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 = array() ) {
  74                 global $wgExceptionHooks;
  75
  76                 if ( !isset( $wgExceptionHooks ) || !is_array( $wgExceptionHooks ) ) {
  77                         return null; // Just silently ignore
  78                 }
  79
  80                 if ( !array_key_exists( $name, $wgExceptionHooks ) ||
  81                         !is_array( $wgExceptionHooks[$name] )
  82                 ) {
  83                         return null;
  84                 }
  85
  86                 $hooks = $wgExceptionHooks[$name];
  87                 $callargs = array_merge( array( $this ), $args );
  88
  89                 foreach ( $hooks as $hook ) {
  90                         if (
  91                                 is_string( $hook ) ||
  92                                 ( is_array( $hook ) && count( $hook ) >= 2 && is_string( $hook[0] ) )
  93                         ) {
  94                                 // 'function' or array( 'class', hook' )
  95                                 $result = call_user_func_array( $hook, $callargs );
  96                         } else {
  97                                 $result = null;
  98                         }
  99
 100                         if ( is_string( $result ) ) {
 101                                 return $result;
 102                         }
 103                 }
 104                 return null;
 105         }
 106
 107         /**
 108          * Get a message from i18n
 109          *
 110          * @param string $key Message name
 111          * @param string $fallback Default message if the message cache can't be
 112          *                  called by the exception
 113          * The function also has other parameters that are arguments for the message
 114          * @return string Message with arguments replaced
 115          */
 116         public function msg( $key, $fallback /*[, params...] */ ) {
 117                 $args = array_slice( func_get_args(), 2 );
 118
 119                 if ( $this->useMessageCache() ) {
 120                         return wfMessage( $key, $args )->text();
 121                 } else {
 122                         return wfMsgReplaceArgs( $fallback, $args );
 123                 }
 124         }
 125
 126         /**
 127          * If $wgShowExceptionDetails is true, return a HTML message with a
 128          * backtrace to the error, otherwise show a message to ask to set it to true
 129          * to show that information.
 130          *
 131          * @return string Html to output
 132          */
 133         public function getHTML() {
 134                 global $wgShowExceptionDetails;
 135
 136                 if ( $wgShowExceptionDetails ) {
 137                         return '<p>' . nl2br( htmlspecialchars( MWExceptionHandler::getLogMessage( $this ) ) ) .
 138                         '</p><p>Backtrace:</p><p>' .
 139                         nl2br( htmlspecialchars( MWExceptionHandler::getRedactedTraceAsString( $this ) ) ) .
 140                         "</p>\n";
 141                 } else {
 142                         return "<div class=\"errorbox\">" .
 143                         '[' . MWExceptionHandler::getLogId( $this ) . '] ' .
 144                         gmdate( 'Y-m-d H:i:s' ) .
 145                         ": Fatal exception of type " . get_class( $this ) . "</div>\n" .
 146                         "<!-- Set \$wgShowExceptionDetails = true; " .
 147                         "at the bottom of LocalSettings.php to show detailed " .
 148                         "debugging information. -->";
 149                 }
 150         }
 151
 152         /**
 153          * Get the text to display when reporting the error on the command line.
 154          * If $wgShowExceptionDetails is true, return a text message with a
 155          * backtrace to the error.
 156          *
 157          * @return string
 158          */
 159         public function getText() {
 160                 global $wgShowExceptionDetails;
 161
 162                 if ( $wgShowExceptionDetails ) {
 163                         return MWExceptionHandler::getLogMessage( $this ) .
 164                         "\nBacktrace:\n" . MWExceptionHandler::getRedactedTraceAsString( $this ) . "\n";
 165                 } else {
 166                         return "Set \$wgShowExceptionDetails = true; " .
 167                         "in LocalSettings.php to show detailed debugging information.\n";
 168                 }
 169         }
 170
 171         /**
 172          * Return the title of the page when reporting this error in a HTTP response.
 173          *
 174          * @return string
 175          */
 176         public function getPageTitle() {
 177                 return $this->msg( 'internalerror', 'Internal error' );
 178         }
 179
 180         /**
 181          * Output the exception report using HTML.
 182          */
 183         public function reportHTML() {
 184                 global $wgOut, $wgSitename;
 185                 if ( $this->useOutputPage() ) {
 186                         $wgOut->prepareErrorPage( $this->getPageTitle() );
 187
 188                         $hookResult = $this->runHooks( get_class( $this ) );
 189                         if ( $hookResult ) {
 190                                 $wgOut->addHTML( $hookResult );
 191                         } else {
 192                                 $wgOut->addHTML( $this->getHTML() );
 193                         }
 194
 195                         $wgOut->output();
 196                 } else {
 197                         self::header( 'Content-Type: text/html; charset=utf-8' );
 198                         echo "<!DOCTYPE html>\n" .
 199                                 '<html><head>' .
 200                                 // Mimick OutputPage::setPageTitle behaviour
 201                                 '<title>' .
 202                                 htmlspecialchars( $this->msg( 'pagetitle', "$1 - $wgSitename", $this->getPageTitle() ) ) .
 203                                 '</title>' .
 204                                 '<style>body { font-family: sans-serif; margin: 0; padding: 0.5em 2em; }</style>' .
 205                                 "</head><body>\n";
 206
 207                         $hookResult = $this->runHooks( get_class( $this ) . 'Raw' );
 208                         if ( $hookResult ) {
 209                                 echo $hookResult;
 210                         } else {
 211                                 echo $this->getHTML();
 212                         }
 213
 214                         echo "</body></html>\n";
 215                 }
 216         }
 217
 218         /**
 219          * Output a report about the exception and takes care of formatting.
 220          * It will be either HTML or plain text based on isCommandLine().
 221          */
 222         public function report() {
 223                 global $wgMimeType;
 224
 225                 MWExceptionHandler::logException( $this );
 226
 227                 if ( defined( 'MW_API' ) ) {
 228                         // Unhandled API exception, we can't be sure that format printer is alive
 229                         self::header( 'MediaWiki-API-Error: internal_api_error_' . get_class( $this ) );
 230                         wfHttpError( 500, 'Internal Server Error', $this->getText() );
 231                 } elseif ( self::isCommandLine() ) {
 232                         MWExceptionHandler::printError( $this->getText() );
 233                 } else {
 234                         self::header( 'HTTP/1.1 500 MediaWiki exception' );
 235                         self::header( 'Status: 500 MediaWiki exception' );
 236                         self::header( "Content-Type: $wgMimeType; charset=utf-8" );
 237
 238                         $this->reportHTML();
 239                 }
 240         }
 241
 242         /**
 243          * Check whether we are in command line mode or not to report the exception
 244          * in the correct format.
 245          *
 246          * @return bool
 247          */
 248         public static function isCommandLine() {
 249                 return !empty( $GLOBALS['wgCommandLineMode'] );
 250         }
 251
 252         /**
 253          * Send a header, if we haven't already sent them. We shouldn't,
 254          * but sometimes we might in a weird case like Export
 255          * @param string $header
 256          */
 257         private static function header( $header ) {
 258                 if ( !headers_sent() ) {
 259                         header( $header );
 260                 }
 261         }
 262 }