lib/externallib.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17
  18 /**
  19  * Support for external API
  20  *
  21  * @package    core_webservice
  22  * @copyright  2009 Petr Skodak
  23  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24  */
  25
  26 defined('MOODLE_INTERNAL') || die();
  27
  28 /**
  29  * Exception indicating user is not allowed to use external function in the current context.
  30  *
  31  * @package    core_webservice
  32  * @copyright  2009 Petr Skodak
  33  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  34  * @since Moodle 2.0
  35  */
  36 class restricted_context_exception extends moodle_exception {
  37     /**
  38      * Constructor
  39      *
  40      * @since Moodle 2.0
  41      */
  42     function __construct() {
  43         parent::__construct('restrictedcontextexception', 'error');
  44     }
  45 }
  46
  47 /**
  48  * Base class for external api methods.
  49  *
  50  * @package    core_webservice
  51  * @copyright  2009 Petr Skodak
  52  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  53  * @since Moodle 2.0
  54  */
  55 class external_api {
  56
  57     /** @var stdClass context where the function calls will be restricted */
  58     private static $contextrestriction;
  59
  60     /**
  61      * Returns detailed function information
  62      *
  63      * @param string|object $function name of external function or record from external_function
  64      * @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
  65      *                        MUST_EXIST means throw exception if no record or multiple records found
  66      * @return stdClass description or false if not found or exception thrown
  67      * @since Moodle 2.0
  68      */
  69     public static function external_function_info($function, $strictness=MUST_EXIST) {
  70         global $DB, $CFG;
  71
  72         if (!is_object($function)) {
  73             if (!$function = $DB->get_record('external_functions', array('name' => $function), '*', $strictness)) {
  74                 return false;
  75             }
  76         }
  77
  78         // First try class autoloading.
  79         if (!class_exists($function->classname)) {
  80             // Fallback to explicit include of externallib.php.
  81             if (empty($function->classpath)) {
  82                 $function->classpath = core_component::get_component_directory($function->component).'/externallib.php';
  83             } else {
  84                 $function->classpath = $CFG->dirroot.'/'.$function->classpath;
  85             }
  86             if (!file_exists($function->classpath)) {
  87                 throw new coding_exception('Cannot find file with external function implementation');
  88             }
  89             require_once($function->classpath);
  90             if (!class_exists($function->classname)) {
  91                 throw new coding_exception('Cannot find external class');
  92             }
  93         }
  94
  95         $function->ajax_method = $function->methodname.'_is_allowed_from_ajax';
  96         $function->parameters_method = $function->methodname.'_parameters';
  97         $function->returns_method    = $function->methodname.'_returns';
  98         $function->deprecated_method = $function->methodname.'_is_deprecated';
  99
 100         // Make sure the implementaion class is ok.
 101         if (!method_exists($function->classname, $function->methodname)) {
 102             throw new coding_exception('Missing implementation method of '.$function->classname.'::'.$function->methodname);
 103         }
 104         if (!method_exists($function->classname, $function->parameters_method)) {
 105             throw new coding_exception('Missing parameters description');
 106         }
 107         if (!method_exists($function->classname, $function->returns_method)) {
 108             throw new coding_exception('Missing returned values description');
 109         }
 110         if (method_exists($function->classname, $function->deprecated_method)) {
 111             if (call_user_func(array($function->classname, $function->deprecated_method)) === true) {
 112                 $function->deprecated = true;
 113             }
 114         }
 115         $function->allowed_from_ajax = false;
 116
 117         // Fetch the parameters description.
 118         $function->parameters_desc = call_user_func(array($function->classname, $function->parameters_method));
 119         if (!($function->parameters_desc instanceof external_function_parameters)) {
 120             throw new coding_exception('Invalid parameters description');
 121         }
 122
 123         // Fetch the return values description.
 124         $function->returns_desc = call_user_func(array($function->classname, $function->returns_method));
 125         // Null means void result or result is ignored.
 126         if (!is_null($function->returns_desc) and !($function->returns_desc instanceof external_description)) {
 127             throw new coding_exception('Invalid return description');
 128         }
 129
 130         // Now get the function description.
 131
 132         // TODO MDL-31115 use localised lang pack descriptions, it would be nice to have
 133         // easy to understand descriptions in admin UI,
 134         // on the other hand this is still a bit in a flux and we need to find some new naming
 135         // conventions for these descriptions in lang packs.
 136         $function->description = null;
 137         $servicesfile = core_component::get_component_directory($function->component).'/db/services.php';
 138         if (file_exists($servicesfile)) {
 139             $functions = null;
 140             include($servicesfile);
 141             if (isset($functions[$function->name]['description'])) {
 142                 $function->description = $functions[$function->name]['description'];
 143             }
 144             if (isset($functions[$function->name]['testclientpath'])) {
 145                 $function->testclientpath = $functions[$function->name]['testclientpath'];
 146             }
 147             if (isset($functions[$function->name]['type'])) {
 148                 $function->type = $functions[$function->name]['type'];
 149             }
 150             if (isset($functions[$function->name]['ajax'])) {
 151                 $function->allowed_from_ajax = $functions[$function->name]['ajax'];
 152             } else if (method_exists($function->classname, $function->ajax_method)) {
 153                 if (call_user_func(array($function->classname, $function->ajax_method)) === true) {
 154                     debugging('External function ' . $function->ajax_method . '() function is deprecated.' .
 155                               'Set ajax=>true in db/service.php instead.', DEBUG_DEVELOPER);
 156                     $function->allowed_from_ajax = true;
 157                 }
 158             }
 159             if (isset($functions[$function->name]['loginrequired'])) {
 160                 $function->loginrequired = $functions[$function->name]['loginrequired'];
 161             } else {
 162                 $function->loginrequired = true;
 163             }
 164         }
 165
 166         return $function;
 167     }
 168
 169     /**
 170      * Call an external function validating all params/returns correctly.
 171      *
 172      * Note that an external function may modify the state of the current page, so this wrapper
 173      * saves and restores tha PAGE and COURSE global variables before/after calling the external function.
 174      *
 175      * @param string $function A webservice function name.
 176      * @param array $args Params array (named params)
 177      * @param boolean $ajaxonly If true, an extra check will be peformed to see if ajax is required.
 178      * @return array containing keys for error (bool), exception and data.
 179      */
 180     public static function call_external_function($function, $args, $ajaxonly=false) {
 181         global $PAGE, $COURSE, $CFG, $SITE;
 182
 183         require_once($CFG->libdir . "/pagelib.php");
 184
 185         $externalfunctioninfo = self::external_function_info($function);
 186
 187         $currentpage = $PAGE;
 188         $currentcourse = $COURSE;
 189         $response = array();
 190
 191         try {
 192             // Taken straight from from setup.php.
 193             if (!empty($CFG->moodlepageclass)) {
 194                 if (!empty($CFG->moodlepageclassfile)) {
 195                     require_once($CFG->moodlepageclassfile);
 196                 }
 197                 $classname = $CFG->moodlepageclass;
 198             } else {
 199                 $classname = 'moodle_page';
 200             }
 201             $PAGE = new $classname();
 202             $COURSE = clone($SITE);
 203
 204             if ($ajaxonly && !$externalfunctioninfo->allowed_from_ajax) {
 205                 throw new moodle_exception('servicenotavailable', 'webservice');
 206             }
 207
 208             // Do not allow access to write or delete webservices as a public user.
 209             if ($externalfunctioninfo->loginrequired) {
 210                 if (defined('NO_MOODLE_COOKIES') && NO_MOODLE_COOKIES && !PHPUNIT_TEST) {
 211                     throw new moodle_exception('servicenotavailable', 'webservice');
 212                 }
 213                 if (!isloggedin()) {
 214                     throw new moodle_exception('servicenotavailable', 'webservice');
 215                 } else {
 216                     require_sesskey();
 217                 }
 218             }
 219
 220             // Validate params, this also sorts the params properly, we need the correct order in the next part.
 221             $callable = array($externalfunctioninfo->classname, 'validate_parameters');
 222             $params = call_user_func($callable,
 223                                      $externalfunctioninfo->parameters_desc,
 224                                      $args);
 225
 226             // Execute - gulp!
 227             $callable = array($externalfunctioninfo->classname, $externalfunctioninfo->methodname);
 228             $result = call_user_func_array($callable,
 229                                            array_values($params));
 230
 231             // Validate the return parameters.
 232             if ($externalfunctioninfo->returns_desc !== null) {
 233                 $callable = array($externalfunctioninfo->classname, 'clean_returnvalue');
 234                 $result = call_user_func($callable, $externalfunctioninfo->returns_desc, $result);
 235             }
 236
 237             $response['error'] = false;
 238             $response['data'] = $result;
 239         } catch (Exception $e) {
 240             $exception = get_exception_info($e);
 241             unset($exception->a);
 242             if (!debugging('', DEBUG_DEVELOPER)) {
 243                 unset($exception->debuginfo);
 244                 unset($exception->backtrace);
 245             }
 246             $response['error'] = true;
 247             $response['exception'] = $exception;
 248             // Do not process the remaining requests.
 249         }
 250
 251         $PAGE = $currentpage;
 252         $COURSE = $currentcourse;
 253
 254         return $response;
 255     }
 256
 257     /**
 258      * Set context restriction for all following subsequent function calls.
 259      *
 260      * @param stdClass $context the context restriction
 261      * @since Moodle 2.0
 262      */
 263     public static function set_context_restriction($context) {
 264         self::$contextrestriction = $context;
 265     }
 266
 267     /**
 268      * This method has to be called before every operation
 269      * that takes a longer time to finish!
 270      *
 271      * @param int $seconds max expected time the next operation needs
 272      * @since Moodle 2.0
 273      */
 274     public static function set_timeout($seconds=360) {
 275         $seconds = ($seconds < 300) ? 300 : $seconds;
 276         core_php_time_limit::raise($seconds);
 277     }
 278
 279     /**
 280      * Validates submitted function parameters, if anything is incorrect
 281      * invalid_parameter_exception is thrown.
 282      * This is a simple recursive method which is intended to be called from
 283      * each implementation method of external API.
 284      *
 285      * @param external_description $description description of parameters
 286      * @param mixed $params the actual parameters
 287      * @return mixed params with added defaults for optional items, invalid_parameters_exception thrown if any problem found
 288      * @since Moodle 2.0
 289      */
 290     public static function validate_parameters(external_description $description, $params) {
 291         if ($description instanceof external_value) {
 292             if (is_array($params) or is_object($params)) {
 293                 throw new invalid_parameter_exception('Scalar type expected, array or object received.');
 294             }
 295
 296             if ($description->type == PARAM_BOOL) {
 297                 // special case for PARAM_BOOL - we want true/false instead of the usual 1/0 - we can not be too strict here ;-)
 298                 if (is_bool($params) or $params === 0 or $params === 1 or $params === '0' or $params === '1') {
 299                     return (bool)$params;
 300                 }
 301             }
 302             $debuginfo = 'Invalid external api parameter: the value is "' . $params .
 303                     '", the server was expecting "' . $description->type . '" type';
 304             return validate_param($params, $description->type, $description->allownull, $debuginfo);
 305
 306         } else if ($description instanceof external_single_structure) {
 307             if (!is_array($params)) {
 308                 throw new invalid_parameter_exception('Only arrays accepted. The bad value is: \''
 309                         . print_r($params, true) . '\'');
 310             }
 311             $result = array();
 312             foreach ($description->keys as $key=>$subdesc) {
 313                 if (!array_key_exists($key, $params)) {
 314                     if ($subdesc->required == VALUE_REQUIRED) {
 315                         throw new invalid_parameter_exception('Missing required key in single structure: '. $key);
 316                     }
 317                     if ($subdesc->required == VALUE_DEFAULT) {
 318                         try {
 319                             $result[$key] = self::validate_parameters($subdesc, $subdesc->default);
 320                         } catch (invalid_parameter_exception $e) {
 321                             //we are only interested by exceptions returned by validate_param() and validate_parameters()
 322                             //(in order to build the path to the faulty attribut)
 323                             throw new invalid_parameter_exception($key." => ".$e->getMessage() . ': ' .$e->debuginfo);
 324                         }
 325                     }
 326                 } else {
 327                     try {
 328                         $result[$key] = self::validate_parameters($subdesc, $params[$key]);
 329                     } catch (invalid_parameter_exception $e) {
 330                         //we are only interested by exceptions returned by validate_param() and validate_parameters()
 331                         //(in order to build the path to the faulty attribut)
 332                         throw new invalid_parameter_exception($key." => ".$e->getMessage() . ': ' .$e->debuginfo);
 333                     }
 334                 }
 335                 unset($params[$key]);
 336             }
 337             if (!empty($params)) {
 338                 throw new invalid_parameter_exception('Unexpected keys (' . implode(', ', array_keys($params)) . ') detected in parameter array.');
 339             }
 340             return $result;
 341
 342         } else if ($description instanceof external_multiple_structure) {
 343             if (!is_array($params)) {
 344                 throw new invalid_parameter_exception('Only arrays accepted. The bad value is: \''
 345                         . print_r($params, true) . '\'');
 346             }
 347             $result = array();
 348             foreach ($params as $param) {
 349                 $result[] = self::validate_parameters($description->content, $param);
 350             }
 351             return $result;
 352
 353         } else {
 354             throw new invalid_parameter_exception('Invalid external api description');
 355         }
 356     }
 357
 358     /**
 359      * Clean response
 360      * If a response attribute is unknown from the description, we just ignore the attribute.
 361      * If a response attribute is incorrect, invalid_response_exception is thrown.
 362      * Note: this function is similar to validate parameters, however it is distinct because
 363      * parameters validation must be distinct from cleaning return values.
 364      *
 365      * @param external_description $description description of the return values
 366      * @param mixed $response the actual response
 367      * @return mixed response with added defaults for optional items, invalid_response_exception thrown if any problem found
 368      * @author 2010 Jerome Mouneyrac
 369      * @since Moodle 2.0
 370      */
 371     public static function clean_returnvalue(external_description $description, $response) {
 372         if ($description instanceof external_value) {
 373             if (is_array($response) or is_object($response)) {
 374                 throw new invalid_response_exception('Scalar type expected, array or object received.');
 375             }
 376
 377             if ($description->type == PARAM_BOOL) {
 378                 // special case for PARAM_BOOL - we want true/false instead of the usual 1/0 - we can not be too strict here ;-)
 379                 if (is_bool($response) or $response === 0 or $response === 1 or $response === '0' or $response === '1') {
 380                     return (bool)$response;
 381                 }
 382             }
 383             $debuginfo = 'Invalid external api response: the value is "' . $response .
 384                     '", the server was expecting "' . $description->type . '" type';
 385             try {
 386                 return validate_param($response, $description->type, $description->allownull, $debuginfo);
 387             } catch (invalid_parameter_exception $e) {
 388                 //proper exception name, to be recursively catched to build the path to the faulty attribut
 389                 throw new invalid_response_exception($e->debuginfo);
 390             }
 391
 392         } else if ($description instanceof external_single_structure) {
 393             if (!is_array($response) && !is_object($response)) {
 394                 throw new invalid_response_exception('Only arrays/objects accepted. The bad value is: \'' .
 395                         print_r($response, true) . '\'');
 396             }
 397
 398             // Cast objects into arrays.
 399             if (is_object($response)) {
 400                 $response = (array) $response;
 401             }
 402
 403             $result = array();
 404             foreach ($description->keys as $key=>$subdesc) {
 405                 if (!array_key_exists($key, $response)) {
 406                     if ($subdesc->required == VALUE_REQUIRED) {
 407                         throw new invalid_response_exception('Error in response - Missing following required key in a single structure: ' . $key);
 408                     }
 409                     if ($subdesc instanceof external_value) {
 410                         if ($subdesc->required == VALUE_DEFAULT) {
 411                             try {
 412                                     $result[$key] = self::clean_returnvalue($subdesc, $subdesc->default);
 413                             } catch (invalid_response_exception $e) {
 414                                 //build the path to the faulty attribut
 415                                 throw new invalid_response_exception($key." => ".$e->getMessage() . ': ' . $e->debuginfo);
 416                             }
 417                         }
 418                     }
 419                 } else {
 420                     try {
 421                         $result[$key] = self::clean_returnvalue($subdesc, $response[$key]);
 422                     } catch (invalid_response_exception $e) {
 423                         //build the path to the faulty attribut
 424                         throw new invalid_response_exception($key." => ".$e->getMessage() . ': ' . $e->debuginfo);
 425                     }
 426                 }
 427                 unset($response[$key]);
 428             }
 429
 430             return $result;
 431
 432         } else if ($description instanceof external_multiple_structure) {
 433             if (!is_array($response)) {
 434                 throw new invalid_response_exception('Only arrays accepted. The bad value is: \'' .
 435                         print_r($response, true) . '\'');
 436             }
 437             $result = array();
 438             foreach ($response as $param) {
 439                 $result[] = self::clean_returnvalue($description->content, $param);
 440             }
 441             return $result;
 442
 443         } else {
 444             throw new invalid_response_exception('Invalid external api response description');
 445         }
 446     }
 447
 448     /**
 449      * Makes sure user may execute functions in this context.
 450      *
 451      * @param stdClass $context
 452      * @since Moodle 2.0
 453      */
 454     public static function validate_context($context) {
 455         global $CFG, $PAGE;
 456
 457         if (empty($context)) {
 458             throw new invalid_parameter_exception('Context does not exist');
 459         }
 460         if (empty(self::$contextrestriction)) {
 461             self::$contextrestriction = context_system::instance();
 462         }
 463         $rcontext = self::$contextrestriction;
 464
 465         if ($rcontext->contextlevel == $context->contextlevel) {
 466             if ($rcontext->id != $context->id) {
 467                 throw new restricted_context_exception();
 468             }
 469         } else if ($rcontext->contextlevel > $context->contextlevel) {
 470             throw new restricted_context_exception();
 471         } else {
 472             $parents = $context->get_parent_context_ids();
 473             if (!in_array($rcontext->id, $parents)) {
 474                 throw new restricted_context_exception();
 475             }
 476         }
 477
 478         $PAGE->reset_theme_and_output();
 479         list($unused, $course, $cm) = get_context_info_array($context->id);
 480         require_login($course, false, $cm, false, true);
 481         $PAGE->set_context($context);
 482     }
 483
 484     /**
 485      * Get context from passed parameters.
 486      * The passed array must either contain a contextid or a combination of context level and instance id to fetch the context.
 487      * For example, the context level can be "course" and instanceid can be courseid.
 488      *
 489      * See context_helper::get_all_levels() for a list of valid context levels.
 490      *
 491      * @param array $param
 492      * @since Moodle 2.6
 493      * @throws invalid_parameter_exception
 494      * @return context
 495      */
 496     protected static function get_context_from_params($param) {
 497         $levels = context_helper::get_all_levels();
 498         if (!empty($param['contextid'])) {
 499             return context::instance_by_id($param['contextid'], IGNORE_MISSING);
 500         } else if (!empty($param['contextlevel']) && isset($param['instanceid'])) {
 501             $contextlevel = "context_".$param['contextlevel'];
 502             if (!array_search($contextlevel, $levels)) {
 503                 throw new invalid_parameter_exception('Invalid context level = '.$param['contextlevel']);
 504             }
 505            return $contextlevel::instance($param['instanceid'], IGNORE_MISSING);
 506         } else {
 507             // No valid context info was found.
 508             throw new invalid_parameter_exception('Missing parameters, please provide either context level with instance id or contextid');
 509         }
 510     }
 511 }
 512
 513 /**
 514  * Common ancestor of all parameter description classes
 515  *
 516  * @package    core_webservice
 517  * @copyright  2009 Petr Skodak
 518  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 519  * @since Moodle 2.0
 520  */
 521 abstract class external_description {
 522     /** @var string Description of element */
 523     public $desc;
 524
 525     /** @var bool Element value required, null not allowed */
 526     public $required;
 527
 528     /** @var mixed Default value */
 529     public $default;
 530
 531     /**
 532      * Contructor
 533      *
 534      * @param string $desc
 535      * @param bool $required
 536      * @param mixed $default
 537      * @since Moodle 2.0
 538      */
 539     public function __construct($desc, $required, $default) {
 540         $this->desc = $desc;
 541         $this->required = $required;
 542         $this->default = $default;
 543     }
 544 }
 545
 546 /**
 547  * Scalar value description class
 548  *
 549  * @package    core_webservice
 550  * @copyright  2009 Petr Skodak
 551  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 552  * @since Moodle 2.0
 553  */
 554 class external_value extends external_description {
 555
 556     /** @var mixed Value type PARAM_XX */
 557     public $type;
 558
 559     /** @var bool Allow null values */
 560     public $allownull;
 561
 562     /**
 563      * Constructor
 564      *
 565      * @param mixed $type
 566      * @param string $desc
 567      * @param bool $required
 568      * @param mixed $default
 569      * @param bool $allownull
 570      * @since Moodle 2.0
 571      */
 572     public function __construct($type, $desc='', $required=VALUE_REQUIRED,
 573             $default=null, $allownull=NULL_ALLOWED) {
 574         parent::__construct($desc, $required, $default);
 575         $this->type      = $type;
 576         $this->allownull = $allownull;
 577     }
 578 }
 579
 580 /**
 581  * Associative array description class
 582  *
 583  * @package    core_webservice
 584  * @copyright  2009 Petr Skodak
 585  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 586  * @since Moodle 2.0
 587  */
 588 class external_single_structure extends external_description {
 589
 590      /** @var array Description of array keys key=>external_description */
 591     public $keys;
 592
 593     /**
 594      * Constructor
 595      *
 596      * @param array $keys
 597      * @param string $desc
 598      * @param bool $required
 599      * @param array $default
 600      * @since Moodle 2.0
 601      */
 602     public function __construct(array $keys, $desc='',
 603             $required=VALUE_REQUIRED, $default=null) {
 604         parent::__construct($desc, $required, $default);
 605         $this->keys = $keys;
 606     }
 607 }
 608
 609 /**
 610  * Bulk array description class.
 611  *
 612  * @package    core_webservice
 613  * @copyright  2009 Petr Skodak
 614  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 615  * @since Moodle 2.0
 616  */
 617 class external_multiple_structure extends external_description {
 618
 619      /** @var external_description content */
 620     public $content;
 621
 622     /**
 623      * Constructor
 624      *
 625      * @param external_description $content
 626      * @param string $desc
 627      * @param bool $required
 628      * @param array $default
 629      * @since Moodle 2.0
 630      */
 631     public function __construct(external_description $content, $desc='',
 632             $required=VALUE_REQUIRED, $default=null) {
 633         parent::__construct($desc, $required, $default);
 634         $this->content = $content;
 635     }
 636 }
 637
 638 /**
 639  * Description of top level - PHP function parameters.
 640  *
 641  * @package    core_webservice
 642  * @copyright  2009 Petr Skodak
 643  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 644  * @since Moodle 2.0
 645  */
 646 class external_function_parameters extends external_single_structure {
 647
 648     /**
 649      * Constructor - does extra checking to prevent top level optional parameters.
 650      *
 651      * @param array $keys
 652      * @param string $desc
 653      * @param bool $required
 654      * @param array $default
 655      */
 656     public function __construct(array $keys, $desc='', $required=VALUE_REQUIRED, $default=null) {
 657         global $CFG;
 658
 659         if ($CFG->debugdeveloper) {
 660             foreach ($keys as $key => $value) {
 661                 if ($value instanceof external_value) {
 662                     if ($value->required == VALUE_OPTIONAL) {
 663                         debugging('External function parameters: invalid OPTIONAL value specified.', DEBUG_DEVELOPER);
 664                         break;
 665                     }
 666                 }
 667             }
 668         }
 669         parent::__construct($keys, $desc, $required, $default);
 670     }
 671 }
 672
 673 /**
 674  * Generate a token
 675  *
 676  * @param string $tokentype EXTERNAL_TOKEN_EMBEDDED|EXTERNAL_TOKEN_PERMANENT
 677  * @param stdClass|int $serviceorid service linked to the token
 678  * @param int $userid user linked to the token
 679  * @param stdClass|int $contextorid
 680  * @param int $validuntil date when the token expired
 681  * @param string $iprestriction allowed ip - if 0 or empty then all ips are allowed
 682  * @return string generated token
 683  * @author  2010 Jamie Pratt
 684  * @since Moodle 2.0
 685  */
 686 function external_generate_token($tokentype, $serviceorid, $userid, $contextorid, $validuntil=0, $iprestriction=''){
 687     global $DB, $USER;
 688     // make sure the token doesn't exist (even if it should be almost impossible with the random generation)
 689     $numtries = 0;
 690     do {
 691         $numtries ++;
 692         $generatedtoken = md5(uniqid(rand(),1));
 693         if ($numtries > 5){
 694             throw new moodle_exception('tokengenerationfailed');
 695         }
 696     } while ($DB->record_exists('external_tokens', array('token'=>$generatedtoken)));
 697     $newtoken = new stdClass();
 698     $newtoken->token = $generatedtoken;
 699     if (!is_object($serviceorid)){
 700         $service = $DB->get_record('external_services', array('id' => $serviceorid));
 701     } else {
 702         $service = $serviceorid;
 703     }
 704     if (!is_object($contextorid)){
 705         $context = context::instance_by_id($contextorid, MUST_EXIST);
 706     } else {
 707         $context = $contextorid;
 708     }
 709     if (empty($service->requiredcapability) || has_capability($service->requiredcapability, $context, $userid)) {
 710         $newtoken->externalserviceid = $service->id;
 711     } else {
 712         throw new moodle_exception('nocapabilitytousethisservice');
 713     }
 714     $newtoken->tokentype = $tokentype;
 715     $newtoken->userid = $userid;
 716     if ($tokentype == EXTERNAL_TOKEN_EMBEDDED){
 717         $newtoken->sid = session_id();
 718     }
 719
 720     $newtoken->contextid = $context->id;
 721     $newtoken->creatorid = $USER->id;
 722     $newtoken->timecreated = time();
 723     $newtoken->validuntil = $validuntil;
 724     if (!empty($iprestriction)) {
 725         $newtoken->iprestriction = $iprestriction;
 726     }
 727     $newtoken->privatetoken = null;
 728     $DB->insert_record('external_tokens', $newtoken);
 729     return $newtoken->token;
 730 }
 731
 732 /**
 733  * Create and return a session linked token. Token to be used for html embedded client apps that want to communicate
 734  * with the Moodle server through web services. The token is linked to the current session for the current page request.
 735  * It is expected this will be called in the script generating the html page that is embedding the client app and that the
 736  * returned token will be somehow passed into the client app being embedded in the page.
 737  *
 738  * @param string $servicename name of the web service. Service name as defined in db/services.php
 739  * @param int $context context within which the web service can operate.
 740  * @return int returns token id.
 741  * @since Moodle 2.0
 742  */
 743 function external_create_service_token($servicename, $context){
 744     global $USER, $DB;
 745     $service = $DB->get_record('external_services', array('name'=>$servicename), '*', MUST_EXIST);
 746     return external_generate_token(EXTERNAL_TOKEN_EMBEDDED, $service, $USER->id, $context, 0);
 747 }
 748
 749 /**
 750  * Delete all pre-built services (+ related tokens) and external functions information defined in the specified component.
 751  *
 752  * @param string $component name of component (moodle, mod_assignment, etc.)
 753  */
 754 function external_delete_descriptions($component) {
 755     global $DB;
 756
 757     $params = array($component);
 758
 759     $DB->delete_records_select('external_tokens',
 760             "externalserviceid IN (SELECT id FROM {external_services} WHERE component = ?)", $params);
 761     $DB->delete_records_select('external_services_users',
 762             "externalserviceid IN (SELECT id FROM {external_services} WHERE component = ?)", $params);
 763     $DB->delete_records_select('external_services_functions',
 764             "functionname IN (SELECT name FROM {external_functions} WHERE component = ?)", $params);
 765     $DB->delete_records('external_services', array('component'=>$component));
 766     $DB->delete_records('external_functions', array('component'=>$component));
 767 }
 768
 769 /**
 770  * Standard Moodle web service warnings
 771  *
 772  * @package    core_webservice
 773  * @copyright  2012 Jerome Mouneyrac
 774  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 775  * @since Moodle 2.3
 776  */
 777 class external_warnings extends external_multiple_structure {
 778
 779     /**
 780      * Constructor
 781      *
 782      * @since Moodle 2.3
 783      */
 784     public function __construct($itemdesc = 'item', $itemiddesc = 'item id',
 785         $warningcodedesc = 'the warning code can be used by the client app to implement specific behaviour') {
 786
 787         parent::__construct(
 788             new external_single_structure(
 789                 array(
 790                     'item' => new external_value(PARAM_TEXT, $itemdesc, VALUE_OPTIONAL),
 791                     'itemid' => new external_value(PARAM_INT, $itemiddesc, VALUE_OPTIONAL),
 792                     'warningcode' => new external_value(PARAM_ALPHANUM, $warningcodedesc),
 793                     'message' => new external_value(PARAM_TEXT,
 794                             'untranslated english message to explain the warning')
 795                 ), 'warning'),
 796             'list of warnings', VALUE_OPTIONAL);
 797     }
 798 }
 799
 800 /**
 801  * A pre-filled external_value class for text format.
 802  *
 803  * Default is FORMAT_HTML
 804  * This should be used all the time in external xxx_params()/xxx_returns functions
 805  * as it is the standard way to implement text format param/return values.
 806  *
 807  * @package    core_webservice
 808  * @copyright  2012 Jerome Mouneyrac
 809  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 810  * @since Moodle 2.3
 811  */
 812 class external_format_value extends external_value {
 813
 814     /**
 815      * Constructor
 816      *
 817      * @param string $textfieldname Name of the text field
 818      * @param int $required if VALUE_REQUIRED then set standard default FORMAT_HTML
 819      * @param int $default Default value.
 820      * @since Moodle 2.3
 821      */
 822     public function __construct($textfieldname, $required = VALUE_REQUIRED, $default = null) {
 823
 824         if ($default == null && $required == VALUE_DEFAULT) {
 825             $default = FORMAT_HTML;
 826         }
 827
 828         $desc = $textfieldname . ' format (' . FORMAT_HTML . ' = HTML, '
 829                 . FORMAT_MOODLE . ' = MOODLE, '
 830                 . FORMAT_PLAIN . ' = PLAIN or '
 831                 . FORMAT_MARKDOWN . ' = MARKDOWN)';
 832
 833         parent::__construct(PARAM_INT, $desc, $required, $default);
 834     }
 835 }
 836
 837 /**
 838  * Validate text field format against known FORMAT_XXX
 839  *
 840  * @param array $format the format to validate
 841  * @return the validated format
 842  * @throws coding_exception
 843  * @since Moodle 2.3
 844  */
 845 function external_validate_format($format) {
 846     $allowedformats = array(FORMAT_HTML, FORMAT_MOODLE, FORMAT_PLAIN, FORMAT_MARKDOWN);
 847     if (!in_array($format, $allowedformats)) {
 848         throw new moodle_exception('formatnotsupported', 'webservice', '' , null,
 849                 'The format with value=' . $format . ' is not supported by this Moodle site');
 850     }
 851     return $format;
 852 }
 853
 854 /**
 855  * Format the string to be returned properly as requested by the either the web service server,
 856  * either by an internally call.
 857  * The caller can change the format (raw) with the external_settings singleton
 858  * All web service servers must set this singleton when parsing the $_GET and $_POST.
 859  *
 860  * <pre>
 861  * Options are the same that in {@link format_string()} with some changes:
 862  *      filter      : Can be set to false to force filters off, else observes {@link external_settings}.
 863  * </pre>
 864  *
 865  * @param string $str The string to be filtered. Should be plain text, expect
 866  * possibly for multilang tags.
 867  * @param boolean $striplinks To strip any link in the result text. Moodle 1.8 default changed from false to true! MDL-8713
 868  * @param int $contextid The id of the context for the string (affects filters).
 869  * @param array $options options array/object or courseid
 870  * @return string text
 871  * @since Moodle 3.0
 872  */
 873 function external_format_string($str, $contextid, $striplinks = true, $options = array()) {
 874
 875     // Get settings (singleton).
 876     $settings = external_settings::get_instance();
 877     if (empty($contextid)) {
 878         throw new coding_exception('contextid is required');
 879     }
 880
 881     if (!$settings->get_raw()) {
 882         $context = context::instance_by_id($contextid);
 883         $options['context'] = $context;
 884         $options['filter'] = isset($options['filter']) && !$options['filter'] ? false : $settings->get_filter();
 885         $str = format_string($str, $striplinks, $options);
 886     }
 887
 888     return $str;
 889 }
 890
 891 /**
 892  * Format the text to be returned properly as requested by the either the web service server,
 893  * either by an internally call.
 894  * The caller can change the format (raw, filter, file, fileurl) with the external_settings singleton
 895  * All web service servers must set this singleton when parsing the $_GET and $_POST.
 896  *
 897  * <pre>
 898  * Options are the same that in {@link format_text()} with some changes in defaults to provide backwards compatibility:
 899  *      trusted     :   If true the string won't be cleaned. Default false.
 900  *      noclean     :   If true the string won't be cleaned only if trusted is also true. Default false.
 901  *      nocache     :   If true the string will not be cached and will be formatted every call. Default false.
 902  *      filter      :   Can be set to false to force filters off, else observes {@link external_settings}.
 903  *      para        :   If true then the returned string will be wrapped in div tags. Default (different from format_text) false.
 904  *                      Default changed because div tags are not commonly needed.
 905  *      newlines    :   If true then lines newline breaks will be converted to HTML newline breaks. Default true.
 906  *      context     :   Not used! Using contextid parameter instead.
 907  *      overflowdiv :   If set to true the formatted text will be encased in a div with the class no-overflow before being
 908  *                      returned. Default false.
 909  *      allowid     :   If true then id attributes will not be removed, even when using htmlpurifier. Default (different from
 910  *                      format_text) true. Default changed id attributes are commonly needed.
 911  *      blanktarget :   If true all <a> tags will have target="_blank" added unless target is explicitly specified.
 912  * </pre>
 913  *
 914  * @param string $text The content that may contain ULRs in need of rewriting.
 915  * @param int $textformat The text format.
 916  * @param int $contextid This parameter and the next two identify the file area to use.
 917  * @param string $component
 918  * @param string $filearea helps identify the file area.
 919  * @param int $itemid helps identify the file area.
 920  * @param object/array $options text formatting options
 921  * @return array text + textformat
 922  * @since Moodle 2.3
 923  * @since Moodle 3.2 component, filearea and itemid are optional parameters
 924  */
 925 function external_format_text($text, $textformat, $contextid, $component = null, $filearea = null, $itemid = null,
 926                                 $options = null) {
 927     global $CFG;
 928
 929     // Get settings (singleton).
 930     $settings = external_settings::get_instance();
 931
 932     if ($component and $filearea and $settings->get_fileurl()) {
 933         require_once($CFG->libdir . "/filelib.php");
 934         $text = file_rewrite_pluginfile_urls($text, $settings->get_file(), $contextid, $component, $filearea, $itemid);
 935     }
 936
 937     if (!$settings->get_raw()) {
 938         $options = (array)$options;
 939
 940         // If context is passed in options, check that is the same to show a debug message.
 941         if (isset($options['context'])) {
 942             if ((is_object($options['context']) && $options['context']->id != $contextid)
 943                     || (!is_object($options['context']) && $options['context'] != $contextid)) {
 944                 debugging('Different contexts found in external_format_text parameters. $options[\'context\'] not allowed.
 945                     Using $contextid parameter...', DEBUG_DEVELOPER);
 946             }
 947         }
 948
 949         $options['filter'] = isset($options['filter']) && !$options['filter'] ? false : $settings->get_filter();
 950         $options['para'] = isset($options['para']) ? $options['para'] : false;
 951         $options['context'] = context::instance_by_id($contextid);
 952         $options['allowid'] = isset($options['allowid']) ? $options['allowid'] : true;
 953
 954         $text = format_text($text, $textformat, $options);
 955         $textformat = FORMAT_HTML; // Once converted to html (from markdown, plain... lets inform consumer this is already HTML).
 956     }
 957
 958     return array($text, $textformat);
 959 }
 960
 961 /**
 962  * Generate or return an existing token for the current authenticated user.
 963  * This function is used for creating a valid token for users authenticathing via login/token.php or admin/tool/mobile/launch.php.
 964  *
 965  * @param stdClass $service external service object
 966  * @return stdClass token object
 967  * @since Moodle 3.2
 968  * @throws moodle_exception
 969  */
 970 function external_generate_token_for_current_user($service) {
 971     global $DB, $USER;
 972
 973     core_user::require_active_user($USER, true, true);
 974
 975     // Check if there is any required system capability.
 976     if ($service->requiredcapability and !has_capability($service->requiredcapability, context_system::instance())) {
 977         throw new moodle_exception('missingrequiredcapability', 'webservice', '', $service->requiredcapability);
 978     }
 979
 980     // Specific checks related to user restricted service.
 981     if ($service->restrictedusers) {
 982         $authoriseduser = $DB->get_record('external_services_users',
 983             array('externalserviceid' => $service->id, 'userid' => $USER->id));
 984
 985         if (empty($authoriseduser)) {
 986             throw new moodle_exception('usernotallowed', 'webservice', '', $service->shortname);
 987         }
 988
 989         if (!empty($authoriseduser->validuntil) and $authoriseduser->validuntil < time()) {
 990             throw new moodle_exception('invalidtimedtoken', 'webservice');
 991         }
 992
 993         if (!empty($authoriseduser->iprestriction) and !address_in_subnet(getremoteaddr(), $authoriseduser->iprestriction)) {
 994             throw new moodle_exception('invalidiptoken', 'webservice');
 995         }
 996     }
 997
 998     // Check if a token has already been created for this user and this service.
 999     $conditions = array(
1000         'userid' => $USER->id,
1001         'externalserviceid' => $service->id,
1002         'tokentype' => EXTERNAL_TOKEN_PERMANENT
1003     );
1004     $tokens = $DB->get_records('external_tokens', $conditions, 'timecreated ASC');
1005
1006     // A bit of sanity checks.
1007     foreach ($tokens as $key => $token) {
1008
1009         // Checks related to a specific token. (script execution continue).
1010         $unsettoken = false;
1011         // If sid is set then there must be a valid associated session no matter the token type.
1012         if (!empty($token->sid)) {
1013             if (!\core\session\manager::session_exists($token->sid)) {
1014                 // This token will never be valid anymore, delete it.
1015                 $DB->delete_records('external_tokens', array('sid' => $token->sid));
1016                 $unsettoken = true;
1017             }
1018         }
1019
1020         // Remove token is not valid anymore.
1021         if (!empty($token->validuntil) and $token->validuntil < time()) {
1022             $DB->delete_records('external_tokens', array('token' => $token->token, 'tokentype' => EXTERNAL_TOKEN_PERMANENT));
1023             $unsettoken = true;
1024         }
1025
1026         // Remove token if its ip not in whitelist.
1027         if (isset($token->iprestriction) and !address_in_subnet(getremoteaddr(), $token->iprestriction)) {
1028             $unsettoken = true;
1029         }
1030
1031         if ($unsettoken) {
1032             unset($tokens[$key]);
1033         }
1034     }
1035
1036     // If some valid tokens exist then use the most recent.
1037     if (count($tokens) > 0) {
1038         $token = array_pop($tokens);
1039     } else {
1040         $context = context_system::instance();
1041         $isofficialservice = $service->shortname == MOODLE_OFFICIAL_MOBILE_SERVICE;
1042
1043         if (($isofficialservice and has_capability('moodle/webservice:createmobiletoken', $context)) or
1044                 (!is_siteadmin($USER) && has_capability('moodle/webservice:createtoken', $context))) {
1045
1046             // Create a new token.
1047             $token = new stdClass;
1048             $token->token = md5(uniqid(rand(), 1));
1049             $token->userid = $USER->id;
1050             $token->tokentype = EXTERNAL_TOKEN_PERMANENT;
1051             $token->contextid = context_system::instance()->id;
1052             $token->creatorid = $USER->id;
1053             $token->timecreated = time();
1054             $token->externalserviceid = $service->id;
1055             // MDL-43119 Token valid for 3 months (12 weeks).
1056             $token->validuntil = $token->timecreated + 12 * WEEKSECS;
1057             // Generate the private token, it must be transmitted only via https.
1058             $token->privatetoken = random_string(64);
1059             $token->id = $DB->insert_record('external_tokens', $token);
1060
1061             $params = array(
1062                 'objectid' => $token->id,
1063                 'relateduserid' => $USER->id,
1064                 'other' => array(
1065                     'auto' => true
1066                 )
1067             );
1068             $event = \core\event\webservice_token_created::create($params);
1069             $event->add_record_snapshot('external_tokens', $token);
1070             $event->trigger();
1071         } else {
1072             throw new moodle_exception('cannotcreatetoken', 'webservice', '', $service->shortname);
1073         }
1074     }
1075     return $token;
1076 }
1077
1078
1079 /**
1080  * Singleton to handle the external settings.
1081  *
1082  * We use singleton to encapsulate the "logic"
1083  *
1084  * @package    core_webservice
1085  * @copyright  2012 Jerome Mouneyrac
1086  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1087  * @since Moodle 2.3
1088  */
1089 class external_settings {
1090
1091     /** @var object the singleton instance */
1092     public static $instance = null;
1093
1094     /** @var boolean Should the external function return raw text or formatted */
1095     private $raw = false;
1096
1097     /** @var boolean Should the external function filter the text */
1098     private $filter = false;
1099
1100     /** @var boolean Should the external function rewrite plugin file url */
1101     private $fileurl = true;
1102
1103     /** @var string In which file should the urls be rewritten */
1104     private $file = 'webservice/pluginfile.php';
1105
1106     /**
1107      * Constructor - protected - can not be instanciated
1108      */
1109     protected function __construct() {
1110         if (!defined('AJAX_SCRIPT') && !defined('CLI_SCRIPT') && !defined('WS_SERVER')) {
1111             // For normal pages, the default should match the default for format_text.
1112             $this->filter = true;
1113         }
1114     }
1115
1116     /**
1117      * Clone - private - can not be cloned
1118      */
1119     private final function __clone() {
1120     }
1121
1122     /**
1123      * Return only one instance
1124      *
1125      * @return object
1126      */
1127     public static function get_instance() {
1128         if (self::$instance === null) {
1129             self::$instance = new external_settings;
1130         }
1131
1132         return self::$instance;
1133     }
1134
1135     /**
1136      * Set raw
1137      *
1138      * @param boolean $raw
1139      */
1140     public function set_raw($raw) {
1141         $this->raw = $raw;
1142     }
1143
1144     /**
1145      * Get raw
1146      *
1147      * @return boolean
1148      */
1149     public function get_raw() {
1150         return $this->raw;
1151     }
1152
1153     /**
1154      * Set filter
1155      *
1156      * @param boolean $filter
1157      */
1158     public function set_filter($filter) {
1159         $this->filter = $filter;
1160     }
1161
1162     /**
1163      * Get filter
1164      *
1165      * @return boolean
1166      */
1167     public function get_filter() {
1168         return $this->filter;
1169     }
1170
1171     /**
1172      * Set fileurl
1173      *
1174      * @param boolean $fileurl
1175      */
1176     public function set_fileurl($fileurl) {
1177         $this->fileurl = $fileurl;
1178     }
1179
1180     /**
1181      * Get fileurl
1182      *
1183      * @return boolean
1184      */
1185     public function get_fileurl() {
1186         return $this->fileurl;
1187     }
1188
1189     /**
1190      * Set file
1191      *
1192      * @param string $file
1193      */
1194     public function set_file($file) {
1195         $this->file = $file;
1196     }
1197
1198     /**
1199      * Get file
1200      *
1201      * @return string
1202      */
1203     public function get_file() {
1204         return $this->file;
1205     }
1206 }
1207
1208 /**
1209  * Utility functions for the external API.
1210  *
1211  * @package    core_webservice
1212  * @copyright  2015 Juan Leyva
1213  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1214  * @since Moodle 3.0
1215  */
1216 class external_util {
1217
1218     /**
1219      * Validate a list of courses, returning the complete course objects for valid courses.
1220      *
1221      * @param  array $courseids A list of course ids
1222      * @param  array $courses   An array of courses already pre-fetched, indexed by course id.
1223      * @param  bool $addcontext True if the returned course object should include the full context object.
1224      * @return array            An array of courses and the validation warnings
1225      */
1226     public static function validate_courses($courseids, $courses = array(), $addcontext = false) {
1227         // Delete duplicates.
1228         $courseids = array_unique($courseids);
1229         $warnings = array();
1230
1231         // Remove courses which are not even requested.
1232         $courses =  array_intersect_key($courses, array_flip($courseids));
1233
1234         foreach ($courseids as $cid) {
1235             // Check the user can function in this context.
1236             try {
1237                 $context = context_course::instance($cid);
1238                 external_api::validate_context($context);
1239
1240                 if (!isset($courses[$cid])) {
1241                     $courses[$cid] = get_course($cid);
1242                 }
1243                 if ($addcontext) {
1244                     $courses[$cid]->context = $context;
1245                 }
1246             } catch (Exception $e) {
1247                 unset($courses[$cid]);
1248                 $warnings[] = array(
1249                     'item' => 'course',
1250                     'itemid' => $cid,
1251                     'warningcode' => '1',
1252                     'message' => 'No access rights in course context'
1253                 );
1254             }
1255         }
1256
1257         return array($courses, $warnings);
1258     }
1259
1260     /**
1261      * Returns all area files (optionally limited by itemid).
1262      *
1263      * @param int $contextid context ID
1264      * @param string $component component
1265      * @param string $filearea file area
1266      * @param int $itemid item ID or all files if not specified
1267      * @param bool $useitemidinurl wether to use the item id in the file URL (modules intro don't use it)
1268      * @return array of files, compatible with the external_files structure.
1269      * @since Moodle 3.2
1270      */
1271     public static function get_area_files($contextid, $component, $filearea, $itemid = false, $useitemidinurl = true) {
1272         $files = array();
1273         $fs = get_file_storage();
1274
1275         if ($areafiles = $fs->get_area_files($contextid, $component, $filearea, $itemid, 'itemid, filepath, filename', false)) {
1276             foreach ($areafiles as $areafile) {
1277                 $file = array();
1278                 $file['filename'] = $areafile->get_filename();
1279                 $file['filepath'] = $areafile->get_filepath();
1280                 $file['mimetype'] = $areafile->get_mimetype();
1281                 $file['filesize'] = $areafile->get_filesize();
1282                 $file['timemodified'] = $areafile->get_timemodified();
1283                 $fileitemid = $useitemidinurl ? $areafile->get_itemid() : null;
1284                 $file['fileurl'] = moodle_url::make_webservice_pluginfile_url($contextid, $component, $filearea,
1285                                     $fileitemid, $areafile->get_filepath(), $areafile->get_filename())->out(false);
1286                 $files[] = $file;
1287             }
1288         }
1289         return $files;
1290     }
1291 }
1292
1293 /**
1294  * External structure representing a set of files.
1295  *
1296  * @package    core_webservice
1297  * @copyright  2016 Juan Leyva
1298  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1299  * @since      Moodle 3.2
1300  */
1301 class external_files extends external_multiple_structure {
1302
1303     /**
1304      * Constructor
1305      * @param string $desc Description for the multiple structure.
1306      * @param int $required The type of value (VALUE_REQUIRED OR VALUE_OPTIONAL).
1307      */
1308     public function __construct($desc = 'List of files.', $required = VALUE_REQUIRED) {
1309
1310         parent::__construct(
1311             new external_single_structure(
1312                 array(
1313                     'filename' => new external_value(PARAM_FILE, 'File name.', VALUE_OPTIONAL),
1314                     'filepath' => new external_value(PARAM_PATH, 'File path.', VALUE_OPTIONAL),
1315                     'filesize' => new external_value(PARAM_INT, 'File size.', VALUE_OPTIONAL),
1316                     'fileurl' => new external_value(PARAM_URL, 'Downloadable file url.', VALUE_OPTIONAL),
1317                     'timemodified' => new external_value(PARAM_INT, 'Time modified.', VALUE_OPTIONAL),
1318                     'mimetype' => new external_value(PARAM_RAW, 'File mime type.', VALUE_OPTIONAL),
1319                 ),
1320                 'File.'
1321             ),
1322             $desc,
1323             $required
1324         );
1325     }
1326 }