caccl-lti

caccl-lti

Validates and parses LTI launch requests.

With caccl-lti, it's easy to enable LTI launches from Canvas. We'll take care of parsing and verifying the validity of launch requests.

Part of the CACCL library

Canvas
App
Complete
Connection
Library

Quickstart

Quickstart:

const initLTI = require('caccl-lti');

initLTI({
  app: /* express app with express-sessions enabled */,
  installationCredentials: /* { consumer_key, consumer_secret }*/,
});

The app will now be set up to accept LTI launches at /launch. See "Launch Parsing" below to find info on parsed launches.

Configuration Options

When initializing caccl-lti, you can pass in many different configuration options to customize caccl-lti's behavior or turn on/off certain functionality.

Note: configuration options are optional unless otherwise stated

Config Option	Type	Description	Default/Required
app	express app	express app to add routes to	Required
installationCredentials	object	LTI consumer credentials of form: { consumer_key, consumer_secret }	Required
launchPath	string	path to accept launches at (new express POST route added)	/launch
redirectToAfterLaunch	string	path to redirect to after successful launch	same as launchPath
nonceStore	NonceStore	a nonce store to use for keeping track of used nonces	memory store
disableAuthorizeOnLaunch	boolean	if false, redirects to authorizePath after launch is validated and parsed (and includes redirectToAfterLaunch) as the 'next link so that caccl-authorizer redirects to redirectToAfterLaunch after finishing authorization	false
authorizePath	string	the authorization path (as set up by caccl-authorizer, required if disableAUthorizeOnLaunch is true	null

Launch Parsing

Launches are automatically parsed and added to session. To retrieve launch info, see the req.session.launchInfo variable, which has the following properties:

For more detailed information, see Canvas' LTI documentation.

User Info

Property	Type	Description
userId	number	Canvas user id of the person who launched the app
userLoginId	string	Canvas login id (e.g., university id)
userEmail	string	the user's primary Canvas email (changeable in user's profile)
userFirstName	string	the user's first name
userLastName	string	the user's last name
userFullName	string	the user's full name
userImage	string	link to user's image
isInstructor	boolean	true if the user is an instructor in the launch course
isTA	boolean	true if the user is a teaching assistant in the launch course
isDesigner	boolean	true if the user is a designer in the launch course
isCreditLearner	boolean	true if the user is a for-credit learner (student) in the launch course
isNonCreditLearner	boolean	true if the user is a not-for-credit learner (student) in the launch course
isLearner	boolean	true if the user any type of learner (student) in the launch course
notInCourse	boolean	true if the user is not enrolled in the course
extRoles	string[]	list of extended Canvas roles
roles	string[]	list of basic Canvas roles (outdated)
locale	string	user locale (e.g., "en")

Launch Info

Property	Type	Description
timestamp	number	launch timestamp (ms)
contextId	string	LTI launch context
launchPresentationTarget	string	LTI launch presentation target (e.g., "iframe")
iframeWidth	number	iframe width (if applicable)
iframeHeight	number	iframe height (if applicable)
returnURL	string	LTI return URL
launchAppTitle	string	the title of the resource link (app title)
customParams	object	mapping (key => value) listing all custom launch parameters and their values

Course Info

Property	Type	Description
courseId	number	Canvas course id of the launch course
sisCourseId	number	Learning Information Services identifier for the course offering
enrollmentState	string	Canvas enrollment state (e.g., "active")

Canvas Info

Property	Type	Description
contextLabel	string	the name of the launch context (e.g., course name)
canvasHost	string	host of the launch Canvas instance
workflowState	string	Canvas workflow status (e.g., "active")