launch.php

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * This file contains the moodle hooks for the submission Mahara plugin
 *
 * @package    assignsubmission_maharaws
 * @copyright  2020 Catalyst IT
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

require("../../../../config.php");

require_once($CFG->dirroot.'/mod/lti/lib.php');
require_once($CFG->dirroot.'/mod/lti/locallib.php');
require_once($CFG->dirroot . '/mod/assign/locallib.php');

confirm_sesskey();

$id = required_param('id', PARAM_INT); // Assignment id.
$target = required_param('url', PARAM_URL); // Mahara view launch.

list ($course, $cm) = get_course_and_cm_from_cmid($id, 'assign');

require_login($course, true, $cm);

$context = context_module::instance($cm->id);

require_capability('mod/assign:view', $context);

$url = new \moodle_url('/mod/assign/view.php', array('id' => $id, 'sesskey' => sesskey()));
$returnurl = $url->out(false);
$urlparts = parse_url($CFG->wwwroot);
$extuserusername = $USER->username;
$assign = new assign($context, $cm, $course);
$maharasubmission = new assign_submission_maharaws($assign, 'assignsubmission_maharaws');
if ( get_config('assignsubmission_maharaws', 'legacy_ext_usr_username') ) {
    // Determine the Mahara field and the username value.
    $usernameattribute = $maharasubmission->get_config_default('username_attribute');
    $remoteuser = $maharasubmission->get_config_default('remoteuser');
    $username = (!empty($CFG->mahara_test_user) ? $CFG->mahara_test_user : $USER->{$usernameattribute});
    $field =
        // Now the trump all - we actually want to test against the institutions auth instances remoteuser.
        ($remoteuser ?
        'remoteuser' :
            // Else idnumber maps to studentid.
            ($usernameattribute == 'idnumber' ?
                'studentid' :
                // Else the same attribute name in Mahara.
                $usernameattribute));
    $extuserusername = $field.':'.$username;
}
$requestparams = array(
        'resource_link_title' => $cm->name,
        'resource_link_description' => $cm->name,
        'user_id' => $USER->id,
        'lis_person_sourcedid' => $USER->idnumber,
        'roles' => 'Learner',
        'context_id' => $course->id,
        'context_label' => $course->shortname,
        'context_title' => $course->fullname,
        'resource_link_id' => $target,
        'context_type' => 'CourseSection',
        'lis_person_contact_email_primary' => $USER->email,
        'lis_person_name_given' => $USER->firstname,
        'lis_person_name_family' => $USER->lastname,
        'lis_person_name_full' => fullname($USER),
        'ext_user_username' => $extuserusername,
        'launch_presentation_return_url' => $returnurl,
        'launch_presentation_locale' => current_language(),
        'ext_lms' => 'moodle-2',
        'tool_consumer_info_product_family_code' => 'moodle',
        'tool_consumer_info_version' => strval($CFG->version),
        'oauth_callback' => 'about:blank',
        'lti_version' => 'LTI-1p0',
        'lti_message_type' => 'basic-lti-launch-request',
        "tool_consumer_instance_guid" => $urlparts['host'],
        'tool_consumer_instance_name' => get_site()->fullname,
        'wsfunction' => 'module_lti_launch',
        );


$endpoint = $maharasubmission->get_config_default('url');
$endpoint = $endpoint.(preg_match('/\/$/', $endpoint) ? '' : '/').'webservice/rest/server.php';
$key = $maharasubmission->get_config_default('key');
$secret = $maharasubmission->get_config_default('secret');

$parms = lti_sign_parameters($requestparams, $endpoint, "POST", $key, $secret);
$debuglaunch = $maharasubmission->get_config_default('debug');
if ($debuglaunch) {
    $parms['ext_submit'] = 'Launch';
}
$endpointurl = new \moodle_url($endpoint);
$endpointparams = $endpointurl->params();
$content = lti_post_launch_html($parms, $endpoint, $debuglaunch);

echo $content;