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