = "MediaWiki internal error.\n\n";
 290                         if ( $GLOBALS['wgShowExceptionDetails'] )
 291                                 $message .= "Original exception: " . $e->__toString();
 292                         $message .= "\n\nException caught inside exception handler";
 293                         if ( $GLOBALS['wgShowExceptionDetails'] )
 294                                 $message .= ": " . $e2->__toString();
 295                         $message .= "\n";
 296                         if ( $cmdLine ) {
 297                                 wfPrintError( $message );
 298                         } else {
 299                                 echo nl2br( htmlspecialchars( $message ) ). "\n";
 300                         }
 301                 }
 302         } else {
 303                 $message = "Unexpected non-MediaWiki exception encountered, of type \"" . get_class( $e ) . "\"\n" .
 304                         $e->__toString() . "\n";
 305                 if ( $GLOBALS['wgShowExceptionDetails'] ) {
 306                         $message .= "\n" . $e->getTraceAsString() ."\n";
 307                 }
 308                 if ( $cmdLine ) {
 309                         wfPrintError( $message );
 310                 } else {
 311                         echo nl2br( htmlspecialchars( $message ) ). "\n";
 312                 }
 313         }
 314 }
 315
 316 /**
 317  * Print a message, if possible to STDERR.
 318  * Use this in command line mode only (see isCommandLine)
 319  */
 320 function wfPrintError( $message ) {
 321         #NOTE: STDERR may not be available, especially if php-cgi is used from the command line (bug #15602).
 322         #      Try to produce meaningful output anyway. Using echo may corrupt output to STDOUT though.
 323         if ( defined( 'STDERR' ) ) {
 324                 fwrite( STDERR, $message );
 325         } else {
 326                 echo( $message );
 327         }
 328 }
 329
 330 /**
 331  * Exception handler which simulates the appropriate catch() handling:
 332  *
 333  *   try {
 334  *       ...
 335  *   } catch ( MWException $e ) {
 336  *       $e->report();
 337  *   } catch ( Exception $e ) {
 338  *       echo $e->__toString();
 339  *   }
 340  */
 341 function wfExceptionHandler( $e ) {
 342         global $wgFullyInitialised;
 343         wfReportException( $e );
 344
 345         // Final cleanup, similar to wfErrorExit()
 346         if ( $wgFullyInitialised ) {
 347                 try {
 348                         wfLogProfilingData(); // uses $wgRequest, hence the $wgFullyInitialised condition
 349                 } catch ( Exception $e ) {}
 350         }
 351
 352         // Exit value should be nonzero for the benefit of shell jobs
 353         exit( 1 );
 354 }