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466 lines
22 KiB
PHP
466 lines
22 KiB
PHP
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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use auth_lti\local\ltiadvantage\entity\user_migration_claim;
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defined('MOODLE_INTERNAL') || die();
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require_once($CFG->libdir.'/authlib.php');
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require_once($CFG->libdir.'/accesslib.php');
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/**
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* LTI Authentication plugin.
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*
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* @package auth_lti
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* @copyright 2016 Mark Nelson <markn@moodle.com>
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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class auth_plugin_lti extends \auth_plugin_base {
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/**
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* @var int constant representing the automatic account provisioning mode.
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* On first launch, for a previously unbound user, this mode dictates that a new Moodle account will be created automatically
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* for the user and bound to their platform credentials {iss, sub}.
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*/
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public const PROVISIONING_MODE_AUTO_ONLY = 1;
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/**
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* @var int constant representing the prompt for new or existing provisioning mode.
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* On first launch, for a previously unbound user, the mode dictates that the launch user will be presented with an options
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* view, allowing them to select either 'link an existing account' or 'create a new account for me'.
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*/
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public const PROVISIONING_MODE_PROMPT_NEW_EXISTING = 2;
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/**
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* @var int constant representing the prompt for existing only provisioning mode.
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* On first launch, for a previously unbound user, the mode dictates that the launch user will be presented with a view allowing
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* them to link an existing account only. This is useful for situations like deep linking, where an existing account is needed.
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*/
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public const PROVISIONING_MODE_PROMPT_EXISTING_ONLY = 3;
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/**
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* Constructor.
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*/
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public function __construct() {
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$this->authtype = 'lti';
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}
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/**
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* Users can not log in via the traditional login form.
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*
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* @param string $username The username
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* @param string $password The password
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* @return bool Authentication success or failure
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*/
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public function user_login($username, $password) {
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return false;
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}
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/**
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* Authenticate the user based on the unique {iss, sub} tuple present in the OIDC JWT.
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*
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* This method ensures a Moodle user account has been found or is created, that the user is linked to the relevant
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* LTI Advantage credentials (iss, sub) and that the user account is logged in.
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*
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* Launch code can therefore rely on this method to get a session before doing things like calling require_login().
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*
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* This method supports two workflows:
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* 1. Automatic account provisioning - where the complete_login() call will ALWAYS create/find a user and return to
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* calling code directly. No user interaction is required.
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*
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* 2. Manual account provisioning - where the complete_login() call will redirect ONLY ONCE to a login page,
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* where the user can decide whether to use an automatically provisioned account, or bind an existing user account.
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* When the decision has been made, the relevant account is bound and the user is redirected back to $returnurl.
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* Once an account has been bound via this selection process, subsequent calls to complete_login() will return to
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* calling code directly. Any calling code must provide its $returnurl to support the return from the account
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* selection process and must also take care to cache any JWT data appropriately, since the return will not inlude
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* that information.
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*
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* Which workflow is chosen depends on the roles present in the JWT.
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* For teachers/admins, manual provisioning will take place. These user type are likely to have existing accounts.
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* For learners, automatic provisioning will take place.
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*
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* Migration of legacy users is supported, however, only for the Learner role (automatic provisioning). Admins and
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* teachers are likely to have existing accounts and we want them to be able to select and bind these, rather than
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* binding an automatically provisioned legacy account which doesn't represent their real user account.
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*
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* The JWT data must be verified elsewhere. The code here assumes its integrity/authenticity.
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*
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* @param array $launchdata the JWT data provided in the link launch.
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* @param moodle_url $returnurl the local URL to return to if authentication workflows are required.
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* @param int $provisioningmode the desired account provisioning mode, which controls the auth flow for unbound users.
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* @param array $legacyconsumersecrets an array of secrets used by the legacy consumer if a migration claim exists.
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* @throws coding_exception if the specified provisioning mode is invalid.
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*/
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public function complete_login(array $launchdata, moodle_url $returnurl, int $provisioningmode,
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array $legacyconsumersecrets = []): void {
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// The platform user is already linked with a user account.
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if ($this->get_user_binding($launchdata['iss'], $launchdata['sub'])) {
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$user = $this->find_or_create_user_from_launch($launchdata);
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if (isloggedin()) {
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// If a different user is currently logged in, authenticate the linked user instead.
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global $USER;
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if ($USER->id !== $user->id) {
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complete_user_login($user);
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}
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// If the linked user is already logged in, skip the call to complete_user_login() because this affects deep linking
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// workflows on sites publishing and consuming resources on the same site, due to the regenerated sesskey.
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} else {
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complete_user_login($user);
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}
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// Always sync the PII, regardless of whether we're already authenticated as this user or not.
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$this->update_user_account($user, $launchdata, $launchdata['iss']);
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return;
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}
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// The platform user is not bound to a user account, check provisioning mode now.
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if (!$this->is_valid_provisioning_mode($provisioningmode)) {
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throw new coding_exception('Invalid account provisioning mode provided to complete_login().');
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}
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switch ($provisioningmode) {
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case self::PROVISIONING_MODE_AUTO_ONLY:
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// Automatic provisioning - this will create/migrate a user account and log the user in.
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$user = $this->find_or_create_user_from_launch($launchdata, $legacyconsumersecrets);
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complete_user_login($user);
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$this->update_user_account($user, $launchdata, $launchdata['iss']);
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break;
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case self::PROVISIONING_MODE_PROMPT_NEW_EXISTING:
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case self::PROVISIONING_MODE_PROMPT_EXISTING_ONLY:
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default:
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// Allow linking an existing account or creation of a new account via an intermediate account options page.
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// Cache the relevant data and take the user to the account options page.
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// Note: This mode also depends on the global auth config 'authpreventaccountcreation'. If set, only existing
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// accounts can be bound in this provisioning mode.
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global $SESSION;
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$SESSION->auth_lti = (object)[
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'launchdata' => $launchdata,
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'returnurl' => $returnurl,
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'provisioningmode' => $provisioningmode
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];
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redirect(new moodle_url('/auth/lti/login.php', [
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'sesskey' => sesskey(),
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]));
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break;
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}
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}
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/**
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* Get a Moodle user account for the LTI user based on the user details returned by a NRPS 2 membership call.
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*
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* This method expects a single member structure, in array format, as defined here:
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* See: https://www.imsglobal.org/spec/lti-nrps/v2p0#membership-container-media-type.
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*
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* This method supports migration of user accounts used in legacy launches, provided the legacy consumerkey corresponding to
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* to the legacy consumer is provided. Calling code will have verified the migration claim during initial launches and should
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* have the consumer key mapped to the deployment, ready to pass in.
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*
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* @param array $member the member data, in array format.
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* @param string $iss the issuer to which the member relates.
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* @param string $legacyconsumerkey optional consumer key mapped to the deployment to facilitate user migration.
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* @return stdClass a Moodle user record.
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*/
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public function find_or_create_user_from_membership(array $member, string $iss,
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string $legacyconsumerkey = ''): stdClass {
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// Picture is not synced with membership-based auths because sync tasks may wish to perform slow operations like this a
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// different way.
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unset($member['picture']);
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if ($binduser = $this->get_user_binding($iss, $member['user_id'])) {
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$user = \core_user::get_user($binduser);
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$this->update_user_account($user, $member, $iss);
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return \core_user::get_user($user->id);
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} else {
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if (!empty($legacyconsumerkey)) {
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// Consumer key is required to attempt user migration because legacy users were identified by a
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// username consisting of the consumer key and user id.
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// See the legacy \enrol_lti\helper::create_username() for details.
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$legacyuserid = $member['lti11_legacy_user_id'] ?? $member['user_id'];
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$username = 'enrol_lti' .
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sha1($legacyconsumerkey . '::' . $legacyconsumerkey . ':' . $legacyuserid);
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if ($user = \core_user::get_user_by_username($username)) {
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$this->create_user_binding($iss, $member['user_id'], $user->id);
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$this->update_user_account($user, $member, $iss);
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return \core_user::get_user($user->id);
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}
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}
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$user = $this->create_new_account($member, $iss);
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return \core_user::get_user($user->id);
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}
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}
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/**
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* Get a Moodle user account for the LTI user corresponding to the user defined in a link launch.
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*
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* This method supports migration of user accounts used in legacy launches, provided the legacy consumer secrets corresponding
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* to the legacy consumer are provided. If calling code wishes migration to be role-specific, it should check roles accordingly
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* itself and pass relevant data in - as auth_plugin_lti::complete_login() does.
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*
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* @param array $launchdata all data in the decoded JWT including iss and sub.
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* @param array $legacyconsumersecrets all secrets found for the legacy consumer, facilitating user migration.
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* @return stdClass the Moodle user who is mapped to the platform user identified in the JWT data.
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*/
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public function find_or_create_user_from_launch(array $launchdata, array $legacyconsumersecrets = []): stdClass {
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if ($binduser = $this->get_user_binding($launchdata['iss'], $launchdata['sub'])) {
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return \core_user::get_user($binduser);
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} else {
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// Is the intent to migrate a user account used in legacy launches?
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if (!empty($legacyconsumersecrets)) {
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try {
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// Validate the migration claim and try to find a legacy user.
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$usermigrationclaim = new user_migration_claim($launchdata, $legacyconsumersecrets);
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$username = 'enrol_lti' .
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sha1($usermigrationclaim->get_consumer_key() . '::' .
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$usermigrationclaim->get_consumer_key() . ':' . $usermigrationclaim->get_user_id());
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if ($user = core_user::get_user_by_username($username)) {
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$this->create_user_binding($launchdata['iss'], $launchdata['sub'], $user->id);
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return core_user::get_user($user->id);
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}
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} catch (Exception $e) {
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// There was an issue validating the user migration claim. We don't want to fail auth entirely though.
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// Rather, we want to fall back to new account creation and log the attempt.
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debugging("There was a problem migrating the LTI user '{$launchdata['sub']}' on the platform " .
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"'{$launchdata['iss']}'. The migration claim could not be validated. A new account will be created.");
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}
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}
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// At the point of the creation, to ensure the user_created event correctly reflects the creating user of '0' (the user
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// performing the action), ensure any active session is terminated and an empty session initialised.
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$this->empty_session();
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$user = $this->create_new_account($launchdata, $launchdata['iss']);
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return core_user::get_user($user->id);
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}
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}
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/**
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* Create a binding between the LTI user, as identified by {iss, sub} tuple and the user id.
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*
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* @param string $iss the issuer URL identifying the platform to which to user belongs.
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* @param string $sub the sub string identifying the user on the platform.
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* @param int $userid the id of the Moodle user account to bind.
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*/
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public function create_user_binding(string $iss, string $sub, int $userid): void {
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global $DB;
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$timenow = time();
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$issuer256 = hash('sha256', $iss);
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$sub256 = hash('sha256', $sub);
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if ($DB->record_exists('auth_lti_linked_login', ['issuer256' => $issuer256, 'sub256' => $sub256])) {
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return;
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}
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$rec = [
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'userid' => $userid,
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'issuer' => $iss,
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'issuer256' => $issuer256,
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'sub' => $sub,
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'sub256' => $sub256,
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'timecreated' => $timenow,
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'timemodified' => $timenow
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];
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$DB->insert_record('auth_lti_linked_login', $rec);
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}
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/**
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* Gets the id of the linked Moodle user account for an LTI user, or null if not found.
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*
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* @param string $issuer the issuer to which the user belongs.
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* @param string $sub the sub string identifying the user on the issuer.
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* @return int|null the id of the corresponding Moodle user record, or null if not found.
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*/
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public function get_user_binding(string $issuer, string $sub): ?int {
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global $DB;
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$issuer256 = hash('sha256', $issuer);
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$sub256 = hash('sha256', $sub);
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try {
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$binduser = $DB->get_field('auth_lti_linked_login', 'userid',
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['issuer256' => $issuer256, 'sub256' => $sub256], MUST_EXIST);
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} catch (\dml_exception $e) {
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$binduser = null;
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}
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return $binduser;
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}
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/**
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* If there's an existing session, inits an empty session.
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*
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* @return void
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*/
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protected function empty_session(): void {
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if (isloggedin()) {
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\core\session\manager::init_empty_session();
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}
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}
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/**
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* Check whether a provisioning mode is valid or not.
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*
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* @param int $mode the mode
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* @return bool true if valid for use, false otherwise.
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*/
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protected function is_valid_provisioning_mode(int $mode): bool {
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$validmodes = [
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self::PROVISIONING_MODE_AUTO_ONLY,
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self::PROVISIONING_MODE_PROMPT_NEW_EXISTING,
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self::PROVISIONING_MODE_PROMPT_EXISTING_ONLY
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];
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return in_array($mode, $validmodes);
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}
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/**
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* Create a new user account based on the user data either in the launch JWT or from a membership call.
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*
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* @param array $userdata the user data coming from either a launch or membership service call.
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* @param string $iss the issuer to which the user belongs.
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* @return stdClass a complete Moodle user record.
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*/
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protected function create_new_account(array $userdata, string $iss): stdClass {
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global $CFG;
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require_once($CFG->dirroot.'/user/lib.php');
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// Launches and membership calls handle the user id differently.
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// Launch uses 'sub', whereas member uses 'user_id'.
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$userid = !empty($userdata['sub']) ? $userdata['sub'] : $userdata['user_id'];
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$user = new stdClass();
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$user->username = 'enrol_lti_13_' . sha1($iss . '_' . $userid);
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// If the email was stripped/not set then fill it with a default one.
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// This stops the user from being redirected to edit their profile page.
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$email = !empty($userdata['email']) ? $userdata['email'] :
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'enrol_lti_13_' . sha1($iss . '_' . $userid) . "@example.com";
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$email = \core_user::clean_field($email, 'email');
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$user->email = $email;
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$user->auth = 'lti';
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$user->mnethostid = $CFG->mnet_localhost_id;
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$user->firstname = $userdata['given_name'] ?? $userid;
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$user->lastname = $userdata['family_name'] ?? $iss;
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$user->password = '';
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$user->confirmed = 1;
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$user->id = user_create_user($user, false);
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// Link this user with the LTI credentials for future use.
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$this->create_user_binding($iss, $userid, $user->id);
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return (object) get_complete_user_data('id', $user->id);
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}
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/**
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* Update the personal fields of the user account, based on data present in either a launch of member sync call.
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*
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* @param stdClass $user the Moodle user account to update.
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* @param array $userdata the user data coming from either a launch or membership service call.
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* @param string $iss the issuer to which the user belongs.
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*/
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public function update_user_account(stdClass $user, array $userdata, string $iss): void {
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global $CFG;
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require_once($CFG->dirroot.'/user/lib.php');
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if ($user->auth !== 'lti') {
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return;
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}
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// Launches and membership calls handle the user id differently.
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// Launch uses 'sub', whereas member uses 'user_id'.
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$platformuserid = !empty($userdata['sub']) ? $userdata['sub'] : $userdata['user_id'];
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$email = !empty($userdata['email']) ? $userdata['email'] :
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'enrol_lti_13_' . sha1($iss . '_' . $platformuserid) . "@example.com";
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$email = \core_user::clean_field($email, 'email');
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$update = [
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'id' => $user->id,
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'firstname' => $userdata['given_name'] ?? $platformuserid,
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'lastname' => $userdata['family_name'] ?? $iss,
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'email' => $email
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];
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$userfieldstocompare = array_intersect_key((array) $user, $update);
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if (!empty(array_diff($update, $userfieldstocompare))) {
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user_update_user($update); // Only update if there's a change.
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}
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if (!empty($userdata['picture'])) {
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try {
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$this->update_user_picture($user->id, $userdata['picture']);
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} catch (Exception $e) {
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debugging("Error syncing the profile picture for user '$user->id' during LTI authentication.");
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}
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}
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}
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/**
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* Update the user's picture with the image stored at $url.
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*
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* @param int $userid the id of the user to update.
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* @param string $url the string URL where the new image can be found.
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* @throws moodle_exception if there were any problems updating the picture.
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*/
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protected function update_user_picture(int $userid, string $url): void {
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global $CFG, $DB;
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require_once($CFG->libdir . '/filelib.php');
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require_once($CFG->libdir . '/gdlib.php');
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$fs = get_file_storage();
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$context = \context_user::instance($userid, MUST_EXIST);
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$fs->delete_area_files($context->id, 'user', 'newicon');
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$filerecord = array(
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'contextid' => $context->id,
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'component' => 'user',
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'filearea' => 'newicon',
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'itemid' => 0,
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'filepath' => '/'
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);
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$urlparams = array(
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'calctimeout' => false,
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'timeout' => 5,
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'skipcertverify' => true,
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'connecttimeout' => 5
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);
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try {
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|
$fs->create_file_from_url($filerecord, $url, $urlparams);
|
|
} catch (\file_exception $e) {
|
|
throw new moodle_exception(get_string($e->errorcode, $e->module, $e->a));
|
|
}
|
|
|
|
$iconfile = $fs->get_area_files($context->id, 'user', 'newicon', false, 'itemid', false);
|
|
|
|
// There should only be one.
|
|
$iconfile = reset($iconfile);
|
|
|
|
// Something went wrong while creating temp file - remove the uploaded file.
|
|
if (!$iconfile = $iconfile->copy_content_to_temp()) {
|
|
$fs->delete_area_files($context->id, 'user', 'newicon');
|
|
throw new moodle_exception('There was a problem copying the profile picture to temp.');
|
|
}
|
|
|
|
// Copy file to temporary location and the send it for processing icon.
|
|
$newpicture = (int) process_new_icon($context, 'user', 'icon', 0, $iconfile);
|
|
// Delete temporary file.
|
|
@unlink($iconfile);
|
|
// Remove uploaded file.
|
|
$fs->delete_area_files($context->id, 'user', 'newicon');
|
|
// Set the user's picture.
|
|
$DB->set_field('user', 'picture', $newpicture, array('id' => $userid));
|
|
}
|
|
}
|