enrol/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  * External course participation api.
  20  *
  21  * This api is mostly read only, the actual enrol and unenrol
  22  * support is in each enrol plugin.
  23  *
  24  * @package    core_enrol
  25  * @category   external
  26  * @copyright  2010 Jerome Mouneyrac
  27  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  28  */
  29
  30 defined('MOODLE_INTERNAL') || die();
  31
  32 require_once("$CFG->libdir/externallib.php");
  33
  34 /**
  35  * Enrol external functions
  36  *
  37  * @package    core_enrol
  38  * @category   external
  39  * @copyright  2011 Jerome Mouneyrac
  40  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  41  * @since Moodle 2.2
  42  */
  43 class core_enrol_external extends external_api {
  44
  45     /**
  46      * Returns description of method parameters
  47      *
  48      * @return external_function_parameters
  49      * @since Moodle 2.4
  50      */
  51     public static function get_enrolled_users_with_capability_parameters() {
  52         return new external_function_parameters(
  53             array (
  54                 'coursecapabilities' => new external_multiple_structure(
  55                     new external_single_structure(
  56                         array (
  57                             'courseid' => new external_value(PARAM_INT, 'Course ID number in the Moodle course table'),
  58                             'capabilities' => new external_multiple_structure(
  59                                 new external_value(PARAM_CAPABILITY, 'Capability name, such as mod/forum:viewdiscussion')),
  60                         )
  61                     )
  62                 , 'course id and associated capability name'),
  63                  'options'  => new external_multiple_structure(
  64                     new external_single_structure(
  65                         array(
  66                             'name'  => new external_value(PARAM_ALPHANUMEXT, 'option name'),
  67                             'value' => new external_value(PARAM_RAW, 'option value')
  68                         )
  69                     ), 'Option names:
  70                             * groupid (integer) return only users in this group id. Requires \'moodle/site:accessallgroups\' .
  71                             * onlyactive (integer) only users with active enrolments. Requires \'moodle/course:enrolreview\' .
  72                             * userfields (\'string, string, ...\') return only the values of these user fields.
  73                             * limitfrom (integer) sql limit from.
  74                             * limitnumber (integer) max number of users per course and capability.', VALUE_DEFAULT, array())
  75             )
  76         );
  77     }
  78
  79     /**
  80      * Return users that have the capabilities for each course specified. For each course and capability specified,
  81      * a list of the users that are enrolled in the course and have that capability are returned.
  82      *
  83      * @param array $coursecapabilities array of course ids and associated capability names {courseid, {capabilities}}
  84      * @return array An array of arrays describing users for each associated courseid and capability
  85      * @since  Moodle 2.4
  86      */
  87     public static function get_enrolled_users_with_capability($coursecapabilities, $options) {
  88         global $CFG, $DB;
  89
  90         require_once($CFG->dirroot . '/course/lib.php');
  91         require_once($CFG->dirroot . "/user/lib.php");
  92
  93         if (empty($coursecapabilities)) {
  94             throw new invalid_parameter_exception('Parameter can not be empty');
  95         }
  96         $params = self::validate_parameters(self::get_enrolled_users_with_capability_parameters(),
  97             array ('coursecapabilities' => $coursecapabilities,  'options'=>$options));
  98         $result = array();
  99         $userlist = array();
 100         $groupid        = 0;
 101         $onlyactive     = false;
 102         $userfields     = array();
 103         $limitfrom = 0;
 104         $limitnumber = 0;
 105         foreach ($params['options'] as $option) {
 106             switch ($option['name']) {
 107                 case 'groupid':
 108                     $groupid = (int)$option['value'];
 109                     break;
 110                 case 'onlyactive':
 111                     $onlyactive = !empty($option['value']);
 112                     break;
 113                 case 'userfields':
 114                     $thefields = explode(',', $option['value']);
 115                     foreach ($thefields as $f) {
 116                         $userfields[] = clean_param($f, PARAM_ALPHANUMEXT);
 117                     }
 118                     break;
 119                 case 'limitfrom' :
 120                     $limitfrom = clean_param($option['value'], PARAM_INT);
 121                     break;
 122                 case 'limitnumber' :
 123                     $limitnumber = clean_param($option['value'], PARAM_INT);
 124                     break;
 125             }
 126         }
 127
 128         foreach ($params['coursecapabilities'] as $coursecapability) {
 129             $courseid = $coursecapability['courseid'];
 130             $course = $DB->get_record('course', array('id'=>$courseid), '*', MUST_EXIST);
 131             $coursecontext = context_course::instance($courseid);
 132             if (!$coursecontext) {
 133                 throw new moodle_exception('cannotfindcourse', 'error', '', null,
 134                         'The course id ' . $courseid . ' doesn\'t exist.');
 135             }
 136             if ($courseid == SITEID) {
 137                 $context = context_system::instance();
 138             } else {
 139                 $context = $coursecontext;
 140             }
 141             try {
 142                 self::validate_context($context);
 143             } catch (Exception $e) {
 144                 $exceptionparam = new stdClass();
 145                 $exceptionparam->message = $e->getMessage();
 146                 $exceptionparam->courseid = $params['courseid'];
 147                 throw new moodle_exception(get_string('errorcoursecontextnotvalid' , 'webservice', $exceptionparam));
 148             }
 149
 150             course_require_view_participants($context);
 151
 152             // The accessallgroups capability is needed to use this option.
 153             if (!empty($groupid) && groups_is_member($groupid)) {
 154                 require_capability('moodle/site:accessallgroups', $coursecontext);
 155             }
 156             // The course:enrolereview capability is needed to use this option.
 157             if ($onlyactive) {
 158                 require_capability('moodle/course:enrolreview', $coursecontext);
 159             }
 160
 161             // To see the permissions of others role:review capability is required.
 162             require_capability('moodle/role:review', $coursecontext);
 163             foreach ($coursecapability['capabilities'] as $capability) {
 164                 $courseusers['courseid'] = $courseid;
 165                 $courseusers['capability'] = $capability;
 166
 167                 list($enrolledsql, $enrolledparams) = get_enrolled_sql($coursecontext, $capability, $groupid, $onlyactive);
 168
 169                 $sql = "SELECT u.* FROM {user} u WHERE u.id IN ($enrolledsql) ORDER BY u.id ASC";
 170
 171                 $enrolledusers = $DB->get_recordset_sql($sql, $enrolledparams, $limitfrom, $limitnumber);
 172                 $users = array();
 173                 foreach ($enrolledusers as $courseuser) {
 174                     if ($userdetails = user_get_user_details($courseuser, $course, $userfields)) {
 175                         $users[] = $userdetails;
 176                     }
 177                 }
 178                 $enrolledusers->close();
 179                 $courseusers['users'] = $users;
 180                 $result[] = $courseusers;
 181             }
 182         }
 183         return $result;
 184     }
 185
 186     /**
 187      * Returns description of method result value
 188      *
 189      * @return external_multiple_structure
 190      * @since Moodle 2.4
 191      */
 192     public static function get_enrolled_users_with_capability_returns() {
 193         return  new external_multiple_structure( new external_single_structure (
 194                 array (
 195                     'courseid' => new external_value(PARAM_INT, 'Course ID number in the Moodle course table'),
 196                     'capability' => new external_value(PARAM_CAPABILITY, 'Capability name'),
 197                     'users' => new external_multiple_structure(
 198                         new external_single_structure(
 199                 array(
 200                     'id'    => new external_value(PARAM_INT, 'ID of the user'),
 201                     'username'    => new external_value(PARAM_RAW, 'Username', VALUE_OPTIONAL),
 202                     'firstname'   => new external_value(PARAM_NOTAGS, 'The first name(s) of the user', VALUE_OPTIONAL),
 203                     'lastname'    => new external_value(PARAM_NOTAGS, 'The family name of the user', VALUE_OPTIONAL),
 204                     'fullname'    => new external_value(PARAM_NOTAGS, 'The fullname of the user'),
 205                     'email'       => new external_value(PARAM_TEXT, 'Email address', VALUE_OPTIONAL),
 206                     'address'     => new external_value(PARAM_MULTILANG, 'Postal address', VALUE_OPTIONAL),
 207                     'phone1'      => new external_value(PARAM_NOTAGS, 'Phone 1', VALUE_OPTIONAL),
 208                     'phone2'      => new external_value(PARAM_NOTAGS, 'Phone 2', VALUE_OPTIONAL),
 209                     'icq'         => new external_value(PARAM_NOTAGS, 'icq number', VALUE_OPTIONAL),
 210                     'skype'       => new external_value(PARAM_NOTAGS, 'skype id', VALUE_OPTIONAL),
 211                     'yahoo'       => new external_value(PARAM_NOTAGS, 'yahoo id', VALUE_OPTIONAL),
 212                     'aim'         => new external_value(PARAM_NOTAGS, 'aim id', VALUE_OPTIONAL),
 213                     'msn'         => new external_value(PARAM_NOTAGS, 'msn number', VALUE_OPTIONAL),
 214                     'department'  => new external_value(PARAM_TEXT, 'department', VALUE_OPTIONAL),
 215                     'institution' => new external_value(PARAM_TEXT, 'institution', VALUE_OPTIONAL),
 216                     'interests'   => new external_value(PARAM_TEXT, 'user interests (separated by commas)', VALUE_OPTIONAL),
 217                     'firstaccess' => new external_value(PARAM_INT, 'first access to the site (0 if never)', VALUE_OPTIONAL),
 218                     'lastaccess'  => new external_value(PARAM_INT, 'last access to the site (0 if never)', VALUE_OPTIONAL),
 219                     'description' => new external_value(PARAM_RAW, 'User profile description', VALUE_OPTIONAL),
 220                     'descriptionformat' => new external_value(PARAM_INT, 'User profile description format', VALUE_OPTIONAL),
 221                     'city'        => new external_value(PARAM_NOTAGS, 'Home city of the user', VALUE_OPTIONAL),
 222                     'url'         => new external_value(PARAM_URL, 'URL of the user', VALUE_OPTIONAL),
 223                     'country'     => new external_value(PARAM_ALPHA, 'Country code of the user, such as AU or CZ', VALUE_OPTIONAL),
 224                     'profileimageurlsmall' => new external_value(PARAM_URL, 'User image profile URL - small', VALUE_OPTIONAL),
 225                     'profileimageurl' => new external_value(PARAM_URL, 'User image profile URL - big', VALUE_OPTIONAL),
 226                     'customfields' => new external_multiple_structure(
 227                         new external_single_structure(
 228                             array(
 229                                 'type'  => new external_value(PARAM_ALPHANUMEXT, 'The type of the custom field'),
 230                                 'value' => new external_value(PARAM_RAW, 'The value of the custom field'),
 231                                 'name' => new external_value(PARAM_RAW, 'The name of the custom field'),
 232                                 'shortname' => new external_value(PARAM_RAW, 'The shortname of the custom field'),
 233                             )
 234                         ), 'User custom fields (also known as user profil fields)', VALUE_OPTIONAL),
 235                     'groups' => new external_multiple_structure(
 236                         new external_single_structure(
 237                             array(
 238                                 'id'  => new external_value(PARAM_INT, 'group id'),
 239                                 'name' => new external_value(PARAM_RAW, 'group name'),
 240                                 'description' => new external_value(PARAM_RAW, 'group description'),
 241                             )
 242                         ), 'user groups', VALUE_OPTIONAL),
 243                     'roles' => new external_multiple_structure(
 244                         new external_single_structure(
 245                             array(
 246                                 'roleid'       => new external_value(PARAM_INT, 'role id'),
 247                                 'name'         => new external_value(PARAM_RAW, 'role name'),
 248                                 'shortname'    => new external_value(PARAM_ALPHANUMEXT, 'role shortname'),
 249                                 'sortorder'    => new external_value(PARAM_INT, 'role sortorder')
 250                             )
 251                         ), 'user roles', VALUE_OPTIONAL),
 252                     'preferences' => new external_multiple_structure(
 253                         new external_single_structure(
 254                             array(
 255                                 'name'  => new external_value(PARAM_RAW, 'The name of the preferences'),
 256                                 'value' => new external_value(PARAM_RAW, 'The value of the custom field'),
 257                             )
 258                     ), 'User preferences', VALUE_OPTIONAL),
 259                     'enrolledcourses' => new external_multiple_structure(
 260                         new external_single_structure(
 261                             array(
 262                                 'id'  => new external_value(PARAM_INT, 'Id of the course'),
 263                                 'fullname' => new external_value(PARAM_RAW, 'Fullname of the course'),
 264                                 'shortname' => new external_value(PARAM_RAW, 'Shortname of the course')
 265                             )
 266                     ), 'Courses where the user is enrolled - limited by which courses the user is able to see', VALUE_OPTIONAL)
 267                 )
 268                         ), 'List of users that are enrolled in the course and have the specified capability'),
 269                     )
 270                 )
 271             );
 272     }
 273
 274     /**
 275      * Returns description of method parameters
 276      *
 277      * @return external_function_parameters
 278      */
 279     public static function get_users_courses_parameters() {
 280         return new external_function_parameters(
 281             array(
 282                 'userid' => new external_value(PARAM_INT, 'user id'),
 283             )
 284         );
 285     }
 286
 287     /**
 288      * Get list of courses user is enrolled in (only active enrolments are returned).
 289      * Please note the current user must be able to access the course, otherwise the course is not included.
 290      *
 291      * @param int $userid
 292      * @return array of courses
 293      */
 294     public static function get_users_courses($userid) {
 295         global $CFG, $USER, $DB;
 296
 297         require_once($CFG->dirroot . '/course/lib.php');
 298
 299         // Do basic automatic PARAM checks on incoming data, using params description
 300         // If any problems are found then exceptions are thrown with helpful error messages
 301         $params = self::validate_parameters(self::get_users_courses_parameters(), array('userid'=>$userid));
 302
 303         $courses = enrol_get_users_courses($params['userid'], true, 'id, shortname, fullname, idnumber, visible,
 304                    summary, summaryformat, format, showgrades, lang, enablecompletion, category, startdate, enddate');
 305         $result = array();
 306
 307         foreach ($courses as $course) {
 308             $context = context_course::instance($course->id, IGNORE_MISSING);
 309             try {
 310                 self::validate_context($context);
 311             } catch (Exception $e) {
 312                 // current user can not access this course, sorry we can not disclose who is enrolled in this course!
 313                 continue;
 314             }
 315
 316             if ($userid != $USER->id and !course_can_view_participants($context)) {
 317                 // we need capability to view participants
 318                 continue;
 319             }
 320
 321             list($enrolledsqlselect, $enrolledparams) = get_enrolled_sql($context);
 322             $enrolledsql = "SELECT COUNT('x') FROM ($enrolledsqlselect) enrolleduserids";
 323             $enrolledusercount = $DB->count_records_sql($enrolledsql, $enrolledparams);
 324
 325             list($course->summary, $course->summaryformat) =
 326                 external_format_text($course->summary, $course->summaryformat, $context->id, 'course', 'summary', null);
 327             $course->fullname = external_format_string($course->fullname, $context->id);
 328             $course->shortname = external_format_string($course->shortname, $context->id);
 329
 330             $progress = null;
 331             if ($course->enablecompletion) {
 332                 $progress = \core_completion\progress::get_course_progress_percentage($course);
 333             }
 334
 335             $result[] = array(
 336                 'id' => $course->id,
 337                 'shortname' => $course->shortname,
 338                 'fullname' => $course->fullname,
 339                 'idnumber' => $course->idnumber,
 340                 'visible' => $course->visible,
 341                 'enrolledusercount' => $enrolledusercount,
 342                 'summary' => $course->summary,
 343                 'summaryformat' => $course->summaryformat,
 344                 'format' => $course->format,
 345                 'showgrades' => $course->showgrades,
 346                 'lang' => clean_param($course->lang, PARAM_LANG),
 347                 'enablecompletion' => $course->enablecompletion,
 348                 'category' => $course->category,
 349                 'progress' => $progress,
 350                 'startdate' => $course->startdate,
 351                 'enddate' => $course->enddate,
 352             );
 353         }
 354
 355         return $result;
 356     }
 357
 358     /**
 359      * Returns description of method result value
 360      *
 361      * @return external_description
 362      */
 363     public static function get_users_courses_returns() {
 364         return new external_multiple_structure(
 365             new external_single_structure(
 366                 array(
 367                     'id'        => new external_value(PARAM_INT, 'id of course'),
 368                     'shortname' => new external_value(PARAM_RAW, 'short name of course'),
 369                     'fullname'  => new external_value(PARAM_RAW, 'long name of course'),
 370                     'enrolledusercount' => new external_value(PARAM_INT, 'Number of enrolled users in this course'),
 371                     'idnumber'  => new external_value(PARAM_RAW, 'id number of course'),
 372                     'visible'   => new external_value(PARAM_INT, '1 means visible, 0 means hidden course'),
 373                     'summary'   => new external_value(PARAM_RAW, 'summary', VALUE_OPTIONAL),
 374                     'summaryformat' => new external_format_value('summary', VALUE_OPTIONAL),
 375                     'format'    => new external_value(PARAM_PLUGIN, 'course format: weeks, topics, social, site', VALUE_OPTIONAL),
 376                     'showgrades' => new external_value(PARAM_BOOL, 'true if grades are shown, otherwise false', VALUE_OPTIONAL),
 377                     'lang'      => new external_value(PARAM_LANG, 'forced course language', VALUE_OPTIONAL),
 378                     'enablecompletion' => new external_value(PARAM_BOOL, 'true if completion is enabled, otherwise false',
 379                                                                 VALUE_OPTIONAL),
 380                     'category' => new external_value(PARAM_INT, 'course category id', VALUE_OPTIONAL),
 381                     'progress' => new external_value(PARAM_FLOAT, 'Progress percentage', VALUE_OPTIONAL),
 382                     'startdate' => new external_value(PARAM_INT, 'Timestamp when the course start', VALUE_OPTIONAL),
 383                     'enddate' => new external_value(PARAM_INT, 'Timestamp when the course end', VALUE_OPTIONAL),
 384                 )
 385             )
 386         );
 387     }
 388
 389     /**
 390      * Returns description of method parameters value
 391      *
 392      * @return external_description
 393      */
 394     public static function get_potential_users_parameters() {
 395         return new external_function_parameters(
 396             array(
 397                 'courseid' => new external_value(PARAM_INT, 'course id'),
 398                 'enrolid' => new external_value(PARAM_INT, 'enrolment id'),
 399                 'search' => new external_value(PARAM_RAW, 'query'),
 400                 'searchanywhere' => new external_value(PARAM_BOOL, 'find a match anywhere, or only at the beginning'),
 401                 'page' => new external_value(PARAM_INT, 'Page number'),
 402                 'perpage' => new external_value(PARAM_INT, 'Number per page'),
 403             )
 404         );
 405     }
 406
 407     /**
 408      * Get potential users.
 409      *
 410      * @param int $courseid Course id
 411      * @param int $enrolid Enrolment id
 412      * @param string $search The query
 413      * @param boolean $searchanywhere Match anywhere in the string
 414      * @param int $page Page number
 415      * @param int $perpage Max per page
 416      * @return array An array of users
 417      */
 418     public static function get_potential_users($courseid, $enrolid, $search, $searchanywhere, $page, $perpage) {
 419         global $PAGE, $DB, $CFG;
 420
 421         require_once($CFG->dirroot.'/enrol/locallib.php');
 422         require_once($CFG->dirroot.'/user/lib.php');
 423
 424         $params = self::validate_parameters(
 425             self::get_potential_users_parameters(),
 426             array(
 427                 'courseid' => $courseid,
 428                 'enrolid' => $enrolid,
 429                 'search' => $search,
 430                 'searchanywhere' => $searchanywhere,
 431                 'page' => $page,
 432                 'perpage' => $perpage
 433             )
 434         );
 435         $context = context_course::instance($params['courseid']);
 436         try {
 437             self::validate_context($context);
 438         } catch (Exception $e) {
 439             $exceptionparam = new stdClass();
 440             $exceptionparam->message = $e->getMessage();
 441             $exceptionparam->courseid = $params['courseid'];
 442             throw new moodle_exception('errorcoursecontextnotvalid' , 'webservice', '', $exceptionparam);
 443         }
 444         require_capability('moodle/course:enrolreview', $context);
 445
 446         $course = $DB->get_record('course', array('id' => $params['courseid']));
 447         $manager = new course_enrolment_manager($PAGE, $course);
 448
 449         $users = $manager->get_potential_users($params['enrolid'],
 450                                                $params['search'],
 451                                                $params['searchanywhere'],
 452                                                $params['page'],
 453                                                $params['perpage']);
 454
 455         $results = array();
 456         // Add also extra user fields.
 457         $requiredfields = array_merge(
 458             ['id', 'fullname', 'profileimageurl', 'profileimageurlsmall'],
 459             get_extra_user_fields($context)
 460         );
 461         foreach ($users['users'] as $id => $user) {
 462             // Note: We pass the course here to validate that the current user can at least view user details in this course.
 463             // The user we are looking at is not in this course yet though - but we only fetch the minimal set of
 464             // user records, and the user has been validated to have course:enrolreview in this course. Otherwise
 465             // there is no way to find users who aren't in the course in order to enrol them.
 466             if ($userdetails = user_get_user_details($user, $course, $requiredfields)) {
 467                 $results[] = $userdetails;
 468             }
 469         }
 470         return $results;
 471     }
 472
 473     /**
 474      * Returns description of method result value
 475      *
 476      * @return external_description
 477      */
 478     public static function get_potential_users_returns() {
 479         global $CFG;
 480         require_once($CFG->dirroot . '/user/externallib.php');
 481         return new external_multiple_structure(core_user_external::user_description());
 482     }
 483
 484     /**
 485      * Returns description of method parameters
 486      *
 487      * @return external_function_parameters
 488      */
 489     public static function get_enrolled_users_parameters() {
 490         return new external_function_parameters(
 491             array(
 492                 'courseid' => new external_value(PARAM_INT, 'course id'),
 493                 'options'  => new external_multiple_structure(
 494                     new external_single_structure(
 495                         array(
 496                             'name'  => new external_value(PARAM_ALPHANUMEXT, 'option name'),
 497                             'value' => new external_value(PARAM_RAW, 'option value')
 498                         )
 499                     ), 'Option names:
 500                             * withcapability (string) return only users with this capability. This option requires \'moodle/role:review\' on the course context.
 501                             * groupid (integer) return only users in this group id. If the course has groups enabled and this param
 502                                                 isn\'t defined, returns all the viewable users.
 503                                                 This option requires \'moodle/site:accessallgroups\' on the course context if the
 504                                                 user doesn\'t belong to the group.
 505                             * onlyactive (integer) return only users with active enrolments and matching time restrictions. This option requires \'moodle/course:enrolreview\' on the course context.
 506                             * userfields (\'string, string, ...\') return only the values of these user fields.
 507                             * limitfrom (integer) sql limit from.
 508                             * limitnumber (integer) maximum number of returned users.
 509                             * sortby (string) sort by id, firstname or lastname. For ordering like the site does, use siteorder.
 510                             * sortdirection (string) ASC or DESC',
 511                             VALUE_DEFAULT, array()),
 512             )
 513         );
 514     }
 515
 516     /**
 517      * Get course participants details
 518      *
 519      * @param int $courseid  course id
 520      * @param array $options options {
 521      *                                'name' => option name
 522      *                                'value' => option value
 523      *                               }
 524      * @return array An array of users
 525      */
 526     public static function get_enrolled_users($courseid, $options = array()) {
 527         global $CFG, $USER, $DB;
 528
 529         require_once($CFG->dirroot . '/course/lib.php');
 530         require_once($CFG->dirroot . "/user/lib.php");
 531
 532         $params = self::validate_parameters(
 533             self::get_enrolled_users_parameters(),
 534             array(
 535                 'courseid'=>$courseid,
 536                 'options'=>$options
 537             )
 538         );
 539         $withcapability = '';
 540         $groupid        = 0;
 541         $onlyactive     = false;
 542         $userfields     = array();
 543         $limitfrom = 0;
 544         $limitnumber = 0;
 545         $sortby = 'us.id';
 546         $sortparams = array();
 547         $sortdirection = 'ASC';
 548         foreach ($options as $option) {
 549             switch ($option['name']) {
 550             case 'withcapability':
 551                 $withcapability = $option['value'];
 552                 break;
 553             case 'groupid':
 554                 $groupid = (int)$option['value'];
 555                 break;
 556             case 'onlyactive':
 557                 $onlyactive = !empty($option['value']);
 558                 break;
 559             case 'userfields':
 560                 $thefields = explode(',', $option['value']);
 561                 foreach ($thefields as $f) {
 562                     $userfields[] = clean_param($f, PARAM_ALPHANUMEXT);
 563                 }
 564                 break;
 565             case 'limitfrom' :
 566                 $limitfrom = clean_param($option['value'], PARAM_INT);
 567                 break;
 568             case 'limitnumber' :
 569                 $limitnumber = clean_param($option['value'], PARAM_INT);
 570                 break;
 571             case 'sortby':
 572                 $sortallowedvalues = array('id', 'firstname', 'lastname', 'siteorder');
 573                 if (!in_array($option['value'], $sortallowedvalues)) {
 574                     throw new invalid_parameter_exception('Invalid value for sortby parameter (value: ' . $option['value'] . '),' .
 575                         'allowed values are: ' . implode(',', $sortallowedvalues));
 576                 }
 577                 if ($option['value'] == 'siteorder') {
 578                     list($sortby, $sortparams) = users_order_by_sql('us');
 579                 } else {
 580                     $sortby = 'us.' . $option['value'];
 581                 }
 582                 break;
 583             case 'sortdirection':
 584                 $sortdirection = strtoupper($option['value']);
 585                 $directionallowedvalues = array('ASC', 'DESC');
 586                 if (!in_array($sortdirection, $directionallowedvalues)) {
 587                     throw new invalid_parameter_exception('Invalid value for sortdirection parameter
 588                         (value: ' . $sortdirection . '),' . 'allowed values are: ' . implode(',', $directionallowedvalues));
 589                 }
 590                 break;
 591             }
 592         }
 593
 594         $course = $DB->get_record('course', array('id'=>$courseid), '*', MUST_EXIST);
 595         $coursecontext = context_course::instance($courseid, IGNORE_MISSING);
 596         if ($courseid == SITEID) {
 597             $context = context_system::instance();
 598         } else {
 599             $context = $coursecontext;
 600         }
 601         try {
 602             self::validate_context($context);
 603         } catch (Exception $e) {
 604             $exceptionparam = new stdClass();
 605             $exceptionparam->message = $e->getMessage();
 606             $exceptionparam->courseid = $params['courseid'];
 607             throw new moodle_exception('errorcoursecontextnotvalid' , 'webservice', '', $exceptionparam);
 608         }
 609
 610         course_require_view_participants($context);
 611
 612         // to overwrite this parameter, you need role:review capability
 613         if ($withcapability) {
 614             require_capability('moodle/role:review', $coursecontext);
 615         }
 616         // need accessallgroups capability if you want to overwrite this option
 617         if (!empty($groupid) && !groups_is_member($groupid)) {
 618             require_capability('moodle/site:accessallgroups', $coursecontext);
 619         }
 620         // to overwrite this option, you need course:enrolereview permission
 621         if ($onlyactive) {
 622             require_capability('moodle/course:enrolreview', $coursecontext);
 623         }
 624
 625         list($enrolledsql, $enrolledparams) = get_enrolled_sql($coursecontext, $withcapability, $groupid, $onlyactive);
 626         $ctxselect = ', ' . context_helper::get_preload_record_columns_sql('ctx');
 627         $ctxjoin = "LEFT JOIN {context} ctx ON (ctx.instanceid = u.id AND ctx.contextlevel = :contextlevel)";
 628         $enrolledparams['contextlevel'] = CONTEXT_USER;
 629
 630         $groupjoin = '';
 631         if (empty($groupid) && groups_get_course_groupmode($course) == SEPARATEGROUPS &&
 632                 !has_capability('moodle/site:accessallgroups', $coursecontext)) {
 633             // Filter by groups the user can view.
 634             $usergroups = groups_get_user_groups($course->id);
 635             if (!empty($usergroups['0'])) {
 636                 list($groupsql, $groupparams) = $DB->get_in_or_equal($usergroups['0'], SQL_PARAMS_NAMED);
 637                 $groupjoin = "JOIN {groups_members} gm ON (u.id = gm.userid AND gm.groupid $groupsql)";
 638                 $enrolledparams = array_merge($enrolledparams, $groupparams);
 639             } else {
 640                 // User doesn't belong to any group, so he can't see any user. Return an empty array.
 641                 return array();
 642             }
 643         }
 644         $sql = "SELECT us.*
 645                   FROM {user} us
 646                   JOIN (
 647                       SELECT DISTINCT u.id $ctxselect
 648                         FROM {user} u $ctxjoin $groupjoin
 649                        WHERE u.id IN ($enrolledsql)
 650                   ) q ON q.id = us.id
 651                 ORDER BY $sortby $sortdirection";
 652         $enrolledparams = array_merge($enrolledparams, $sortparams);
 653         $enrolledusers = $DB->get_recordset_sql($sql, $enrolledparams, $limitfrom, $limitnumber);
 654         $users = array();
 655         foreach ($enrolledusers as $user) {
 656             context_helper::preload_from_record($user);
 657             if ($userdetails = user_get_user_details($user, $course, $userfields)) {
 658                 $users[] = $userdetails;
 659             }
 660         }
 661         $enrolledusers->close();
 662
 663         return $users;
 664     }
 665
 666     /**
 667      * Returns description of method result value
 668      *
 669      * @return external_description
 670      */
 671     public static function get_enrolled_users_returns() {
 672         return new external_multiple_structure(
 673             new external_single_structure(
 674                 array(
 675                     'id'    => new external_value(PARAM_INT, 'ID of the user'),
 676                     'username'    => new external_value(PARAM_RAW, 'Username policy is defined in Moodle security config', VALUE_OPTIONAL),
 677                     'firstname'   => new external_value(PARAM_NOTAGS, 'The first name(s) of the user', VALUE_OPTIONAL),
 678                     'lastname'    => new external_value(PARAM_NOTAGS, 'The family name of the user', VALUE_OPTIONAL),
 679                     'fullname'    => new external_value(PARAM_NOTAGS, 'The fullname of the user'),
 680                     'email'       => new external_value(PARAM_TEXT, 'An email address - allow email as root@localhost', VALUE_OPTIONAL),
 681                     'address'     => new external_value(PARAM_TEXT, 'Postal address', VALUE_OPTIONAL),
 682                     'phone1'      => new external_value(PARAM_NOTAGS, 'Phone 1', VALUE_OPTIONAL),
 683                     'phone2'      => new external_value(PARAM_NOTAGS, 'Phone 2', VALUE_OPTIONAL),
 684                     'icq'         => new external_value(PARAM_NOTAGS, 'icq number', VALUE_OPTIONAL),
 685                     'skype'       => new external_value(PARAM_NOTAGS, 'skype id', VALUE_OPTIONAL),
 686                     'yahoo'       => new external_value(PARAM_NOTAGS, 'yahoo id', VALUE_OPTIONAL),
 687                     'aim'         => new external_value(PARAM_NOTAGS, 'aim id', VALUE_OPTIONAL),
 688                     'msn'         => new external_value(PARAM_NOTAGS, 'msn number', VALUE_OPTIONAL),
 689                     'department'  => new external_value(PARAM_TEXT, 'department', VALUE_OPTIONAL),
 690                     'institution' => new external_value(PARAM_TEXT, 'institution', VALUE_OPTIONAL),
 691                     'idnumber'    => new external_value(PARAM_RAW, 'An arbitrary ID code number perhaps from the institution', VALUE_OPTIONAL),
 692                     'interests'   => new external_value(PARAM_TEXT, 'user interests (separated by commas)', VALUE_OPTIONAL),
 693                     'firstaccess' => new external_value(PARAM_INT, 'first access to the site (0 if never)', VALUE_OPTIONAL),
 694                     'lastaccess'  => new external_value(PARAM_INT, 'last access to the site (0 if never)', VALUE_OPTIONAL),
 695                     'description' => new external_value(PARAM_RAW, 'User profile description', VALUE_OPTIONAL),
 696                     'descriptionformat' => new external_format_value('description', VALUE_OPTIONAL),
 697                     'city'        => new external_value(PARAM_NOTAGS, 'Home city of the user', VALUE_OPTIONAL),
 698                     'url'         => new external_value(PARAM_URL, 'URL of the user', VALUE_OPTIONAL),
 699                     'country'     => new external_value(PARAM_ALPHA, 'Home country code of the user, such as AU or CZ', VALUE_OPTIONAL),
 700                     'profileimageurlsmall' => new external_value(PARAM_URL, 'User image profile URL - small version', VALUE_OPTIONAL),
 701                     'profileimageurl' => new external_value(PARAM_URL, 'User image profile URL - big version', VALUE_OPTIONAL),
 702                     'customfields' => new external_multiple_structure(
 703                         new external_single_structure(
 704                             array(
 705                                 'type'  => new external_value(PARAM_ALPHANUMEXT, 'The type of the custom field - text field, checkbox...'),
 706                                 'value' => new external_value(PARAM_RAW, 'The value of the custom field'),
 707                                 'name' => new external_value(PARAM_RAW, 'The name of the custom field'),
 708                                 'shortname' => new external_value(PARAM_RAW, 'The shortname of the custom field - to be able to build the field class in the code'),
 709                             )
 710                         ), 'User custom fields (also known as user profil fields)', VALUE_OPTIONAL),
 711                     'groups' => new external_multiple_structure(
 712                         new external_single_structure(
 713                             array(
 714                                 'id'  => new external_value(PARAM_INT, 'group id'),
 715                                 'name' => new external_value(PARAM_RAW, 'group name'),
 716                                 'description' => new external_value(PARAM_RAW, 'group description'),
 717                                 'descriptionformat' => new external_format_value('description'),
 718                             )
 719                         ), 'user groups', VALUE_OPTIONAL),
 720                     'roles' => new external_multiple_structure(
 721                         new external_single_structure(
 722                             array(
 723                                 'roleid'       => new external_value(PARAM_INT, 'role id'),
 724                                 'name'         => new external_value(PARAM_RAW, 'role name'),
 725                                 'shortname'    => new external_value(PARAM_ALPHANUMEXT, 'role shortname'),
 726                                 'sortorder'    => new external_value(PARAM_INT, 'role sortorder')
 727                             )
 728                         ), 'user roles', VALUE_OPTIONAL),
 729                     'preferences' => new external_multiple_structure(
 730                         new external_single_structure(
 731                             array(
 732                                 'name'  => new external_value(PARAM_RAW, 'The name of the preferences'),
 733                                 'value' => new external_value(PARAM_RAW, 'The value of the custom field'),
 734                             )
 735                     ), 'User preferences', VALUE_OPTIONAL),
 736                     'enrolledcourses' => new external_multiple_structure(
 737                         new external_single_structure(
 738                             array(
 739                                 'id'  => new external_value(PARAM_INT, 'Id of the course'),
 740                                 'fullname' => new external_value(PARAM_RAW, 'Fullname of the course'),
 741                                 'shortname' => new external_value(PARAM_RAW, 'Shortname of the course')
 742                             )
 743                     ), 'Courses where the user is enrolled - limited by which courses the user is able to see', VALUE_OPTIONAL)
 744                 )
 745             )
 746         );
 747     }
 748
 749     /**
 750      * Returns description of get_course_enrolment_methods() parameters
 751      *
 752      * @return external_function_parameters
 753      */
 754     public static function get_course_enrolment_methods_parameters() {
 755         return new external_function_parameters(
 756             array(
 757                 'courseid' => new external_value(PARAM_INT, 'Course id')
 758             )
 759         );
 760     }
 761
 762     /**
 763      * Get list of active course enrolment methods for current user.
 764      *
 765      * @param int $courseid
 766      * @return array of course enrolment methods
 767      * @throws moodle_exception
 768      */
 769     public static function get_course_enrolment_methods($courseid) {
 770         global $DB;
 771
 772         $params = self::validate_parameters(self::get_course_enrolment_methods_parameters(), array('courseid' => $courseid));
 773         self::validate_context(context_system::instance());
 774
 775         $course = $DB->get_record('course', array('id' => $params['courseid']), '*', MUST_EXIST);
 776         $context = context_course::instance($course->id);
 777         if (!$course->visible and !has_capability('moodle/course:viewhiddencourses', $context)) {
 778             throw new moodle_exception('coursehidden');
 779         }
 780
 781         $result = array();
 782         $enrolinstances = enrol_get_instances($params['courseid'], true);
 783         foreach ($enrolinstances as $enrolinstance) {
 784             if ($enrolplugin = enrol_get_plugin($enrolinstance->enrol)) {
 785                 if ($instanceinfo = $enrolplugin->get_enrol_info($enrolinstance)) {
 786                     $result[] = (array) $instanceinfo;
 787                 }
 788             }
 789         }
 790         return $result;
 791     }
 792
 793     /**
 794      * Returns description of get_course_enrolment_methods() result value
 795      *
 796      * @return external_description
 797      */
 798     public static function get_course_enrolment_methods_returns() {
 799         return new external_multiple_structure(
 800             new external_single_structure(
 801                 array(
 802                     'id' => new external_value(PARAM_INT, 'id of course enrolment instance'),
 803                     'courseid' => new external_value(PARAM_INT, 'id of course'),
 804                     'type' => new external_value(PARAM_PLUGIN, 'type of enrolment plugin'),
 805                     'name' => new external_value(PARAM_RAW, 'name of enrolment plugin'),
 806                     'status' => new external_value(PARAM_RAW, 'status of enrolment plugin'),
 807                     'wsfunction' => new external_value(PARAM_ALPHANUMEXT, 'webservice function to get more information', VALUE_OPTIONAL),
 808                 )
 809             )
 810         );
 811     }
 812
 813     /**
 814      * Returns description of edit_user_enrolment() parameters
 815      *
 816      * @return external_function_parameters
 817      */
 818     public static function edit_user_enrolment_parameters() {
 819         return new external_function_parameters(
 820             array(
 821                 'courseid' => new external_value(PARAM_INT, 'User enrolment ID'),
 822                 'ueid' => new external_value(PARAM_INT, 'User enrolment ID'),
 823                 'status' => new external_value(PARAM_INT, 'Enrolment status'),
 824                 'timestart' => new external_value(PARAM_INT, 'Enrolment start timestamp', VALUE_DEFAULT, 0),
 825                 'timeend' => new external_value(PARAM_INT, 'Enrolment end timestamp', VALUE_DEFAULT, 0),
 826             )
 827         );
 828     }
 829
 830     /**
 831      * External function that updates a given user enrolment.
 832      *
 833      * @param int $courseid The course ID.
 834      * @param int $ueid The user enrolment ID.
 835      * @param int $status The enrolment status.
 836      * @param int $timestart Enrolment start timestamp.
 837      * @param int $timeend Enrolment end timestamp.
 838      * @return array An array consisting of the processing result, errors and form output, if available.
 839      */
 840     public static function edit_user_enrolment($courseid, $ueid, $status, $timestart = 0, $timeend = 0) {
 841         global $CFG, $DB, $PAGE;
 842
 843         $params = self::validate_parameters(self::edit_user_enrolment_parameters(), [
 844             'courseid' => $courseid,
 845             'ueid' => $ueid,
 846             'status' => $status,
 847             'timestart' => $timestart,
 848             'timeend' => $timeend,
 849         ]);
 850
 851         $course = get_course($courseid);
 852         $context = context_course::instance($course->id);
 853         self::validate_context($context);
 854
 855         $userenrolment = $DB->get_record('user_enrolments', ['id' => $params['ueid']], '*', MUST_EXIST);
 856         $userenroldata = [
 857             'status' => $params['status'],
 858             'timestart' => $params['timestart'],
 859             'timeend' => $params['timeend'],
 860         ];
 861
 862         $result = false;
 863         $errors = [];
 864
 865         // Validate data against the edit user enrolment form.
 866         $instance = $DB->get_record('enrol', ['id' => $userenrolment->enrolid], '*', MUST_EXIST);
 867         $plugin = enrol_get_plugin($instance->enrol);
 868         require_once("$CFG->dirroot/enrol/editenrolment_form.php");
 869         $customformdata = [
 870             'ue' => $userenrolment,
 871             'modal' => true,
 872             'enrolinstancename' => $plugin->get_instance_name($instance)
 873         ];
 874         $mform = new \enrol_user_enrolment_form(null, $customformdata, 'post', '', null, true, $userenroldata);
 875         $mform->set_data($userenroldata);
 876         $validationerrors = $mform->validation($userenroldata, null);
 877         if (empty($validationerrors)) {
 878             require_once($CFG->dirroot . '/enrol/locallib.php');
 879             $manager = new course_enrolment_manager($PAGE, $course);
 880             $result = $manager->edit_enrolment($userenrolment, (object)$userenroldata);
 881         } else {
 882             foreach ($validationerrors as $key => $errormessage) {
 883                 $errors[] = (object)[
 884                     'key' => $key,
 885                     'message' => $errormessage
 886                 ];
 887             }
 888         }
 889
 890         return [
 891             'result' => $result,
 892             'errors' => $errors,
 893         ];
 894     }
 895
 896     /**
 897      * Returns description of edit_user_enrolment() result value
 898      *
 899      * @return external_description
 900      */
 901     public static function edit_user_enrolment_returns() {
 902         return new external_single_structure(
 903             array(
 904                 'result' => new external_value(PARAM_BOOL, 'True if the user\'s enrolment was successfully updated'),
 905                 'errors' => new external_multiple_structure(
 906                     new external_single_structure(
 907                         array(
 908                             'key' => new external_value(PARAM_TEXT, 'The data that failed the validation'),
 909                             'message' => new external_value(PARAM_TEXT, 'The error message'),
 910                         )
 911                     ), 'List of validation errors'
 912                 ),
 913             )
 914         );
 915     }
 916
 917     /**
 918      * Returns description of unenrol_user_enrolment() parameters
 919      *
 920      * @return external_function_parameters
 921      */
 922     public static function unenrol_user_enrolment_parameters() {
 923         return new external_function_parameters(
 924             array(
 925                 'ueid' => new external_value(PARAM_INT, 'User enrolment ID')
 926             )
 927         );
 928     }
 929
 930     /**
 931      * External function that unenrols a given user enrolment.
 932      *
 933      * @param int $ueid The user enrolment ID.
 934      * @return array An array consisting of the processing result, errors.
 935      */
 936     public static function unenrol_user_enrolment($ueid) {
 937         global $CFG, $DB, $PAGE;
 938
 939         $params = self::validate_parameters(self::unenrol_user_enrolment_parameters(), [
 940             'ueid' => $ueid
 941         ]);
 942
 943         $result = false;
 944         $errors = [];
 945
 946         $userenrolment = $DB->get_record('user_enrolments', ['id' => $params['ueid']], '*');
 947         if ($userenrolment) {
 948             $userid = $userenrolment->userid;
 949             $enrolid = $userenrolment->enrolid;
 950             $enrol = $DB->get_record('enrol', ['id' => $enrolid], '*', MUST_EXIST);
 951             $courseid = $enrol->courseid;
 952             $course = get_course($courseid);
 953             $context = context_course::instance($course->id);
 954             self::validate_context($context);
 955         } else {
 956             $validationerrors['invalidrequest'] = get_string('invalidrequest', 'enrol');
 957         }
 958
 959         // If the userenrolment exists, unenrol the user.
 960         if (!isset($validationerrors)) {
 961             require_once($CFG->dirroot . '/enrol/locallib.php');
 962             $manager = new course_enrolment_manager($PAGE, $course);
 963             $result = $manager->unenrol_user($userenrolment);
 964         } else {
 965             foreach ($validationerrors as $key => $errormessage) {
 966                 $errors[] = (object)[
 967                     'key' => $key,
 968                     'message' => $errormessage
 969                 ];
 970             }
 971         }
 972
 973         return [
 974             'result' => $result,
 975             'errors' => $errors,
 976         ];
 977     }
 978
 979     /**
 980      * Returns description of unenrol_user_enrolment() result value
 981      *
 982      * @return external_description
 983      */
 984     public static function unenrol_user_enrolment_returns() {
 985         return new external_single_structure(
 986             array(
 987                 'result' => new external_value(PARAM_BOOL, 'True if the user\'s enrolment was successfully updated'),
 988                 'errors' => new external_multiple_structure(
 989                     new external_single_structure(
 990                         array(
 991                             'key' => new external_value(PARAM_TEXT, 'The data that failed the validation'),
 992                             'message' => new external_value(PARAM_TEXT, 'The error message'),
 993                         )
 994                     ), 'List of validation errors'
 995                 ),
 996             )
 997         );
 998     }
 999 }
1000
1001 /**
1002  * Role external functions
1003  *
1004  * @package    core_role
1005  * @category   external
1006  * @copyright  2011 Jerome Mouneyrac
1007  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
1008  * @since Moodle 2.2
1009  */
1010 class core_role_external extends external_api {
1011
1012     /**
1013      * Returns description of method parameters
1014      *
1015      * @return external_function_parameters
1016      */
1017     public static function assign_roles_parameters() {
1018         return new external_function_parameters(
1019             array(
1020                 'assignments' => new external_multiple_structure(
1021                     new external_single_structure(
1022                         array(
1023                             'roleid'    => new external_value(PARAM_INT, 'Role to assign to the user'),
1024                             'userid'    => new external_value(PARAM_INT, 'The user that is going to be assigned'),
1025                             'contextid' => new external_value(PARAM_INT, 'The context to assign the user role in', VALUE_OPTIONAL),
1026                             'contextlevel' => new external_value(PARAM_ALPHA, 'The context level to assign the user role in
1027                                     (block, course, coursecat, system, user, module)', VALUE_OPTIONAL),
1028                             'instanceid' => new external_value(PARAM_INT, 'The Instance id of item where the role needs to be assigned', VALUE_OPTIONAL),
1029                         )
1030                     )
1031                 )
1032             )
1033         );
1034     }
1035
1036     /**
1037      * Manual role assignments to users
1038      *
1039      * @param array $assignments An array of manual role assignment
1040      */
1041     public static function assign_roles($assignments) {
1042         global $DB;
1043
1044         // Do basic automatic PARAM checks on incoming data, using params description
1045         // If any problems are found then exceptions are thrown with helpful error messages
1046         $params = self::validate_parameters(self::assign_roles_parameters(), array('assignments'=>$assignments));
1047
1048         $transaction = $DB->start_delegated_transaction();
1049
1050         foreach ($params['assignments'] as $assignment) {
1051             // Ensure correct context level with a instance id or contextid is passed.
1052             $context = self::get_context_from_params($assignment);
1053
1054             // Ensure the current user is allowed to run this function in the enrolment context.
1055             self::validate_context($context);
1056             require_capability('moodle/role:assign', $context);
1057
1058             // throw an exception if user is not able to assign the role in this context
1059             $roles = get_assignable_roles($context, ROLENAME_SHORT);
1060
1061             if (!array_key_exists($assignment['roleid'], $roles)) {
1062                 throw new invalid_parameter_exception('Can not assign roleid='.$assignment['roleid'].' in contextid='.$assignment['contextid']);
1063             }
1064
1065             role_assign($assignment['roleid'], $assignment['userid'], $context->id);
1066         }
1067
1068         $transaction->allow_commit();
1069     }
1070
1071     /**
1072      * Returns description of method result value
1073      *
1074      * @return null
1075      */
1076     public static function assign_roles_returns() {
1077         return null;
1078     }
1079
1080
1081     /**
1082      * Returns description of method parameters
1083      *
1084      * @return external_function_parameters
1085      */
1086     public static function unassign_roles_parameters() {
1087         return new external_function_parameters(
1088             array(
1089                 'unassignments' => new external_multiple_structure(
1090                     new external_single_structure(
1091                         array(
1092                             'roleid'    => new external_value(PARAM_INT, 'Role to assign to the user'),
1093                             'userid'    => new external_value(PARAM_INT, 'The user that is going to be assigned'),
1094                             'contextid' => new external_value(PARAM_INT, 'The context to unassign the user role from', VALUE_OPTIONAL),
1095                             'contextlevel' => new external_value(PARAM_ALPHA, 'The context level to unassign the user role in
1096 +                                    (block, course, coursecat, system, user, module)', VALUE_OPTIONAL),
1097                             'instanceid' => new external_value(PARAM_INT, 'The Instance id of item where the role needs to be unassigned', VALUE_OPTIONAL),
1098                         )
1099                     )
1100                 )
1101             )
1102         );
1103     }
1104
1105      /**
1106      * Unassign roles from users
1107      *
1108      * @param array $unassignments An array of unassignment
1109      */
1110     public static function unassign_roles($unassignments) {
1111          global $DB;
1112
1113         // Do basic automatic PARAM checks on incoming data, using params description
1114         // If any problems are found then exceptions are thrown with helpful error messages
1115         $params = self::validate_parameters(self::unassign_roles_parameters(), array('unassignments'=>$unassignments));
1116
1117         $transaction = $DB->start_delegated_transaction();
1118
1119         foreach ($params['unassignments'] as $unassignment) {
1120             // Ensure the current user is allowed to run this function in the unassignment context
1121             $context = self::get_context_from_params($unassignment);
1122             self::validate_context($context);
1123             require_capability('moodle/role:assign', $context);
1124
1125             // throw an exception if user is not able to unassign the role in this context
1126             $roles = get_assignable_roles($context, ROLENAME_SHORT);
1127             if (!array_key_exists($unassignment['roleid'], $roles)) {
1128                 throw new invalid_parameter_exception('Can not unassign roleid='.$unassignment['roleid'].' in contextid='.$unassignment['contextid']);
1129             }
1130
1131             role_unassign($unassignment['roleid'], $unassignment['userid'], $context->id);
1132         }
1133
1134         $transaction->allow_commit();
1135     }
1136
1137    /**
1138      * Returns description of method result value
1139      *
1140      * @return null
1141      */
1142     public static function unassign_roles_returns() {
1143         return null;
1144     }
1145 }