08 April 2020, 4:18

Context:
Version 1.1 of the IMS LTI specification to integrate Mahara with other LMS platforms only states launch_presentation_return_URL as an optional field in the LTI launch from the tool consumer to the tool provider; however, it appears to be required for the Mahara integration to launch appropriately. The use case of launch_presentation_return_URL is to give the tool provider a hook as to where to send the user and any tool content back from the tool consumer. For LTI links to launch into Mahara for portfolio selection, submission, and feedback, it all happens within Mahara.

Ask:
What content is being passed back to the LMS from Mahara that makes this optional field about content return required for a basic LTI tool launch?

Thanks!

08 April 2020, 16:05

Hi Gary,

From taking a quick looks at the code it looks like Mahara requires this to allow for

1) Correctly handling SSO logout - eg if a user authenticates via an external site via LTI then when they logout from the Mahara site it also logs them out of the external site.

2) If using grading then some sites load the Mahara pages in iframes and Mahara normally does not allow this but using the launch_presentation_return_url we can add a csp-ancestor-exemption to the headers of the Mahara site for that external site

Though, looking at this it does seem that we could make launch_presentation_return_url only required if lis_outcome_service_url is also supplied

Hope that helps

Cheers

Robert

10 April 2020, 9:28

Thanks, Robert. A couple of clarification follow-ups to your findings:

1. SSO Logout - does this mean that if a user logs out of Mahara, it will also end their LMS session?
   I don't imagine any LMS wanting that functionality from a LTI tool provider. Regardless, I'm not sure that the launch_presentation_return_URL is the correct field from the specification for that direction.
2. iFrames - if Mahara is loaded in an iFrame, isn't launch_presentation_return_URL redundant because the iFrame is rendered in the return destination already?
   That said, if there is an opportunity for Mahara to recognize the tool consumer and provide an exception to support the use of iFrames, that could be a fantastic next step towards a more functional integration. This is noted as a blocker in another thread of the Support forum, topic id=8432 (I can't post links as a new forum member).

I remain hopeful that this conversation can continue and result in the minimum effort needed to improve the integration of Mahara with other LMS platforms!