new implementation of core_user_get_users

externallib.php

<?php
    public static function get_users_parameters() {
        return new external_function_parameters(
            array(
                'criteria' => new external_multiple_structure(
                    new external_single_structure(
                        array(
                            'key'        => new external_value(PARAM_ALPHA, 'the user column to search'),
                            'value'      => new external_value(PARAM_TEXT, 'the value to match')
                        )
                    )
                ),
                'addcourseprofiles' =>  new external_value(PARAM_BOOL, 'return the user\'s course profiles (0 - default)
                                            otherwise only the user system profile (0)', VALUE_DEFAULT, 0)
            )
        );
    }

    /**
     * Get user information, filtered by key/value pairs.
     * - This function is matching the permissions of /user/profile.php
     * - It is also matching some permissions from /user/editadvanced.php for the following fields:
     *   auth, confirmed, idnumber, lang, theme, timezone, mailformat
     * @param array $keys  array of keys
     * @return array An array of arrays describing users
     */
    public static function get_users($criteria = array(), $addcourseprofiles = false) {
        global $CFG, $USER, $DB;
        require_once($CFG->dirroot . "user/lib.php");
        require_once($CFG->dirroot . "enrol/enrollib.php");

        $params = self::validate_parameters(self::get_users_parameters(), array('criteria' => $criteria));

        $users = array();
        if (!empty($params['criteria'])) {
            $conditions = array();
            $wheres = array();
            foreach ($params['criteria'] as $crit) {
                $key = trim($crit['key']);

                // Trying to avoid duplicate keys.
                if (!isset($conditions[$key])) {

                    switch($key) {
                        case 'id':
                            $value = clean_param($crit['value'], PARAM_INT);
                            break;
                        case 'idnumber':
                            $value = clean_param($crit['value'], PARAM_RAW);
                            break;
                        case 'username':
                            $value = clean_param($crit['value'], PARAM_RAW);
                            break;
                        case 'fullname':
                        case 'firstname':
                        case 'lastname':
                            $value = clean_param($crit['value'], PARAM_NOTAGS);
                            break;
                        case 'email':
                            $value = clean_param($crit['value'], PARAM_EMAIL);
                            break;
                        case 'auth':
                            $value = clean_param($crit['value'], PARAM_PLUGIN);
                            break;
                        default:
                            throw new moodle_exception('invalidextparam', 'webservice', '', $key);
                    }

                    if ($value != '') {
                        $conditions[$key] = $crit['value'];
                        $wheres[] = $key . " = :" . $key;
                    }
                }
            }

            list($uselect, $ujoin) = context_instance_preload_sql('u.id', CONTEXT_USER, 'ctx');
            if (!empty($wheres)) {
                $wheres = implode(" AND ", $wheres);
                $usersql = "SELECT u.* $uselect
                      FROM {user} u $ujoin
                      WHERE $wheres
                      ORDER BY username ASC";
            }
            else {
                $usersql = "SELECT u.* $uselect
                      FROM {user} u $ujoin
                      ORDER BY username ASC";
            }
            $users = $DB->get_recordset_sql($usersql, $conditions);

            foreach ($users as $user) {
                if ($addcourseprofiles) {
                    //get courses this user is in and add the profile info of each to the user info
                }
                else {
                    if ($userarray = user_get_user_details($user)) {
                        $result[] = $userarray;
                    }
                }
            }
        }
        return $result;
    }
?>