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

<?php

/*
 * Created on Sep 5, 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
 */

/**
 * This abstract class implements many basic API functions, and is the base of all API classes.
 * The class functions are divided into several areas of functionality:
 * 
 * Module parameters: Derived classes can define getAllowedParams() to specify which parameters to expect,
 *      how to parse and validate them.
 * 
 * Profiling: various methods to allow keeping tabs on various tasks and their time costs
 * 
 * Self-documentation: code to allow api to document its own state.
 * 
 * @addtogroup API
 */
abstract class ApiBase {

        // These constants allow modules to specify exactly how to treat incomming parameters.

        const PARAM_DFLT = 0;
        const PARAM_ISMULTI = 1;
        const PARAM_TYPE = 2;
        const PARAM_MAX = 3;
        const PARAM_MAX2 = 4;
        const PARAM_MIN = 5;

        const LIMIT_BIG1 = 500; // Fast query, std user limit
        const LIMIT_BIG2 = 5000; // Fast query, bot/sysop limit
        const LIMIT_SML1 = 50; // Slow query, std user limit
        const LIMIT_SML2 = 500; // Slow query, bot/sysop limit

        private $mMainModule, $mModuleName, $mParamPrefix;

        /**
        * Constructor
        */
        public function __construct($mainModule, $moduleName, $paramPrefix = '') {
                $this->mMainModule = $mainModule;
                $this->mModuleName = $moduleName;
                $this->mParamPrefix = $paramPrefix;
        }

        /**
         * Executes this module
         */
        public abstract function execute();

        /**
         * Get the name of the module being executed by this instance 
         */
        public function getModuleName() {
                return $this->mModuleName;
        }

        /**
         * Get parameter prefix (usually two letters or an empty string). 
         */
        public function getParamPrefix() {
                return $this->mParamPrefix;
        }       

        /**
         * Get the name of the module as shown in the profiler log 
         */
        public function getModuleProfileName($db = false) {
                if ($db)
                        return 'API:' . $this->mModuleName . '-DB';
                else
                        return 'API:' . $this->mModuleName;
        }

        /**
         * Get main module
         */
        public function getMain() {
                return $this->mMainModule;
        }

        /**
         * If this module's $this is the same as $this->mMainModule, its the root, otherwise no
         */
        public function isMain() {
                return $this === $this->mMainModule;
        }

        /**
         * Get result object
         */
        public function getResult() {
                // Main module has getResult() method overriden
                // Safety - avoid infinite loop:
                if ($this->isMain())
                        ApiBase :: dieDebug(__METHOD__, 'base method was called on main module. ');
                return $this->getMain()->getResult();
        }

        /**
         * Get the result data array
         */
        public function & getResultData() {
                return $this->getResult()->getData();
        }

        /**
         * If the module may only be used with a certain format module,
         * it should override this method to return an instance of that formatter.
         * A value of null means the default format will be used.  
         */
        public function getCustomPrinter() {
                return null;
        }

        /**
         * Generates help message for this module, or false if there is no description
         */
        public function makeHelpMsg() {

                static $lnPrfx = "\n  ";

                $msg = $this->getDescription();

                if ($msg !== false) {

                        if (!is_array($msg))
                                $msg = array (
                                        $msg
                                );
                        $msg = $lnPrfx . implode($lnPrfx, $msg) . "\n";

                        // Parameters
                        $paramsMsg = $this->makeHelpMsgParameters();
                        if ($paramsMsg !== false) {
                                $msg .= "Parameters:\n$paramsMsg";
                        }

                        // Examples
                        $examples = $this->getExamples();
                        if ($examples !== false) {
                                if (!is_array($examples))
                                        $examples = array (
                                                $examples
                                        );
                                $msg .= 'Example' . (count($examples) > 1 ? 's' : '') . ":\n  ";
                                $msg .= implode($lnPrfx, $examples) . "\n";
                        }

                        if ($this->getMain()->getShowVersions()) {
                                $versions = $this->getVersion();
                                $pattern = '(\$.*) ([0-9a-z_]+\.php) (.*\$)';
                                $replacement = '\\0' . "\n    " . 'http://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/includes/api/\\2';
                                
                                if (is_array($versions)) {
                                        foreach ($versions as &$v)
                                                $v = eregi_replace($pattern, $replacement, $v);
                                        $versions = implode("\n  ", $versions);
                                }
                                else
                                        $versions = eregi_replace($pattern, $replacement, $versions);

                                $msg .= "Version:\n  $versions\n";
                        }
                }

                return $msg;
        }

        public function makeHelpMsgParameters() {
                $params = $this->getAllowedParams();
                if ($params !== false) {

                        $paramsDescription = $this->getParamDescription();
                        $msg = '';
                        $paramPrefix = "\n" . str_repeat(' ', 19);
                        foreach ($params as $paramName => $paramSettings) {
                                $desc = isset ($paramsDescription[$paramName]) ? $paramsDescription[$paramName] : '';
                                if (is_array($desc))
                                        $desc = implode($paramPrefix, $desc);

                                @ $type = $paramSettings[self :: PARAM_TYPE];
                                if (isset ($type)) {
                                        if (isset ($paramSettings[self :: PARAM_ISMULTI]))
                                                $prompt = 'Values (separate with \'|\'): ';
                                        else
                                                $prompt = 'One value: ';

                                        if (is_array($type)) {
                                                $choices = array();
                                                $nothingPrompt = false;
                                                foreach ($type as $t)
                                                        if ($t=='')
                                                                $nothingPrompt = 'Can be empty, or ';
                                                        else
                                                                $choices[] =  $t;
                                                $desc .= $paramPrefix . $nothingPrompt . $prompt . implode(', ', $choices);
                                        } else {
                                                switch ($type) {
                                                        case 'namespace':
                                                                // Special handling because namespaces are type-limited, yet they are not given
                                                                $desc .= $paramPrefix . $prompt . implode(', ', ApiBase :: getValidNamespaces());
                                                                break;
                                                        case 'limit':
                                                                $desc .= $paramPrefix . "No more than {$paramSettings[self :: PARAM_MAX]} ({$paramSettings[self :: PARAM_MAX2]} for bots) allowed.";
                                                                break;
                                                        case 'integer':
                                                                $hasMin = isset($paramSettings[self :: PARAM_MIN]);
                                                                $hasMax = isset($paramSettings[self :: PARAM_MAX]);
                                                                if ($hasMin || $hasMax) {
                                                                        if (!$hasMax)
                                                                                $intRangeStr = "The value must be no less than {$paramSettings[self :: PARAM_MIN]}";
                                                                        elseif (!$hasMin)
                                                                                $intRangeStr = "The value must be no more than {$paramSettings[self :: PARAM_MAX]}";
                                                                        else
                                                                                $intRangeStr = "The value must be between {$paramSettings[self :: PARAM_MIN]} and {$paramSettings[self :: PARAM_MAX]}";
                                                                                
                                                                        $desc .= $paramPrefix . $intRangeStr;
                                                                }
                                                                break;
                                                }
                                        }
                                }

                                $default = is_array($paramSettings) ? (isset ($paramSettings[self :: PARAM_DFLT]) ? $paramSettings[self :: PARAM_DFLT] : null) : $paramSettings;
                                if (!is_null($default) && $default !== false)
                                        $desc .= $paramPrefix . "Default: $default";

                                $msg .= sprintf("  %-14s - %s\n", $this->encodeParamName($paramName), $desc);
                        }
                        return $msg;

                } else
                        return false;
        }

        /**
         * Returns the description string for this module
         */
        protected function getDescription() {
                return false;
        }

        /**
         * Returns usage examples for this module. Return null if no examples are available.
         */
        protected function getExamples() {
                return false;
        }

        /**
         * Returns an array of allowed parameters (keys) => default value for that parameter
         */
        protected function getAllowedParams() {
                return false;
        }

        /**
         * Returns the description string for the given parameter.
         */
        protected function getParamDescription() {
                return false;
        }

        /**
         * This method mangles parameter name based on the prefix supplied to the constructor.
         * Override this method to change parameter name during runtime 
         */
        public function encodeParamName($paramName) {
                return $this->mParamPrefix . $paramName;
        }

        /**
        * Using getAllowedParams(), makes an array of the values provided by the user,
        * with key being the name of the variable, and value - validated value from user or default.
        * This method can be used to generate local variables using extract().
        */
        public function extractRequestParams() {
                $params = $this->getAllowedParams();
                $results = array ();

                foreach ($params as $paramName => $paramSettings)
                        $results[$paramName] = $this->getParameterFromSettings($paramName, $paramSettings);

                return $results;
        }

        /**
         * Get a value for the given parameter 
         */
        protected function getParameter($paramName) {
                $params = $this->getAllowedParams();
                $paramSettings = $params[$paramName];
                return $this->getParameterFromSettings($paramName, $paramSettings);
        }

        public static function getValidNamespaces() {
                static $mValidNamespaces = null;
                if (is_null($mValidNamespaces)) {

                        global $wgContLang;
                        $mValidNamespaces = array ();
                        foreach (array_keys($wgContLang->getNamespaces()) as $ns) {
                                if ($ns >= 0)
                                        $mValidNamespaces[] = $ns;
                        }
                }
                return $mValidNamespaces;
        }

        /**
         * Using the settings determine the value for the given parameter
         * @param $paramName String: parameter name
         * @param $paramSettings Mixed: default value or an array of settings using PARAM_* constants.
         */
        protected function getParameterFromSettings($paramName, $paramSettings) {

                // Some classes may decide to change parameter names
                $paramName = $this->encodeParamName($paramName);

                if (!is_array($paramSettings)) {
                        $default = $paramSettings;
                        $multi = false;
                        $type = gettype($paramSettings);
                } else {
                        $default = isset ($paramSettings[self :: PARAM_DFLT]) ? $paramSettings[self :: PARAM_DFLT] : null;
                        $multi = isset ($paramSettings[self :: PARAM_ISMULTI]) ? $paramSettings[self :: PARAM_ISMULTI] : false;
                        $type = isset ($paramSettings[self :: PARAM_TYPE]) ? $paramSettings[self :: PARAM_TYPE] : null;

                        // When type is not given, and no choices, the type is the same as $default
                        if (!isset ($type)) {
                                if (isset ($default))
                                        $type = gettype($default);
                                else
                                        $type = 'NULL'; // allow everything
                        }
                }

                if ($type == 'boolean') {
                        if (isset ($default) && $default !== false) {
                                // Having a default value of anything other than 'false' is pointless
                                ApiBase :: dieDebug(__METHOD__, "Boolean param $paramName's default is set to '$default'");
                        }

                        $value = $this->getMain()->getRequest()->getCheck($paramName);
                } else {
                        $value = $this->getMain()->getRequest()->getVal($paramName, $default);

                        if (isset ($value) && $type == 'namespace')
                                $type = ApiBase :: getValidNamespaces();
                }

                if (isset ($value) && ($multi || is_array($type)))
                        $value = $this->parseMultiValue($paramName, $value, $multi, is_array($type) ? $type : null);

                // More validation only when choices were not given
                // choices were validated in parseMultiValue()
                if (isset ($value)) {
                        if (!is_array($type)) {
                                switch ($type) {
                                        case 'NULL' : // nothing to do
                                                break;
                                        case 'string' : // nothing to do
                                                break;
                                        case 'integer' : // Force everything using intval() and optionally validate limits

                                                $value = is_array($value) ? array_map('intval', $value) : intval($value);
                                                $checkMin = isset ($paramSettings[self :: PARAM_MIN]);
                                                $checkMax = isset ($paramSettings[self :: PARAM_MAX]);
                                                
                                                if ($checkMin || $checkMax) {
                                                        $min = $checkMin ? $paramSettings[self :: PARAM_MIN] : false;
                                                        $max = $checkMax ? $paramSettings[self :: PARAM_MAX] : false;
                                                
                                                        $values = is_array($value) ? $value : array($value);
                                                        foreach ($values as $v) {
                                                                if ($checkMin && $v < $min)
                                                                        $this->dieUsage("$paramName may not be less than $min (set to $v)", $paramName);
                                                                if ($checkMax && $v > $max)
                                                                        $this->dieUsage("$paramName may not be over $max (set to $v)", $paramName);
                                                        }
                                                }
                                                break;
                                        case 'limit' :
                                                if (!isset ($paramSettings[self :: PARAM_MAX]) || !isset ($paramSettings[self :: PARAM_MAX2]))
                                                        ApiBase :: dieDebug(__METHOD__, "MAX1 or MAX2 are not defined for the limit $paramName");
                                                if ($multi)
                                                        ApiBase :: dieDebug(__METHOD__, "Multi-values not supported for $paramName");
                                                $min = isset ($paramSettings[self :: PARAM_MIN]) ? $paramSettings[self :: PARAM_MIN] : 0;
                                                $value = intval($value);
                                                $this->validateLimit($paramName, $value, $min, $paramSettings[self :: PARAM_MAX], $paramSettings[self :: PARAM_MAX2]);
                                                break;
                                        case 'boolean' :
                                                if ($multi)
                                                        ApiBase :: dieDebug(__METHOD__, "Multi-values not supported for $paramName");
                                                break;
                                        case 'timestamp' :
                                                if ($multi)
                                                        ApiBase :: dieDebug(__METHOD__, "Multi-values not supported for $paramName");
                                                $value = wfTimestamp(TS_UNIX, $value);
                                                if ($value === 0)
                                                        $this->dieUsage("Invalid value '$value' for timestamp parameter $paramName", "badtimestamp_{$paramName}");
                                                $value = wfTimestamp(TS_MW, $value);
                                                break;
                                        case 'user' :
                                                $title = Title::makeTitleSafe( NS_USER, $value );
                                                if ( is_null( $title ) )
                                                        $this->dieUsage("Invalid value $user for user parameter $paramName", "baduser_{$paramName}");
                                                $value = $title->getText();
                                                break;
                                        default :
                                                ApiBase :: dieDebug(__METHOD__, "Param $paramName's type is unknown - $type");
                                }
                        }

                        // There should never be any duplicate values in a list
                        if (is_array($value))
                                $value = array_unique($value);
                }

                return $value;
        }

        /**
        * Return an array of values that were given in a 'a|b|c' notation,
        * after it optionally validates them against the list allowed values.
        * 
        * @param valueName - The name of the parameter (for error reporting)
        * @param value - The value being parsed
        * @param allowMultiple - Can $value contain more than one value separated by '|'?
        * @param allowedValues - An array of values to check against. If null, all values are accepted.
        * @return (allowMultiple ? an_array_of_values : a_single_value) 
        */
        protected function parseMultiValue($valueName, $value, $allowMultiple, $allowedValues) {
                $valuesList = explode('|', $value);
                if (!$allowMultiple && count($valuesList) != 1) {
                        $possibleValues = is_array($allowedValues) ? "of '" . implode("', '", $allowedValues) . "'" : '';
                        $this->dieUsage("Only one $possibleValues is allowed for parameter '$valueName'", "multival_$valueName");
                }
                if (is_array($allowedValues)) {
                        $unknownValues = array_diff($valuesList, $allowedValues);
                        if ($unknownValues) {
                                $this->dieUsage('Unrecognised value' . (count($unknownValues) > 1 ? "s" : "") . " for parameter '$valueName'", "unknown_$valueName");
                        }
                }

                return $allowMultiple ? $valuesList : $valuesList[0];
        }

        /**
        * Validate the value against the minimum and user/bot maximum limits. Prints usage info on failure.
        */
        function validateLimit($varname, $value, $min, $max, $botMax) {
                if ($value < $min) {
                        $this->dieUsage("$varname may not be less than $min (set to $value)", $varname);
                }

                if ($this->getMain()->isBot() || $this->getMain()->isSysop()) {
                        if ($value > $botMax) {
                                $this->dieUsage("$varname may not be over $botMax (set to $value) for bots or sysops", $varname);
                        }
                }
                elseif ($value > $max) {
                        $this->dieUsage("$varname may not be over $max (set to $value) for users", $varname);
                }
        }

        /**
         * Call main module's error handler 
         */
        public function dieUsage($description, $errorCode, $httpRespCode = 0) {
                throw new UsageException($description, $this->encodeParamName($errorCode), $httpRespCode);
        }

        /**
         * Internal code errors should be reported with this method
         */
        protected static function dieDebug($method, $message) {
                wfDebugDieBacktrace("Internal error in $method: $message");
        }

        /**
         * Profiling: total module execution time
         */
        private $mTimeIn = 0, $mModuleTime = 0;

        /**
         * Start module profiling
         */
        public function profileIn() {
                if ($this->mTimeIn !== 0)
                        ApiBase :: dieDebug(__METHOD__, 'called twice without calling profileOut()');
                $this->mTimeIn = microtime(true);
                wfProfileIn($this->getModuleProfileName());
        }

        /**
         * End module profiling
         */
        public function profileOut() {
                if ($this->mTimeIn === 0)
                        ApiBase :: dieDebug(__METHOD__, 'called without calling profileIn() first');
                if ($this->mDBTimeIn !== 0)
                        ApiBase :: dieDebug(__METHOD__, 'must be called after database profiling is done with profileDBOut()');

                $this->mModuleTime += microtime(true) - $this->mTimeIn;
                $this->mTimeIn = 0;
                wfProfileOut($this->getModuleProfileName());
        }

        /**
         * When modules crash, sometimes it is needed to do a profileOut() regardless
         * of the profiling state the module was in. This method does such cleanup. 
         */
        public function safeProfileOut() {
                if ($this->mTimeIn !== 0) {
                        if ($this->mDBTimeIn !== 0)
                                $this->profileDBOut();
                        $this->profileOut();
                }
        }

        /**
         * Total time the module was executed
         */
        public function getProfileTime() {
                if ($this->mTimeIn !== 0)
                        ApiBase :: dieDebug(__METHOD__, 'called without calling profileOut() first');
                return $this->mModuleTime;
        }

        /**
         * Profiling: database execution time
         */
        private $mDBTimeIn = 0, $mDBTime = 0;

        /**
         * Start module profiling
         */
        public function profileDBIn() {
                if ($this->mTimeIn === 0)
                        ApiBase :: dieDebug(__METHOD__, 'must be called while profiling the entire module with profileIn()');
                if ($this->mDBTimeIn !== 0)
                        ApiBase :: dieDebug(__METHOD__, 'called twice without calling profileDBOut()');
                $this->mDBTimeIn = microtime(true);
                wfProfileIn($this->getModuleProfileName(true));
        }

        /**
         * End database profiling
         */
        public function profileDBOut() {
                if ($this->mTimeIn === 0)
                        ApiBase :: dieDebug(__METHOD__, 'must be called while profiling the entire module with profileIn()');
                if ($this->mDBTimeIn === 0)
                        ApiBase :: dieDebug(__METHOD__, 'called without calling profileDBIn() first');

                $time = microtime(true) - $this->mDBTimeIn;
                $this->mDBTimeIn = 0;

                $this->mDBTime += $time;
                $this->getMain()->mDBTime += $time;
                wfProfileOut($this->getModuleProfileName(true));
        }

        /**
         * Total time the module used the database
         */
        public function getProfileDBTime() {
                if ($this->mDBTimeIn !== 0)
                        ApiBase :: dieDebug(__METHOD__, 'called without calling profileDBOut() first');
                return $this->mDBTime;
        }
        
        public static function debugPrint($value, $name = 'unknown', $backtrace = false) {
                print "\n\n<pre><b>Debuging value '$name':</b>\n\n";
                var_export($value);
                if ($backtrace)
                        print "\n" . wfBacktrace();
                print "\n</pre>\n";
        }

        public abstract function getVersion();

        public static function getBaseVersion() {
                return __CLASS__ . ': $Id$';
        }
}
?>