Is it possible to intercept the assignment submission?

[joncarlson]

I've built a tool with LTI 1.3 that works great within the assignment submission area.

However, the student has to click a tab for my tool in order to use it, it's disconnected from the assignment submission process.

My ideal flow would be: student uploads a file, Canvas sends the file to my tool which either responds with "success" or "error".

If "success", Canvas continues as normal with submitting the assignment.

If "error", Canvas halts submitting the assignment.

Is that flow possible in Canvas and/or with LTI 1.3? Thank you in advance

[seanbeirnes · Accepted solution]

Hello @joncarlson,

As far as I know this is not possible, nor do I think it is ideal. This does not align with the LTI specification. A proper implementation would have the student submit the file directly to your tool, and then your tool does whatever it needs to do before posting the grade back to Canvas using the Assignments and Grading Services as stated in the LTI Specification. Alternatively, you could implement something that pulls the files via the assignment submissions API endpoints after a student has submitted the assignment, but I do not see a way for you to route the file to your tool during the assignment submission process in Canvas.