Introduction

Content-Item is an extension to LTI that allows data to be passed back to the Tool Consumer in context of an LTI Launch. A few common use cases are:

  • Providing a teacher the ability to select a customized LTI launch link from the tool provider to be placed in the the tool consumer.

  • Allowing a student to submit an attachment for an assignment that is provided by a tool provider.

  • Embedding custom content into a rich text editor from a tool provider.

Content-Item Process

The first step in the content-item process is the sending of the ContentItemSelectionRequest message from the Tool Consumer to the Tool Provider. An example message is included below:

ContentItemRequest: Tool Consumer -> Tool Provider

lti_message_type: ContentItemSelectionRequest
lti_version: LTI-1p0
accept_media_types: application/vnd.ims.lti.v1.ltilink
accept_presentation_document_targets: frame,window
content_item_return_url: http://lms.example/courses/5/external_content/success/external_tool_dialog

Some of the important paramaters are: accept_media_types, accept_presentation_document_targets, and content_item_return_url.

accept_media_types is a comma separated list of MIME types the Tool Consumer supports.

accept_presentation_document_targets is a comma separated list of presentation formats the Tool Consumer supports.

content_item_return_url is where the tool provider should redirect to at the end of the content-item process.

After the Tool Provider receives the ContentItemSelectionRequest message it will need to send back a ContentItemSelection message that includes the content-items they wish to send back. An example of this message is shown below:

ContentItemSelection: Tool Consumer <- Tool Provider

lti_message_type: ContentItemSelection
lti_version: LTI-1p0
content_items: {
                 "@context": "http://purl.imsglobal.org/ctx/lti/v1/ContentItem",
                 "@graph": [
                   {
                     "@type": "LtiLinkItem",
                     "@id": "http://example.com/messages/launch",
                     "url": "http://example.com/messages/launch",
                     "title": "test",
                     "text": "text",
                     "mediaType": "application/vnd.ims.lti.v1.ltilink",
                     "placementAdvice": {                       
                       "presentationDocumentTarget": "frame"
                     }
                   }
                 ]
               }

The main points of interest here is the content_items parameter. It contains a json object that includes an array of content-item objects. Inside the json object, the @graph object contains an array that holds all of the content-item objects.

The content-item object in this example is sending back a single LTI link that is to be launched in the current frame. the url specifies the lti launch point, and the mediaType specifies that it is an lti launch.

IMS Documentation