Integrating Opencast using LTI

About LTI

LTI provides an easy way to integrate Opencast into any system which can act as an LTI tool consumer such as many learning management systems (LMS). Popular examples for LTI consumers include Sakai, Moodle or ILIAS.

Using the LTI integration, students can access Opencast through an LTI tool in the LMS course site, and can play back Opencast videos without ever leaving their course.

More information about the LTI specification is available at IMS Learning Tools Interoperability. For a better understanding of what LTI is and what it is not, consider this introductory webinar.

Configuration

Configure OAuth

LTI uses OAuth to authenticate users. To enable OAuth in Opencast, edit etc/security/mh_default_org.xml and uncomment the oauthProtectedResourceFilter in the authentication filters section:

<ref bean="oauthProtectedResourceFilter" />

Next, configure the OAuth consumer by setting custom credentials in etc/org.opencastproject.kernel.security.OAuthConsumerDetailsService.cfg:

oauth.consumer.name.1=CONSUMERNAME
oauth.consumer.key.1=CONSUMERKEY
oauth.consumer.secret.1=CONSUMERSECRET

Configure LTI

Opencast's LTI module allows additional configuration like making a OAuth consumer key a highly trusted key, preventing Opencast from generating a temporary username, or to block some specific usernames like the system administrator.

For more details, take a look at the options in etc/org.opencastproject.security.lti.LtiLaunchAuthenticationHandler.cfg.

The “delete” key in the series overview tool can be configured by specifying the retraction workflow in etc/org.opencastproject.lti.service.impl.LtiServiceImpl.cfg. The property is called retract-workflow-id, and it defaults to retract.

Configure and test an LTI tool in the LMS

Configure an LTI tool in the LMS with these values:

• LTI launch URL: <presentation-node-url>/lti
• LTI key: the value of oauth.consumer.key
• LTI secret: the value of oauth.consumer.secret

Access the LTI tool configured for Opencast in the LMS. The Opencast LTI welcome page should appear. Use the links provided there to verify the LTI connection.

LTI Roles

LTI users will only see Opencast series and videos which are public, or those to which they have access because of the Opencast roles which they have. The Opencast LTI module grants an LTI user the role(s) formed from the LTI parameters context_id and roles.

The LTI context is typically the LMS course ID, and the default LTI role for a student in a course is Learner. The Opencast role granted would therefore be <context-id>_Learner.

To make a series or video visible to students who access Opencast through LTI in an LMS course, add the role <context-id>_Learner to the series or event access control list (ACL).

An additional prefix for these generated roles may be defined in Opencast's LTI configuration file based on the used OAuth consumer. That way, you can distinguish between users from multiple different consumers.

LTI users may also have additional roles if the LTI user is created as an Opencast user in the Admin UI and given additional roles, or if one or more Opencast User Providers or Role Providers are configured.

Specifying LTI Tools

Opencast will redirect an LTI user to the URL specified by the LTI custom tool parameter. Some LMS systems allow custom parameters to be defined separately in each place where an LTI tool is used, whereas other systems only allow custom parameters to be defined globally.

• To show the media module, use engage/ui/ as LTI custom_tool launch parameter
• To show all videos for a single series, use ltitools/index.html as LTI custom_tool launch parameter and specify the following query parameters:
  • subtool=series
  • series=SERIESID if you have the series ID
  • series_name=SERIESNAME if you just have the series name (has to be unique)
  • deletion=true to show a delete button next to each episode
  • edit=true if you want to display an edit button next to each episode
  • annotate=true if you want to display an annotate (annotation tool) button next to each episode
  • download=true to show a button next to each episode that allows for downloading individual video files
  • lng=LANG to force a language (the browser language is used otherwise)
• To show an upload dialog, use ltitools/index.html as LTI custom_tool launch parameter and specify the following query parameters:
  • subtool=upload
  • series=SERIESID if you have the series ID
  • series_name=SERIESNAME if you just have the series name (has to be unique)
  • lng=LANG to force a language (the browser language is used otherwise)
• To show a single video, use /play/<id> as LTI custom_tool launch parameter
• To show a debug page before proceeding to the tool, append the parameter test=true

For more information about how to set custom LTI parameters, please check the documentation of your LMS.

Customizing LTI’s look

The LTI module provides the option to provide custom style sheets for configuring the look and feel of the tools which may be important to match the design of the LTI consumer in which it is included. The CSS file can be found in the user interface configuration directory usually located at:

etc/ui-config/mh_default_org/ltitools/lti.css