Discourse LTI allows Discourse to integrate with a number of learning management systems via the LTI 1.3 standard.
Install Guide
This plugin is bundled with Discourse core. There is no need to install the plugin separately.
This plugin implements the LTI 1.3 standard for authentication, which is supported by a number of learning management systems. Discourse acts as a “Tool” within the LTI standard. Once configured, users will be able to click a button/link on the learning management system, and instantly be logged into Discourse.
Precise setup instructions will vary based on your Learning Management System. But in general:
Create a new “Tool” entry in your learning management system
LTI Version: 1.3
Launch URL: any URL on your site. Users will be directed here after login
Tool Public Key - leave blank. Discourse never sends data to the LMS
In your LMS, find the 'Authorization endpoint", “Tool Client ID”, “Platform Issuer ID”, and the “Platform Public Key”, and add them to the relevant site settings in Discourse. In Discourse, the settings can be found by searching for lti in the Discourse site settings UI.
If your learning management system guarantees User emails have been validated, enable the lti email verified site setting. Warning: If your LMS does not verify emails, enabling lti email verified is a security risk.
Turn on the lti enabled site setting
If these instructions don’t make sense for your LMS, please post in the topic below and we’ll do our best to update the instructions accordingly.
What if my site is invite_required?
If you want your users to go through the Discourse invite redemption flow when they first log in, you can use LTI “Custom Properties” to specify a Discourse invite link. New users will be directed to the invite, while existing users will be sent to the regular launch URL. For example:
I am one of our admins and also a software engineer. I think the issue I am having has to do with cookies and the “state” between discourse and Canvas not matching.
This is the error I am getting in Discourse logs
(lti) Authentication failure! state_mismatch: StandardError, State parameter did not match the session
For the public key, you can navigate to https://<your_canvas_url>/api/lti/security/jwks and copy the second key. Then you can go to https://8gwifi.org/jwkconvertfunctions.jsp and paste it in there and convert. Then copy the text between-----BEGIN/END PUBLIC KEY----- and paste that into the Lti platform public key in the Discourse LTI settings. Then save.
Here’s the caveat. Those JWKs that Canvas generate are rotated, seemingly monthly. Once that second key changes, the LTI will break and you’ll need to go replace it with the new one following Step 3.
Discourse LTI plugin will have to support a Public JWK URL for it to stay current.
This plugin is now bundled with Discourse core as part of Bundling more popular plugins with Discourse core. If you are self-hosting and use the plugin, you need to remove it from your app.yml before your next upgrade.