From 3b3535c7ea74ef92e8d65dce40b2fbf2d0e327e8 Mon Sep 17 00:00:00 2001
From: David Knuplesch <david.knuplesch@uni-ulm.de>
Date: Fri, 1 Sep 2017 12:58:02 +0200
Subject: [PATCH] MDL-55358 mod_lti: Add group variable
 Moodle.Person.userGroupIds

---
 mod/lti/locallib.php | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/mod/lti/locallib.php b/mod/lti/locallib.php
index 949644998ad..0d6c17f6b51 100644
--- a/mod/lti/locallib.php
+++ b/mod/lti/locallib.php
@@ -373,7 +373,7 @@ function lti_build_sourcedid($instanceid, $userid, $servicesalt, $typeid = null,
  * @return array                    Request details
  */
 function lti_build_request($instance, $typeconfig, $course, $typeid = null, $islti2 = false) {
-    global $USER, $COURSE, $CFG;
+    global $USER, $CFG;
 
     if (empty($instance->cmid)) {
         $instance->cmid = 0;
@@ -385,7 +385,6 @@ function lti_build_request($instance, $typeconfig, $course, $typeid = null, $isl
         'user_id' => $USER->id,
         'lis_person_sourcedid' => $USER->idnumber,
         'roles' => $role,
-        'groups' => implode(",", groups_get_user_groups($COURSE->id, $USER->id)[0]),
         'context_id' => $course->id,
         'context_label' => trim(html_to_text($course->shortname, 0)),
         'context_title' => trim(html_to_text($course->fullname, 0)),
@@ -1248,6 +1247,8 @@ function lti_parse_custom_parameter($toolproxy, $tool, $params, $value, $islti2)
                             $value = str_replace('<br>' , ' ', $value);
                             $value = format_string($value);
                         }
+                    } else {
+                        $value = lti_calculate_custom_parameter($value1);
                     }
                 } else if ($islti2) {
                     $val = $value;
@@ -1266,6 +1267,23 @@ function lti_parse_custom_parameter($toolproxy, $tool, $params, $value, $islti2)
     return $value;
 }
 
+/**
+ * Calculates the value of a custom parameter that has not been specified earlier
+ *
+ * @param string    $value          Custom parameter value
+ *
+ * @return string Calculated value of custom parameter
+ */
+function lti_calculate_custom_parameter($value) {
+    global $USER, $COURSE;
+
+    switch ($value) {
+        case 'Moodle.Person.userGroupIds':
+            return implode(",", groups_get_user_groups($COURSE->id, $USER->id)[0]);
+    }
+    return null;
+}
+
 /**
  * Used for building the names of the different custom parameters
  *
@@ -2556,7 +2574,7 @@ function lti_get_capabilities() {
        'Membership.role' => 'roles',
        'Result.sourcedId' => 'lis_result_sourcedid',
        'Result.autocreate' => 'lis_outcome_service_url',
-       'Group.sourceId' => 'groups');
+       'Moodle.Person.userGroupIds' => null);
 
     return $capabilities;