Configuring multiple External Tools with the same base URL

Question

If we configure more than one external (LTI) tool with the same URL (but with different custom fields) there doesn't seem to be a way to select the one you want. When setting up the "External Tool URL" it always chooses the same one. Is there a way around this?

garth · Answer

I took the leap into LTI for the purpose of exposing additional SIS integration tools and custom reports for faculty.

So my initial cartridge XML contained a  pointing to my default web page, and I had a single extension entry for the toolkit  pointing to the same URL as the launch_url.

This worked perfectly.

My next goal was to understand how to pass a grade back to the gradebook, so I created a custom assignment in the same domain as my toolkit, and tried to create a new extension for the  entry.  I pointed  to the URL of my custom assignment, re-installed my config, and voila, I had a custom assignment type to choose from.  Unfortunately it launched to , which was unexpected, I mean, what is the point of the  property if it's ignored, right?

So for testing purposes, i.e. I wanted to continue testing my custom assignment and confirm it was properly posting the grade, I updated the  to point to my custom assignment, re-installed my app, and boom, I was able to create an assignment using my custom assignment, and grades posted back to the gradebook properly.  Yay : )

At this point, just for fun, I clicked on the toolkit from the menu option...low and behold it launched!

So the  works as expected for the "course_navigation", but not for the "homework_submission"?

Here is a sample to illustrate how the XML was defined:

I am not at all sure I would do this in production, it feels very "hackish", and I haven't spent a lot of time testing additional variations.  But, I stumbled across this conversation and thought I would share my observation.

DavidMcCool · Answer

It seems like with this change they are forcing/encouraging content selection at assignment creation time rather than when setting up an App. So each external service will only appear once in the list of Apps?

cesbrandt · Answer

This is an issue caused by the 2016-02-20 update. When this change was deployed, they essentially cut down the number of possible ​external tools within a given account/course​ path to one per Launch URL. This was a HUGE issue for our use of Chalk & Wire​, as it's configuration utilized the Custom Parameters for identify the assignment within the external tool that was to be loaded. Same Launch URL, different Custom Parameters.

Sadly, it was determined that Instructure has no plans to alter the current functionality of Canvas to accommodate multiple external tools with a single Launch URL.

In our case, it was determined that an alternate implementation was possible wherein we would have the single external tool without any Custom Parameters. When it is selected as the submission type for an assignment or to be linked into the Modules page, we then append the Custom Parameters to the end of the URL as GET variables. Thus far, it has worked for us.

I can't promise this will work for you, though. I'm not an expert on external tools and don't want to get your hopes up, but it may be worth looking into.

Basically, you'd set-up the external tool exactly as you normally would, except that any UNIQUE Custom Parameters would not be included. Say you have an LTI portal for third-party assessments for various types, you only use the "quiz" type, but the configuration requires a type to still be specified. The type can still appear in the Custom Parameters field of the external tool configuration, but any unique identifier for the target activity would need to be appended when the external tool is attached to the course.

Basic External Tool

Name: LTI QuizzesLaunch URL: https://tool.ltiurl.com/ltiCustom Parameters: type=quiz

Default URL When Linking

https://tool.ltiurl.com/lti

Modified URL When Linking

https://tool.ltiurl.com/lti?quiz_id=1234

I made a little video the other day that basically demonstrates the process: Canvas External Tool (Multi)