How to update a dynamically registered LTI tool configuration

Question

I have an LTI developer key which was configured using a dynamic registration URL.  I cannot find a way of updating this configuration via the UI, and the documentation for the API states that "updating the base tool configuration of a registration that is associated with a Dynamic Registration will return a 422".

So my question is, when the tool moves to a new domain, how can I update Canvas so that existing links send their messages to the new location?

If I cannot update the URLs associated with the developer key, is it possible to create a new one and migrate all links associated with the old one to the new one?  Or some other solution such that existing links will continue to work?

Thanks.

EricHarvey21363320 · Answer

Hi Xander!

It's mentioned here that it's possible to remove and recreate dynamic registration links, which are replaced by new ones. For our Deep Linked LTI Application launches, this doesn't work for us.

Deleting the developer key in Canvas and re-registering causes an assignment of a new client_id. This breaks all existing connections between Canvas and our platform for that institution:

* Course module links break. The deep link that launches students into our platform from a Canvas module references the old registration. It would need to be recreated in every course.
* Grade postback breaks. Assignment line items in the Canvas gradebook are tied to the old registration. Grade syncing stops until instructors re-link assignments.
* Any course using our tool would need the instructor to remove and re-add the tool, recreate the module link, and re-link graded assignments.

Is there an alternate workflow to make this work or would we need to rely on the Canvas API (overlay system) to update existing registrations without deleting them?

Xander Moffatt · Answer

Hey! I will try to answer your questions and clarify some stuff from the replies as well.

As Paul answered in the 1EdTech Slack, we are currently working on supporting this feature, and allowing a re-registration for updating a dynamically registered tool.

> when the tool moves to a new domain, how can I update Canvas so that existing links send their messages to the new location?

As Chris detailed below, it _really_ depends on what you mean by "links". If you mean placements, like "my tool is showing in the course nav", then updating the DR tool using the future re-registration flow will help. Currently, deleting and re-creating the developer key will also work. I know that is not ideal, but also consider that "changing the tool's domain" is a pretty fundamental change for the tool!

If by "links" you mean content items created from deep linking (which I see from replies you are not using, so that makes this easier), then changing domain will break many of those existing content items, because the whole matching process from "I have an LTI launch url" to "I have the right tool to launch it" is built around matching on the tool's configured URL and domain, which is why changing the domain can be such a big deal. Which means that even if you had a non-dynamically-registered tool, if you changed the domain and all the fundamental URLs, those content items _still_ would not work any more. Luckily, you don't have to worry about this 🙂

> So, as dev keys created in other ways can be updated, it seems like dynamic registration is best avoided.  I have not yet been able to discover why dynamically registered dev keys are being treated differently from others.

The main reason that they are treated differently is that they are backed by a different database model, and as part of that we made some choices about what parts of the config are owned by the tool and shouldn't be changed by the admin (at the risk of becoming a "different" tool). I realize that without the update re-registration flow this is very inconvenient, and we are working to remedy that and make this a lot easier for you! The new Canvas Apps page will make it a lot easier to update things about DR keys and soon, to ask the tool for an updated registration as well.

> If I cannot update the URLs associated with the developer key, is it possible to create a new one and migrate all links associated with the old one to the new one?  Or some other solution such that existing links will continue to work?

Yes! You can delete and re-register the tool with the different domain. the old "links" (placements) will be gone, and replaced by the new placement configs from the new tool with the new domain - so to your canvas users, it will look and function the same. that is safe and very doable!

svickers2 · Answer

I received this response from Instructure Support:

"There is currently no possibility of updating the dynamically created dev key once it's configured."

So, as dev keys created in other ways can be updated, it seems like dynamic registration is best avoided.  I have not yet been able to discover why dynamically registered dev keys are being treated differently from others.