Claude Vervoort
c02324d96a
A huge thanks goes to 'Diego del Blanco' and 'Chris Lawson' for contributing much of their code and time to this project, and to Cengage for sponsoring it. Much appreciated!
333 lines
9.3 KiB
PHP
333 lines
9.3 KiB
PHP
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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/**
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* This file contains an abstract definition of an LTI service
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*
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* @package mod_lti
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* @copyright 2014 Vital Source Technologies http://vitalsource.com
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* @author Stephen Vickers
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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namespace mod_lti\local\ltiservice;
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defined('MOODLE_INTERNAL') || die();
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global $CFG;
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require_once($CFG->dirroot . '/mod/lti/locallib.php');
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require_once($CFG->dirroot . '/mod/lti/OAuthBody.php');
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// TODO: Switch to core oauthlib once implemented - MDL-30149.
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use moodle\mod\lti as lti;
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use stdClass;
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/**
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* The mod_lti\local\ltiservice\service_base class.
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*
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* @package mod_lti
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* @since Moodle 2.8
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* @copyright 2014 Vital Source Technologies http://vitalsource.com
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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abstract class service_base {
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/** Label representing an LTI 2 message type */
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const LTI_VERSION2P0 = 'LTI-2p0';
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/** @var string ID for the service. */
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protected $id;
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/** @var string Human readable name for the service. */
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protected $name;
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/** @var boolean <code>true</code> if requests for this service do not need to be signed. */
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protected $unsigned;
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/** @var stdClass Tool proxy object for the current service request. */
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private $toolproxy;
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/** @var array Instances of the resources associated with this service. */
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protected $resources;
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/**
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* Class constructor.
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*/
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public function __construct() {
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$this->id = null;
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$this->name = null;
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$this->unsigned = false;
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$this->toolproxy = null;
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$this->resources = null;
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}
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/**
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* Get the service ID.
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*
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* @return string
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*/
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public function get_id() {
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return $this->id;
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}
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/**
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* Get the service name.
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*
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* @return string
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*/
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public function get_name() {
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return $this->name;
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}
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/**
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* Get whether the service requests need to be signed.
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*
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* @return boolean
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*/
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public function is_unsigned() {
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return $this->unsigned;
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}
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/**
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* Get the tool proxy object.
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*
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* @return stdClass
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*/
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public function get_tool_proxy() {
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return $this->toolproxy;
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}
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/**
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* Set the tool proxy object.
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*
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* @param object $toolproxy The tool proxy for this service request
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*
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* @var stdClass
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*/
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public function set_tool_proxy($toolproxy) {
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$this->toolproxy = $toolproxy;
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}
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/**
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* Get the resources for this service.
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*
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* @return resource_base[]
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*/
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abstract public function get_resources();
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/**
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* Returns the configuration options for this service.
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*
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* @param \MoodleQuickForm $mform Moodle quickform object definition
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*/
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public function get_configuration_options(&$mform) {
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}
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/**
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* Return an array with the names of the parameters that the service will be saving in the configuration
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*
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* @return array Names list of the parameters that the service will be saving in the configuration
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*/
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public function get_configuration_parameter_names() {
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return array();
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}
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/**
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* Default implementation will check for the existence of at least one mod_lti entry for that tool and context.
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*
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* It may be overridden if other inferences can be done.
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*
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* Ideally a Site Tool should be explicitly engaged with a course, the check on the presence of a link is a proxy
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* to infer a Site Tool engagement until an explicit Site Tool - Course relationship exists.
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*
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* @param int $typeid The tool lti type id.
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* @param int $courseid The course id.
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* @return bool returns True if tool is used in context, false otherwise.
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*/
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public function is_used_in_context($typeid, $courseid) {
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global $DB;
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$ok = $DB->record_exists('lti', array('course' => $courseid, 'typeid' => $typeid));
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return $ok || $DB->record_exists('lti_types', array('course' => $courseid, 'id' => $typeid));
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}
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/**
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* Checks if there is a site tool or a course tool for this site.
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*
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* @param int $typeid The tool lti type id.
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* @param int $courseid The course id.
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* @return bool returns True if tool is allowed in context, false otherwise.
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*/
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public function is_allowed_in_context($typeid, $courseid) {
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global $DB;
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// Check if it is a Course tool for this course or a Site tool.
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$type = $DB->get_record('lti_types', array('id' => $typeid));
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return $type && ($type->course == $courseid || $type->course == SITEID);
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}
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/**
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* Return an array of key/values to add to the launch parameters.
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*
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* @param string $messagetype 'basic-lti-launch-request' or 'ContentItemSelectionRequest'.
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* @param string $courseid The course id.
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* @param string $userid The user id.
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* @param string $typeid The tool lti type id.
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* @param string $modlti The id of the lti activity.
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*
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* The type is passed to check the configuration and not return parameters for services not used.
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*
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* @return array Key/value pairs to add as launch parameters.
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*/
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public function get_launch_parameters($messagetype, $courseid, $userid, $typeid, $modlti = null) {
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return array();
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}
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/**
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* Get the path for service requests.
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*
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* @return string
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*/
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public static function get_service_path() {
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$url = new \moodle_url('/mod/lti/services.php');
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return $url->out(false);
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}
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/**
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* Parse a string for custom substitution parameter variables supported by this service's resources.
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*
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* @param string $value Value to be parsed
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*
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* @return string
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*/
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public function parse_value($value) {
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if (empty($this->resources)) {
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$this->resources = $this->get_resources();
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}
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if (!empty($this->resources)) {
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foreach ($this->resources as $resource) {
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$value = $resource->parse_value($value);
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}
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}
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return $value;
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}
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/**
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* Check that the request has been properly signed.
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*
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* @param string $toolproxyguid Tool Proxy GUID
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* @param string $body Request body (null if none)
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*
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* @return boolean
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*/
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public function check_tool_proxy($toolproxyguid, $body = null) {
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$ok = false;
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$toolproxy = null;
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$consumerkey = lti\get_oauth_key_from_headers();
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if (empty($toolproxyguid)) {
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$toolproxyguid = $consumerkey;
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}
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if (!empty($toolproxyguid)) {
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$toolproxy = lti_get_tool_proxy_from_guid($toolproxyguid);
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if ($toolproxy !== false) {
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if (!$this->is_unsigned() && ($toolproxy->guid == $consumerkey)) {
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$ok = $this->check_signature($toolproxy->guid, $toolproxy->secret, $body);
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} else {
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$ok = $this->is_unsigned();
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}
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}
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}
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if ($ok) {
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$this->toolproxy = $toolproxy;
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}
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return $ok;
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}
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/**
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* Check that the request has been properly signed.
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*
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* @param int $typeid The tool id
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* @param int $courseid The course we are at
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* @param string $body Request body (null if none)
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*
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* @return bool
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*/
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public function check_type($typeid, $courseid, $body = null) {
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$ok = false;
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$tool = null;
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$consumerkey = lti\get_oauth_key_from_headers();
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if (empty($typeid)) {
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return $ok;
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} else if ($this->is_allowed_in_context($typeid, $courseid)) {
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$tool = lti_get_type_type_config($typeid);
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if ($tool !== false) {
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if (!$this->is_unsigned() && ($tool->lti_resourcekey == $consumerkey)) {
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$ok = $this->check_signature($tool->lti_resourcekey, $tool->lti_password, $body);
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} else {
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$ok = $this->is_unsigned();
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}
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}
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}
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return $ok;
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}
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/**
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* Check the request signature.
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*
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* @param string $consumerkey Consumer key
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* @param string $secret Shared secret
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* @param string $body Request body
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*
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* @return boolean
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*/
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private function check_signature($consumerkey, $secret, $body) {
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$ok = true;
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try {
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// TODO: Switch to core oauthlib once implemented - MDL-30149.
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lti\handle_oauth_body_post($consumerkey, $secret, $body);
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} catch (\Exception $e) {
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debugging($e->getMessage() . "\n");
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$ok = false;
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}
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return $ok;
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}
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}
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