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arunkottol
Community Participant

Identifying the origin of a LTI launch

Hi,

The Canvas LTI APP XML Extensions allows placement of the LTI Tool in different sections. Example: Course Navigation, Homework Submission, Resource Selection etc. 

Although the XML allows different URL's to be configured for each of these extensions, it seems to only use the primary LTI Launch URL at any placement of the tool. Here are the question(s):

  1. Are there any parameters that indicate the origin of the LTI launch ?
  2. Is there a way to have different URLs for each extension?

Thanks,

Arun

Labels (1)
10 Replies
peter3
Community Participant

When the LTI Launch it triggered it doesn't give any indication of which launch placement originated the launch request.  However when you are specifying the LTI XML Configuration you *can* give each placement its own launch URL.

Take a look at the XML Config Builder and see where you can add the optional URLs for each of the placement extensions. 

ColinMurtaugh
Community Champion

Hi Arun --

As Peter says, you can have different launch URLs for different placements, and Canvas will use the placement-specific URL if one is defined.  Canvas will fall back to using the main launch URL if there isn't one defined for the particular placement you're looking at. 

Also, the each launch will contain a 'resource_link_id' and 'resource_link_title' parameter.  The resource_link_id will be unique for each placement, and the resource_link_title will match the name of the placement (i.e. it'll contain the assignment name, module name, or the text of the navigation link, to name a few). 

Hope this helps!

--Colin

arunkottol
Community Participant

Thanks Peter. I am aware of the fact that we can provide a different URL for each placement. However in my case somehow it did not seem to work and it seemed to always use the primary LTI Launch URL. Probably the XML may not be correct. Will check and confirm. 

Thanks Colin.

phanley
Community Contributor

Colin Murtaugh wrote:

 

Also, the each launch will contain a 'resource_link_id' and 'resource_link_title' parameter.  The resource_link_id will be unique for each placement....

I'm trying to fix a problematic LTI suite with a vendor and I've noticed that what you said is not true for Course Navigation links to LTIs - every course navigation link duplicates the context_id as the resource_link_id (however if you put the same tools in a module they will use unique values )

Since as you mention the LTI spec is clear that resource_link_id is  "an opaque unique identifier that ... will be unique ... for every placement of the link. If the tool / activity is placed multiple times in the same context, each of those placements will be distinct. This value will also change if the item is exported from one system or context and imported into another system or context" -- is it fair to call this behaviour a bug?

I guess I should file a case  

phanley
Community Contributor

Follow Up - Canvas support confirmed that the resource_link_id being identical to the context_id in and LTI launch from Course Navigation isn't the expected behavior and the issue has been escalated (to the next level of support)

Ah, good to know! Does seem like a bug to me...

arunkottol
Community Participant

Hi Peter,

Thanks for the info. Any ETA for this issue to get fixed. Also is there a link to where this issue is logged? Thanks.

- Arun

arunkottol
Community Participant

Hi Peter,

I still seem to have this problem. I am aware of the XML config builder as well as the EDU App center tool to generate the APP XML. 

I use "canvas.instructure.com" and the feature of specifying a URL for each placement does not seem to be supported.

In my case I have the following specified:

<blti:launch_url>mylaunchURL</blti:launch_url>

<lticm:options name="homework_submission">
      <lticm:property name="url">My Assignments link</lticm:property>
</lticm:options>

<lticm:options name="course_navigation">
   <lticm:property name="url">my course navigation link</lticm:property>
</lticm:options>

I noticed that in case of the course navigation link it took correct URL specified under course_navigation. However, it does not seem to honor the URL under homework_submission. Instead it used the "blti:launch_url" when the external tool was configured in the assignment.

I am wondering if anyone else has faced this problem. Any inputs on this will be appreciated. Thanks.

- Arun