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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/>.
/**
* This file contains an abstract definition of an LTI service
*
* @package mod_lti
* @copyright 2014 Vital Source Technologies http://vitalsource.com
* @author Stephen Vickers
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace mod_lti\local\ltiservice;
defined('MOODLE_INTERNAL') || die();
global $CFG;
require_once($CFG->dirroot . '/mod/lti/locallib.php');
require_once($CFG->dirroot . '/mod/lti/OAuthBody.php');
// TODO: Switch to core oauthlib once implemented - MDL-30149.
use moodle\mod\lti as lti;
use stdClass;
/**
* The mod_lti\local\ltiservice\service_base class.
*
* @package mod_lti
* @since Moodle 2.8
* @copyright 2014 Vital Source Technologies http://vitalsource.com
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class service_base {
/** Label representing an LTI 2 message type */
const LTI_VERSION2P0 = 'LTI-2p0';
/** Service enabled */
const SERVICE_ENABLED = 1;
/** @var string ID for the service. */
protected $id;
/** @var string Human readable name for the service. */
protected $name;
/** @var boolean <code>true</code> if requests for this service do not need to be signed. */
protected $unsigned;
/** @var stdClass Tool proxy object for the current service request. */
private $toolproxy;
/** @var stdClass LTI type object for the current service request. */
private $type;
/** @var array LTI type config array for the current service request. */
private $typeconfig;
/** @var array Instances of the resources associated with this service. */
protected $resources;
/**
* Class constructor.
*/
public function __construct() {
$this->id = null;
$this->name = null;
$this->unsigned = false;
$this->toolproxy = null;
$this->type = null;
$this->typeconfig = null;
$this->resources = null;
}
/**
* Get the service ID.
*
* @return string
*/
public function get_id() {
return $this->id;
}
/**
* Get the service compoent ID.
*
* @return string
*/
public function get_component_id() {
return 'ltiservice_' . $this->id;
}
/**
* Get the service name.
*
* @return string
*/
public function get_name() {
return $this->name;
}
/**
* Get whether the service requests need to be signed.
*
* @return boolean
*/
public function is_unsigned() {
return $this->unsigned;
}
/**
* Get the tool proxy object.
*
* @return stdClass
*/
public function get_tool_proxy() {
return $this->toolproxy;
}
/**
* Set the tool proxy object.
*
* @param object $toolproxy The tool proxy for this service request
*
* @var stdClass
*/
public function set_tool_proxy($toolproxy) {
$this->toolproxy = $toolproxy;
}
/**
* Get the type object.
*
* @return stdClass
*/
public function get_type() {
return $this->type;
}
/**
* Set the LTI type object.
*
* @param object $type The LTI type for this service request
*
* @var stdClass
*/
public function set_type($type) {
$this->type = $type;
}
/**
* Get the type config array.
*
* @return array|null
*/
public function get_typeconfig() {
return $this->typeconfig;
}
/**
* Set the LTI type config object.
*
* @param array $typeconfig The LTI type config for this service request
*
* @var array
*/
public function set_typeconfig($typeconfig) {
$this->typeconfig = $typeconfig;
}
/**
* Get the resources for this service.
*
* @return resource_base[]
*/
abstract public function get_resources();
/**
* Get the scope(s) permitted for this service.
*
* A null value indicates that no scopes are required to access the service.
*
* @return array|null
*/
public function get_permitted_scopes() {
return null;
}
/**
* Returns the configuration options for this service.
*
* @param \MoodleQuickForm $mform Moodle quickform object definition
*/
public function get_configuration_options(&$mform) {
}
/**
* Called when a new LTI Instance is added.
*
* @param object $lti LTI Instance.
*/
public function instance_added(object $lti): void {
}
/**
* Called when a new LTI Instance is updated.
*
* @param object $lti LTI Instance.
*/
public function instance_updated(object $lti): void {
}
/**
* Called when a new LTI Instance is deleted.
*
* @param int $id LTI Instance.
*/
public function instance_deleted(int $id): void {
}
/**
* Set the form data when displaying the LTI Instance form.
*
* @param object $defaultvalues Default form values.
*/
public function set_instance_form_values(object $defaultvalues): void {
}
/**
* Return an array with the names of the parameters that the service will be saving in the configuration
*
* @return array Names list of the parameters that the service will be saving in the configuration
* @deprecated since Moodle 3.7 - please do not use this function any more.
*/
public function get_configuration_parameter_names() {
debugging('get_configuration_parameter_names() has been deprecated.', DEBUG_DEVELOPER);
return array();
}
/**
* Default implementation will check for the existence of at least one mod_lti entry for that tool and context.
*
* It may be overridden if other inferences can be done.
*
* Ideally a Site Tool should be explicitly engaged with a course, the check on the presence of a link is a proxy
* to infer a Site Tool engagement until an explicit Site Tool - Course relationship exists.
*
* @param int $typeid The tool lti type id.
* @param int $courseid The course id.
* @return bool returns True if tool is used in context, false otherwise.
*/
public function is_used_in_context($typeid, $courseid) {
global $DB;
$ok = $DB->record_exists('lti', array('course' => $courseid, 'typeid' => $typeid));
return $ok || $DB->record_exists('lti_types', array('course' => $courseid, 'id' => $typeid));
}
/**
* Checks if there is a site tool or a course tool for this site.
*
* @param int $typeid The tool lti type id.
* @param int $courseid The course id.
* @return bool returns True if tool is allowed in context, false otherwise.
*/
public function is_allowed_in_context($typeid, $courseid) {
global $DB;
// Check if it is a Course tool for this course or a Site tool.
$type = $DB->get_record('lti_types', array('id' => $typeid));
return $type && ($type->course == $courseid || $type->course == SITEID);
}
/**
* Return an array of key/values to add to the launch parameters.
*
* @param string $messagetype 'basic-lti-launch-request' or 'ContentItemSelectionRequest'.
* @param string $courseid The course id.
* @param string $userid The user id.
* @param string $typeid The tool lti type id.
* @param string $modlti The id of the lti activity.
*
* The type is passed to check the configuration and not return parameters for services not used.
*
* @return array Key/value pairs to add as launch parameters.
*/
public function get_launch_parameters($messagetype, $courseid, $userid, $typeid, $modlti = null) {
return array();
}
/**
* Get the path for service requests.
*
* @return string
*/
public static function get_service_path() {
$url = new \moodle_url('/mod/lti/services.php');
return $url->out(false);
}
/**
* Parse a string for custom substitution parameter variables supported by this service's resources.
*
* @param string $value Value to be parsed
*
* @return string
*/
public function parse_value($value) {
if (empty($this->resources)) {
$this->resources = $this->get_resources();
}
if (!empty($this->resources)) {
foreach ($this->resources as $resource) {
$value = $resource->parse_value($value);
}
}
return $value;
}
/**
* Check that the request has been properly signed and is permitted.
*
* @param string $typeid LTI type ID
* @param string $body Request body (null if none)
* @param string[] $scopes Array of required scope(s) for incoming request
*
* @return boolean
*/
public function check_tool($typeid, $body = null, $scopes = null) {
$ok = true;
$toolproxy = null;
$consumerkey = lti\get_oauth_key_from_headers($typeid, $scopes);
if ($consumerkey === false) {
$ok = $this->is_unsigned();
} else {
if (empty($typeid) && is_int($consumerkey)) {
$typeid = $consumerkey;
}
if (!empty($typeid)) {
$this->type = lti_get_type($typeid);
$this->typeconfig = lti_get_type_config($typeid);
$ok = !empty($this->type->id);
if ($ok && !empty($this->type->toolproxyid)) {
$this->toolproxy = lti_get_tool_proxy($this->type->toolproxyid);
}
} else {
$toolproxy = lti_get_tool_proxy_from_guid($consumerkey);
if ($toolproxy !== false) {
$this->toolproxy = $toolproxy;
}
}
}
if ($ok && is_string($consumerkey)) {
if (!empty($this->toolproxy)) {
$key = $this->toolproxy->guid;
$secret = $this->toolproxy->secret;
} else {
$key = $this->typeconfig['resourcekey'];
$secret = $this->typeconfig['password'];
}
if (!$this->is_unsigned() && ($key == $consumerkey)) {
$ok = $this->check_signature($key, $secret, $body);
} else {
$ok = $this->is_unsigned();
}
}
return $ok;
}
/**
* Check that the request has been properly signed.
*
* @param string $toolproxyguid Tool Proxy GUID
* @param string $body Request body (null if none)
*
* @return boolean
* @deprecated since Moodle 3.7 MDL-62599 - please do not use this function any more.
* @see service_base::check_tool()
*/
public function check_tool_proxy($toolproxyguid, $body = null) {
debugging('check_tool_proxy() is deprecated to allow LTI 1 connections to support services. ' .
'Please use service_base::check_tool() instead.', DEBUG_DEVELOPER);
$ok = false;
$toolproxy = null;
$consumerkey = lti\get_oauth_key_from_headers();
if (empty($toolproxyguid)) {
$toolproxyguid = $consumerkey;
}
if (!empty($toolproxyguid)) {
$toolproxy = lti_get_tool_proxy_from_guid($toolproxyguid);
if ($toolproxy !== false) {
if (!$this->is_unsigned() && ($toolproxy->guid == $consumerkey)) {
$ok = $this->check_signature($toolproxy->guid, $toolproxy->secret, $body);
} else {
$ok = $this->is_unsigned();
}
}
}
if ($ok) {
$this->toolproxy = $toolproxy;
}
return $ok;
}
/**
* Check that the request has been properly signed.
*
* @param int $typeid The tool id
* @param int $courseid The course we are at
* @param string $body Request body (null if none)
*
* @return bool
* @deprecated since Moodle 3.7 MDL-62599 - please do not use this function any more.
* @see service_base::check_tool()
*/
public function check_type($typeid, $courseid, $body = null) {
debugging('check_type() is deprecated to allow LTI 1 connections to support services. ' .
'Please use service_base::check_tool() instead.', DEBUG_DEVELOPER);
$ok = false;
$tool = null;
$consumerkey = lti\get_oauth_key_from_headers();
if (empty($typeid)) {
return $ok;
} else if ($this->is_allowed_in_context($typeid, $courseid)) {
$tool = lti_get_type_type_config($typeid);
if ($tool !== false) {
if (!$this->is_unsigned() && ($tool->lti_resourcekey == $consumerkey)) {
$ok = $this->check_signature($tool->lti_resourcekey, $tool->lti_password, $body);
} else {
$ok = $this->is_unsigned();
}
}
}
return $ok;
}
/**
* Check the request signature.
*
* @param string $consumerkey Consumer key
* @param string $secret Shared secret
* @param string $body Request body
*
* @return boolean
*/
private function check_signature($consumerkey, $secret, $body) {
$ok = true;
try {
// TODO: Switch to core oauthlib once implemented - MDL-30149.
lti\handle_oauth_body_post($consumerkey, $secret, $body);
} catch (\Exception $e) {
debugging($e->getMessage() . "\n");
$ok = false;
}
return $ok;
}
}