enrol/lti/launch.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  * Handles LTI 1.3 resource link launches.
  19  *
  20  * See enrol/lti/launch_deeplink.php for deep linking launches.
  21  *
  22  * There are 2 pathways through this page:
  23  * 1. When first making a resource linking launch from the platform. The launch data is cached at this point, pending user
  24  * authentication, and the page is set such that the post-authentication redirect will return here.
  25  * 2. The post-authentication redirect. The launch data is fetched from the session launch cache, and the resource is displayed.
  26  *
  27  * @package    enrol_lti
  28  * @copyright  2021 Jake Dallimore <jrhdallimore@gmail.com>
  29  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  30  */
  31
  32 use core\http_client;
  33 use enrol_lti\local\ltiadvantage\lib\lti_cookie;
  34 use enrol_lti\local\ltiadvantage\lib\issuer_database;
  35 use enrol_lti\local\ltiadvantage\lib\launch_cache_session;
  36 use enrol_lti\local\ltiadvantage\repository\application_registration_repository;
  37 use enrol_lti\local\ltiadvantage\repository\context_repository;
  38 use enrol_lti\local\ltiadvantage\repository\deployment_repository;
  39 use enrol_lti\local\ltiadvantage\repository\legacy_consumer_repository;
  40 use enrol_lti\local\ltiadvantage\repository\resource_link_repository;
  41 use enrol_lti\local\ltiadvantage\repository\user_repository;
  42 use enrol_lti\local\ltiadvantage\service\tool_launch_service;
  43 use enrol_lti\local\ltiadvantage\utility\message_helper;
  44 use Packback\Lti1p3\LtiMessageLaunch;
  45 use Packback\Lti1p3\LtiServiceConnector;
  46
  47 require_once(__DIR__ . '/../../config.php');
  48 global $CFG;
  49 require_once($CFG->libdir . '/filelib.php');
  50
  51 $idtoken = optional_param('id_token', null, PARAM_RAW);
  52 $launchid = optional_param('launchid', null, PARAM_RAW);
  53
  54 if (!is_enabled_auth('lti')) {
  55     throw new moodle_exception('pluginnotenabled', 'auth', '', get_string('pluginname', 'auth_lti'));
  56 }
  57 if (!enrol_is_enabled('lti')) {
  58     throw new moodle_exception('enrolisdisabled', 'enrol_lti');
  59 }
  60 if (empty($idtoken) && empty($launchid)) {
  61     throw new coding_exception('Error: launch requires id_token');
  62 }
  63
  64 // Support caching the launch and retrieving it after the account binding process described in auth::complete_login().
  65 $sesscache = new launch_cache_session();
  66 $issdb = new issuer_database(new application_registration_repository(), new deployment_repository());
  67 $cookie = new lti_cookie();
  68 $serviceconnector = new LtiServiceConnector($sesscache, new http_client());
  69 if ($idtoken) {
  70     $messagelaunch = LtiMessageLaunch::new($issdb, $sesscache, $cookie, $serviceconnector)
  71         ->initialize($_POST);
  72 }
  73 if ($launchid) {
  74     $messagelaunch = LtiMessageLaunch::fromCache($launchid, $issdb, $sesscache, $cookie, $serviceconnector);
  75 }
  76 if (empty($messagelaunch)) {
  77     throw new moodle_exception('Bad launch. Message launch data could not be found');
  78 }
  79
  80 // Authenticate the platform user, which could be an instructor, an admin or a learner.
  81 // Auth code needs to be told about consumer secrets for the purposes of migration, since these reside in enrol_lti.
  82 $launchdata = $messagelaunch->getLaunchData();
  83 if (!empty($launchdata['https://purl.imsglobal.org/spec/lti/claim/lti1p1']['oauth_consumer_key'])) {
  84     $legacyconsumerrepo = new legacy_consumer_repository();
  85     $legacyconsumersecrets = $legacyconsumerrepo->get_consumer_secrets(
  86         $launchdata['https://purl.imsglobal.org/spec/lti/claim/lti1p1']['oauth_consumer_key']
  87     );
  88 }
  89
  90 // To authenticate, we need the resource's account provisioning mode for the given LTI role.
  91 if (empty($launchdata['https://purl.imsglobal.org/spec/lti/claim/custom']['id'])) {
  92     throw new \moodle_exception('ltiadvlauncherror:missingid', 'enrol_lti');
  93 }
  94 $resourceuuid = $launchdata['https://purl.imsglobal.org/spec/lti/claim/custom']['id'];
  95 $resource = array_values(\enrol_lti\helper::get_lti_tools(['uuid' => $resourceuuid]));
  96 $resource = $resource[0] ?? null;
  97 if (empty($resource) || $resource->status != ENROL_INSTANCE_ENABLED) {
  98     throw new \moodle_exception('ltiadvlauncherror:invalidid', 'enrol_lti', '', $resourceuuid);
  99 }
 100
 101 $provisioningmode = message_helper::is_instructor_launch($launchdata) ? $resource->provisioningmodeinstructor
 102     : $resource->provisioningmodelearner;
 103 $auth = get_auth_plugin('lti');
 104 $auth->complete_login(
 105     $messagelaunch->getLaunchData(),
 106     new moodle_url('/enrol/lti/launch.php', ['launchid' => $messagelaunch->getLaunchId()]),
 107     $provisioningmode,
 108     $legacyconsumersecrets ?? []
 109 );
 110
 111 global $USER, $CFG, $PAGE;
 112 // Page URL must be set before the require_login check, so that things like policies can redirect back with the launchid.
 113 $PAGE->set_url(new moodle_url('/enrol/lti/launch.php'), ['launchid' => $messagelaunch->getLaunchId()]);
 114
 115 require_login(null, false);
 116 $PAGE->set_context(context_system::instance());
 117 $PAGE->set_pagelayout('popup'); // Same layout as the tool.php page in Legacy 1.1/2.0 launches.
 118 $PAGE->set_title(get_string('opentool', 'enrol_lti'));
 119
 120 $toollaunchservice = new tool_launch_service(
 121     new deployment_repository(),
 122     new application_registration_repository(),
 123     new resource_link_repository(),
 124     new user_repository(),
 125     new context_repository()
 126 );
 127 [$userid, $resource] = $toollaunchservice->user_launches_tool($USER, $messagelaunch);
 128
 129 $context = context::instance_by_id($resource->contextid);
 130 if ($context->contextlevel == CONTEXT_COURSE) {
 131     $courseid = $context->instanceid;
 132     $redirecturl = new moodle_url('/course/view.php', ['id' => $courseid]);
 133 } else if ($context->contextlevel == CONTEXT_MODULE) {
 134     $cm = get_coursemodule_from_id(false, $context->instanceid, 0, false, MUST_EXIST);
 135     $redirecturl = new moodle_url('/mod/' . $cm->modname . '/view.php', ['id' => $cm->id]);
 136 } else {
 137     throw new moodle_exception('invalidcontext');
 138 }
 139
 140 if (empty($CFG->allowframembedding)) {
 141     $stropentool = get_string('opentool', 'enrol_lti');
 142     echo html_writer::tag('p', get_string('frameembeddingnotenabled', 'enrol_lti'));
 143     echo html_writer::link($redirecturl, $stropentool, ['target' => '_blank']);
 144 } else {
 145     redirect($redirecturl);
 146 }