* changed display function for length to Linker::formatRevisionSize

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

<?php
/**
 *
 *
 * Created on Sep 4, 2006
 *
 * Copyright © 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @defgroup API API
 */

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

/**
 * 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',
                'rsd' => 'ApiRsd',
                'compare' => 'ApiComparePages',

                // Write modules
                'purge' => 'ApiPurge',
                'rollback' => 'ApiRollback',
                'delete' => 'ApiDelete',
                'undelete' => 'ApiUndelete',
                'protect' => 'ApiProtect',
                'block' => 'ApiBlock',
                'unblock' => 'ApiUnblock',
                'move' => 'ApiMove',
                'edit' => 'ApiEditPage',
                'upload' => 'ApiUpload',
                'filerevert' => 'ApiFileRevert',
                'emailuser' => 'ApiEmailUser',
                'watch' => 'ApiWatch',
                'patrol' => 'ApiPatrol',
                'import' => 'ApiImport',
                'userrights' => 'ApiUserrights',
        );

        /**
         * 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',
                'dump' => 'ApiFormatDump',
                'dumpfm' => 'ApiFormatDump',
        );

        /**
         * List of user roles that are specifically relevant to the API.
         * array( 'right' => array ( 'msg'    => 'Some message with a $1',
         *                           'params' => array ( $someVarToSubst ) ),
         *                          );
         */
        private static $mRights = array(
                'writeapi' => array(
                        'msg' => 'Use of the write API',
                        'params' => array()
                ),
                'apihighlimits' => array(
                        'msg' => 'Use higher limits in API queries (Slow queries: $1 results; Fast queries: $2 results). The limits for slow queries also apply to multivalue parameters.',
                        'params' => array( ApiBase::LIMIT_SML2, ApiBase::LIMIT_BIG2 )
                )
        );

        /**
         * @var ApiFormatBase
         */
        private $mPrinter;

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

        private $mCacheMode = 'private';
        private $mCacheControl = array();

        /**
         * Constructs an instance of ApiMain that utilizes the module and format specified by $request.
         *
         * @param $request WebRequest - 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();
                        }
                }

                global $wgAPIModules; // extension modules
                $this->mModules = $wgAPIModules + self::$Modules;

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

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

                $this->mRequest = &$request;

                $this->mSquidMaxage = - 1; // flag for executeActionWithErrorHandling()
                $this->mCommit = false;
        }

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

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

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

        /**
         * Get the API module object. Only works after executeAction()
         *
         * @return ApiBase
         */
        public function getModule() {
                return $this->mModule;
        }

        /**
         * Get the result formatter object. Only works after setupExecuteAction()
         *
         * @return ApiFormatBase
         */
        public function getPrinter() {
                return $this->mPrinter;
        }

        /**
         * Set how long the response should be cached.
         *
         * @param $maxage
         */
        public function setCacheMaxAge( $maxage ) {
                $this->setCacheControl( array(
                        'max-age' => $maxage,
                        's-maxage' => $maxage
                ) );
        }

        /**
         * Set the type of caching headers which will be sent.
         *
         * @param $mode String One of:
         *    - 'public':     Cache this object in public caches, if the maxage or smaxage
         *         parameter is set, or if setCacheMaxAge() was called. If a maximum age is
         *         not provided by any of these means, the object will be private.
         *    - 'private':    Cache this object only in private client-side caches.
         *    - 'anon-public-user-private': Make this object cacheable for logged-out
         *         users, but private for logged-in users. IMPORTANT: If this is set, it must be
         *         set consistently for a given URL, it cannot be set differently depending on
         *         things like the contents of the database, or whether the user is logged in.
         *
         *  If the wiki does not allow anonymous users to read it, the mode set here
         *  will be ignored, and private caching headers will always be sent. In other words,
         *  the "public" mode is equivalent to saying that the data sent is as public as a page
         *  view.
         *
         *  For user-dependent data, the private mode should generally be used. The
         *  anon-public-user-private mode should only be used where there is a particularly
         *  good performance reason for caching the anonymous response, but where the
         *  response to logged-in users may differ, or may contain private data.
         *
         *  If this function is never called, then the default will be the private mode.
         */
        public function setCacheMode( $mode ) {
                if ( !in_array( $mode, array( 'private', 'public', 'anon-public-user-private' ) ) ) {
                        wfDebug( __METHOD__ . ": unrecognised cache mode \"$mode\"\n" );
                        // Ignore for forwards-compatibility
                        return;
                }

                if ( !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) ) {
                        // Private wiki, only private headers
                        if ( $mode !== 'private' ) {
                                wfDebug( __METHOD__ . ": ignoring request for $mode cache mode, private wiki\n" );
                                return;
                        }
                }

                wfDebug( __METHOD__ . ": setting cache mode $mode\n" );
                $this->mCacheMode = $mode;
        }

        /**
         * @deprecated since 1.17 Private caching is now the default, so there is usually no
         * need to call this function. If there is a need, you can use
         * $this->setCacheMode('private')
         */
        public function setCachePrivate() {
                $this->setCacheMode( 'private' );
        }

        /**
         * Set directives (key/value pairs) for the Cache-Control header.
         * Boolean values will be formatted as such, by including or omitting
         * without an equals sign.
         *
         * Cache control values set here will only be used if the cache mode is not
         * private, see setCacheMode().
         */
        public function setCacheControl( $directives ) {
                $this->mCacheControl = $directives + $this->mCacheControl;
        }

        /**
         * Make sure Vary: Cookie and friends are set. Use this when the output of a request
         * may be cached for anons but may not be cached for logged-in users.
         *
         * WARNING: This function must be called CONSISTENTLY for a given URL. This means that a
         * given URL must either always or never call this function; if it sometimes does and
         * sometimes doesn't, stuff will break.
         *
         * @deprecated since 1.17 Use setCacheMode( 'anon-public-user-private' )
         */
        public function setVaryCookie() {
                $this->setCacheMode( 'anon-public-user-private' );
        }

        /**
         * Create an instance of an output formatter by its name
         *
         * @param $format string
         *
         * @return ApiFormatBase
         */
        public function createPrinterByName( $format ) {
                if ( !isset( $this->mFormats[$format] ) ) {
                        $this->dieUsage( "Unrecognized format: {$format}", 'unknown_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 ) {
                        // Log it
                        if ( $e instanceof MWException ) {
                                wfDebugLog( 'exception', $e->getLogMessage() );
                        }

                        //
                        // 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->setCacheMode( 'private' );

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

                // Send cache headers after any code which might generate an error, to
                // avoid sending public cache headers for errors.
                $this->sendCacheHeaders();

                if ( $this->mPrinter->getIsHtml() && !$this->mPrinter->isDisabled() ) {
                        echo wfReportTime();
                }

                ob_end_flush();
        }

        protected function sendCacheHeaders() {
                if ( $this->mCacheMode == 'private' ) {
                        header( 'Cache-Control: private' );
                        return;
                }

                if ( $this->mCacheMode == 'anon-public-user-private' ) {
                        global $wgUseXVO, $wgOut;
                        header( 'Vary: Accept-Encoding, Cookie' );
                        if ( $wgUseXVO ) {
                                header( $wgOut->getXVO() );
                                if ( $wgOut->haveCacheVaryCookies() ) {
                                        // Logged in, mark this request private
                                        header( 'Cache-Control: private' );
                                        return;
                                }
                                // Logged out, send normal public headers below
                        } elseif ( session_id() != '' ) {
                                // Logged in or otherwise has session (e.g. anonymous users who have edited)
                                // Mark request private
                                header( 'Cache-Control: private' );
                                return;
                        } // else no XVO and anonymous, send public headers below
                }

                // If nobody called setCacheMaxAge(), use the (s)maxage parameters
                if ( !isset( $this->mCacheControl['s-maxage'] ) ) {
                        $this->mCacheControl['s-maxage'] = $this->getParameter( 'smaxage' );
                }
                if ( !isset( $this->mCacheControl['max-age'] ) ) {
                        $this->mCacheControl['max-age'] = $this->getParameter( 'maxage' );
                }

                if ( !$this->mCacheControl['s-maxage'] && !$this->mCacheControl['max-age'] ) {
                        // Public cache not requested
                        // Sending a Vary header in this case is harmless, and protects us
                        // against conditional calls of setCacheMaxAge().
                        header( 'Cache-Control: private' );
                        return;
                }

                $this->mCacheControl['public'] = true;

                // Send an Expires header
                $maxAge = min( $this->mCacheControl['s-maxage'], $this->mCacheControl['max-age'] );
                $expiryUnixTime = ( $maxAge == 0 ? 1 : time() + $maxAge );
                header( 'Expires: ' . wfTimestamp( TS_RFC2822, $expiryUnixTime ) );

                // Construct the Cache-Control header
                $ccHeader = '';
                $separator = '';
                foreach ( $this->mCacheControl as $name => $value ) {
                        if ( is_bool( $value ) ) {
                                if ( $value ) {
                                        $ccHeader .= $separator . $name;
                                        $separator = ', ';
                                }
                        } else {
                                $ccHeader .= $separator . "$name=$value";
                                $separator = ', ';
                        }
                }

                header( "Cache-Control: $ccHeader" );
        }

        /**
         * Replace the result data with the information about an exception.
         * Returns the error code
         * @param $e Exception
         * @return string
         */
        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 = $e->getMessageArray();

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

                } else {
                        global $wgShowSQLErrors, $wgShowExceptionDetails;
                        // Something is seriously wrong
                        if ( ( $e instanceof DBQueryError ) && !$wgShowSQLErrors ) {
                                $info = 'Database query error';
                        } else {
                                $info = "Exception Caught: {$e->getMessage()}";
                        }

                        $errMessage = array(
                                'code' => 'internal_api_error_' . get_class( $e ),
                                'info' => $info,
                        );
                        ApiResult::setContent( $errMessage, $wgShowExceptionDetails ? "\n\n{$e->getTraceAsString()}\n\n" : '' );
                }

                $this->getResult()->reset();
                $this->getResult()->disableSizeCheck();
                // Re-add the id
                $requestid = $this->getParameter( 'requestid' );
                if ( !is_null( $requestid ) ) {
                        $this->getResult()->addValue( null, 'requestid', $requestid );
                }
                // servedby is especially useful when debugging errors
                $this->getResult()->addValue( null, 'servedby', wfHostName() );
                $this->getResult()->addValue( null, 'error', $errMessage );

                return $errMessage['code'];
        }

        /**
         * Set up for the execution.
         * @return array
         */
        protected function setupExecuteAction() {
                // First add the id to the top element
                $requestid = $this->getParameter( 'requestid' );
                if ( !is_null( $requestid ) ) {
                        $this->getResult()->addValue( null, 'requestid', $requestid );
                }
                $servedby = $this->getParameter( 'servedby' );
                if ( $servedby ) {
                        $this->getResult()->addValue( null, 'servedby', wfHostName() );
                }

                $params = $this->extractRequestParams();

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

                if ( !is_string( $this->mAction ) ) {
                        $this->dieUsage( 'The API requires a valid action parameter', 'unknown_action' );
                }

                return $params;
        }

        /**
         * Set up the module for response
         * @return ApiBase The module that will handle this action
         */
        protected function setupModule() {
                // Instantiate the module requested by the user
                $module = new $this->mModules[$this->mAction] ( $this, $this->mAction );
                $this->mModule = $module;

                $moduleParams = $module->extractRequestParams();

                // Die if token required, but not provided (unless there is a gettoken parameter)
                $salt = $module->getTokenSalt();
                if ( $salt !== false && !isset( $moduleParams['gettoken'] ) ) {
                        if ( !isset( $moduleParams['token'] ) ) {
                                $this->dieUsageMsg( array( 'missingparam', 'token' ) );
                        } else {
                                global $wgUser;
                                if ( !$wgUser->matchEditToken( $moduleParams['token'], $salt, $this->getMain()->getRequest() ) ) {
                                        $this->dieUsageMsg( array( 'sessionfailure' ) );
                                }
                        }
                }
                return $module;
        }

        /**
         * Check the max lag if necessary
         * @param $module ApiBase object: Api module being used
         * @param $params Array an array containing the request parameters.
         * @return boolean True on success, false should exit immediately
         */
        protected function checkMaxLag( $module, $params ) {
                if ( $module->shouldCheckMaxlag() && isset( $params['maxlag'] ) ) {
                        // Check for maxlag
                        global $wgShowHostnames;
                        $maxLag = $params['maxlag'];
                        list( $host, $lag ) = wfGetLB()->getMaxLag();
                        if ( $lag > $maxLag ) {
                                header( 'Retry-After: ' . max( intval( $maxLag ), 5 ) );
                                header( 'X-Database-Lag: ' . intval( $lag ) );
                                if ( $wgShowHostnames ) {
                                        $this->dieUsage( "Waiting for $host: $lag seconds lagged", 'maxlag' );
                                } else {
                                        $this->dieUsage( "Waiting for a database server: $lag seconds lagged", 'maxlag' );
                                }
                                return false;
                        }
                }
                return true;
        }


        /**
         * Check for sufficient permissions to execute
         * @param $module ApiBase An Api module
         */
        protected function checkExecutePermissions( $module ) {
                global $wgUser;
                if ( $module->isReadMode() && !in_array( 'read', User::getGroupPermissions( array( '*' ) ), true ) &&
                        !$wgUser->isAllowed( 'read' ) )
                {
                        $this->dieUsageMsg( array( 'readrequired' ) );
                }
                if ( $module->isWriteMode() ) {
                        if ( !$this->mEnableWrite ) {
                                $this->dieUsageMsg( array( 'writedisabled' ) );
                        }
                        if ( !$wgUser->isAllowed( 'writeapi' ) ) {
                                $this->dieUsageMsg( array( 'writerequired' ) );
                        }
                        if ( wfReadOnly() ) {
                                $this->dieReadOnly();
                        }
                }
        }

        /**
         * Check POST for external response and setup result printer
         * @param $module ApiBase An Api module
         * @param $params Array an array with the request parameters
         */
        protected function setupExternalResponse( $module, $params ) {
                // Ignore mustBePosted() for internal calls
                if ( $module->mustBePosted() && !$this->mRequest->wasPosted() ) {
                        $this->dieUsageMsg( array( 'mustbeposted', $this->mAction ) );
                }

                // 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 the actual module, without any error handling
         */
        protected function executeAction() {
                $params = $this->setupExecuteAction();
                $module = $this->setupModule();

                $this->checkExecutePermissions( $module );

                if ( !$this->checkMaxLag( $module, $params ) ) {
                        return;
                }

                if ( !$this->mInternalMode ) {
                        $this->setupExternalResponse( $module, $params );
                }

                // Execute
                $module->profileIn();
                $module->execute();
                wfRunHooks( 'APIAfterExecute', array( &$module ) );
                $module->profileOut();

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

        /**
         * Print results using the current printer
         *
         * @param $isError bool
         */
        protected function printResult( $isError ) {
                $this->getResult()->cleanUpUTF8();
                $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 )
                                && $printer->getFormat() == 'XML' && $printer->getIsHtml() );

                $printer->initPrinter( $isError );

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

        /**
         * @return bool
         */
        public function isReadMode() {
                return false;
        }

        /**
         * See ApiBase for description.
         *
         * @return array
         */
        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'
                        ),
                        'smaxage' => array(
                                ApiBase::PARAM_TYPE => 'integer',
                                ApiBase::PARAM_DFLT => 0
                        ),
                        'maxage' => array(
                                ApiBase::PARAM_TYPE => 'integer',
                                ApiBase::PARAM_DFLT => 0
                        ),
                        'requestid' => null,
                        'servedby'  => false,
                );
        }

        /**
         * See ApiBase for description.
         *
         * @return array
         */
        public function getParamDescription() {
                return array(
                        'format' => 'The format of the output',
                        'action' => 'What action you would like to perform. See below for module help',
                        'version' => 'When showing help, include version for each module',
                        'maxlag' => 'Maximum lag',
                        'smaxage' => 'Set the s-maxage header to this many seconds. Errors are never cached',
                        'maxage' => 'Set the max-age header to this many seconds. Errors are never cached',
                        'requestid' => 'Request ID to distinguish requests. This will just be output back to you',
                        'servedby' => 'Include the hostname that served the request in the results. Unconditionally shown on error',
                );
        }

        /**
         * See ApiBase for description.
         *
         * @return array
         */
        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',
                        'Api Announcements:     http://lists.wikimedia.org/mailman/listinfo/mediawiki-api-announce',
                        'Bugs & Requests:       http://bugzilla.wikimedia.org/buglist.cgi?component=API&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&order=bugs.delta_ts',
                        '',
                        '',
                        '',
                        '',
                        '',
                );
        }

        /**
         * @return array
         */
        public function getPossibleErrors() {
                return array_merge( parent::getPossibleErrors(), array(
                        array( 'readonlytext' ),
                        array( 'code' => 'unknown_format', 'info' => 'Unrecognized format: format' ),
                        array( 'code' => 'unknown_action', 'info' => 'The API requires a valid action parameter' ),
                        array( 'code' => 'maxlag', 'info' => 'Waiting for host: x seconds lagged' ),
                        array( 'code' => 'maxlag', 'info' => 'Waiting for a database server: x seconds lagged' ),
                ) );
        }

        /**
         * Returns an array of strings with credits for the API
         * @return array
         */
        protected function getCredits() {
                return array(
                        'API developers:',
                        '    Roan Kattouw <Firstname>.<Lastname>@gmail.com (lead developer Sep 2007-present)',
                        '    Victor Vasiliev - vasilvv at gee mail dot com',
                        '    Bryan Tong Minh - bryan . tongminh @ gmail . com',
                        '    Sam Reed - sam @ reedyboy . net',
                        '    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/'
                );
        }

        /**
         * Sets whether the pretty-printer should format *bold* and $italics$
         *
         * @param $help bool
         */
        public function setHelp( $help = true ) {
                $this->mPrinter->setHelp( $help );
        }

        /**
         * Override the parent to generate help messages for all available modules.
         *
         * @return string
         */
        public function makeHelpMsg() {
                global $wgMemc, $wgAPICacheHelpTimeout;
                $this->setHelp();
                // Get help text from cache if present
                $key = wfMemcKey( 'apihelp', $this->getModuleName(),
                        SpecialVersion::getVersion( 'nodb' ) .
                        $this->getMain()->getShowVersions() );
                if ( $wgAPICacheHelpTimeout > 0 ) {
                        $cached = $wgMemc->get( $key );
                        if ( $cached ) {
                                return $cached;
                        }
                }
                $retval = $this->reallyMakeHelpMsg();
                if ( $wgAPICacheHelpTimeout > 0 ) {
                        $wgMemc->set( $key, $retval, $wgAPICacheHelpTimeout );
                }
                return $retval;
        }

        /**
         * @return mixed|string
         */
        public function reallyMakeHelpMsg() {
                $this->setHelp();

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

                $astriks = str_repeat( '*** ', 14 );
                $msg .= "\n\n$astriks Modules  $astriks\n\n";
                foreach ( array_keys( $this->mModules ) as $moduleName ) {
                        $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 Permissions $astriks\n\n";
                foreach ( self::$mRights as $right => $rightMsg ) {
                        $groups = User::getGroupsWithPermission( $right );
                        $msg .= "* " . $right . " *\n  " . wfMsgReplaceArgs( $rightMsg[ 'msg' ], $rightMsg[ 'params' ] ) .
                                                "\nGranted to:\n  " . str_replace( '*', 'all', implode( ', ', $groups ) ) . "\n\n";

                }

                $msg .= "\n$astriks Formats  $astriks\n\n";
                foreach ( array_keys( $this->mFormats ) as $formatName ) {
                        $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;
        }

        /**
         * @param $module ApiBase
         * @param $paramName String What type of request is this? e.g. action, query, list, prop, meta, format
         * @return string
         */
        public static function makeHelpMsgHeader( $module, $paramName ) {
                $modulePrefix = $module->getModulePrefix();
                if ( strval( $modulePrefix ) !== '' ) {
                        $modulePrefix = "($modulePrefix) ";
                }

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

        private $mCanApiHighLimits = null;

        /**
         * 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
         *
         * @return array
         */
        public function getVersion() {
                $vers = array();
                $vers[] = 'MediaWiki: ' . SpecialVersion::getVersion() . "\n    http://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/";
                $vers[] = __CLASS__ . ': $Id$';
                $vers[] = ApiBase::getBaseVersion();
                $vers[] = ApiFormatBase::getBaseVersion();
                $vers[] = ApiQueryBase::getBaseVersion();
                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.
         *
         * @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.
         *
         * @param $fmtName string The identifier for this format.
         * @param $fmtClass ApiFormatBase The class implementing this format.
         */
        protected function addFormat( $fmtName, $fmtClass ) {
                $this->mFormats[$fmtName] = $fmtClass;
        }

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

        /**
         * Returns the list of supported formats in form ( 'format' => 'ClassName' )
         *
         * @since 1.18
         * @return array
         */
        public function getFormats() {
                return $this->mFormats;
        }
}

/**
 * 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;
        private $mExtraData;

        public function __construct( $message, $codestr, $code = 0, $extradata = null ) {
                parent::__construct( $message, $code );
                $this->mCodestr = $codestr;
                $this->mExtraData = $extradata;
        }

        public function getCodeString() {
                return $this->mCodestr;
        }

        public function getMessageArray() {
                $result = array(
                        'code' => $this->mCodestr,
                        'info' => $this->getMessage()
                );
                if ( is_array( $this->mExtraData ) ) {
                        $result = array_merge( $result, $this->mExtraData );
                }
                return $result;
        }

        public function __toString() {
                return "{$this->getCodeString()}: {$this->getMessage()}";
        }
}