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<?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/>.
/**
* LTI enrolment plugin helper.
*
* @package enrol_lti
* @copyright 2016 Mark Nelson <markn@moodle.com>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace enrol_lti;
defined('MOODLE_INTERNAL') || die();
/**
* LTI enrolment plugin helper class.
*
* @package enrol_lti
* @copyright 2016 Mark Nelson <markn@moodle.com>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class helper {
/*
* The value used when we want to enrol new members and unenrol old ones.
*/
const MEMBER_SYNC_ENROL_AND_UNENROL = 1;
/*
* The value used when we want to enrol new members only.
*/
const MEMBER_SYNC_ENROL_NEW = 2;
/*
* The value used when we want to unenrol missing users.
*/
const MEMBER_SYNC_UNENROL_MISSING = 3;
/**
* Code for when an enrolment was successful.
*/
const ENROLMENT_SUCCESSFUL = true;
/**
* Error code for enrolment when max enrolled reached.
*/
const ENROLMENT_MAX_ENROLLED = 'maxenrolledreached';
/**
* Error code for enrolment has not started.
*/
const ENROLMENT_NOT_STARTED = 'enrolmentnotstarted';
/**
* Error code for enrolment when enrolment has finished.
*/
const ENROLMENT_FINISHED = 'enrolmentfinished';
/**
* Error code for when an image file fails to upload.
*/
const PROFILE_IMAGE_UPDATE_SUCCESSFUL = true;
/**
* Error code for when an image file fails to upload.
*/
const PROFILE_IMAGE_UPDATE_FAILED = 'profileimagefailed';
/**
* Creates a unique username.
*
* @param string $consumerkey Consumer key
* @param string $ltiuserid External tool user id
* @return string The new username
*/
public static function create_username($consumerkey, $ltiuserid) {
if (!empty($ltiuserid) && !empty($consumerkey)) {
$userkey = $consumerkey . ':' . $ltiuserid;
} else {
$userkey = false;
}
return 'enrol_lti' . sha1($consumerkey . '::' . $userkey);
}
/**
* Adds default values for the user object based on the tool provided.
*
* @param \stdClass $tool
* @param \stdClass $user
* @return \stdClass The $user class with added default values
*/
public static function assign_user_tool_data($tool, $user) {
global $CFG;
$user->city = (!empty($tool->city)) ? $tool->city : "";
$user->country = (!empty($tool->country)) ? $tool->country : "";
$user->institution = (!empty($tool->institution)) ? $tool->institution : "";
$user->timezone = (!empty($tool->timezone)) ? $tool->timezone : "";
if (isset($tool->maildisplay)) {
$user->maildisplay = $tool->maildisplay;
} else if (isset($CFG->defaultpreference_maildisplay)) {
$user->maildisplay = $CFG->defaultpreference_maildisplay;
} else {
$user->maildisplay = 2;
}
$user->mnethostid = $CFG->mnet_localhost_id;
$user->confirmed = 1;
$user->lang = $tool->lang;
return $user;
}
/**
* Compares two users.
*
* @param \stdClass $newuser The new user
* @param \stdClass $olduser The old user
* @return bool True if both users are the same
*/
public static function user_match($newuser, $olduser) {
if ($newuser->firstname != $olduser->firstname) {
return false;
}
if ($newuser->lastname != $olduser->lastname) {
return false;
}
if ($newuser->email != $olduser->email) {
return false;
}
if ($newuser->city != $olduser->city) {
return false;
}
if ($newuser->country != $olduser->country) {
return false;
}
if ($newuser->institution != $olduser->institution) {
return false;
}
if ($newuser->timezone != $olduser->timezone) {
return false;
}
if ($newuser->maildisplay != $olduser->maildisplay) {
return false;
}
if ($newuser->mnethostid != $olduser->mnethostid) {
return false;
}
if ($newuser->confirmed != $olduser->confirmed) {
return false;
}
if ($newuser->lang != $olduser->lang) {
return false;
}
return true;
}
/**
* Updates the users profile image.
*
* @param int $userid the id of the user
* @param string $url the url of the image
* @return bool|string true if successful, else a string explaining why it failed
*/
public static function update_user_profile_image($userid, $url) {
global $CFG, $DB;
require_once($CFG->libdir . '/filelib.php');
require_once($CFG->libdir . '/gdlib.php');
$fs = get_file_storage();
$context = \context_user::instance($userid, MUST_EXIST);
$fs->delete_area_files($context->id, 'user', 'newicon');
$filerecord = array(
'contextid' => $context->id,
'component' => 'user',
'filearea' => 'newicon',
'itemid' => 0,
'filepath' => '/'
);
$urlparams = array(
'calctimeout' => false,
'timeout' => 5,
'skipcertverify' => true,
'connecttimeout' => 5
);
try {
$fs->create_file_from_url($filerecord, $url, $urlparams);
} catch (\file_exception $e) {
return get_string($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');
return self::PROFILE_IMAGE_UPDATE_FAILED;
}
// 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));
return self::PROFILE_IMAGE_UPDATE_SUCCESSFUL;
}
/**
* Enrol a user in a course.
*
* @param \stdclass $tool The tool object (retrieved using self::get_lti_tool() or self::get_lti_tools())
* @param int $userid The user id
* @return bool|string returns true if successful, else an error code
*/
public static function enrol_user($tool, $userid) {
global $DB;
// Check if the user enrolment exists.
if (!$DB->record_exists('user_enrolments', array('enrolid' => $tool->enrolid, 'userid' => $userid))) {
// Check if the maximum enrolled limit has been met.
if ($tool->maxenrolled) {
if ($DB->count_records('user_enrolments', array('enrolid' => $tool->enrolid)) >= $tool->maxenrolled) {
return self::ENROLMENT_MAX_ENROLLED;
}
}
// Check if the enrolment has not started.
if ($tool->enrolstartdate && time() < $tool->enrolstartdate) {
return self::ENROLMENT_NOT_STARTED;
}
// Check if the enrolment has finished.
if ($tool->enrolenddate && time() > $tool->enrolenddate) {
return self::ENROLMENT_FINISHED;
}
$timeend = 0;
if ($tool->enrolperiod) {
$timeend = time() + $tool->enrolperiod;
}
// Finally, enrol the user.
$instance = new \stdClass();
$instance->id = $tool->enrolid;
$instance->courseid = $tool->courseid;
$instance->enrol = 'lti';
$instance->status = $tool->status;
$ltienrol = enrol_get_plugin('lti');
// Hack - need to do this to workaround DB caching hack. See MDL-53977.
$timestart = intval(substr(time(), 0, 8) . '00') - 1;
$ltienrol->enrol_user($instance, $userid, null, $timestart, $timeend);
}
return self::ENROLMENT_SUCCESSFUL;
}
/**
* Returns the LTI tool.
*
* @param int $toolid
* @return \stdClass the tool
*/
public static function get_lti_tool($toolid) {
global $DB;
$sql = "SELECT elt.*, e.name, e.courseid, e.status, e.enrolstartdate, e.enrolenddate, e.enrolperiod
FROM {enrol_lti_tools} elt
JOIN {enrol} e
ON elt.enrolid = e.id
WHERE elt.id = :tid";
return $DB->get_record_sql($sql, array('tid' => $toolid), MUST_EXIST);
}
/**
* Returns the LTI tools requested.
*
* @param array $params The list of SQL params (eg. array('columnname' => value, 'columnname2' => value)).
* @param int $limitfrom return a subset of records, starting at this point (optional).
* @param int $limitnum return a subset comprising this many records in total
* @return array of tools
*/
public static function get_lti_tools($params = array(), $limitfrom = 0, $limitnum = 0) {
global $DB;
$sql = "SELECT elt.*, e.name, e.courseid, e.status, e.enrolstartdate, e.enrolenddate, e.enrolperiod
FROM {enrol_lti_tools} elt
JOIN {enrol} e
ON elt.enrolid = e.id";
if ($params) {
$where = "WHERE";
foreach ($params as $colname => $value) {
$sql .= " $where $colname = :$colname";
$where = "AND";
}
}
$sql .= " ORDER BY elt.timecreated";
return $DB->get_records_sql($sql, $params, $limitfrom, $limitnum);
}
/**
* Returns the number of LTI tools.
*
* @param array $params The list of SQL params (eg. array('columnname' => value, 'columnname2' => value)).
* @return int The number of tools
*/
public static function count_lti_tools($params = array()) {
global $DB;
$sql = "SELECT COUNT(*)
FROM {enrol_lti_tools} elt
JOIN {enrol} e
ON elt.enrolid = e.id";
if ($params) {
$where = "WHERE";
foreach ($params as $colname => $value) {
$sql .= " $where $colname = :$colname";
$where = "AND";
}
}
return $DB->count_records_sql($sql, $params);
}
/**
* Create a IMS POX body request for sync grades.
*
* @param string $source Sourceid required for the request
* @param float $grade User final grade
* @return string
*/
public static function create_service_body($source, $grade) {
return '<?xml version="1.0" encoding="UTF-8"?>
<imsx_POXEnvelopeRequest xmlns="http://www.imsglobal.org/services/ltiv1p1/xsd/imsoms_v1p0">
<imsx_POXHeader>
<imsx_POXRequestHeaderInfo>
<imsx_version>V1.0</imsx_version>
<imsx_messageIdentifier>' . (time()) . '</imsx_messageIdentifier>
</imsx_POXRequestHeaderInfo>
</imsx_POXHeader>
<imsx_POXBody>
<replaceResultRequest>
<resultRecord>
<sourcedGUID>
<sourcedId>' . $source . '</sourcedId>
</sourcedGUID>
<result>
<resultScore>
<language>en-us</language>
<textString>' . $grade . '</textString>
</resultScore>
</result>
</resultRecord>
</replaceResultRequest>
</imsx_POXBody>
</imsx_POXEnvelopeRequest>';
}
/**
* Returns the url to launch the lti tool.
*
* @param int $toolid the id of the shared tool
* @return \moodle_url the url to launch the tool
* @since Moodle 3.2
*/
public static function get_launch_url($toolid) {
return new \moodle_url('/enrol/lti/tool.php', array('id' => $toolid));
}
/**
* Returns the name of the lti enrolment instance, or the name of the course/module being shared.
*
* @param \stdClass $tool The lti tool
* @return string The name of the tool
* @since Moodle 3.2
*/
public static function get_name($tool) {
$name = null;
if (empty($tool->name)) {
$toolcontext = \context::instance_by_id($tool->contextid);
$name = $toolcontext->get_context_name();
} else {
$name = $tool->name;
};
return $name;
}
/**
* Returns a description of the course or module that this lti instance points to.
*
* @param \stdClass $tool The lti tool
* @return string A description of the tool
* @since Moodle 3.2
*/
public static function get_description($tool) {
global $DB;
$description = '';
$context = \context::instance_by_id($tool->contextid);
if ($context->contextlevel == CONTEXT_COURSE) {
$course = $DB->get_record('course', array('id' => $context->instanceid));
$description = $course->summary;
} else if ($context->contextlevel == CONTEXT_MODULE) {
$cmid = $context->instanceid;
$cm = get_coursemodule_from_id(false, $context->instanceid, 0, false, MUST_EXIST);
$module = $DB->get_record($cm->modname, array('id' => $cm->instance));
$description = $module->intro;
}
return trim(html_to_text($description));
}
/**
* Returns the icon of the tool.
*
* @param \stdClass $tool The lti tool
* @return \moodle_url A url to the icon of the tool
* @since Moodle 3.2
*/
public static function get_icon($tool) {
global $OUTPUT;
return $OUTPUT->favicon();
}
/**
* Returns the url to the cartridge representing the tool.
*
* If you have slash arguments enabled, this will be a nice url ending in cartridge.xml.
* If not it will be a php page with some parameters passed.
*
* @param \stdClass $tool The lti tool
* @return string The url to the cartridge representing the tool
* @since Moodle 3.2
*/
public static function get_cartridge_url($tool) {
global $CFG;
$url = null;
$id = $tool->id;
$token = self::generate_cartridge_token($tool->id);
if ($CFG->slasharguments) {
$url = new \moodle_url('/enrol/lti/cartridge.php/' . $id . '/' . $token . '/cartridge.xml');
} else {
$url = new \moodle_url('/enrol/lti/cartridge.php',
array(
'id' => $id,
'token' => $token
)
);
}
return $url;
}
/**
* Returns the url to the tool proxy registration url.
*
* If you have slash arguments enabled, this will be a nice url ending in cartridge.xml.
* If not it will be a php page with some parameters passed.
*
* @param \stdClass $tool The lti tool
* @return string The url to the cartridge representing the tool
*/
public static function get_proxy_url($tool) {
global $CFG;
$url = null;
$id = $tool->id;
$token = self::generate_proxy_token($tool->id);
if ($CFG->slasharguments) {
$url = new \moodle_url('/enrol/lti/proxy.php/' . $id . '/' . $token . '/');
} else {
$url = new \moodle_url('/enrol/lti/proxy.php',
array(
'id' => $id,
'token' => $token
)
);
}
return $url;
}
/**
* Returns a unique hash for this site and this enrolment instance.
*
* Used to verify that the link to the cartridge has not just been guessed.
*
* @param int $toolid The id of the shared tool
* @return string MD5 hash of combined site ID and enrolment instance ID.
* @since Moodle 3.2
*/
public static function generate_cartridge_token($toolid) {
$siteidentifier = get_site_identifier();
$checkhash = md5($siteidentifier . '_enrol_lti_cartridge_' . $toolid);
return $checkhash;
}
/**
* Returns a unique hash for this site and this enrolment instance.
*
* Used to verify that the link to the proxy has not just been guessed.
*
* @param int $toolid The id of the shared tool
* @return string MD5 hash of combined site ID and enrolment instance ID.
* @since Moodle 3.2
*/
public static function generate_proxy_token($toolid) {
$siteidentifier = get_site_identifier();
$checkhash = md5($siteidentifier . '_enrol_lti_proxy_' . $toolid);
return $checkhash;
}
/**
* Verifies that the given token matches the cartridge token of the given shared tool.
*
* @param int $toolid The id of the shared tool
* @param string $token hash for this site and this enrolment instance
* @return boolean True if the token matches, false if it does not
* @since Moodle 3.2
*/
public static function verify_cartridge_token($toolid, $token) {
return $token == self::generate_cartridge_token($toolid);
}
/**
* Verifies that the given token matches the proxy token of the given shared tool.
*
* @param int $toolid The id of the shared tool
* @param string $token hash for this site and this enrolment instance
* @return boolean True if the token matches, false if it does not
* @since Moodle 3.2
*/
public static function verify_proxy_token($toolid, $token) {
return $token == self::generate_proxy_token($toolid);
}
/**
* Returns the parameters of the cartridge as an associative array of partial xpath.
*
* @param int $toolid The id of the shared tool
* @return array Recursive associative array with partial xpath to be concatenated into an xpath expression
* before setting the value.
* @since Moodle 3.2
*/
protected static function get_cartridge_parameters($toolid) {
global $PAGE, $SITE;
$PAGE->set_context(\context_system::instance());
// Get the tool.
$tool = self::get_lti_tool($toolid);
// Work out the name of the tool.
$title = self::get_name($tool);
$launchurl = self::get_launch_url($toolid);
$launchurl = $launchurl->out(false);
$iconurl = self::get_icon($tool);
$iconurl = $iconurl->out(false);
$securelaunchurl = null;
$secureiconurl = null;
$vendorurl = new \moodle_url('/');
$vendorurl = $vendorurl->out(false);
$description = self::get_description($tool);
// If we are a https site, we can add the launch url and icon urls as secure equivalents.
if (\is_https()) {
$securelaunchurl = $launchurl;
$secureiconurl = $iconurl;
}
return array(
"/cc:cartridge_basiclti_link" => array(
"/blti:title" => $title,
"/blti:description" => $description,
"/blti:extensions" => array(
"/lticm:property[@name='icon_url']" => $iconurl,
"/lticm:property[@name='secure_icon_url']" => $secureiconurl
),
"/blti:launch_url" => $launchurl,
"/blti:secure_launch_url" => $securelaunchurl,
"/blti:icon" => $iconurl,
"/blti:secure_icon" => $secureiconurl,
"/blti:vendor" => array(
"/lticp:code" => $SITE->shortname,
"/lticp:name" => $SITE->fullname,
"/lticp:description" => trim(html_to_text($SITE->summary)),
"/lticp:url" => $vendorurl
)
)
);
}
/**
* Traverses a recursive associative array, setting the properties of the corresponding
* xpath element.
*
* @param \DOMXPath $xpath The xpath with the xml to modify
* @param array $parameters The array of xpaths to search through
* @param string $prefix The current xpath prefix (gets longer the deeper into the array you go)
* @return void
* @since Moodle 3.2
*/
protected static function set_xpath($xpath, $parameters, $prefix = '') {
foreach ($parameters as $key => $value) {
if (is_array($value)) {
self::set_xpath($xpath, $value, $prefix . $key);
} else {
$result = @$xpath->query($prefix . $key);
if ($result) {
$node = $result->item(0);
if ($node) {
if (is_null($value)) {
$node->parentNode->removeChild($node);
} else {
$node->nodeValue = s($value);
}
}
} else {
throw new \coding_exception('Please check your XPATH and try again.');
}
}
}
}
/**
* Create an IMS cartridge for the tool.
*
* @param int $toolid The id of the shared tool
* @return string representing the generated cartridge
* @since Moodle 3.2
*/
public static function create_cartridge($toolid) {
$cartridge = new \DOMDocument();
$cartridge->load(realpath(__DIR__ . '/../xml/imslticc.xml'));
$xpath = new \DOMXpath($cartridge);
$xpath->registerNamespace('cc', 'http://www.imsglobal.org/xsd/imslticc_v1p0');
$parameters = self::get_cartridge_parameters($toolid);
self::set_xpath($xpath, $parameters);
return $cartridge->saveXML();
}
}