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                         $msg = wfMessage( $key );
 121                 } else {
 122                         $msg = new RawMessage( $fallback );
 123                 }
 124
 125                 return $msg->params( $args )->text();
 126         }
 127
 128         /**
 129          * If $wgShowExceptionDetails is true, return a HTML message with a
 130          * backtrace to the error, otherwise show a message to ask to set it to true
 131          * to show that information.
 132          *
 133          * @return string Html to output
 134          */
 135         public function getHTML() {
 136                 global $wgShowExceptionDetails;
 137
 138                 if ( $wgShowExceptionDetails ) {
 139                         return '<p>' . nl2br( htmlspecialchars( MWExceptionHandler::getLogMessage( $this ) ) ) .
 140                         '</p><p>Backtrace:</p><p>' .
 141                         nl2br( htmlspecialchars( MWExceptionHandler::getRedactedTraceAsString( $this ) ) ) .
 142                         "</p>\n";
 143                 } else {
 144                         return "<div class=\"errorbox\">" .
 145                         '[' . MWExceptionHandler::getLogId( $this ) . '] ' .
 146                         gmdate( 'Y-m-d H:i:s' ) .
 147                         ": Fatal exception of type " . get_class( $this ) . "</div>\n" .
 148                         "<!-- Set \$wgShowExceptionDetails = true; " .
 149                         "at the bottom of LocalSettings.php to show detailed " .
 150                         "debugging information. -->";
 151                 }
 152         }
 153
 154         /**
 155          * Get the text to display when reporting the error on the command line.
 156          * If $wgShowExceptionDetails is true, return a text message with a
 157          * backtrace to the error.
 158          *
 159          * @return string
 160          */
 161         public function getText() {
 162                 global $wgShowExceptionDetails;
 163
 164                 if ( $wgShowExceptionDetails ) {
 165                         return MWExceptionHandler::getLogMessage( $this ) .
 166                         "\nBacktrace:\n" . MWExceptionHandler::getRedactedTraceAsString( $this ) . "\n";
 167                 } else {
 168                         return "Set \$wgShowExceptionDetails = true; " .
 169                         "in LocalSettings.php to show detailed debugging information.\n";
 170                 }
 171         }
 172
 173         /**
 174          * Return the title of the page when reporting this error in a HTTP response.
 175          *
 176          * @return string
 177          */
 178         public function getPageTitle() {
 179                 return $this->msg( 'internalerror', 'Internal error' );
 180         }
 181
 182         /**
 183          * Output the exception report using HTML.
 184          */
 185         public function reportHTML() {
 186                 global $wgOut, $wgSitename;
 187                 if ( $this->useOutputPage() ) {
 188                         $wgOut->prepareErrorPage( $this->getPageTitle() );
 189
 190                         $hookResult = $this->runHooks( get_class( $this ) );
 191                         if ( $hookResult ) {
 192                                 $wgOut->addHTML( $hookResult );
 193                         } else {
 194                                 $wgOut->addHTML( $this->getHTML() );
 195                         }
 196
 197                         $wgOut->output();
 198                 } else {
 199                         self::header( 'Content-Type: text/html; charset=utf-8' );
 200                         echo "<!DOCTYPE html>\n" .
 201                                 '<html><head>' .
 202                                 // Mimick OutputPage::setPageTitle behaviour
 203                                 '<title>' .
 204                                 htmlspecialchars( $this->msg( 'pagetitle', "$1 - $wgSitename", $this->getPageTitle() ) ) .
 205                                 '</title>' .
 206                                 '<style>body { font-family: sans-serif; margin: 0; padding: 0.5em 2em; }</style>' .
 207                                 "</head><body>\n";
 208
 209                         $hookResult = $this->runHooks( get_class( $this ) . 'Raw' );
 210                         if ( $hookResult ) {
 211                                 echo $hookResult;
 212                         } else {
 213                                 echo $this->getHTML();
 214                         }
 215
 216                         echo "</body></html>\n";
 217                 }
 218         }
 219
 220         /**
 221          * Output a report about the exception and takes care of formatting.
 222          * It will be either HTML or plain text based on isCommandLine().
 223          */
 224         public function report() {
 225                 global $wgMimeType;
 226
 227                 MWExceptionHandler::logException( $this );
 228
 229                 if ( defined( 'MW_API' ) ) {
 230                         // Unhandled API exception, we can't be sure that format printer is alive
 231                         self::header( 'MediaWiki-API-Error: internal_api_error_' . get_class( $this ) );
 232                         wfHttpError( 500, 'Internal Server Error', $this->getText() );
 233                 } elseif ( self::isCommandLine() ) {
 234                         MWExceptionHandler::printError( $this->getText() );
 235                 } else {
 236                         self::header( 'HTTP/1.1 500 MediaWiki exception' );
 237                         self::header( 'Status: 500 MediaWiki exception' );
 238                         self::header( "Content-Type: $wgMimeType; charset=utf-8" );
 239
 240                         $this->reportHTML();
 241                 }
 242         }
 243
 244         /**
 245          * Check whether we are in command line mode or not to report the exception
 246          * in the correct format.
 247          *
 248          * @return bool
 249          */
 250         public static function isCommandLine() {
 251                 return !empty( $GLOBALS['wgCommandLineMode'] );
 252         }
 253
 254         /**
 255          * Send a header, if we haven't already sent them. We shouldn't,
 256          * but sometimes we might in a weird case like Export
 257          * @param string $header
 258          */
 259         private static function header( $header ) {
 260                 if ( !headers_sent() ) {
 261                         header( $header );
 262                 }
 263         }
 264 }