[Summary view] [Print] [Text view]

   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(dirname(__FILE__) . "/../../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 moodle\mod\lti as lti;
  35  
  36  $rawbody = file_get_contents("php://input");
  37  
  38  if (lti_should_log_request($rawbody)) {
  39      lti_log_request($rawbody);
  40  }
  41  
  42  foreach (lti\OAuthUtil::get_headers() as $name => $value) {
  43      if ($name === 'Authorization') {
  44          // TODO: Switch to core oauthlib once implemented - MDL-30149.
  45          $oauthparams = lti\OAuthUtil::split_header($value);
  46  
  47          $consumerkey = $oauthparams['oauth_consumer_key'];
  48          break;
  49      }
  50  }
  51  
  52  if (empty($consumerkey)) {
  53      throw new Exception('Consumer key is missing.');
  54  }
  55  
  56  $sharedsecret = lti_verify_message($consumerkey, lti_get_shared_secrets_by_key($consumerkey), $rawbody);
  57  
  58  if ($sharedsecret === false) {
  59      throw new Exception('Message signature not valid');
  60  }
  61  
  62  // TODO MDL-46023 Replace this code with a call to the new library.
  63  $origentity = libxml_disable_entity_loader(true);
  64  $xml = simplexml_load_string($rawbody);
  65  if (!$xml) {
  66      libxml_disable_entity_loader($origentity);
  67      throw new Exception('Invalid XML content');
  68  }
  69  libxml_disable_entity_loader($origentity);
  70  
  71  $body = $xml->imsx_POXBody;
  72  foreach ($body->children() as $child) {
  73      $messagetype = $child->getName();
  74  }
  75  
  76  switch ($messagetype) {
  77      case 'replaceResultRequest':
  78          try {
  79              $parsed = lti_parse_grade_replace_message($xml);
  80          } catch (Exception $e) {
  81              $responsexml = lti_get_response_xml(
  82                  'failure',
  83                  $e->getMessage(),
  84                  uniqid(),
  85                  'replaceResultResponse');
  86  
  87              echo $responsexml->asXML();
  88              break;
  89          }
  90  
  91          $ltiinstance = $DB->get_record('lti', array('id' => $parsed->instanceid));
  92  
  93          if (!lti_accepts_grades($ltiinstance)) {
  94              throw new Exception('Tool does not accept grades');
  95          }
  96  
  97          lti_verify_sourcedid($ltiinstance, $parsed);
  98          lti_set_session_user($parsed->userid);
  99  
 100          $gradestatus = lti_update_grade($ltiinstance, $parsed->userid, $parsed->launchid, $parsed->gradeval);
 101  
 102          $responsexml = lti_get_response_xml(
 103                  $gradestatus ? 'success' : 'failure',
 104                  'Grade replace response',
 105                  $parsed->messageid,
 106                  'replaceResultResponse'
 107          );
 108  
 109          echo $responsexml->asXML();
 110  
 111          break;
 112  
 113      case 'readResultRequest':
 114          $parsed = lti_parse_grade_read_message($xml);
 115  
 116          $ltiinstance = $DB->get_record('lti', array('id' => $parsed->instanceid));
 117  
 118          if (!lti_accepts_grades($ltiinstance)) {
 119              throw new Exception('Tool does not accept grades');
 120          }
 121  
 122          // Getting the grade requires the context is set.
 123          $context = context_course::instance($ltiinstance->course);
 124          $PAGE->set_context($context);
 125  
 126          lti_verify_sourcedid($ltiinstance, $parsed);
 127  
 128          $grade = lti_read_grade($ltiinstance, $parsed->userid);
 129  
 130          $responsexml = lti_get_response_xml(
 131                  'success',  // Empty grade is also 'success'.
 132                  'Result read',
 133                  $parsed->messageid,
 134                  'readResultResponse'
 135          );
 136  
 137          $node = $responsexml->imsx_POXBody->readResultResponse;
 138          $node = $node->addChild('result')->addChild('resultScore');
 139          $node->addChild('language', 'en');
 140          $node->addChild('textString', isset($grade) ? $grade : '');
 141  
 142          echo $responsexml->asXML();
 143  
 144          break;
 145  
 146      case 'deleteResultRequest':
 147          $parsed = lti_parse_grade_delete_message($xml);
 148  
 149          $ltiinstance = $DB->get_record('lti', array('id' => $parsed->instanceid));
 150  
 151          if (!lti_accepts_grades($ltiinstance)) {
 152              throw new Exception('Tool does not accept grades');
 153          }
 154  
 155          lti_verify_sourcedid($ltiinstance, $parsed);
 156          lti_set_session_user($parsed->userid);
 157  
 158          $gradestatus = lti_delete_grade($ltiinstance, $parsed->userid);
 159  
 160          $responsexml = lti_get_response_xml(
 161                  $gradestatus ? 'success' : 'failure',
 162                  'Grade delete request',
 163                  $parsed->messageid,
 164                  'deleteResultResponse'
 165          );
 166  
 167          echo $responsexml->asXML();
 168  
 169          break;
 170  
 171      default:
 172          // Fire an event if we get a web service request which we don't support directly.
 173          // This will allow others to extend the LTI services, which I expect to be a common
 174          // use case, at least until the spec matures.
 175          $data = new stdClass();
 176          $data->body = $rawbody;
 177          $data->xml = $xml;
 178          $data->messageid = lti_parse_message_id($xml);
 179          $data->messagetype = $messagetype;
 180          $data->consumerkey = $consumerkey;
 181          $data->sharedsecret = $sharedsecret;
 182          $eventdata = array();
 183          $eventdata['other'] = array();
 184          $eventdata['other']['messageid'] = $data->messageid;
 185          $eventdata['other']['messagetype'] = $messagetype;
 186          $eventdata['other']['consumerkey'] = $consumerkey;
 187  
 188          // Before firing the event, allow subplugins a chance to handle.
 189          if (lti_extend_lti_services($data)) {
 190              break;
 191          }
 192  
 193          // If an event handler handles the web service, it should set this global to true
 194          // So this code knows whether to send an "operation not supported" or not.
 195          global $ltiwebservicehandled;
 196          $ltiwebservicehandled = false;
 197  
 198          try {
 199              $event = \mod_lti\event\unknown_service_api_called::create($eventdata);
 200              $event->set_message_data($data);
 201              $event->trigger();
 202          } catch (Exception $e) {
 203              $ltiwebservicehandled = false;
 204          }
 205  
 206          if (!$ltiwebservicehandled) {
 207              $responsexml = lti_get_response_xml(
 208                  'unsupported',
 209                  'unsupported',
 210                   lti_parse_message_id($xml),
 211                   $messagetype
 212              );
 213  
 214              echo $responsexml->asXML();
 215          }
 216  
 217          break;
 218  }