I'm implementing my first grade pass back from an External LTI which I've developed. Based on my use case, my plan is to associate a canvas user_id with the lis_result_sourcedid as well as the lis_outcome_service_url when the user initiates a launch of an assignment through Canvas; this information will then be saved in my database. Then, at a future point in time, I'll run a CRON job to actually pass back the score to the gradebook.
I've been able to perform this action on a one time basis. However, I would like to verify that this unique combination of canvas user_id, lis_result_sourcedid, and lis_outcome_service_url never changes for a particular assignment. In other words, if a student re-logs in at a future date, creating a new instance, can it be guaranteed that my post back to Canvas will still hit the same gradebook entry?
Thanks so much!