Bb resource_link_description signatures

Bb resource_link_description signatures

Having issues with OAuth signatures within Bb

Bb resource_link_description signatures

Since we've launched our BasicLTI Tool Provider we've had excellent feedback on the ease of setup and use within several LMS's, which I must thank IMS Global for.

Recently we've come across an issue with Invalid OAuth signatures when users supply descriptions in the LTI tools within Blackboard, and wanted to gather input on how I should go about debugging this. A description is below:

- When users setup an BasicLTI link, it works great and they can launch successfully into our app.
- When a description is added to their BasicLTI link within Blackboard, we are not able to verify the OAuth signature correctly and we report an error to the user.
- I've debugged this down to the point where Blackboard will send HTML br tags within the resource_link_description that are not shown within the Bb description of the resource (since HTML isn't allowed in the post, I've attached an example).
- As soon as the description is removed, or no hard returns are used in the description, the launch works fine.

Again, we've only seen this problem in Blackboard LTI launches (we've setup integrations with at least 5 other types of LMS's). Can anyone else replicate this issue? Is this an issue with our signature generation, or Blackboard's?


Ben Pritchett