Tweak two messages: add warnings "for experts only".

[mediawiki.git] / includes / api / ApiMain.php

<?php

/*
 * Created on Sep 4, 2006
 *
 * API for MediaWiki 1.8+
 *
 * Copyright (C) 2006 Yuri Astrakhan <Firstname><Lastname>@gmail.com
 *
 * 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.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 * http://www.gnu.org/copyleft/gpl.html
 */

if (!defined('MEDIAWIKI')) {
        // Eclipse helper - will be ignored in production
        require_once ('ApiBase.php');
}

/**
 * @defgroup API API
 */

/**
 * This is the main API class, used for both external and internal processing.
 * When executed, it will create the requested formatter object,
 * instantiate and execute an object associated with the needed action,
 * and use formatter to print results.
 * In case of an exception, an error message will be printed using the same formatter.
 *
 * To use API from another application, run it using FauxRequest object, in which
 * case any internal exceptions will not be handled but passed up to the caller.
 * After successful execution, use getResult() for the resulting data.
 *
 * @ingroup API
 */
class ApiMain extends ApiBase {

        /**
         * When no format parameter is given, this format will be used
         */
        const API_DEFAULT_FORMAT = 'xmlfm';

        /**
         * List of available modules: action name => module class
         */
        private static $Modules = array (
                'login' => 'ApiLogin',
                'logout' => 'ApiLogout',
                'query' => 'ApiQuery',
                'expandtemplates' => 'ApiExpandTemplates',
                'parse' => 'ApiParse',
                'opensearch' => 'ApiOpenSearch',
                'feedwatchlist' => 'ApiFeedWatchlist',
                'help' => 'ApiHelp',
                'paraminfo' => 'ApiParamInfo',
        );

        private static $WriteModules = array (
                'rollback' => 'ApiRollback',
                'delete' => 'ApiDelete',
                'undelete' => 'ApiUndelete',
                'protect' => 'ApiProtect',
                'block' => 'ApiBlock',
                'unblock' => 'ApiUnblock',
                'move' => 'ApiMove',
                'edit' => 'ApiEditPage',
                'emailuser' => 'ApiEmailUser',
        );

        /**
         * List of available formats: format name => format class
         */
        private static $Formats = array (
                'json' => 'ApiFormatJson',
                'jsonfm' => 'ApiFormatJson',
                'php' => 'ApiFormatPhp',
                'phpfm' => 'ApiFormatPhp',
                'wddx' => 'ApiFormatWddx',
                'wddxfm' => 'ApiFormatWddx',
                'xml' => 'ApiFormatXml',
                'xmlfm' => 'ApiFormatXml',
                'yaml' => 'ApiFormatYaml',
                'yamlfm' => 'ApiFormatYaml',
                'rawfm' => 'ApiFormatJson',
                'txt' => 'ApiFormatTxt',
                'txtfm' => 'ApiFormatTxt',
                'dbg' => 'ApiFormatDbg',
                'dbgfm' => 'ApiFormatDbg'
        );

        private $mPrinter, $mModules, $mModuleNames, $mFormats, $mFormatNames;
        private $mResult, $mAction, $mShowVersions, $mEnableWrite, $mRequest, $mInternalMode, $mSquidMaxage;

        /**
        * Constructs an instance of ApiMain that utilizes the module and format specified by $request.
        *
        * @param $request object - if this is an instance of FauxRequest, errors are thrown and no printing occurs
        * @param $enableWrite bool should be set to true if the api may modify data
        */
        public function __construct($request, $enableWrite = false) {

                $this->mInternalMode = ($request instanceof FauxRequest);

                // Special handling for the main module: $parent === $this
                parent :: __construct($this, $this->mInternalMode ? 'main_int' : 'main');

                if (!$this->mInternalMode) {

                        // Impose module restrictions.
                        // If the current user cannot read,
                        // Remove all modules other than login
                        global $wgUser;

                        if( $request->getVal( 'callback' ) !== null ) {
                                // JSON callback allows cross-site reads.
                                // For safety, strip user credentials.
                                wfDebug( "API: stripping user credentials for JSON callback\n" );
                                $wgUser = new User();
                        }

                        if (!$wgUser->isAllowed('read')) {
                                self::$Modules = array(
                                        'login'  => self::$Modules['login'],
                                        'logout' => self::$Modules['logout'],
                                        'help'   => self::$Modules['help'],
                                        );
                        }
                }

                global $wgAPIModules, $wgEnableWriteAPI; // extension modules
                $this->mModules = $wgAPIModules + self :: $Modules;
                if($wgEnableWriteAPI)
                        $this->mModules += self::$WriteModules;

                $this->mModuleNames = array_keys($this->mModules); // todo: optimize
                $this->mFormats = self :: $Formats;
                $this->mFormatNames = array_keys($this->mFormats); // todo: optimize

                $this->mResult = new ApiResult($this);
                $this->mShowVersions = false;
                $this->mEnableWrite = $enableWrite;

                $this->mRequest = & $request;

                $this->mSquidMaxage = 0;
                $this->mCommit = false;
        }

        /**
         * Return true if the API was started by other PHP code using FauxRequest
         */
        public function isInternalMode() {
                return $this->mInternalMode;
        }

        /**
         * Return the request object that contains client's request
         */
        public function getRequest() {
                return $this->mRequest;
        }

        /**
         * Get the ApiResult object asscosiated with current request
         */
        public function getResult() {
                return $this->mResult;
        }

        /**
         * This method will simply cause an error if the write mode was disabled
         * or if the current user doesn't have the right to use it
         */
        public function requestWriteMode() {
                global $wgUser;
                if (!$this->mEnableWrite)
                        $this->dieUsage('Editing of this wiki through the API' .
                        ' is disabled. Make sure the $wgEnableWriteAPI=true; ' .
                        'statement is included in the wiki\'s ' .
                        'LocalSettings.php file', 'noapiwrite');
                if (!$wgUser->isAllowed('writeapi'))
                        $this->dieUsage('You\'re not allowed to edit this ' .
                        'wiki through the API', 'writeapidenied');
        }

        /**
         * Set how long the response should be cached.
         */
        public function setCacheMaxAge($maxage) {
                $this->mSquidMaxage = $maxage;
        }

        /**
         * Create an instance of an output formatter by its name
         */
        public function createPrinterByName($format) {
                return new $this->mFormats[$format] ($this, $format);
        }

        /**
         * Execute api request. Any errors will be handled if the API was called by the remote client.
         */
        public function execute() {
                $this->profileIn();
                if ($this->mInternalMode)
                        $this->executeAction();
                else
                        $this->executeActionWithErrorHandling();
        
                $this->profileOut();
        }

        /**
         * Execute an action, and in case of an error, erase whatever partial results
         * have been accumulated, and replace it with an error message and a help screen.
         */
        protected function executeActionWithErrorHandling() {

                // In case an error occurs during data output,
                // clear the output buffer and print just the error information
                ob_start();

                try {
                        $this->executeAction();
                } catch (Exception $e) {
                        //
                        // Handle any kind of exception by outputing properly formatted error message.
                        // If this fails, an unhandled exception should be thrown so that global error
                        // handler will process and log it.
                        //

                        $errCode = $this->substituteResultWithError($e);

                        // Error results should not be cached
                        $this->setCacheMaxAge(0);

                        $headerStr = 'MediaWiki-API-Error: ' . $errCode;
                        if ($e->getCode() === 0)
                                header($headerStr, true);
                        else
                                header($headerStr, true, $e->getCode());

                        // Reset and print just the error message
                        ob_clean();

                        // If the error occured during printing, do a printer->profileOut()
                        $this->mPrinter->safeProfileOut();
                        $this->printResult(true);
                }

                // Set the cache expiration at the last moment, as any errors may change the expiration.
                // if $this->mSquidMaxage == 0, the expiry time is set to the first second of unix epoch
                $expires = $this->mSquidMaxage == 0 ? 1 : time() + $this->mSquidMaxage;
                header('Expires: ' . wfTimestamp(TS_RFC2822, $expires));
                header('Cache-Control: s-maxage=' . $this->mSquidMaxage . ', must-revalidate, max-age=0');

                if($this->mPrinter->getIsHtml())
                        echo wfReportTime();

                ob_end_flush();
        }

        /**
         * Replace the result data with the information about an exception.
         * Returns the error code
         */
        protected function substituteResultWithError($e) {

                        // Printer may not be initialized if the extractRequestParams() fails for the main module
                        if (!isset ($this->mPrinter)) {
                                // The printer has not been created yet. Try to manually get formatter value.
                                $value = $this->getRequest()->getVal('format', self::API_DEFAULT_FORMAT);
                                if (!in_array($value, $this->mFormatNames))
                                        $value = self::API_DEFAULT_FORMAT;

                                $this->mPrinter = $this->createPrinterByName($value);
                                if ($this->mPrinter->getNeedsRawData())
                                        $this->getResult()->setRawMode();
                        }

                        if ($e instanceof UsageException) {
                                //
                                // User entered incorrect parameters - print usage screen
                                //
                                $errMessage = array (
                                'code' => $e->getCodeString(),
                                'info' => $e->getMessage());

                                // Only print the help message when this is for the developer, not runtime
                                if ($this->mPrinter->getIsHtml() || $this->mAction == 'help')
                                        ApiResult :: setContent($errMessage, $this->makeHelpMsg());

                        } else {
                                //
                                // Something is seriously wrong
                                //
                                $errMessage = array (
                                        'code' => 'internal_api_error_'. get_class($e),
                                        'info' => "Exception Caught: {$e->getMessage()}"
                                );
                                ApiResult :: setContent($errMessage, "\n\n{$e->getTraceAsString()}\n\n");
                        }

                        $this->getResult()->reset();
                        $this->getResult()->addValue(null, 'error', $errMessage);

                return $errMessage['code'];
        }

        /**
         * Execute the actual module, without any error handling
         */
        protected function executeAction() {

                $params = $this->extractRequestParams();

                $this->mShowVersions = $params['version'];
                $this->mAction = $params['action'];

                // Instantiate the module requested by the user
                $module = new $this->mModules[$this->mAction] ($this, $this->mAction);

                if( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
                        // Check for maxlag
                        global $wgShowHostnames;
                        $maxLag = $params['maxlag'];
                        list( $host, $lag ) = wfGetLB()->getMaxLag();
                        if ( $lag > $maxLag ) {
                                if( $wgShowHostnames ) {
                                        ApiBase :: dieUsage( "Waiting for $host: $lag seconds lagged", 'maxlag' );
                                } else {
                                        ApiBase :: dieUsage( "Waiting for a database server: $lag seconds lagged", 'maxlag' );
                                }
                                return;
                        }
                }

                if (!$this->mInternalMode) {
                        // Ignore mustBePosted() for internal calls
                        if($module->mustBePosted() && !$this->mRequest->wasPosted())
                                $this->dieUsage("The {$this->mAction} module requires a POST request", 'mustbeposted');

                        // See if custom printer is used
                        $this->mPrinter = $module->getCustomPrinter();
                        if (is_null($this->mPrinter)) {
                                // Create an appropriate printer
                                $this->mPrinter = $this->createPrinterByName($params['format']);
                        }

                        if ($this->mPrinter->getNeedsRawData())
                                $this->getResult()->setRawMode();
                }

                // Execute
                $module->profileIn();
                $module->execute();
                $module->profileOut();

                if (!$this->mInternalMode) {
                        // Print result data
                        $this->printResult(false);
                }
        }

        /**
         * Print results using the current printer
         */
        protected function printResult($isError) {
                $printer = $this->mPrinter;
                $printer->profileIn();

                /* If the help message is requested in the default (xmlfm) format,
                 * tell the printer not to escape ampersands so that our links do
                 * not break. */
                $printer->setUnescapeAmps ( ( $this->mAction == 'help' || $isError )
                                && $this->getParameter('format') == ApiMain::API_DEFAULT_FORMAT );

                $printer->initPrinter($isError);

                $printer->execute();
                $printer->closePrinter();
                $printer->profileOut();
        }

        /**
         * See ApiBase for description.
         */
        public function getAllowedParams() {
                return array (
                        'format' => array (
                                ApiBase :: PARAM_DFLT => ApiMain :: API_DEFAULT_FORMAT,
                                ApiBase :: PARAM_TYPE => $this->mFormatNames
                        ),
                        'action' => array (
                                ApiBase :: PARAM_DFLT => 'help',
                                ApiBase :: PARAM_TYPE => $this->mModuleNames
                        ),
                        'version' => false,
                        'maxlag'  => array (
                                ApiBase :: PARAM_TYPE => 'integer'
                        ),
                );
        }

        /**
         * See ApiBase for description.
         */
        public function getParamDescription() {
                return array (
                        'format' => 'The format of the output',
                        'action' => 'What action you would like to perform',
                        'version' => 'When showing help, include version for each module',
                        'maxlag' => 'Maximum lag'
                );
        }

        /**
         * See ApiBase for description.
         */
        public function getDescription() {
                return array (
                        '',
                        '',
                        '******************************************************************',
                        '**                                                              **',
                        '**  This is an auto-generated MediaWiki API documentation page  **',
                        '**                                                              **',
                        '**                  Documentation and Examples:                 **',
                        '**               http://www.mediawiki.org/wiki/API              **',
                        '**                                                              **',
                        '******************************************************************',
                        '',
                        'Status:          All features shown on this page should be working, but the API',
                        '                 is still in active development, and  may change at any time.',
                        '                 Make sure to monitor our mailing list for any updates.',
                        '',
                        'Documentation:   http://www.mediawiki.org/wiki/API',
                        'Mailing list:    http://lists.wikimedia.org/mailman/listinfo/mediawiki-api',
                        'Bugs & Requests: http://bugzilla.wikimedia.org/buglist.cgi?component=API&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&order=bugs.delta_ts',
                        '',
                        '',
                        '',
                        '',
                        '',
                );
        }

        /**
         * Returns an array of strings with credits for the API
         */
        protected function getCredits() {
                return array(
                        'API developers:',
                        '    Roan Kattouw <Firstname>.<Lastname>@home.nl (lead developer Sep 2007-present)',
                        '    Victor Vasiliev - vasilvv at gee mail dot com',
                        '    Yuri Astrakhan <Firstname><Lastname>@gmail.com (creator, lead developer Sep 2006-Sep 2007)',
                        '',
                        'Please send your comments, suggestions and questions to mediawiki-api@lists.wikimedia.org',
                        'or file a bug report at http://bugzilla.wikimedia.org/'
                );
        }

        /**
         * Override the parent to generate help messages for all available modules.
         */
        public function makeHelpMsg() {

                $this->mPrinter->setHelp();

                // Use parent to make default message for the main module
                $msg = parent :: makeHelpMsg();

                $astriks = str_repeat('*** ', 10);
                $msg .= "\n\n$astriks Modules  $astriks\n\n";
                foreach( $this->mModules as $moduleName => $unused ) {
                        $module = new $this->mModules[$moduleName] ($this, $moduleName);
                        $msg .= self::makeHelpMsgHeader($module, 'action');
                        $msg2 = $module->makeHelpMsg();
                        if ($msg2 !== false)
                                $msg .= $msg2;
                        $msg .= "\n";
                }

                $msg .= "\n$astriks Formats  $astriks\n\n";
                foreach( $this->mFormats as $formatName => $unused ) {
                        $module = $this->createPrinterByName($formatName);
                        $msg .= self::makeHelpMsgHeader($module, 'format');
                        $msg2 = $module->makeHelpMsg();
                        if ($msg2 !== false)
                                $msg .= $msg2;
                        $msg .= "\n";
                }

                $msg .= "\n*** Credits: ***\n   " . implode("\n   ", $this->getCredits()) . "\n";


                return $msg;
        }

        public static function makeHelpMsgHeader($module, $paramName) {
                $modulePrefix = $module->getModulePrefix();
                if (!empty($modulePrefix))
                        $modulePrefix = "($modulePrefix) ";

                return "* $paramName={$module->getModuleName()} $modulePrefix*";
        }

        private $mIsBot = null;
        private $mIsSysop = null;
        private $mCanApiHighLimits = null;

        /**
         * Returns true if the currently logged in user is a bot, false otherwise
         * OBSOLETE, use canApiHighLimits() instead
         */
        public function isBot() {
                if (!isset ($this->mIsBot)) {
                        global $wgUser;
                        $this->mIsBot = $wgUser->isAllowed('bot');
                }
                return $this->mIsBot;
        }

        /**
         * Similar to isBot(), this method returns true if the logged in user is
         * a sysop, and false if not.
         * OBSOLETE, use canApiHighLimits() instead
         */
        public function isSysop() {
                if (!isset ($this->mIsSysop)) {
                        global $wgUser;
                        $this->mIsSysop = in_array( 'sysop', $wgUser->getGroups());
                }

                return $this->mIsSysop;
        }

        /**
         * Check whether the current user is allowed to use high limits
         * @return bool
         */
        public function canApiHighLimits() {
                if (!isset($this->mCanApiHighLimits)) {
                        global $wgUser;
                        $this->mCanApiHighLimits = $wgUser->isAllowed('apihighlimits');
                }

                return $this->mCanApiHighLimits;
        }

        /**
         * Check whether the user wants us to show version information in the API help
         * @return bool
         */
        public function getShowVersions() {
                return $this->mShowVersions;
        }

        /**
         * Returns the version information of this file, plus it includes
         * the versions for all files that are not callable proper API modules
         */
        public function getVersion() {
                $vers = array ();
                $vers[] = 'MediaWiki ' . SpecialVersion::getVersion();
                $vers[] = __CLASS__ . ': $Id$';
                $vers[] = ApiBase :: getBaseVersion();
                $vers[] = ApiFormatBase :: getBaseVersion();
                $vers[] = ApiQueryBase :: getBaseVersion();
                $vers[] = ApiFormatFeedWrapper :: getVersion(); // not accessible with format=xxx
                return $vers;
        }

        /**
         * Add or overwrite a module in this ApiMain instance. Intended for use by extending
         * classes who wish to add their own modules to their lexicon or override the
         * behavior of inherent ones.
         *
         * @access protected
         * @param $mdlName String The identifier for this module.
         * @param $mdlClass String The class where this module is implemented.
         */
        protected function addModule( $mdlName, $mdlClass ) {
                $this->mModules[$mdlName] = $mdlClass;
        }

        /**
         * Add or overwrite an output format for this ApiMain. Intended for use by extending
         * classes who wish to add to or modify current formatters.
         *
         * @access protected
         * @param $fmtName The identifier for this format.
         * @param $fmtClass The class implementing this format.
         */
        protected function addFormat( $fmtName, $fmtClass ) {
                $this->mFormats[$fmtName] = $fmtClass;
        }

        /**
         * Get the array mapping module names to class names
         */
        function getModules() {
                return $this->mModules;
        }
}

/**
 * This exception will be thrown when dieUsage is called to stop module execution.
 * The exception handling code will print a help screen explaining how this API may be used.
 *
 * @ingroup API
 */
class UsageException extends Exception {

        private $mCodestr;

        public function __construct($message, $codestr, $code = 0) {
                parent :: __construct($message, $code);
                $this->mCodestr = $codestr;
        }
        public function getCodeString() {
                return $this->mCodestr;
        }
        public function __toString() {
                return "{$this->getCodeString()}: {$this->getMessage()}";
        }
}