includes/exception/MWException.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20
  21 /**
  22  * MediaWiki exception
  23  *
  24  * @ingroup Exception
  25  */
  26 class MWException extends Exception {
  27         /**
  28          * Should the exception use $wgOut to output the error?
  29          *
  30          * @return bool
  31          */
  32         public function useOutputPage() {
  33                 return $this->useMessageCache() &&
  34                 !empty( $GLOBALS['wgFullyInitialised'] ) &&
  35                 !empty( $GLOBALS['wgOut'] ) &&
  36                 !defined( 'MEDIAWIKI_INSTALL' );
  37         }
  38
  39         /**
  40          * Whether to log this exception in the exception debug log.
  41          *
  42          * @since 1.23
  43          * @return bool
  44          */
  45         public function isLoggable() {
  46                 return true;
  47         }
  48
  49         /**
  50          * Can the extension use the Message class/wfMessage to get i18n-ed messages?
  51          *
  52          * @return bool
  53          */
  54         public function useMessageCache() {
  55                 global $wgLang;
  56
  57                 foreach ( $this->getTrace() as $frame ) {
  58                         if ( isset( $frame['class'] ) && $frame['class'] === 'LocalisationCache' ) {
  59                                 return false;
  60                         }
  61                 }
  62
  63                 return $wgLang instanceof Language;
  64         }
  65
  66         /**
  67          * Run hook to allow extensions to modify the text of the exception
  68          *
  69          * @param string $name Class name of the exception
  70          * @param array $args Arguments to pass to the callback functions
  71          * @return string|null String to output or null if any hook has been called
  72          */
  73         public function runHooks( $name, $args = [] ) {
  74                 return MWExceptionRenderer::runHooks( $this, $name, $args );
  75         }
  76
  77         /**
  78          * Get a message from i18n
  79          *
  80          * @param string $key Message name
  81          * @param string $fallback Default message if the message cache can't be
  82          *                  called by the exception
  83          * The function also has other parameters that are arguments for the message
  84          * @return string Message with arguments replaced
  85          */
  86         public function msg( $key, $fallback /*[, params...] */ ) {
  87                 $args = array_slice( func_get_args(), 2 );
  88
  89                 if ( $this->useMessageCache() ) {
  90                         try {
  91                                 return wfMessage( $key, $args )->text();
  92                         } catch ( Exception $e ) {
  93                         }
  94                 }
  95                 return wfMsgReplaceArgs( $fallback, $args );
  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         public function getHTML() {
 106                 global $wgShowExceptionDetails;
 107
 108                 if ( $wgShowExceptionDetails ) {
 109                         return '<p>' . nl2br( htmlspecialchars( MWExceptionHandler::getLogMessage( $this ) ) ) .
 110                         '</p><p>Backtrace:</p><p>' .
 111                         nl2br( htmlspecialchars( MWExceptionHandler::getRedactedTraceAsString( $this ) ) ) .
 112                         "</p>\n";
 113                 } else {
 114                         $logId = WebRequest::getRequestId();
 115                         $type = get_class( $this );
 116                         return "<div class=\"errorbox\">" .
 117                         '[' . $logId . '] ' .
 118                         gmdate( 'Y-m-d H:i:s' ) . ": " .
 119                         $this->msg( "internalerror-fatal-exception",
 120                                 "Fatal exception of type $1",
 121                                 $type,
 122                                 $logId,
 123                                 MWExceptionHandler::getURL( $this )
 124                         ) . "</div>\n" .
 125                         "<!-- Set \$wgShowExceptionDetails = true; " .
 126                         "at the bottom of LocalSettings.php to show detailed " .
 127                         "debugging information. -->";
 128                 }
 129         }
 130
 131         /**
 132          * Get the text to display when reporting the error on the command line.
 133          * If $wgShowExceptionDetails is true, return a text message with a
 134          * backtrace to the error.
 135          *
 136          * @return string
 137          */
 138         public function getText() {
 139                 global $wgShowExceptionDetails;
 140
 141                 if ( $wgShowExceptionDetails ) {
 142                         return MWExceptionHandler::getLogMessage( $this ) .
 143                         "\nBacktrace:\n" . MWExceptionHandler::getRedactedTraceAsString( $this ) . "\n";
 144                 } else {
 145                         return "Set \$wgShowExceptionDetails = true; " .
 146                         "in LocalSettings.php to show detailed debugging information.\n";
 147                 }
 148         }
 149
 150         /**
 151          * Return the title of the page when reporting this error in a HTTP response.
 152          *
 153          * @return string
 154          */
 155         public function getPageTitle() {
 156                 return $this->msg( 'internalerror', 'Internal error' );
 157         }
 158
 159         /**
 160          * Output the exception report using HTML.
 161          */
 162         public function reportHTML() {
 163                 global $wgOut, $wgSitename;
 164                 if ( $this->useOutputPage() ) {
 165                         $wgOut->prepareErrorPage( $this->getPageTitle() );
 166
 167                         $hookResult = $this->runHooks( get_class( $this ) );
 168                         if ( $hookResult ) {
 169                                 $wgOut->addHTML( $hookResult );
 170                         } else {
 171                                 $wgOut->addHTML( $this->getHTML() );
 172                         }
 173
 174                         $wgOut->output();
 175                 } else {
 176                         self::header( 'Content-Type: text/html; charset=utf-8' );
 177                         echo "<!DOCTYPE html>\n" .
 178                                 '<html><head>' .
 179                                 // Mimick OutputPage::setPageTitle behaviour
 180                                 '<title>' .
 181                                 htmlspecialchars( $this->msg( 'pagetitle', "$1 - $wgSitename", $this->getPageTitle() ) ) .
 182                                 '</title>' .
 183                                 '<style>body { font-family: sans-serif; margin: 0; padding: 0.5em 2em; }</style>' .
 184                                 "</head><body>\n";
 185
 186                         $hookResult = $this->runHooks( get_class( $this ) . 'Raw' );
 187                         if ( $hookResult ) {
 188                                 echo $hookResult;
 189                         } else {
 190                                 echo $this->getHTML();
 191                         }
 192
 193                         echo "</body></html>\n";
 194                 }
 195         }
 196
 197         /**
 198          * Output a report about the exception and takes care of formatting.
 199          * It will be either HTML or plain text based on isCommandLine().
 200          */
 201         public function report() {
 202                 global $wgMimeType;
 203
 204                 if ( defined( 'MW_API' ) ) {
 205                         // Unhandled API exception, we can't be sure that format printer is alive
 206                         self::header( 'MediaWiki-API-Error: internal_api_error_' . get_class( $this ) );
 207                         wfHttpError( 500, 'Internal Server Error', $this->getText() );
 208                 } elseif ( self::isCommandLine() ) {
 209                         $message = $this->getText();
 210                         // T17602: STDERR may not be available
 211                         if ( defined( 'STDERR' ) ) {
 212                                 fwrite( STDERR, $message );
 213                         } else {
 214                                 echo $message;
 215                         }
 216                 } else {
 217                         self::statusHeader( 500 );
 218                         self::header( "Content-Type: $wgMimeType; charset=utf-8" );
 219
 220                         $this->reportHTML();
 221                 }
 222         }
 223
 224         /**
 225          * Check whether we are in command line mode or not to report the exception
 226          * in the correct format.
 227          *
 228          * @return bool
 229          */
 230         public static function isCommandLine() {
 231                 return !empty( $GLOBALS['wgCommandLineMode'] );
 232         }
 233
 234         /**
 235          * Send a header, if we haven't already sent them. We shouldn't,
 236          * but sometimes we might in a weird case like Export
 237          * @param string $header
 238          */
 239         private static function header( $header ) {
 240                 if ( !headers_sent() ) {
 241                         header( $header );
 242                 }
 243         }
 244         private static function statusHeader( $code ) {
 245                 if ( !headers_sent() ) {
 246                         HttpStatus::header( $code );
 247                 }
 248         }
 249 }