Modify roles claim in LtiResourceLinkRequest and NRPS membership container

[ayub02]

Background

LtiResourceLinkRequest and NRPS membership container requires roles claim and must contain at least one role URI from the published role vocabularies.

IMS 1.3 spec lists 3 role vocabularies (link) but does NOT limit their use to specific cases.

1. System roles
2. Institution roles
3. Context roles

Spec further subdivides each of these into core and non-core URIs and states: Core roles are those which are most likely to be relevant within LTI and hence vendors should support them by best practice. Vendors may also use the non-core roles, but they may not be widely used

Table in the image below shows roles supported by some LTI tools vs Open edX.

Here are some observations from the table above:

1. All tools support context roles which makes sense because a typical LTI launch happens from within a course and therefore the role of the user in that course is most relevant to the launch.
2. Open edX does NOT support any context roles. This is why integration fails with most of these tools (see test results).
3. The institution roles that Open edX supports are really context roles because they are tied to a course and not an org.

The following table shows mapping between role URIs from the spec vs roles in Open edX.

Course role	Current URIs in roles claim
Course Admin	/institution/person#Instructor (non-core)
Course Staff	/system/person#Administrator (core) /institution/person#Instructor (non-core)
Limited Staff	/system/person#Administrator (core) /institution/person#Instructor (non-core)
None	/institution/person#Student (core)
All other roles	/institution/person#Student (core)

Proposed way forward

The table below shows current and proposed mapping between Open edX course roles and roles in the spec. Please refer to the spec to get full URIs and other relevant details: https://www.imsglobal.org/spec/lti/v1p3#roles-claim

[ayub02]

Response from Atomic Assessments on failed launch:

Atomic Assessments is expecting context roles:
https://www.imsglobal.org/spec/lti/v1p3/#lis-vocabulary-for-context-roles

The institution roles tell us the person's role in the institution,
but that doesn't reflect on what they are in a particular class. You
could be a teacher in the institution but a student in the class they
are launching

[ayub02]

Response from ChemVantage on launch failure.

Here is a snippet from the ChemVantage code showing which roles are accepted for LtiResourceLinkRequest launches:

while(roles_iterator.hasNext()){
                String role = roles_iterator.next().getAsString();
                user.setIsTeachingAssistant(role.equals("http://purl.imsglobal.org/vocab/lis/v2/membership/Instructor#TeachingAssistant"));
                user.setIsInstructor(role.equals("http://purl.imsglobal.org/vocab/lis/v2/membership#Instructor"));
                user.setIsAdministrator(role.equals("http://purl.imsglobal.org/vocab/lis/v2/membership#Administrator"));
                user.setIsAdministrator(role.equals("http://purl.imsglobal.org/vocab/lis/v2/institution/person#Administrator"));
                user.setIsAdministrator(role.equals("http://purl.imsglobal.org/vocab/lis/v2/system/person#Administrator"));
                if (role.equals("http://purl.imsglobal.org/vocab/lis/v2/membership#Learner")) isLearner = true;
                if (role.equals("http://purl.imsglobal.org/vocab/lis/v2/membership#Mentor")) isMentor = true;
            }

The reason why we don't use institutional roles (except for admins) is that instructors of one class may be students in others (e.g., professional development classes or trainings), so we focus on the role of the person in the context of the course that the app is serving. I hope that makes sense.

[ayub02]

From CourseArc:

I believe the role we are looking for with instructors is:
http://purl.imsglobal.org/vocab/lis/v2/membership#Instructor
I thought our system was more flexible with roles but it appears not to be the case.