includes/Exception.php

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