user Session issue in LTI 1.3

[citv257]

Dear group members.

I am developing an application to integrate with Canvas Open Source, through LTI.

The application is normally integrated, but I have a great difficulty in storing the session with the user's data (context_id, custom_canvas_user_id, custom_canvas_user_login_id, oauth_signature, oauth_consumer_key, and other fields).

On the side of the LTI application (TP - Tool Provider) I can get the data that is passed via post by Canvas (context_id, custom_canvas_user_id, custom_canvas_user_login_id, oauth_signature, oauth_consumer_key and other fields) and I'm storing it in a session. If I run my application outside of Canvas, the session data is persisted correctly. If I access the application from within Canvas, I cannot recover the data persisted in the session.

Has anyone ever had to save the data in session in an LTI application? Is this the correct procedure or is there any other way to do this? Does anyone have an example? Any useful documentation?
Note : I have implemented LTI 1.3 using dot net technology.

Thanks.
Suresh Shaw

[matthew_buckett]

Hiya,

By inside/outside of Canvas, do you mean launching the LTI application in a iframe embedded within Canvas as opposed to launching the application in a popup window?

If so then it could well be that your browser is blocking the cookies that you are using to store your session data. Browsers have recently become much more strict about what cookies they will send when a page is being loaded in an iframe (as is common with LTI tools). There's some workarounds you can try to encourage the browser to accept the cookies outlined on: https://community.canvaslms.com/t5/Canvas-Developers-Group/SameSite-Cookies-and-Canvas/ba-p/257967

We've developed some tools locally and have moved away from cookies to avoid these problems. We ended up developing single page applications and using fetch/XHR requests with a JWT to load further data.

Matthew