Proyectos de Subversion Moodle

<?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/>.

/**

 * Utility code for LTI service handling.

 *

 * @package mod_lti

 * @copyright  Copyright (c) 2011 Moodlerooms Inc. (http://www.moodlerooms.com)

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 * @author     Chris Scribner

 */

defined('MOODLE_INTERNAL') || die;

require_once($CFG->dirroot.'/mod/lti/OAuthBody.php');

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

// TODO: Switch to core oauthlib once implemented - MDL-30149.

use moodle\mod\lti as lti;

define('LTI_ITEM_TYPE', 'mod');

define('LTI_ITEM_MODULE', 'lti');

define('LTI_SOURCE', 'mod/lti');

function lti_get_response_xml($codemajor, $description, $messageref, $messagetype) {

    $xml = new SimpleXMLElement('<?xml version="1.0" encoding="UTF-8"?><imsx_POXEnvelopeResponse />');

    $xml->addAttribute('xmlns', 'http://www.imsglobal.org/services/ltiv1p1/xsd/imsoms_v1p0');

    $headerinfo = $xml->addChild('imsx_POXHeader')->addChild('imsx_POXResponseHeaderInfo');

    $headerinfo->addChild('imsx_version', 'V1.0');

    $headerinfo->addChild('imsx_messageIdentifier', (string)mt_rand());

    $statusinfo = $headerinfo->addChild('imsx_statusInfo');

    $statusinfo->addchild('imsx_codeMajor', $codemajor);

    $statusinfo->addChild('imsx_severity', 'status');

    $statusinfo->addChild('imsx_description', $description);

    $statusinfo->addChild('imsx_messageRefIdentifier', $messageref);

    $incomingtype = str_replace('Response', 'Request', $messagetype);

    $statusinfo->addChild('imsx_operationRefIdentifier', $incomingtype);

    $xml->addChild('imsx_POXBody')->addChild($messagetype);

    return $xml;

}

function lti_parse_message_id($xml) {

    if (empty($xml->imsx_POXHeader)) {

        return '';

    }

    $node = $xml->imsx_POXHeader->imsx_POXRequestHeaderInfo->imsx_messageIdentifier;

    $messageid = (string)$node;

    return $messageid;

}

function lti_parse_grade_replace_message($xml) {

    $node = $xml->imsx_POXBody->replaceResultRequest->resultRecord->sourcedGUID->sourcedId;

    $resultjson = json_decode((string)$node);

    if ( is_null($resultjson) ) {

        throw new Exception('Invalid sourcedId in result message');

    }

    $node = $xml->imsx_POXBody->replaceResultRequest->resultRecord->result->resultScore->textString;

    $score = (string) $node;

    if ( ! is_numeric($score) ) {

        throw new Exception('Score must be numeric');

    }

    $grade = floatval($score);

    if ( $grade < 0.0 || $grade > 1.0 ) {

        throw new Exception('Score not between 0.0 and 1.0');

    }

    $parsed = new stdClass();

    $parsed->gradeval = $grade;

    $parsed->instanceid = $resultjson->data->instanceid;

    $parsed->userid = $resultjson->data->userid;

    $parsed->launchid = $resultjson->data->launchid;

    $parsed->typeid = $resultjson->data->typeid;

    $parsed->sourcedidhash = $resultjson->hash;

    $parsed->messageid = lti_parse_message_id($xml);

    return $parsed;

}

function lti_parse_grade_read_message($xml) {

    $node = $xml->imsx_POXBody->readResultRequest->resultRecord->sourcedGUID->sourcedId;

    $resultjson = json_decode((string)$node);

    if ( is_null($resultjson) ) {

        throw new Exception('Invalid sourcedId in result message');

    }

    $parsed = new stdClass();

    $parsed->instanceid = $resultjson->data->instanceid;

    $parsed->userid = $resultjson->data->userid;

    $parsed->launchid = $resultjson->data->launchid;

    $parsed->typeid = $resultjson->data->typeid;

    $parsed->sourcedidhash = $resultjson->hash;

    $parsed->messageid = lti_parse_message_id($xml);

    return $parsed;

}

function lti_parse_grade_delete_message($xml) {

    $node = $xml->imsx_POXBody->deleteResultRequest->resultRecord->sourcedGUID->sourcedId;

    $resultjson = json_decode((string)$node);

    if ( is_null($resultjson) ) {

        throw new Exception('Invalid sourcedId in result message');

    }

    $parsed = new stdClass();

    $parsed->instanceid = $resultjson->data->instanceid;

    $parsed->userid = $resultjson->data->userid;

    $parsed->launchid = $resultjson->data->launchid;

    $parsed->typeid = $resultjson->data->typeid;

    $parsed->sourcedidhash = $resultjson->hash;

    $parsed->messageid = lti_parse_message_id($xml);

    return $parsed;

}

function lti_accepts_grades($ltiinstance) {

    global $DB;

    $acceptsgrades = true;

    $ltitype = $DB->get_record('lti_types', array('id' => $ltiinstance->typeid));

    if (empty($ltitype->toolproxyid)) {

        $typeconfig = lti_get_config($ltiinstance);

        $typeacceptgrades = isset($typeconfig['acceptgrades']) ? $typeconfig['acceptgrades'] : LTI_SETTING_DELEGATE;

        if (!($typeacceptgrades == LTI_SETTING_ALWAYS ||

            ($typeacceptgrades == LTI_SETTING_DELEGATE && $ltiinstance->instructorchoiceacceptgrades == LTI_SETTING_ALWAYS))) {

            $acceptsgrades = false;

        }

    } else {

        $enabledcapabilities = explode("\n", $ltitype->enabledcapability);

        $acceptsgrades = in_array('Result.autocreate', $enabledcapabilities) || in_array('BasicOutcome.url', $enabledcapabilities);

    }

    return $acceptsgrades;

}

/**

 * Set the passed user ID to the session user.

 *

 * @param int $userid

 */

function lti_set_session_user($userid) {

    global $DB;

    if ($user = $DB->get_record('user', array('id' => $userid))) {

        \core\session\manager::set_user($user);

    }

}

function lti_update_grade($ltiinstance, $userid, $launchid, $gradeval) {

    global $CFG, $DB;

    require_once($CFG->libdir . '/gradelib.php');

    $params = array();

    $params['itemname'] = $ltiinstance->name;

    $gradeval = $gradeval * floatval($ltiinstance->grade);

    $grade = new stdClass();

    $grade->userid   = $userid;

    $grade->rawgrade = $gradeval;

    $status = grade_update(LTI_SOURCE, $ltiinstance->course, LTI_ITEM_TYPE, LTI_ITEM_MODULE, $ltiinstance->id, 0, $grade, $params);

    $record = $DB->get_record('lti_submission', array('ltiid' => $ltiinstance->id, 'userid' => $userid,

        'launchid' => $launchid), 'id');

    if ($record) {

        $id = $record->id;

    } else {

        $id = null;

    }

    if (!empty($id)) {

        $DB->update_record('lti_submission', array(

            'id' => $id,

            'dateupdated' => time(),

            'gradepercent' => $gradeval,

            'state' => 2

        ));

    } else {

        $DB->insert_record('lti_submission', array(

            'ltiid' => $ltiinstance->id,

            'userid' => $userid,

            'datesubmitted' => time(),

            'dateupdated' => time(),

            'gradepercent' => $gradeval,

            'originalgrade' => $gradeval,

            'launchid' => $launchid,

            'state' => 1

        ));

    }

    return $status == GRADE_UPDATE_OK;

}

function lti_read_grade($ltiinstance, $userid) {

    global $CFG;

    require_once($CFG->libdir . '/gradelib.php');

    $grades = grade_get_grades($ltiinstance->course, LTI_ITEM_TYPE, LTI_ITEM_MODULE, $ltiinstance->id, $userid);

    $ltigrade = floatval($ltiinstance->grade);

    if (!empty($ltigrade) && isset($grades) && isset($grades->items[0]) && is_array($grades->items[0]->grades)) {

        foreach ($grades->items[0]->grades as $agrade) {

            $grade = $agrade->grade;

            if (isset($grade)) {

                return $grade / $ltigrade;

            }

        }

    }

}

function lti_delete_grade($ltiinstance, $userid) {

    global $CFG;

    require_once($CFG->libdir . '/gradelib.php');

    $grade = new stdClass();

    $grade->userid   = $userid;

    $grade->rawgrade = null;

    $status = grade_update(LTI_SOURCE, $ltiinstance->course, LTI_ITEM_TYPE, LTI_ITEM_MODULE, $ltiinstance->id, 0, $grade);

    return $status == GRADE_UPDATE_OK;

}

function lti_verify_message($key, $sharedsecrets, $body, $headers = null) {

    foreach ($sharedsecrets as $secret) {

        $signaturefailed = false;

        try {

            // TODO: Switch to core oauthlib once implemented - MDL-30149.

            lti\handle_oauth_body_post($key, $secret, $body, $headers);

        } catch (Exception $e) {

            debugging('LTI message verification failed: '.$e->getMessage());

            $signaturefailed = true;

        }

        if (!$signaturefailed) {

            return $secret; // Return the secret used to sign the message).

        }

    }

    return false;

}

/**

 * Validate source ID from external request

 *

 * @param object $ltiinstance

 * @param object $parsed

 * @throws Exception

 */

function lti_verify_sourcedid($ltiinstance, $parsed) {

    $sourceid = lti_build_sourcedid($parsed->instanceid, $parsed->userid,

        $ltiinstance->servicesalt, $parsed->typeid, $parsed->launchid);

    if ($sourceid->hash != $parsed->sourcedidhash) {

        throw new Exception('SourcedId hash not valid');

    }

}

/**

 * Extend the LTI services through the ltisource plugins

 *

 * @param stdClass $data LTI request data

 * @return bool

 * @throws coding_exception

 */

function lti_extend_lti_services($data) {

    $plugins = get_plugin_list_with_function('ltisource', $data->messagetype);

    if (!empty($plugins)) {

        // There can only be one.

        if (count($plugins) > 1) {

            throw new coding_exception('More than one ltisource plugin handler found');

        }

        $data->xml = new SimpleXMLElement($data->body);

        $callback = current($plugins);

        call_user_func($callback, $data);

        return true;

    }

    return false;

}