Expose $wgMaxArticleSize in siteinfo query api

[mediawiki.git] / includes / db / DatabaseError.php

<?php
/**
 * This file contains database error classes.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Database
 */

/**
 * Database error base class
 * @ingroup Database
 */
class DBError extends MWException {
        /** @var DatabaseBase */
        public $db;

        /**
         * Construct a database error
         * @param DatabaseBase $db Object which threw the error
         * @param string $error A simple error message to be used for debugging
         */
        function __construct( DatabaseBase $db = null, $error ) {
                $this->db = $db;
                parent::__construct( $error );
        }
}

/**
 * Base class for the more common types of database errors. These are known to occur
 * frequently, so we try to give friendly error messages for them.
 *
 * @ingroup Database
 * @since 1.23
 */
class DBExpectedError extends DBError {
        /**
         * @return string
         */
        function getText() {
                global $wgShowDBErrorBacktrace;

                $s = $this->getTextContent() . "\n";

                if ( $wgShowDBErrorBacktrace ) {
                        $s .= "Backtrace:\n" . $this->getTraceAsString() . "\n";
                }

                return $s;
        }

        /**
         * @return string
         */
        function getHTML() {
                global $wgShowDBErrorBacktrace;

                $s = $this->getHTMLContent();

                if ( $wgShowDBErrorBacktrace ) {
                        $s .= '<p>Backtrace:</p><pre>' . htmlspecialchars( $this->getTraceAsString() ) . '</pre>';
                }

                return $s;
        }

        function getPageTitle() {
                return $this->msg( 'databaseerror', 'Database error' );
        }

        /**
         * @return string
         */
        protected function getTextContent() {
                return $this->getMessage();
        }

        /**
         * @return string
         */
        protected function getHTMLContent() {
                return '<p>' . nl2br( htmlspecialchars( $this->getTextContent() ) ) . '</p>';
        }
}

/**
 * @ingroup Database
 */
class DBConnectionError extends DBExpectedError {
        /** @var string Error text */
        public $error;

        /**
         * @param DatabaseBase $db Object throwing the error
         * @param string $error Error text
         */
        function __construct( DatabaseBase $db = null, $error = 'unknown error' ) {
                $msg = 'DB connection error';

                if ( trim( $error ) != '' ) {
                        $msg .= ": $error";
                } elseif ( $db ) {
                        $error = $this->db->getServer();
                }

                parent::__construct( $db, $msg );
                $this->error = $error;
        }

        /**
         * @return bool
         */
        function useOutputPage() {
                // Not likely to work
                return false;
        }

        /**
         * @param string $key
         * @param string $fallback Unescaped alternative error text in case the
         *   message cache cannot be used. Can contain parameters as in regular
         *   messages, that should be passed as additional parameters.
         * @return string Unprocessed plain error text with parameters replaced
         */
        function msg( $key, $fallback /*[, params...] */ ) {
                $args = array_slice( func_get_args(), 2 );

                if ( $this->useMessageCache() ) {
                        return wfMessage( $key, $args )->useDatabase( false )->text();
                } else {
                        return wfMsgReplaceArgs( $fallback, $args );
                }
        }

        /**
         * @return bool
         */
        function isLoggable() {
                // Don't send to the exception log, already in dberror log
                return false;
        }

        /**
         * @return string Safe HTML
         */
        function getHTML() {
                global $wgShowDBErrorBacktrace, $wgShowHostnames, $wgShowSQLErrors;

                $sorry = htmlspecialchars( $this->msg(
                        'dberr-problems',
                        'Sorry! This site is experiencing technical difficulties.'
                ) );
                $again = htmlspecialchars( $this->msg(
                        'dberr-again',
                        'Try waiting a few minutes and reloading.'
                ) );

                if ( $wgShowHostnames || $wgShowSQLErrors ) {
                        $info = str_replace(
                                '$1', Html::element( 'span', [ 'dir' => 'ltr' ], $this->error ),
                                htmlspecialchars( $this->msg( 'dberr-info', '(Cannot access the database: $1)' ) )
                        );
                } else {
                        $info = htmlspecialchars( $this->msg(
                                'dberr-info-hidden',
                                '(Cannot access the database)'
                        ) );
                }

                # No database access
                MessageCache::singleton()->disable();

                $html = "<h1>$sorry</h1><p>$again</p><p><small>$info</small></p>";

                if ( $wgShowDBErrorBacktrace ) {
                        $html .= '<p>Backtrace:</p><pre>' . htmlspecialchars( $this->getTraceAsString() ) . '</pre>';
                }

                $html .= '<hr />';
                $html .= $this->searchForm();

                return $html;
        }

        protected function getTextContent() {
                global $wgShowHostnames, $wgShowSQLErrors;

                if ( $wgShowHostnames || $wgShowSQLErrors ) {
                        return $this->getMessage();
                } else {
                        return 'DB connection error';
                }
        }

        /**
         * Output the exception report using HTML.
         *
         * @return void
         */
        public function reportHTML() {
                global $wgUseFileCache;

                // Check whether we can serve a file-cached copy of the page with the error underneath
                if ( $wgUseFileCache ) {
                        try {
                                $cache = $this->fileCachedPage();
                                // Cached version on file system?
                                if ( $cache !== null ) {
                                        // Hack: extend the body for error messages
                                        $cache = str_replace( [ '</html>', '</body>' ], '', $cache );
                                        // Add cache notice...
                                        $cache .= '<div style="border:1px solid #ffd0d0;padding:1em;">' .
                                                htmlspecialchars( $this->msg( 'dberr-cachederror',
                                                        'This is a cached copy of the requested page, and may not be up to date.' ) ) .
                                                '</div>';

                                        // Output cached page with notices on bottom and re-close body
                                        echo "{$cache}<hr />{$this->getHTML()}</body></html>";

                                        return;
                                }
                        } catch ( Exception $e ) {
                                // Do nothing, just use the default page
                        }
                }

                // We can't, cough and die in the usual fashion
                parent::reportHTML();
        }

        /**
         * @return string
         */
        function searchForm() {
                global $wgSitename, $wgCanonicalServer, $wgRequest;

                $usegoogle = htmlspecialchars( $this->msg(
                        'dberr-usegoogle',
                        'You can try searching via Google in the meantime.'
                ) );
                $outofdate = htmlspecialchars( $this->msg(
                        'dberr-outofdate',
                        'Note that their indexes of our content may be out of date.'
                ) );
                $googlesearch = htmlspecialchars( $this->msg( 'searchbutton', 'Search' ) );

                $search = htmlspecialchars( $wgRequest->getVal( 'search' ) );

                $server = htmlspecialchars( $wgCanonicalServer );
                $sitename = htmlspecialchars( $wgSitename );

                $trygoogle = <<<EOT
<div style="margin: 1.5em">$usegoogle<br />
<small>$outofdate</small>
</div>
<form method="get" action="//www.google.com/search" id="googlesearch">
        <input type="hidden" name="domains" value="$server" />
        <input type="hidden" name="num" value="50" />
        <input type="hidden" name="ie" value="UTF-8" />
        <input type="hidden" name="oe" value="UTF-8" />

        <input type="text" name="q" size="31" maxlength="255" value="$search" />
        <input type="submit" name="btnG" value="$googlesearch" />
        <p>
                <label><input type="radio" name="sitesearch" value="$server" checked="checked" />$sitename</label>
                <label><input type="radio" name="sitesearch" value="" />WWW</label>
        </p>
</form>
EOT;

                return $trygoogle;
        }

        /**
         * @return string
         */
        private function fileCachedPage() {
                $context = RequestContext::getMain();

                if ( $context->getOutput()->isDisabled() ) {
                        // Done already?
                        return '';
                }

                if ( $context->getTitle() ) {
                        // Use the main context's title if we managed to set it
                        $t = $context->getTitle()->getPrefixedDBkey();
                } else {
                        // Fallback to the raw title URL param. We can't use the Title
                        // class is it may hit the interwiki table and give a DB error.
                        // We may get a cache miss due to not sanitizing the title though.
                        $t = str_replace( ' ', '_', $context->getRequest()->getVal( 'title' ) );
                        if ( $t == '' ) { // fallback to main page
                                $t = Title::newFromText(
                                        $this->msg( 'mainpage', 'Main Page' ) )->getPrefixedDBkey();
                        }
                }

                $cache = new HTMLFileCache( $t, 'view' );
                if ( $cache->isCached() ) {
                        return $cache->fetchText();
                } else {
                        return '';
                }
        }
}

/**
 * @ingroup Database
 */
class DBQueryError extends DBExpectedError {
        public $error, $errno, $sql, $fname;

        /**
         * @param DatabaseBase $db
         * @param string $error
         * @param int|string $errno
         * @param string $sql
         * @param string $fname
         */
        function __construct( DatabaseBase $db, $error, $errno, $sql, $fname ) {
                if ( $db->wasConnectionError( $errno ) ) {
                        $message = "A connection error occured. \n" .
                                "Query: $sql\n" .
                                "Function: $fname\n" .
                                "Error: $errno $error\n";
                } else {
                        $message = "A database error has occurred. Did you forget to run " .
                                "maintenance/update.php after upgrading?  See: " .
                                "https://www.mediawiki.org/wiki/Manual:Upgrading#Run_the_update_script\n" .
                                "Query: $sql\n" .
                                "Function: $fname\n" .
                                "Error: $errno $error\n";
                }
                parent::__construct( $db, $message );

                $this->error = $error;
                $this->errno = $errno;
                $this->sql = $sql;
                $this->fname = $fname;
        }

        /**
         * @return string
         */
        function getPageTitle() {
                return $this->msg( 'databaseerror', 'Database error' );
        }

        /**
         * @return string
         */
        protected function getHTMLContent() {
                $key = 'databaseerror-text';
                $s = Html::element( 'p', [], $this->msg( $key, $this->getFallbackMessage( $key ) ) );

                $details = $this->getTechnicalDetails();
                if ( $details ) {
                        $s .= '<ul>';
                        foreach ( $details as $key => $detail ) {
                                $s .= str_replace(
                                        '$1', call_user_func_array( 'Html::element', $detail ),
                                        Html::element( 'li', [],
                                                $this->msg( $key, $this->getFallbackMessage( $key ) )
                                        )
                                );
                        }
                        $s .= '</ul>';
                }

                return $s;
        }

        /**
         * @return string
         */
        protected function getTextContent() {
                $key = 'databaseerror-textcl';
                $s = $this->msg( $key, $this->getFallbackMessage( $key ) ) . "\n";

                foreach ( $this->getTechnicalDetails() as $key => $detail ) {
                        $s .= $this->msg( $key, $this->getFallbackMessage( $key ), $detail[2] ) . "\n";
                }

                return $s;
        }

        /**
         * Make a list of technical details that can be shown to the user. This information can
         * aid in debugging yet may be useful to an attacker trying to exploit a security weakness
         * in the software or server configuration.
         *
         * Thus no such details are shown by default, though if $wgShowHostnames is true, only the
         * full SQL query is hidden; in fact, the error message often does contain a hostname, and
         * sites using this option probably don't care much about "security by obscurity". Of course,
         * if $wgShowSQLErrors is true, the SQL query *is* shown.
         *
         * @return array Keys are message keys; values are arrays of arguments for Html::element().
         *   Array will be empty if users are not allowed to see any of these details at all.
         */
        protected function getTechnicalDetails() {
                global $wgShowHostnames, $wgShowSQLErrors;

                $attribs = [ 'dir' => 'ltr' ];
                $details = [];

                if ( $wgShowSQLErrors ) {
                        $details['databaseerror-query'] = [
                                'div', [ 'class' => 'mw-code' ] + $attribs, $this->sql ];
                }

                if ( $wgShowHostnames || $wgShowSQLErrors ) {
                        $errorMessage = $this->errno . ' ' . $this->error;
                        $details['databaseerror-function'] = [ 'code', $attribs, $this->fname ];
                        $details['databaseerror-error'] = [ 'samp', $attribs, $errorMessage ];
                }

                return $details;
        }

        /**
         * @param string $key Message key
         * @return string English message text
         */
        private function getFallbackMessage( $key ) {
                $messages = [
                        'databaseerror-text' => 'A database query error has occurred.
This may indicate a bug in the software.',
                        'databaseerror-textcl' => 'A database query error has occurred.',
                        'databaseerror-query' => 'Query: $1',
                        'databaseerror-function' => 'Function: $1',
                        'databaseerror-error' => 'Error: $1',
                ];

                return $messages[$key];
        }
}

/**
 * @ingroup Database
 */
class DBUnexpectedError extends DBError {
}

/**
 * @ingroup Database
 */
class DBReadOnlyError extends DBExpectedError {
        function getPageTitle() {
                return $this->msg( 'readonly', 'Database is locked' );
        }
}

/**
 * @ingroup Database
 */
class DBTransactionError extends DBExpectedError {
}