I'm creating an external tool concept that will necessitate about 50 external tools for a given course (same endpoint on my site but with a different custom variable). I know that I can use the Canvas API to create the external tools and the assignments. I also know how to do grade passback using the lis_outcome_service_url and lis_result_sourcedid.
I can make this work by having each student go to Canvas, visit the assignment and then have my database save this information along with the custom variable so that they can either complete the assignment in Canvas or at my website. However, I don't want them to have to do this for all 50 tools. Instead, I'd like them to do just complete the assignments on my website with the information silently passing back to Canvas without even having to go to Canvas in the first place.
So, my question is: Can I get lis_outcome_service_url and lis_result_sourcedid for each student/external tool combination using the Canvas API without having to have them go to Canvas, opening the Assignment at which point I would get it via the LTI variables?