How does my LTI app communicate with Canvas?

Question

I think I'm missing something sort of fundamental. I've used the API before (written some nice command line tools). I've taken the LTI course, and I'm at the point where I have OAuth working and I can get my LTI app to show up in the menu in canvas and have it appear inside an iFrame.

So my question is:

How does my LTI app query/get stuff out of canvas?

Am I supposed to use the API as I have been doing with my command line tools? If so, what APIKey do I use, or is there someway to use the API with the same credentials as the incoming user? Or is there an entirely different set of commands I can do with LTI.

Thanks!

-Carmine

pklove · Accepted Answer

LTI itself only has very limited capabilities to interact with Canvas.  It will receive some information on launch and it can send some limited things to Canvas, eg., pass a grade back.  LTI itself has nothing to do with OAuth or the API.

To do anything more than this, you need to use the API.  For your LTI tool to do this, it needs to get a token using OAuth or, depending on what the tool is/does, it might use a user generated token.