What is the purpose of the 'domain' field in an LTI config

[janeklb]

Can anyone explain, or point to a resource that might explain, the purpose of the 'domain' field in an LTI configuration. How is this field used by the LTI Consumer? Does it have to match the LTI Launch Url?

Thanks

[sonya_corcoran1]

Hi there 877396,

I think your answers lies within 4.1 of the | IMS Global Learning Consortium

Once the TP domain credentials are established for a TP, all Basic LTI tool launches to the TP will use this same secret.  Using TP domain credentials gives TPs the option of trusting user information and context information across multiple contexts within a particular TC instance as being maintained properly by the TC.

Although, I'd really appreciate if this was confirmed by someone more experienced.

Cheers

Sonya

[janeklb]

Thanks for posting this Sonya. Indeed, out of that entire spec document, this section seems to be the most relevant w.r.t. the 'domain', but I'm still not sure how it exactly relates.. mainly due to the fact that it speaks of 'domain credentials'.

Again, if someone could confirm or elaborate, that would be much appreciated..

[dan_hammari]

I also am confused by this field. I am unsure whether to set this domain field to my local domain or the remote domain which will receive the LTI request for content.

[janeklb]

If by local domain you mean the domain of the LTI Consumer (eg. the LMS) then I can say with near certainty that this would not be correct. It's likely that it should match the LTI Tool Provider domain, though still I'm not 100% sure about that..

[jonathan_bird]

Just found this in Instructure course/docs at: Domain: LTI from scratch (ruby) 

"The domain parameter is optional, and may be included along with or by replacing the launch URL. A tool's domain tells canvas that all launch urls in this domain should be automatically associated with this tool. This allows you to specify a specific URL within the domain configured when you actually place the LTI link instead of here during tool install. However, the actual URL used when placing the link will still be subject to all the same restrictions as the Launch URL.

<...>
If no domain is provided, then Canvas will attempt to match on the launch URL exactly. This means that you cannot embed any LTI links that are different from the launch URL configured for the tool; if you do, then Canvas won't be able to find the tool."

with illustration: