mod/lti/service.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 /**
  18  * LTI web service endpoints
  19  *
  20  * @package mod_lti
  21  * @copyright  Copyright (c) 2011 Moodlerooms Inc. (http://www.moodlerooms.com)
  22  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  23  * @author     Chris Scribner
  24  */
  25
  26 define('NO_DEBUG_DISPLAY', true);
  27 define('NO_MOODLE_COOKIES', true);
  28
  29 require_once(__DIR__ . "/../../config.php");
  30 require_once($CFG->dirroot.'/mod/lti/locallib.php');
  31 require_once($CFG->dirroot.'/mod/lti/servicelib.php');
  32
  33 // TODO: Switch to core oauthlib once implemented - MDL-30149.
  34 use mod_lti\service_exception_handler;
  35 use moodle\mod\lti as lti;
  36 use ltiservice_basicoutcomes\local\service\basicoutcomes;
  37
  38 $rawbody = file_get_contents("php://input");
  39
  40 $logrequests  = lti_should_log_request($rawbody);
  41 $errorhandler = new service_exception_handler($logrequests);
  42
  43 // Register our own error handler so we can always send valid XML response.
  44 set_exception_handler(array($errorhandler, 'handle'));
  45
  46 if ($logrequests) {
  47     lti_log_request($rawbody);
  48 }
  49
  50 $ok = true;
  51 $type = null;
  52 $toolproxy = false;
  53
  54 $consumerkey = lti\get_oauth_key_from_headers(null, array(basicoutcomes::SCOPE_BASIC_OUTCOMES));
  55 if ($consumerkey === false) {
  56     throw new Exception('Missing or invalid consumer key or access token.');
  57 } else if (is_string($consumerkey)) {
  58     $toolproxy = lti_get_tool_proxy_from_guid($consumerkey);
  59     if ($toolproxy !== false) {
  60         $secrets = array($toolproxy->secret);
  61     } else if (!empty($tool)) {
  62         $secrets = array($typeconfig['password']);
  63     } else {
  64         $secrets = lti_get_shared_secrets_by_key($consumerkey);
  65     }
  66     $sharedsecret = lti_verify_message($consumerkey, lti_get_shared_secrets_by_key($consumerkey), $rawbody);
  67     if ($sharedsecret === false) {
  68         throw new Exception('Message signature not valid');
  69     }
  70 }
  71
  72 // TODO MDL-46023 Replace this code with a call to the new library.
  73 $origentity = libxml_disable_entity_loader(true);
  74 $xml = simplexml_load_string($rawbody);
  75 if (!$xml) {
  76     libxml_disable_entity_loader($origentity);
  77     throw new Exception('Invalid XML content');
  78 }
  79 libxml_disable_entity_loader($origentity);
  80
  81 $body = $xml->imsx_POXBody;
  82 foreach ($body->children() as $child) {
  83     $messagetype = $child->getName();
  84 }
  85
  86 // We know more about the message, update error handler to send better errors.
  87 $errorhandler->set_message_id(lti_parse_message_id($xml));
  88 $errorhandler->set_message_type($messagetype);
  89
  90 switch ($messagetype) {
  91     case 'replaceResultRequest':
  92         $parsed = lti_parse_grade_replace_message($xml);
  93
  94         $ltiinstance = $DB->get_record('lti', array('id' => $parsed->instanceid));
  95
  96         if (!lti_accepts_grades($ltiinstance)) {
  97             throw new Exception('Tool does not accept grades');
  98         }
  99
 100         lti_verify_sourcedid($ltiinstance, $parsed);
 101         lti_set_session_user($parsed->userid);
 102
 103         $gradestatus = lti_update_grade($ltiinstance, $parsed->userid, $parsed->launchid, $parsed->gradeval);
 104
 105         if (!$gradestatus) {
 106             throw new Exception('Grade replace response');
 107         }
 108
 109         $responsexml = lti_get_response_xml(
 110                 'success',
 111                 'Grade replace response',
 112                 $parsed->messageid,
 113                 'replaceResultResponse'
 114         );
 115
 116         echo $responsexml->asXML();
 117
 118         break;
 119
 120     case 'readResultRequest':
 121         $parsed = lti_parse_grade_read_message($xml);
 122
 123         $ltiinstance = $DB->get_record('lti', array('id' => $parsed->instanceid));
 124
 125         if (!lti_accepts_grades($ltiinstance)) {
 126             throw new Exception('Tool does not accept grades');
 127         }
 128
 129         // Getting the grade requires the context is set.
 130         $context = context_course::instance($ltiinstance->course);
 131         $PAGE->set_context($context);
 132
 133         lti_verify_sourcedid($ltiinstance, $parsed);
 134
 135         $grade = lti_read_grade($ltiinstance, $parsed->userid);
 136
 137         $responsexml = lti_get_response_xml(
 138                 'success',  // Empty grade is also 'success'.
 139                 'Result read',
 140                 $parsed->messageid,
 141                 'readResultResponse'
 142         );
 143
 144         $node = $responsexml->imsx_POXBody->readResultResponse;
 145         $node = $node->addChild('result')->addChild('resultScore');
 146         $node->addChild('language', 'en');
 147         $node->addChild('textString', isset($grade) ? $grade : '');
 148
 149         echo $responsexml->asXML();
 150
 151         break;
 152
 153     case 'deleteResultRequest':
 154         $parsed = lti_parse_grade_delete_message($xml);
 155
 156         $ltiinstance = $DB->get_record('lti', array('id' => $parsed->instanceid));
 157
 158         if (!lti_accepts_grades($ltiinstance)) {
 159             throw new Exception('Tool does not accept grades');
 160         }
 161
 162         lti_verify_sourcedid($ltiinstance, $parsed);
 163         lti_set_session_user($parsed->userid);
 164
 165         $gradestatus = lti_delete_grade($ltiinstance, $parsed->userid);
 166
 167         if (!$gradestatus) {
 168             throw new Exception('Grade delete request');
 169         }
 170
 171         $responsexml = lti_get_response_xml(
 172                 'success',
 173                 'Grade delete request',
 174                 $parsed->messageid,
 175                 'deleteResultResponse'
 176         );
 177
 178         echo $responsexml->asXML();
 179
 180         break;
 181
 182     default:
 183         // Fire an event if we get a web service request which we don't support directly.
 184         // This will allow others to extend the LTI services, which I expect to be a common
 185         // use case, at least until the spec matures.
 186         $data = new stdClass();
 187         $data->body = $rawbody;
 188         $data->xml = $xml;
 189         $data->messageid = lti_parse_message_id($xml);
 190         $data->messagetype = $messagetype;
 191         $data->consumerkey = $consumerkey;
 192         $data->sharedsecret = $sharedsecret;
 193         $eventdata = array();
 194         $eventdata['other'] = array();
 195         $eventdata['other']['messageid'] = $data->messageid;
 196         $eventdata['other']['messagetype'] = $messagetype;
 197         $eventdata['other']['consumerkey'] = $consumerkey;
 198
 199         // Before firing the event, allow subplugins a chance to handle.
 200         if (lti_extend_lti_services($data)) {
 201             break;
 202         }
 203
 204         // If an event handler handles the web service, it should set this global to true
 205         // So this code knows whether to send an "operation not supported" or not.
 206         global $ltiwebservicehandled;
 207         $ltiwebservicehandled = false;
 208
 209         try {
 210             $event = \mod_lti\event\unknown_service_api_called::create($eventdata);
 211             $event->set_message_data($data);
 212             $event->trigger();
 213         } catch (Exception $e) {
 214             $ltiwebservicehandled = false;
 215         }
 216
 217         if (!$ltiwebservicehandled) {
 218             $responsexml = lti_get_response_xml(
 219                 'unsupported',
 220                 'unsupported',
 221                  lti_parse_message_id($xml),
 222                  $messagetype
 223             );
 224
 225             echo $responsexml->asXML();
 226         }
 227
 228         break;
 229 }