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  * Returns detailed function information
  30  *
  31  * @param string|object $function name of external function or record from external_function
  32  * @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
  33  *                        MUST_EXIST means throw exception if no record or multiple records found
  34  * @return stdClass description or false if not found or exception thrown
  35  * @since Moodle 2.0
  36  */
  37 function external_function_info($function, $strictness=MUST_EXIST) {
  38     global $DB, $CFG;
  39
  40     if (!is_object($function)) {
  41         if (!$function = $DB->get_record('external_functions', array('name'=>$function), '*', $strictness)) {
  42             return false;
  43         }
  44     }
  45
  46     // First try class autoloading.
  47     if (!class_exists($function->classname)) {
  48         // Fallback to explicit include of externallib.php.
  49         $function->classpath = empty($function->classpath) ? core_component::get_component_directory($function->component).'/externallib.php' : $CFG->dirroot.'/'.$function->classpath;
  50         if (!file_exists($function->classpath)) {
  51             throw new coding_exception('Cannot find file with external function implementation: ' . $function->classname);
  52         }
  53         require_once($function->classpath);
  54         if (!class_exists($function->classname)) {
  55             throw new coding_exception('Cannot find external class');
  56         }
  57     }
  58
  59     $function->ajax_method = $function->methodname.'_is_allowed_from_ajax';
  60     $function->parameters_method = $function->methodname.'_parameters';
  61     $function->returns_method    = $function->methodname.'_returns';
  62     $function->deprecated_method = $function->methodname.'_is_deprecated';
  63
  64     // make sure the implementaion class is ok
  65     if (!method_exists($function->classname, $function->methodname)) {
  66         throw new coding_exception('Missing implementation method of '.$function->classname.'::'.$function->methodname);
  67     }
  68     if (!method_exists($function->classname, $function->parameters_method)) {
  69         throw new coding_exception('Missing parameters description');
  70     }
  71     if (!method_exists($function->classname, $function->returns_method)) {
  72         throw new coding_exception('Missing returned values description');
  73     }
  74     if (method_exists($function->classname, $function->deprecated_method)) {
  75         if (call_user_func(array($function->classname, $function->deprecated_method)) === true) {
  76             $function->deprecated = true;
  77         }
  78     }
  79     $function->allowed_from_ajax = false;
  80
  81     // fetch the parameters description
  82     $function->parameters_desc = call_user_func(array($function->classname, $function->parameters_method));
  83     if (!($function->parameters_desc instanceof external_function_parameters)) {
  84         throw new coding_exception('Invalid parameters description');
  85     }
  86
  87     // fetch the return values description
  88     $function->returns_desc = call_user_func(array($function->classname, $function->returns_method));
  89     // null means void result or result is ignored
  90     if (!is_null($function->returns_desc) and !($function->returns_desc instanceof external_description)) {
  91         throw new coding_exception('Invalid return description');
  92     }
  93
  94     //now get the function description
  95     //TODO MDL-31115 use localised lang pack descriptions, it would be nice to have
  96     //      easy to understand descriptions in admin UI,
  97     //      on the other hand this is still a bit in a flux and we need to find some new naming
  98     //      conventions for these descriptions in lang packs
  99     $function->description = null;
 100     $servicesfile = core_component::get_component_directory($function->component).'/db/services.php';
 101     if (file_exists($servicesfile)) {
 102         $functions = null;
 103         include($servicesfile);
 104         if (isset($functions[$function->name]['description'])) {
 105             $function->description = $functions[$function->name]['description'];
 106         }
 107         if (isset($functions[$function->name]['testclientpath'])) {
 108             $function->testclientpath = $functions[$function->name]['testclientpath'];
 109         }
 110         if (isset($functions[$function->name]['type'])) {
 111             $function->type = $functions[$function->name]['type'];
 112         }
 113         if (isset($functions[$function->name]['ajax'])) {
 114             $function->allowed_from_ajax = $functions[$function->name]['ajax'];
 115         } else if (method_exists($function->classname, $function->ajax_method)) {
 116             if (call_user_func(array($function->classname, $function->ajax_method)) === true) {
 117                 debugging('External function ' . $function->ajax_method . '() function is deprecated.' .
 118                           'Set ajax=>true in db/service.php instead.', DEBUG_DEVELOPER);
 119                 $function->allowed_from_ajax = true;
 120             }
 121         }
 122         if (isset($functions[$function->name]['loginrequired'])) {
 123             $function->loginrequired = $functions[$function->name]['loginrequired'];
 124         } else {
 125             $function->loginrequired = true;
 126         }
 127     }
 128
 129     return $function;
 130 }
 131
 132 /**
 133  * Exception indicating user is not allowed to use external function in the current context.
 134  *
 135  * @package    core_webservice
 136  * @copyright  2009 Petr Skodak
 137  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 138  * @since Moodle 2.0
 139  */
 140 class restricted_context_exception extends moodle_exception {
 141     /**
 142      * Constructor
 143      *
 144      * @since Moodle 2.0
 145      */
 146     function __construct() {
 147         parent::__construct('restrictedcontextexception', 'error');
 148     }
 149 }
 150
 151 /**
 152  * Base class for external api methods.
 153  *
 154  * @package    core_webservice
 155  * @copyright  2009 Petr Skodak
 156  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 157  * @since Moodle 2.0
 158  */
 159 class external_api {
 160
 161     /** @var stdClass context where the function calls will be restricted */
 162     private static $contextrestriction;
 163
 164     /**
 165      * Set context restriction for all following subsequent function calls.
 166      *
 167      * @param stdClass $context the context restriction
 168      * @since Moodle 2.0
 169      */
 170     public static function set_context_restriction($context) {
 171         self::$contextrestriction = $context;
 172     }
 173
 174     /**
 175      * This method has to be called before every operation
 176      * that takes a longer time to finish!
 177      *
 178      * @param int $seconds max expected time the next operation needs
 179      * @since Moodle 2.0
 180      */
 181     public static function set_timeout($seconds=360) {
 182         $seconds = ($seconds < 300) ? 300 : $seconds;
 183         core_php_time_limit::raise($seconds);
 184     }
 185
 186     /**
 187      * Validates submitted function parameters, if anything is incorrect
 188      * invalid_parameter_exception is thrown.
 189      * This is a simple recursive method which is intended to be called from
 190      * each implementation method of external API.
 191      *
 192      * @param external_description $description description of parameters
 193      * @param mixed $params the actual parameters
 194      * @return mixed params with added defaults for optional items, invalid_parameters_exception thrown if any problem found
 195      * @since Moodle 2.0
 196      */
 197     public static function validate_parameters(external_description $description, $params) {
 198         if ($description instanceof external_value) {
 199             if (is_array($params) or is_object($params)) {
 200                 throw new invalid_parameter_exception('Scalar type expected, array or object received.');
 201             }
 202
 203             if ($description->type == PARAM_BOOL) {
 204                 // special case for PARAM_BOOL - we want true/false instead of the usual 1/0 - we can not be too strict here ;-)
 205                 if (is_bool($params) or $params === 0 or $params === 1 or $params === '0' or $params === '1') {
 206                     return (bool)$params;
 207                 }
 208             }
 209             $debuginfo = 'Invalid external api parameter: the value is "' . $params .
 210                     '", the server was expecting "' . $description->type . '" type';
 211             return validate_param($params, $description->type, $description->allownull, $debuginfo);
 212
 213         } else if ($description instanceof external_single_structure) {
 214             if (!is_array($params)) {
 215                 throw new invalid_parameter_exception('Only arrays accepted. The bad value is: \''
 216                         . print_r($params, true) . '\'');
 217             }
 218             $result = array();
 219             foreach ($description->keys as $key=>$subdesc) {
 220                 if (!array_key_exists($key, $params)) {
 221                     if ($subdesc->required == VALUE_REQUIRED) {
 222                         throw new invalid_parameter_exception('Missing required key in single structure: '. $key);
 223                     }
 224                     if ($subdesc->required == VALUE_DEFAULT) {
 225                         try {
 226                             $result[$key] = self::validate_parameters($subdesc, $subdesc->default);
 227                         } catch (invalid_parameter_exception $e) {
 228                             //we are only interested by exceptions returned by validate_param() and validate_parameters()
 229                             //(in order to build the path to the faulty attribut)
 230                             throw new invalid_parameter_exception($key." => ".$e->getMessage() . ': ' .$e->debuginfo);
 231                         }
 232                     }
 233                 } else {
 234                     try {
 235                         $result[$key] = self::validate_parameters($subdesc, $params[$key]);
 236                     } catch (invalid_parameter_exception $e) {
 237                         //we are only interested by exceptions returned by validate_param() and validate_parameters()
 238                         //(in order to build the path to the faulty attribut)
 239                         throw new invalid_parameter_exception($key." => ".$e->getMessage() . ': ' .$e->debuginfo);
 240                     }
 241                 }
 242                 unset($params[$key]);
 243             }
 244             if (!empty($params)) {
 245                 throw new invalid_parameter_exception('Unexpected keys (' . implode(', ', array_keys($params)) . ') detected in parameter array.');
 246             }
 247             return $result;
 248
 249         } else if ($description instanceof external_multiple_structure) {
 250             if (!is_array($params)) {
 251                 throw new invalid_parameter_exception('Only arrays accepted. The bad value is: \''
 252                         . print_r($params, true) . '\'');
 253             }
 254             $result = array();
 255             foreach ($params as $param) {
 256                 $result[] = self::validate_parameters($description->content, $param);
 257             }
 258             return $result;
 259
 260         } else {
 261             throw new invalid_parameter_exception('Invalid external api description');
 262         }
 263     }
 264
 265     /**
 266      * Clean response
 267      * If a response attribute is unknown from the description, we just ignore the attribute.
 268      * If a response attribute is incorrect, invalid_response_exception is thrown.
 269      * Note: this function is similar to validate parameters, however it is distinct because
 270      * parameters validation must be distinct from cleaning return values.
 271      *
 272      * @param external_description $description description of the return values
 273      * @param mixed $response the actual response
 274      * @return mixed response with added defaults for optional items, invalid_response_exception thrown if any problem found
 275      * @author 2010 Jerome Mouneyrac
 276      * @since Moodle 2.0
 277      */
 278     public static function clean_returnvalue(external_description $description, $response) {
 279         if ($description instanceof external_value) {
 280             if (is_array($response) or is_object($response)) {
 281                 throw new invalid_response_exception('Scalar type expected, array or object received.');
 282             }
 283
 284             if ($description->type == PARAM_BOOL) {
 285                 // special case for PARAM_BOOL - we want true/false instead of the usual 1/0 - we can not be too strict here ;-)
 286                 if (is_bool($response) or $response === 0 or $response === 1 or $response === '0' or $response === '1') {
 287                     return (bool)$response;
 288                 }
 289             }
 290             $debuginfo = 'Invalid external api response: the value is "' . $response .
 291                     '", the server was expecting "' . $description->type . '" type';
 292             try {
 293                 return validate_param($response, $description->type, $description->allownull, $debuginfo);
 294             } catch (invalid_parameter_exception $e) {
 295                 //proper exception name, to be recursively catched to build the path to the faulty attribut
 296                 throw new invalid_response_exception($e->debuginfo);
 297             }
 298
 299         } else if ($description instanceof external_single_structure) {
 300             if (!is_array($response) && !is_object($response)) {
 301                 throw new invalid_response_exception('Only arrays/objects accepted. The bad value is: \'' .
 302                         print_r($response, true) . '\'');
 303             }
 304
 305             // Cast objects into arrays.
 306             if (is_object($response)) {
 307                 $response = (array) $response;
 308             }
 309
 310             $result = array();
 311             foreach ($description->keys as $key=>$subdesc) {
 312                 if (!array_key_exists($key, $response)) {
 313                     if ($subdesc->required == VALUE_REQUIRED) {
 314                         throw new invalid_response_exception('Error in response - Missing following required key in a single structure: ' . $key);
 315                     }
 316                     if ($subdesc instanceof external_value) {
 317                         if ($subdesc->required == VALUE_DEFAULT) {
 318                             try {
 319                                     $result[$key] = self::clean_returnvalue($subdesc, $subdesc->default);
 320                             } catch (invalid_response_exception $e) {
 321                                 //build the path to the faulty attribut
 322                                 throw new invalid_response_exception($key." => ".$e->getMessage() . ': ' . $e->debuginfo);
 323                             }
 324                         }
 325                     }
 326                 } else {
 327                     try {
 328                         $result[$key] = self::clean_returnvalue($subdesc, $response[$key]);
 329                     } catch (invalid_response_exception $e) {
 330                         //build the path to the faulty attribut
 331                         throw new invalid_response_exception($key." => ".$e->getMessage() . ': ' . $e->debuginfo);
 332                     }
 333                 }
 334                 unset($response[$key]);
 335             }
 336
 337             return $result;
 338
 339         } else if ($description instanceof external_multiple_structure) {
 340             if (!is_array($response)) {
 341                 throw new invalid_response_exception('Only arrays accepted. The bad value is: \'' .
 342                         print_r($response, true) . '\'');
 343             }
 344             $result = array();
 345             foreach ($response as $param) {
 346                 $result[] = self::clean_returnvalue($description->content, $param);
 347             }
 348             return $result;
 349
 350         } else {
 351             throw new invalid_response_exception('Invalid external api response description');
 352         }
 353     }
 354
 355     /**
 356      * Makes sure user may execute functions in this context.
 357      *
 358      * @param stdClass $context
 359      * @since Moodle 2.0
 360      */
 361     public static function validate_context($context) {
 362         global $CFG;
 363
 364         if (empty($context)) {
 365             throw new invalid_parameter_exception('Context does not exist');
 366         }
 367         if (empty(self::$contextrestriction)) {
 368             self::$contextrestriction = context_system::instance();
 369         }
 370         $rcontext = self::$contextrestriction;
 371
 372         if ($rcontext->contextlevel == $context->contextlevel) {
 373             if ($rcontext->id != $context->id) {
 374                 throw new restricted_context_exception();
 375             }
 376         } else if ($rcontext->contextlevel > $context->contextlevel) {
 377             throw new restricted_context_exception();
 378         } else {
 379             $parents = $context->get_parent_context_ids();
 380             if (!in_array($rcontext->id, $parents)) {
 381                 throw new restricted_context_exception();
 382             }
 383         }
 384
 385         if ($context->contextlevel >= CONTEXT_COURSE) {
 386             list($context, $course, $cm) = get_context_info_array($context->id);
 387             require_login($course, false, $cm, false, true);
 388         }
 389     }
 390
 391     /**
 392      * Get context from passed parameters.
 393      * The passed array must either contain a contextid or a combination of context level and instance id to fetch the context.
 394      * For example, the context level can be "course" and instanceid can be courseid.
 395      *
 396      * See context_helper::get_all_levels() for a list of valid context levels.
 397      *
 398      * @param array $param
 399      * @since Moodle 2.6
 400      * @throws invalid_parameter_exception
 401      * @return context
 402      */
 403     protected static function get_context_from_params($param) {
 404         $levels = context_helper::get_all_levels();
 405         if (!empty($param['contextid'])) {
 406             return context::instance_by_id($param['contextid'], IGNORE_MISSING);
 407         } else if (!empty($param['contextlevel']) && isset($param['instanceid'])) {
 408             $contextlevel = "context_".$param['contextlevel'];
 409             if (!array_search($contextlevel, $levels)) {
 410                 throw new invalid_parameter_exception('Invalid context level = '.$param['contextlevel']);
 411             }
 412            return $contextlevel::instance($param['instanceid'], IGNORE_MISSING);
 413         } else {
 414             // No valid context info was found.
 415             throw new invalid_parameter_exception('Missing parameters, please provide either context level with instance id or contextid');
 416         }
 417     }
 418 }
 419
 420 /**
 421  * Common ancestor of all parameter description classes
 422  *
 423  * @package    core_webservice
 424  * @copyright  2009 Petr Skodak
 425  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 426  * @since Moodle 2.0
 427  */
 428 abstract class external_description {
 429     /** @var string Description of element */
 430     public $desc;
 431
 432     /** @var bool Element value required, null not allowed */
 433     public $required;
 434
 435     /** @var mixed Default value */
 436     public $default;
 437
 438     /**
 439      * Contructor
 440      *
 441      * @param string $desc
 442      * @param bool $required
 443      * @param mixed $default
 444      * @since Moodle 2.0
 445      */
 446     public function __construct($desc, $required, $default) {
 447         $this->desc = $desc;
 448         $this->required = $required;
 449         $this->default = $default;
 450     }
 451 }
 452
 453 /**
 454  * Scalar value description class
 455  *
 456  * @package    core_webservice
 457  * @copyright  2009 Petr Skodak
 458  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 459  * @since Moodle 2.0
 460  */
 461 class external_value extends external_description {
 462
 463     /** @var mixed Value type PARAM_XX */
 464     public $type;
 465
 466     /** @var bool Allow null values */
 467     public $allownull;
 468
 469     /**
 470      * Constructor
 471      *
 472      * @param mixed $type
 473      * @param string $desc
 474      * @param bool $required
 475      * @param mixed $default
 476      * @param bool $allownull
 477      * @since Moodle 2.0
 478      */
 479     public function __construct($type, $desc='', $required=VALUE_REQUIRED,
 480             $default=null, $allownull=NULL_ALLOWED) {
 481         parent::__construct($desc, $required, $default);
 482         $this->type      = $type;
 483         $this->allownull = $allownull;
 484     }
 485 }
 486
 487 /**
 488  * Associative array description class
 489  *
 490  * @package    core_webservice
 491  * @copyright  2009 Petr Skodak
 492  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 493  * @since Moodle 2.0
 494  */
 495 class external_single_structure extends external_description {
 496
 497      /** @var array Description of array keys key=>external_description */
 498     public $keys;
 499
 500     /**
 501      * Constructor
 502      *
 503      * @param array $keys
 504      * @param string $desc
 505      * @param bool $required
 506      * @param array $default
 507      * @since Moodle 2.0
 508      */
 509     public function __construct(array $keys, $desc='',
 510             $required=VALUE_REQUIRED, $default=null) {
 511         parent::__construct($desc, $required, $default);
 512         $this->keys = $keys;
 513     }
 514 }
 515
 516 /**
 517  * Bulk array description class.
 518  *
 519  * @package    core_webservice
 520  * @copyright  2009 Petr Skodak
 521  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 522  * @since Moodle 2.0
 523  */
 524 class external_multiple_structure extends external_description {
 525
 526      /** @var external_description content */
 527     public $content;
 528
 529     /**
 530      * Constructor
 531      *
 532      * @param external_description $content
 533      * @param string $desc
 534      * @param bool $required
 535      * @param array $default
 536      * @since Moodle 2.0
 537      */
 538     public function __construct(external_description $content, $desc='',
 539             $required=VALUE_REQUIRED, $default=null) {
 540         parent::__construct($desc, $required, $default);
 541         $this->content = $content;
 542     }
 543 }
 544
 545 /**
 546  * Description of top level - PHP function parameters.
 547  *
 548  * @package    core_webservice
 549  * @copyright  2009 Petr Skodak
 550  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 551  * @since Moodle 2.0
 552  */
 553 class external_function_parameters extends external_single_structure {
 554
 555     /**
 556      * Constructor - does extra checking to prevent top level optional parameters.
 557      *
 558      * @param array $keys
 559      * @param string $desc
 560      * @param bool $required
 561      * @param array $default
 562      */
 563     public function __construct(array $keys, $desc='', $required=VALUE_REQUIRED, $default=null) {
 564         global $CFG;
 565
 566         if ($CFG->debugdeveloper) {
 567             foreach ($keys as $key => $value) {
 568                 if ($value instanceof external_value) {
 569                     if ($value->required == VALUE_OPTIONAL) {
 570                         debugging('External function parameters: invalid OPTIONAL value specified.', DEBUG_DEVELOPER);
 571                         break;
 572                     }
 573                 }
 574             }
 575         }
 576         parent::__construct($keys, $desc, $required, $default);
 577     }
 578 }
 579
 580 /**
 581  * Generate a token
 582  *
 583  * @param string $tokentype EXTERNAL_TOKEN_EMBEDDED|EXTERNAL_TOKEN_PERMANENT
 584  * @param stdClass|int $serviceorid service linked to the token
 585  * @param int $userid user linked to the token
 586  * @param stdClass|int $contextorid
 587  * @param int $validuntil date when the token expired
 588  * @param string $iprestriction allowed ip - if 0 or empty then all ips are allowed
 589  * @return string generated token
 590  * @author  2010 Jamie Pratt
 591  * @since Moodle 2.0
 592  */
 593 function external_generate_token($tokentype, $serviceorid, $userid, $contextorid, $validuntil=0, $iprestriction=''){
 594     global $DB, $USER;
 595     // make sure the token doesn't exist (even if it should be almost impossible with the random generation)
 596     $numtries = 0;
 597     do {
 598         $numtries ++;
 599         $generatedtoken = md5(uniqid(rand(),1));
 600         if ($numtries > 5){
 601             throw new moodle_exception('tokengenerationfailed');
 602         }
 603     } while ($DB->record_exists('external_tokens', array('token'=>$generatedtoken)));
 604     $newtoken = new stdClass();
 605     $newtoken->token = $generatedtoken;
 606     if (!is_object($serviceorid)){
 607         $service = $DB->get_record('external_services', array('id' => $serviceorid));
 608     } else {
 609         $service = $serviceorid;
 610     }
 611     if (!is_object($contextorid)){
 612         $context = context::instance_by_id($contextorid, MUST_EXIST);
 613     } else {
 614         $context = $contextorid;
 615     }
 616     if (empty($service->requiredcapability) || has_capability($service->requiredcapability, $context, $userid)) {
 617         $newtoken->externalserviceid = $service->id;
 618     } else {
 619         throw new moodle_exception('nocapabilitytousethisservice');
 620     }
 621     $newtoken->tokentype = $tokentype;
 622     $newtoken->userid = $userid;
 623     if ($tokentype == EXTERNAL_TOKEN_EMBEDDED){
 624         $newtoken->sid = session_id();
 625     }
 626
 627     $newtoken->contextid = $context->id;
 628     $newtoken->creatorid = $USER->id;
 629     $newtoken->timecreated = time();
 630     $newtoken->validuntil = $validuntil;
 631     if (!empty($iprestriction)) {
 632         $newtoken->iprestriction = $iprestriction;
 633     }
 634     $DB->insert_record('external_tokens', $newtoken);
 635     return $newtoken->token;
 636 }
 637
 638 /**
 639  * Create and return a session linked token. Token to be used for html embedded client apps that want to communicate
 640  * with the Moodle server through web services. The token is linked to the current session for the current page request.
 641  * It is expected this will be called in the script generating the html page that is embedding the client app and that the
 642  * returned token will be somehow passed into the client app being embedded in the page.
 643  *
 644  * @param string $servicename name of the web service. Service name as defined in db/services.php
 645  * @param int $context context within which the web service can operate.
 646  * @return int returns token id.
 647  * @since Moodle 2.0
 648  */
 649 function external_create_service_token($servicename, $context){
 650     global $USER, $DB;
 651     $service = $DB->get_record('external_services', array('name'=>$servicename), '*', MUST_EXIST);
 652     return external_generate_token(EXTERNAL_TOKEN_EMBEDDED, $service, $USER->id, $context, 0);
 653 }
 654
 655 /**
 656  * Delete all pre-built services (+ related tokens) and external functions information defined in the specified component.
 657  *
 658  * @param string $component name of component (moodle, mod_assignment, etc.)
 659  */
 660 function external_delete_descriptions($component) {
 661     global $DB;
 662
 663     $params = array($component);
 664
 665     $DB->delete_records_select('external_tokens',
 666             "externalserviceid IN (SELECT id FROM {external_services} WHERE component = ?)", $params);
 667     $DB->delete_records_select('external_services_users',
 668             "externalserviceid IN (SELECT id FROM {external_services} WHERE component = ?)", $params);
 669     $DB->delete_records_select('external_services_functions',
 670             "functionname IN (SELECT name FROM {external_functions} WHERE component = ?)", $params);
 671     $DB->delete_records('external_services', array('component'=>$component));
 672     $DB->delete_records('external_functions', array('component'=>$component));
 673 }
 674
 675 /**
 676  * Standard Moodle web service warnings
 677  *
 678  * @package    core_webservice
 679  * @copyright  2012 Jerome Mouneyrac
 680  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 681  * @since Moodle 2.3
 682  */
 683 class external_warnings extends external_multiple_structure {
 684
 685     /**
 686      * Constructor
 687      *
 688      * @since Moodle 2.3
 689      */
 690     public function __construct($itemdesc = 'item', $itemiddesc = 'item id',
 691         $warningcodedesc = 'the warning code can be used by the client app to implement specific behaviour') {
 692
 693         parent::__construct(
 694             new external_single_structure(
 695                 array(
 696                     'item' => new external_value(PARAM_TEXT, $itemdesc, VALUE_OPTIONAL),
 697                     'itemid' => new external_value(PARAM_INT, $itemiddesc, VALUE_OPTIONAL),
 698                     'warningcode' => new external_value(PARAM_ALPHANUM, $warningcodedesc),
 699                     'message' => new external_value(PARAM_TEXT,
 700                             'untranslated english message to explain the warning')
 701                 ), 'warning'),
 702             'list of warnings', VALUE_OPTIONAL);
 703     }
 704 }
 705
 706 /**
 707  * A pre-filled external_value class for text format.
 708  *
 709  * Default is FORMAT_HTML
 710  * This should be used all the time in external xxx_params()/xxx_returns functions
 711  * as it is the standard way to implement text format param/return values.
 712  *
 713  * @package    core_webservice
 714  * @copyright  2012 Jerome Mouneyrac
 715  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 716  * @since Moodle 2.3
 717  */
 718 class external_format_value extends external_value {
 719
 720     /**
 721      * Constructor
 722      *
 723      * @param string $textfieldname Name of the text field
 724      * @param int $required if VALUE_REQUIRED then set standard default FORMAT_HTML
 725      * @since Moodle 2.3
 726      */
 727     public function __construct($textfieldname, $required = VALUE_REQUIRED) {
 728
 729         $default = ($required == VALUE_DEFAULT) ? FORMAT_HTML : null;
 730
 731         $desc = $textfieldname . ' format (' . FORMAT_HTML . ' = HTML, '
 732                 . FORMAT_MOODLE . ' = MOODLE, '
 733                 . FORMAT_PLAIN . ' = PLAIN or '
 734                 . FORMAT_MARKDOWN . ' = MARKDOWN)';
 735
 736         parent::__construct(PARAM_INT, $desc, $required, $default);
 737     }
 738 }
 739
 740 /**
 741  * Validate text field format against known FORMAT_XXX
 742  *
 743  * @param array $format the format to validate
 744  * @return the validated format
 745  * @throws coding_exception
 746  * @since Moodle 2.3
 747  */
 748 function external_validate_format($format) {
 749     $allowedformats = array(FORMAT_HTML, FORMAT_MOODLE, FORMAT_PLAIN, FORMAT_MARKDOWN);
 750     if (!in_array($format, $allowedformats)) {
 751         throw new moodle_exception('formatnotsupported', 'webservice', '' , null,
 752                 'The format with value=' . $format . ' is not supported by this Moodle site');
 753     }
 754     return $format;
 755 }
 756
 757 /**
 758  * Format the string to be returned properly as requested by the either the web service server,
 759  * either by an internally call.
 760  * The caller can change the format (raw) with the external_settings singleton
 761  * All web service servers must set this singleton when parsing the $_GET and $_POST.
 762  *
 763  * @param string $str The string to be filtered. Should be plain text, expect
 764  * possibly for multilang tags.
 765  * @param boolean $striplinks To strip any link in the result text. Moodle 1.8 default changed from false to true! MDL-8713
 766  * @param int $contextid The id of the context for the string (affects filters).
 767  * @param array $options options array/object or courseid
 768  * @return string text
 769  * @since Moodle 3.0
 770  */
 771 function external_format_string($str, $contextid, $striplinks = true, $options = array()) {
 772
 773     // Get settings (singleton).
 774     $settings = external_settings::get_instance();
 775     if (empty($contextid)) {
 776         throw new coding_exception('contextid is required');
 777     }
 778
 779     if (!$settings->get_raw()) {
 780         $context = context::instance_by_id($contextid);
 781         $options['context'] = $context;
 782         $options['filter'] = $settings->get_filter();
 783         $str = format_string($str, $striplinks, $options);
 784     }
 785
 786     return $str;
 787 }
 788
 789 /**
 790  * Format the text to be returned properly as requested by the either the web service server,
 791  * either by an internally call.
 792  * The caller can change the format (raw, filter, file, fileurl) with the external_settings singleton
 793  * All web service servers must set this singleton when parsing the $_GET and $_POST.
 794  *
 795  * @param string $text The content that may contain ULRs in need of rewriting.
 796  * @param int $textformat The text format.
 797  * @param int $contextid This parameter and the next two identify the file area to use.
 798  * @param string $component
 799  * @param string $filearea helps identify the file area.
 800  * @param int $itemid helps identify the file area.
 801  * @return array text + textformat
 802  * @since Moodle 2.3
 803  */
 804 function external_format_text($text, $textformat, $contextid, $component, $filearea, $itemid) {
 805     global $CFG;
 806
 807     // Get settings (singleton).
 808     $settings = external_settings::get_instance();
 809
 810     if ($settings->get_fileurl()) {
 811         require_once($CFG->libdir . "/filelib.php");
 812         $text = file_rewrite_pluginfile_urls($text, $settings->get_file(), $contextid, $component, $filearea, $itemid);
 813     }
 814
 815     if (!$settings->get_raw()) {
 816         $context = context::instance_by_id($contextid);
 817         $text = format_text($text, $textformat, array('para' => false, 'filter' => $settings->get_filter(), 'context' => $context));
 818         $textformat = FORMAT_HTML; // Once converted to html (from markdown, plain... lets inform consumer this is already HTML).
 819     }
 820
 821     return array($text, $textformat);
 822 }
 823
 824 /**
 825  * Singleton to handle the external settings.
 826  *
 827  * We use singleton to encapsulate the "logic"
 828  *
 829  * @package    core_webservice
 830  * @copyright  2012 Jerome Mouneyrac
 831  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 832  * @since Moodle 2.3
 833  */
 834 class external_settings {
 835
 836     /** @var object the singleton instance */
 837     public static $instance = null;
 838
 839     /** @var boolean Should the external function return raw text or formatted */
 840     private $raw = false;
 841
 842     /** @var boolean Should the external function filter the text */
 843     private $filter = false;
 844
 845     /** @var boolean Should the external function rewrite plugin file url */
 846     private $fileurl = true;
 847
 848     /** @var string In which file should the urls be rewritten */
 849     private $file = 'webservice/pluginfile.php';
 850
 851     /**
 852      * Constructor - protected - can not be instanciated
 853      */
 854     protected function __construct() {
 855         if (!defined('AJAX_SCRIPT') && !defined('CLI_SCRIPT') && !defined('WS_SERVER')) {
 856             // For normal pages, the default should match the default for format_text.
 857             $this->filter = true;
 858         }
 859     }
 860
 861     /**
 862      * Clone - private - can not be cloned
 863      */
 864     private final function __clone() {
 865     }
 866
 867     /**
 868      * Return only one instance
 869      *
 870      * @return object
 871      */
 872     public static function get_instance() {
 873         if (self::$instance === null) {
 874             self::$instance = new external_settings;
 875         }
 876
 877         return self::$instance;
 878     }
 879
 880     /**
 881      * Set raw
 882      *
 883      * @param boolean $raw
 884      */
 885     public function set_raw($raw) {
 886         $this->raw = $raw;
 887     }
 888
 889     /**
 890      * Get raw
 891      *
 892      * @return boolean
 893      */
 894     public function get_raw() {
 895         return $this->raw;
 896     }
 897
 898     /**
 899      * Set filter
 900      *
 901      * @param boolean $filter
 902      */
 903     public function set_filter($filter) {
 904         $this->filter = $filter;
 905     }
 906
 907     /**
 908      * Get filter
 909      *
 910      * @return boolean
 911      */
 912     public function get_filter() {
 913         return $this->filter;
 914     }
 915
 916     /**
 917      * Set fileurl
 918      *
 919      * @param boolean $fileurl
 920      */
 921     public function set_fileurl($fileurl) {
 922         $this->fileurl = $fileurl;
 923     }
 924
 925     /**
 926      * Get fileurl
 927      *
 928      * @return boolean
 929      */
 930     public function get_fileurl() {
 931         return $this->fileurl;
 932     }
 933
 934     /**
 935      * Set file
 936      *
 937      * @param string $file
 938      */
 939     public function set_file($file) {
 940         $this->file = $file;
 941     }
 942
 943     /**
 944      * Get file
 945      *
 946      * @return string
 947      */
 948     public function get_file() {
 949         return $this->file;
 950     }
 951 }
 952
 953 /**
 954  * Utility functions for the external API.
 955  *
 956  * @package    core_webservice
 957  * @copyright  2015 Juan Leyva
 958  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 959  * @since Moodle 3.0
 960  */
 961 class external_util {
 962
 963     /**
 964      * Validate a list of courses, returning the complete course objects for valid courses.
 965      *
 966      * @param  array $courseids A list of course ids
 967      * @return array            An array of courses and the validation warnings
 968      */
 969     public static function validate_courses($courseids) {
 970         // Delete duplicates.
 971         $courseids = array_unique($courseids);
 972         $courses = array();
 973         $warnings = array();
 974
 975         foreach ($courseids as $cid) {
 976             // Check the user can function in this context.
 977             try {
 978                 $context = context_course::instance($cid);
 979                 external_api::validate_context($context);
 980                 $courses[$cid] = get_course($cid);
 981             } catch (Exception $e) {
 982                 $warnings[] = array(
 983                     'item' => 'course',
 984                     'itemid' => $cid,
 985                     'warningcode' => '1',
 986                     'message' => 'No access rights in course context'
 987                 );
 988             }
 989         }
 990
 991         return array($courses, $warnings);
 992     }
 993
 994 }