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Developer Documentation

See Release Notes

  • Bug fixes for general core bugs in 3.10.x will end 8 November 2021 (12 months).
  • Bug fixes for security issues in 3.10.x will end 9 May 2022 (18 months).
  • PHP version: minimum PHP 7.2.0 Note: minimum PHP version has increased since Moodle 3.8. PHP 7.3.x and 7.4.x are supported too.

Differences Between: [Versions 310 and 400] [Versions 310 and 401] [Versions 310 and 402] [Versions 310 and 403]

   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   * Manual enrolment plugin main library file.
  19   *
  20   * @package    enrol_manual
  21   * @copyright  2010 Petr Skoda {@link http://skodak.org}
  22   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23   */
  24  
  25  defined('MOODLE_INTERNAL') || die();
  26  
  27  class enrol_manual_plugin extends enrol_plugin {
  28  
  29      protected $lasternoller = null;
  30      protected $lasternollerinstanceid = 0;
  31  
  32      public function roles_protected() {
  33          // Users may tweak the roles later.
  34          return false;
  35      }
  36  
  37      public function allow_enrol(stdClass $instance) {
  38          // Users with enrol cap may unenrol other users manually manually.
  39          return true;
  40      }
  41  
  42      public function allow_unenrol(stdClass $instance) {
  43          // Users with unenrol cap may unenrol other users manually manually.
  44          return true;
  45      }
  46  
  47      public function allow_manage(stdClass $instance) {
  48          // Users with manage cap may tweak period and status.
  49          return true;
  50      }
  51  
  52      /**
  53       * Returns link to manual enrol UI if exists.
  54       * Does the access control tests automatically.
  55       *
  56       * @param stdClass $instance
  57       * @return moodle_url
  58       */
  59      public function get_manual_enrol_link($instance) {
  60          $name = $this->get_name();
  61          if ($instance->enrol !== $name) {
  62              throw new coding_exception('invalid enrol instance!');
  63          }
  64  
  65          if (!enrol_is_enabled($name)) {
  66              return NULL;
  67          }
  68  
  69          $context = context_course::instance($instance->courseid, MUST_EXIST);
  70  
  71          if (!has_capability('enrol/manual:enrol', $context)) {
  72              // Note: manage capability not used here because it is used for editing
  73              // of existing enrolments which is not possible here.
  74              return NULL;
  75          }
  76  
  77          return new moodle_url('/enrol/manual/manage.php', array('enrolid'=>$instance->id, 'id'=>$instance->courseid));
  78      }
  79  
  80      /**
  81       * Return true if we can add a new instance to this course.
  82       *
  83       * @param int $courseid
  84       * @return boolean
  85       */
  86      public function can_add_instance($courseid) {
  87          global $DB;
  88  
  89          $context = context_course::instance($courseid, MUST_EXIST);
  90          if (!has_capability('moodle/course:enrolconfig', $context) or !has_capability('enrol/manual:config', $context)) {
  91              return false;
  92          }
  93  
  94          if ($DB->record_exists('enrol', array('courseid'=>$courseid, 'enrol'=>'manual'))) {
  95              // Multiple instances not supported.
  96              return false;
  97          }
  98  
  99          return true;
 100      }
 101  
 102      /**
 103       * Returns edit icons for the page with list of instances.
 104       * @param stdClass $instance
 105       * @return array
 106       */
 107      public function get_action_icons(stdClass $instance) {
 108          global $OUTPUT;
 109  
 110          $context = context_course::instance($instance->courseid);
 111  
 112          $icons = array();
 113          if (has_capability('enrol/manual:enrol', $context) or has_capability('enrol/manual:unenrol', $context)) {
 114              $managelink = new moodle_url("/enrol/manual/manage.php", array('enrolid'=>$instance->id));
 115              $icons[] = $OUTPUT->action_icon($managelink, new pix_icon('t/enrolusers', get_string('enrolusers', 'enrol_manual'), 'core', array('class'=>'iconsmall')));
 116          }
 117          $parenticons = parent::get_action_icons($instance);
 118          $icons = array_merge($icons, $parenticons);
 119  
 120          return $icons;
 121      }
 122  
 123      /**
 124       * Add new instance of enrol plugin with default settings.
 125       * @param stdClass $course
 126       * @return int id of new instance, null if can not be created
 127       */
 128      public function add_default_instance($course) {
 129          $expirynotify = $this->get_config('expirynotify', 0);
 130          if ($expirynotify == 2) {
 131              $expirynotify = 1;
 132              $notifyall = 1;
 133          } else {
 134              $notifyall = 0;
 135          }
 136          $fields = array(
 137              'status'          => $this->get_config('status'),
 138              'roleid'          => $this->get_config('roleid', 0),
 139              'enrolperiod'     => $this->get_config('enrolperiod', 0),
 140              'expirynotify'    => $expirynotify,
 141              'notifyall'       => $notifyall,
 142              'expirythreshold' => $this->get_config('expirythreshold', 86400),
 143          );
 144          return $this->add_instance($course, $fields);
 145      }
 146  
 147      /**
 148       * Add new instance of enrol plugin.
 149       * @param stdClass $course
 150       * @param array instance fields
 151       * @return int id of new instance, null if can not be created
 152       */
 153      public function add_instance($course, array $fields = NULL) {
 154          global $DB;
 155  
 156          if ($DB->record_exists('enrol', array('courseid'=>$course->id, 'enrol'=>'manual'))) {
 157              // only one instance allowed, sorry
 158              return NULL;
 159          }
 160  
 161          return parent::add_instance($course, $fields);
 162      }
 163  
 164      /**
 165       * Update instance of enrol plugin.
 166       * @param stdClass $instance
 167       * @param stdClass $data modified instance fields
 168       * @return boolean
 169       */
 170      public function update_instance($instance, $data) {
 171          global $DB;
 172  
 173          // Delete all other instances, leaving only one.
 174          if ($instances = $DB->get_records('enrol', array('courseid' => $instance->courseid, 'enrol' => 'manual'), 'id ASC')) {
 175              foreach ($instances as $anotherinstance) {
 176                  if ($anotherinstance->id != $instance->id) {
 177                      $this->delete_instance($anotherinstance);
 178                  }
 179              }
 180          }
 181          return parent::update_instance($instance, $data);
 182      }
 183  
 184      /**
 185       * Returns a button to manually enrol users through the manual enrolment plugin.
 186       *
 187       * By default the first manual enrolment plugin instance available in the course is used.
 188       * If no manual enrolment instances exist within the course then false is returned.
 189       *
 190       * This function also adds a quickenrolment JS ui to the page so that users can be enrolled
 191       * via AJAX.
 192       *
 193       * @param course_enrolment_manager $manager
 194       * @return enrol_user_button
 195       */
 196      public function get_manual_enrol_button(course_enrolment_manager $manager) {
 197          global $CFG, $PAGE;
 198          require_once($CFG->dirroot.'/cohort/lib.php');
 199  
 200          static $called = false;
 201  
 202          $instance = null;
 203          foreach ($manager->get_enrolment_instances() as $tempinstance) {
 204              if ($tempinstance->enrol == 'manual') {
 205                  if ($instance === null) {
 206                      $instance = $tempinstance;
 207                  }
 208              }
 209          }
 210          if (empty($instance)) {
 211              return false;
 212          }
 213  
 214          $link = $this->get_manual_enrol_link($instance);
 215          if (!$link) {
 216              return false;
 217          }
 218  
 219          $button = new enrol_user_button($link, get_string('enrolusers', 'enrol_manual'), 'get');
 220          $button->class .= ' enrol_manual_plugin';
 221  
 222          $context = context_course::instance($instance->courseid);
 223          $arguments = array('contextid' => $context->id);
 224  
 225          if (!$called) {
 226              $called = true;
 227              // Calling the following more than once will cause unexpected results.
 228              $PAGE->requires->js_call_amd('enrol_manual/quickenrolment', 'init', array($arguments));
 229          }
 230  
 231          return $button;
 232      }
 233  
 234      /**
 235       * Sync all meta course links.
 236       *
 237       * @param progress_trace $trace
 238       * @param int $courseid one course, empty mean all
 239       * @return int 0 means ok, 1 means error, 2 means plugin disabled
 240       */
 241      public function sync(progress_trace $trace, $courseid = null) {
 242          global $DB;
 243  
 244          if (!enrol_is_enabled('manual')) {
 245              $trace->finished();
 246              return 2;
 247          }
 248  
 249          // Unfortunately this may take a long time, execution can be interrupted safely here.
 250          core_php_time_limit::raise();
 251          raise_memory_limit(MEMORY_HUGE);
 252  
 253          $trace->output('Verifying manual enrolment expiration...');
 254  
 255          $params = array('now'=>time(), 'useractive'=>ENROL_USER_ACTIVE, 'courselevel'=>CONTEXT_COURSE);
 256          $coursesql = "";
 257          if ($courseid) {
 258              $coursesql = "AND e.courseid = :courseid";
 259              $params['courseid'] = $courseid;
 260          }
 261  
 262          // Deal with expired accounts.
 263          $action = $this->get_config('expiredaction', ENROL_EXT_REMOVED_KEEP);
 264  
 265          if ($action == ENROL_EXT_REMOVED_UNENROL) {
 266              $instances = array();
 267              $sql = "SELECT ue.*, e.courseid, c.id AS contextid
 268                        FROM {user_enrolments} ue
 269                        JOIN {enrol} e ON (e.id = ue.enrolid AND e.enrol = 'manual')
 270                        JOIN {context} c ON (c.instanceid = e.courseid AND c.contextlevel = :courselevel)
 271                       WHERE ue.timeend > 0 AND ue.timeend < :now
 272                             $coursesql";
 273              $rs = $DB->get_recordset_sql($sql, $params);
 274              foreach ($rs as $ue) {
 275                  if (empty($instances[$ue->enrolid])) {
 276                      $instances[$ue->enrolid] = $DB->get_record('enrol', array('id'=>$ue->enrolid));
 277                  }
 278                  $instance = $instances[$ue->enrolid];
 279                  // Always remove all manually assigned roles here, this may break enrol_self roles but we do not want hardcoded hacks here.
 280                  role_unassign_all(array('userid'=>$ue->userid, 'contextid'=>$ue->contextid, 'component'=>'', 'itemid'=>0), true);
 281                  $this->unenrol_user($instance, $ue->userid);
 282                  $trace->output("unenrolling expired user $ue->userid from course $instance->courseid", 1);
 283              }
 284              $rs->close();
 285              unset($instances);
 286  
 287          } else if ($action == ENROL_EXT_REMOVED_SUSPENDNOROLES or $action == ENROL_EXT_REMOVED_SUSPEND) {
 288              $instances = array();
 289              $sql = "SELECT ue.*, e.courseid, c.id AS contextid
 290                        FROM {user_enrolments} ue
 291                        JOIN {enrol} e ON (e.id = ue.enrolid AND e.enrol = 'manual')
 292                        JOIN {context} c ON (c.instanceid = e.courseid AND c.contextlevel = :courselevel)
 293                       WHERE ue.timeend > 0 AND ue.timeend < :now
 294                             AND ue.status = :useractive
 295                             $coursesql";
 296              $rs = $DB->get_recordset_sql($sql, $params);
 297              foreach ($rs as $ue) {
 298                  if (empty($instances[$ue->enrolid])) {
 299                      $instances[$ue->enrolid] = $DB->get_record('enrol', array('id'=>$ue->enrolid));
 300                  }
 301                  $instance = $instances[$ue->enrolid];
 302                  if ($action == ENROL_EXT_REMOVED_SUSPENDNOROLES) {
 303                      // Remove all manually assigned roles here, this may break enrol_self roles but we do not want hardcoded hacks here.
 304                      role_unassign_all(array('userid'=>$ue->userid, 'contextid'=>$ue->contextid, 'component'=>'', 'itemid'=>0), true);
 305                      $this->update_user_enrol($instance, $ue->userid, ENROL_USER_SUSPENDED);
 306                      $trace->output("suspending expired user $ue->userid in course $instance->courseid, roles unassigned", 1);
 307                  } else {
 308                      $this->update_user_enrol($instance, $ue->userid, ENROL_USER_SUSPENDED);
 309                      $trace->output("suspending expired user $ue->userid in course $instance->courseid, roles kept", 1);
 310                  }
 311              }
 312              $rs->close();
 313              unset($instances);
 314  
 315          } else {
 316              // ENROL_EXT_REMOVED_KEEP means no changes.
 317          }
 318  
 319          $trace->output('...manual enrolment updates finished.');
 320          $trace->finished();
 321  
 322          return 0;
 323      }
 324  
 325      /**
 326       * Returns the user who is responsible for manual enrolments in given instance.
 327       *
 328       * Usually it is the first editing teacher - the person with "highest authority"
 329       * as defined by sort_by_roleassignment_authority() having 'enrol/manual:manage'
 330       * capability.
 331       *
 332       * @param int $instanceid enrolment instance id
 333       * @return stdClass user record
 334       */
 335      protected function get_enroller($instanceid) {
 336          global $DB;
 337  
 338          if ($this->lasternollerinstanceid == $instanceid and $this->lasternoller) {
 339              return $this->lasternoller;
 340          }
 341  
 342          $instance = $DB->get_record('enrol', array('id'=>$instanceid, 'enrol'=>$this->get_name()), '*', MUST_EXIST);
 343          $context = context_course::instance($instance->courseid);
 344  
 345          if ($users = get_enrolled_users($context, 'enrol/manual:manage')) {
 346              $users = sort_by_roleassignment_authority($users, $context);
 347              $this->lasternoller = reset($users);
 348              unset($users);
 349          } else {
 350              $this->lasternoller = parent::get_enroller($instanceid);
 351          }
 352  
 353          $this->lasternollerinstanceid = $instanceid;
 354  
 355          return $this->lasternoller;
 356      }
 357  
 358      /**
 359       * The manual plugin has several bulk operations that can be performed.
 360       * @param course_enrolment_manager $manager
 361       * @return array
 362       */
 363      public function get_bulk_operations(course_enrolment_manager $manager) {
 364          global $CFG;
 365          require_once($CFG->dirroot.'/enrol/manual/locallib.php');
 366          $context = $manager->get_context();
 367          $bulkoperations = array();
 368          if (has_capability("enrol/manual:manage", $context)) {
 369              $bulkoperations['editselectedusers'] = new enrol_manual_editselectedusers_operation($manager, $this);
 370          }
 371          if (has_capability("enrol/manual:unenrol", $context)) {
 372              $bulkoperations['deleteselectedusers'] = new enrol_manual_deleteselectedusers_operation($manager, $this);
 373          }
 374          return $bulkoperations;
 375      }
 376  
 377      /**
 378       * Restore instance and map settings.
 379       *
 380       * @param restore_enrolments_structure_step $step
 381       * @param stdClass $data
 382       * @param stdClass $course
 383       * @param int $oldid
 384       */
 385      public function restore_instance(restore_enrolments_structure_step $step, stdClass $data, $course, $oldid) {
 386          global $DB;
 387          // There is only I manual enrol instance allowed per course.
 388          if ($instances = $DB->get_records('enrol', array('courseid'=>$data->courseid, 'enrol'=>'manual'), 'id')) {
 389              $instance = reset($instances);
 390              $instanceid = $instance->id;
 391          } else {
 392              $instanceid = $this->add_instance($course, (array)$data);
 393          }
 394          $step->set_mapping('enrol', $oldid, $instanceid);
 395      }
 396  
 397      /**
 398       * Restore user enrolment.
 399       *
 400       * @param restore_enrolments_structure_step $step
 401       * @param stdClass $data
 402       * @param stdClass $instance
 403       * @param int $oldinstancestatus
 404       * @param int $userid
 405       */
 406      public function restore_user_enrolment(restore_enrolments_structure_step $step, $data, $instance, $userid, $oldinstancestatus) {
 407          global $DB;
 408  
 409          // Note: this is a bit tricky because other types may be converted to manual enrolments,
 410          //       and manual is restricted to one enrolment per user.
 411  
 412          $ue = $DB->get_record('user_enrolments', array('enrolid'=>$instance->id, 'userid'=>$userid));
 413          $enrol = false;
 414          if ($ue and $ue->status == ENROL_USER_ACTIVE) {
 415              // We do not want to restrict current active enrolments, let's kind of merge the times only.
 416              // This prevents some teacher lockouts too.
 417              if ($data->status == ENROL_USER_ACTIVE) {
 418                  if ($data->timestart > $ue->timestart) {
 419                      $data->timestart = $ue->timestart;
 420                      $enrol = true;
 421                  }
 422  
 423                  if ($data->timeend == 0) {
 424                      if ($ue->timeend != 0) {
 425                          $enrol = true;
 426                      }
 427                  } else if ($ue->timeend == 0) {
 428                      $data->timeend = 0;
 429                  } else if ($data->timeend < $ue->timeend) {
 430                      $data->timeend = $ue->timeend;
 431                      $enrol = true;
 432                  }
 433              }
 434          } else {
 435              if ($instance->status == ENROL_INSTANCE_ENABLED and $oldinstancestatus != ENROL_INSTANCE_ENABLED) {
 436                  // Make sure that user enrolments are not activated accidentally,
 437                  // we do it only here because it is not expected that enrolments are migrated to other plugins.
 438                  $data->status = ENROL_USER_SUSPENDED;
 439              }
 440              $enrol = true;
 441          }
 442  
 443          if ($enrol) {
 444              $this->enrol_user($instance, $userid, null, $data->timestart, $data->timeend, $data->status);
 445          }
 446      }
 447  
 448      /**
 449       * Restore role assignment.
 450       *
 451       * @param stdClass $instance
 452       * @param int $roleid
 453       * @param int $userid
 454       * @param int $contextid
 455       */
 456      public function restore_role_assignment($instance, $roleid, $userid, $contextid) {
 457          // This is necessary only because we may migrate other types to this instance,
 458          // we do not use component in manual or self enrol.
 459          role_assign($roleid, $userid, $contextid, '', 0);
 460      }
 461  
 462      /**
 463       * Restore user group membership.
 464       * @param stdClass $instance
 465       * @param int $groupid
 466       * @param int $userid
 467       */
 468      public function restore_group_member($instance, $groupid, $userid) {
 469          global $CFG;
 470          require_once("$CFG->dirroot/group/lib.php");
 471  
 472          // This might be called when forcing restore as manual enrolments.
 473  
 474          groups_add_member($groupid, $userid);
 475      }
 476  
 477      /**
 478       * Is it possible to delete enrol instance via standard UI?
 479       *
 480       * @param object $instance
 481       * @return bool
 482       */
 483      public function can_delete_instance($instance) {
 484          $context = context_course::instance($instance->courseid);
 485          return has_capability('enrol/manual:config', $context);
 486      }
 487  
 488      /**
 489       * Is it possible to hide/show enrol instance via standard UI?
 490       *
 491       * @param stdClass $instance
 492       * @return bool
 493       */
 494      public function can_hide_show_instance($instance) {
 495          $context = context_course::instance($instance->courseid);
 496          return has_capability('enrol/manual:config', $context);
 497      }
 498  
 499      /**
 500       * Enrol all not enrolled cohort members into course via enrol instance.
 501       *
 502       * @param stdClass $instance
 503       * @param int $cohortid
 504       * @param int $roleid optional role id
 505       * @param int $timestart 0 means unknown
 506       * @param int $timeend 0 means forever
 507       * @param int $status default to ENROL_USER_ACTIVE for new enrolments, no change by default in updates
 508       * @param bool $recovergrades restore grade history
 509       * @return int The number of enrolled cohort users
 510       */
 511      public function enrol_cohort(stdClass $instance, $cohortid, $roleid = null, $timestart = 0, $timeend = 0, $status = null, $recovergrades = null) {
 512          global $DB;
 513          $context = context_course::instance($instance->courseid);
 514          list($esql, $params) = get_enrolled_sql($context);
 515          $sql = "SELECT cm.userid FROM {cohort_members} cm LEFT JOIN ($esql) u ON u.id = cm.userid ".
 516              "WHERE cm.cohortid = :cohortid AND u.id IS NULL";
 517          $params['cohortid'] = $cohortid;
 518          $members = $DB->get_fieldset_sql($sql, $params);
 519          foreach ($members as $userid) {
 520              $this->enrol_user($instance, $userid, $roleid, $timestart, $timeend, $status, $recovergrades);
 521          }
 522          return count($members);
 523      }
 524  
 525      /**
 526       * We are a good plugin and don't invent our own UI/validation code path.
 527       *
 528       * @return boolean
 529       */
 530      public function use_standard_editing_ui() {
 531          return true;
 532      }
 533  
 534      /**
 535       * Return an array of valid options for the status.
 536       *
 537       * @return array
 538       */
 539      protected function get_status_options() {
 540          $options = array(ENROL_INSTANCE_ENABLED  => get_string('yes'),
 541                           ENROL_INSTANCE_DISABLED => get_string('no'));
 542          return $options;
 543      }
 544  
 545      /**
 546       * Return an array of valid options for the roleid.
 547       *
 548       * @param stdClass $instance
 549       * @param context $context
 550       * @return array
 551       */
 552      protected function get_roleid_options($instance, $context) {
 553          if ($instance->id) {
 554              $roles = get_default_enrol_roles($context, $instance->roleid);
 555          } else {
 556              $roles = get_default_enrol_roles($context, $this->get_config('roleid'));
 557          }
 558          return $roles;
 559      }
 560  
 561      /**
 562       * Return an array of valid options for the expirynotify.
 563       *
 564       * @return array
 565       */
 566      protected function get_expirynotify_options() {
 567          $options = array(
 568              0 => get_string('no'),
 569              1 => get_string('expirynotifyenroller', 'core_enrol'),
 570              2 => get_string('expirynotifyall', 'core_enrol')
 571          );
 572          return $options;
 573      }
 574  
 575      /**
 576       * Add elements to the edit instance form.
 577       *
 578       * @param stdClass $instance
 579       * @param MoodleQuickForm $mform
 580       * @param context $context
 581       * @return bool
 582       */
 583      public function edit_instance_form($instance, MoodleQuickForm $mform, $context) {
 584  
 585          $options = $this->get_status_options();
 586          $mform->addElement('select', 'status', get_string('status', 'enrol_manual'), $options);
 587          $mform->addHelpButton('status', 'status', 'enrol_manual');
 588          $mform->setDefault('status', $this->get_config('status'));
 589  
 590          $roles = $this->get_roleid_options($instance, $context);
 591          $mform->addElement('select', 'roleid', get_string('defaultrole', 'role'), $roles);
 592          $mform->setDefault('roleid', $this->get_config('roleid'));
 593  
 594          $options = array('optional' => true, 'defaultunit' => 86400);
 595          $mform->addElement('duration', 'enrolperiod', get_string('defaultperiod', 'enrol_manual'), $options);
 596          $mform->setDefault('enrolperiod', $this->get_config('enrolperiod'));
 597          $mform->addHelpButton('enrolperiod', 'defaultperiod', 'enrol_manual');
 598  
 599          $options = $this->get_expirynotify_options();
 600          $mform->addElement('select', 'expirynotify', get_string('expirynotify', 'core_enrol'), $options);
 601          $mform->addHelpButton('expirynotify', 'expirynotify', 'core_enrol');
 602  
 603          $options = array('optional' => false, 'defaultunit' => 86400);
 604          $mform->addElement('duration', 'expirythreshold', get_string('expirythreshold', 'core_enrol'), $options);
 605          $mform->addHelpButton('expirythreshold', 'expirythreshold', 'core_enrol');
 606          $mform->disabledIf('expirythreshold', 'expirynotify', 'eq', 0);
 607  
 608          if (enrol_accessing_via_instance($instance)) {
 609              $warntext = get_string('instanceeditselfwarningtext', 'core_enrol');
 610              $mform->addElement('static', 'selfwarn', get_string('instanceeditselfwarning', 'core_enrol'), $warntext);
 611          }
 612      }
 613  
 614      /**
 615       * Perform custom validation of the data used to edit the instance.
 616       *
 617       * @param array $data array of ("fieldname"=>value) of submitted data
 618       * @param array $files array of uploaded files "element_name"=>tmp_file_path
 619       * @param object $instance The instance loaded from the DB
 620       * @param context $context The context of the instance we are editing
 621       * @return array of "element_name"=>"error_description" if there are errors,
 622       *         or an empty array if everything is OK.
 623       * @return void
 624       */
 625      public function edit_instance_validation($data, $files, $instance, $context) {
 626          $errors = array();
 627  
 628          if ($data['expirynotify'] > 0 and $data['expirythreshold'] < 86400) {
 629              $errors['expirythreshold'] = get_string('errorthresholdlow', 'core_enrol');
 630          }
 631  
 632          $validstatus = array_keys($this->get_status_options());
 633          $validroles = array_keys($this->get_roleid_options($instance, $context));
 634          $validexpirynotify = array_keys($this->get_expirynotify_options());
 635  
 636          $tovalidate = array(
 637              'status' => $validstatus,
 638              'roleid' => $validroles,
 639              'enrolperiod' => PARAM_INT,
 640              'expirynotify' => $validexpirynotify,
 641              'expirythreshold' => PARAM_INT
 642          );
 643  
 644          $typeerrors = $this->validate_param_types($data, $tovalidate);
 645          $errors = array_merge($errors, $typeerrors);
 646  
 647          return $errors;
 648      }
 649  
 650  }
 651  
 652  /**
 653   * Serve the manual enrol users form as a fragment.
 654   *
 655   * @param array $args List of named arguments for the fragment loader.
 656   * @return string
 657   */
 658  function enrol_manual_output_fragment_enrol_users_form($args) {
 659      $args = (object) $args;
 660      $context = $args->context;
 661      $o = '';
 662  
 663      require_capability('enrol/manual:enrol', $context);
 664      $mform = new enrol_manual_enrol_users_form(null, $args);
 665  
 666      ob_start();
 667      $mform->display();
 668      $o .= ob_get_contents();
 669      ob_end_clean();
 670  
 671      return $o;
 672  }