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Using Deep Linking to Select Resources

Introduction

Deep Linking (formerly named Content-Item) is an extension to LTI that allows data to be passed back to the Tool Consumer (i.e., Canvas) 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 tool consumer.

  • Allowing a student to submit an attachment for an assignment that is provided by a tool provider (i.e., the external tool).

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

  • Providing a teacher the ability to select a customized LTI launch link from the tool and include grading information with it, which is used to create an assignment directly from the tool.

  • Using an external tool to create multiple pieces of content directly from, the tool, whether ungraded (like module items), or graded (like assignments), and return them to Canvas in bulk.

Deep Linking is supported in the LTI 1.1 Outcomes Service and LTI Advantage specifications. To see the full spec for content item and other code examples see these documents:

Deep Linking is not applicable to all placements in Canvas, but can be used with the following placements:

  • editor_button: Allows users that have access to the Canvas Rich Content Editor to select a variety of content types from the tool and embed them directly in the editor.

  • homework_submission: Allows students to select a resource from the external tool for assignments that are set up as File Upload submission types.

  • migration_selection: Allows users that have permission to import course content to launch to a tool to select a file (ex: a common cartridge file) from a tool and have it imported into the course.

  • assignment_selection: Allows users that have permission to create assignments to launch to a tool, select a deep link, and return it as an External Tool submission type.

  • link_selection: Allows users that have permission to create module items to launch to a tool, select a deep link, and return it as a module item.

The following placements support deep linking with LTI 1.3/Advantage tools, but not with LTI 1.1 tools:

  • course_assignments_menu: Appears in the dropdown menu in the top right of the assignments page. Allows users that have permission to create module items to launch to a tool, select one or many deep links, and return them as module items or assignments.

  • module_index_menu_modal: Appears in the dropdown menu in the top right of the modules page. Allows users that have permission to create module items to launch to a tool, select one or many deep links, and return them as module items or assignments. Adds all returned deep links to a newly created module.

This document will continue referring to this process as "Content-Item" for LTI 1.1 and Deep Linking for LTI Advantage.

LTI Advantage Deep Linking Process

LTI Advantage tools can be configured in Canvas to send an LTI launch request with a deep linking message type for certain placements. The specific details of a deep linking interaction are best presented in the IMS LTI Deep Linking specification. Instead this section will focus on tool configuration.

Supported Content Item Types

The IMS LTI Deep Linking specification defines several content items types that a tool may return to the platform via Deep linking. Canvas supports all of these content item types and their respective required properties with additional support for the optional properties listed here:

File

Full support for require properties.

Support for the following optional properties:

  • text (should be filename)

Link

Full support for required properties.

Support for the following optional properties:

  • title
  • text
  • icon
  • thumbnail
  • iframe

LTI Resource Link

Full support for required properties.

Support for the following optional properties:

  • url
  • title
  • text
  • icon
  • thumbnail
  • iframe
  • custom (allows for setting link-specific LTI launch parameters. See documentation here.)
  • lineItem
  • available
  • submission (except startDateTime)

Line Items

If a returned content item has the lineItem property, then it is used to create a new assignment, instead of a normal LTI link. The available and submission properties are also used for the assignment unlock, lock, and due dates. Note that since Canvas has no notion of a start date for submissions, it ignores the submission.startDateTime sub-property.

There are only 3 places that support assigment creation using Line Items, and each of them respond differently:

  • assignment_selection: creates an assignment using the given data and presents it to the user for further editing.

  • course_assignments_menu: creates one or many assignments from the given Line Items. If any given content items do not have the lineItem property, a new module is created and they are added to it as new module items.

  • module_index_menu_modal: creates a new module and adds all given content items to it as either module items or assignments, based on the presence or absence of the lineItem property.

Assignment Selection Deep Linking

When a tool is launched from the assignment_selection placement, any previous LTI parameters (URL, iframe width, etc.) are overwritten with the information in the Deep Linking Response. In addition, if the following properties are present and non-empty in the content item in the Deep Linking Response, they will set the following fields, potentially overwriting user-inputted values:

  • text sets/overwrites the assignment description
  • lineItem.scoreMaximum sets/overwrites the maximum score for the assignment
  • lineItem.label or title sets the assignment name, and overwrites unless "https://canvas.instructure.com/lti/preserveExistingAssignmentName": true is given in the content item.

HTML fragment

Full support for required properties.

Full support for all optional properties.

Image

Full support for required properties.

Support for the following optional properties:

  • title
  • text
  • thumbnail
  • width
  • height

Configuring Deep Linking

Deep linking is configured by creating a Canvas LTI Developer Key with a LtiDeepLinkingRequest message type set on a supported placement. This can be done via the UI, or by supplying Canvas with JSON.

For example, the following JSON would allow an LTI Advantage tool to be installed that uses deep linking return items back to Canvas as an assignment or within the canvas Rich Content Editor:

{
   "title":"Cool Deep Linking Tool ",
   "scopes":[],
   "extensions":[
      {
         "domain":"deeplinkexample.com",
         "tool_id":"deep-linky",
         "platform":"canvas.instructure.com",
         "settings":{
            "text":"Cool Deep Linking Text",
            "icon_url":"https://some.icon.url",
            "placements":[
               {
                  "text":"Embed Tool Content in Canvas RCE",
                  "enabled":true,
                  "icon_url":"https://some.icon.url",
                  "placement":"editor_button",
                  "message_type":"LtiDeepLinkingRequest",
                  "target_link_uri":"https://your.target_link_uri/deeplinkexample"
               },
               {
                  "text":"Embed Tool Content as a Canvas Assignment",
                  "enabled":true,
                  "icon_url":"https://some.icon.url",
                  "placement":"assignment_selection",
                  "message_type":"LtiDeepLinkingRequest",
                  "target_link_uri":"https://your.target_link_uri/deeplinkexample"
               }
            ]
         }
      }
   ],
   "public_jwk":{
      "kty":"RSA",
      "alg":"RS256",
      "e":"AQAB",
      "kid":"8f796169-0ac4-48a3-a202-fa4f3d814fcd",
      "n":"nZD7QWmIwj-3N_RZ1qJjX6CdibU87y2l02yMay4KunambalP9g0fU9yZLwLX9WYJINcXZDUf6QeZ-SSbblET-h8Q4OvfSQ7iuu0WqcvBGy8M0qoZ7I-NiChw8dyybMJHgpiP_AyxpCQnp3bQ6829kb3fopbb4cAkOilwVRBYPhRLboXma0cwcllJHPLvMp1oGa7Ad8osmmJhXhM9qdFFASg_OCQdPnYVzp8gOFeOGwlXfSFEgt5vgeU25E-ycUOREcnP7BnMUk7wpwYqlE537LWGOV5z_1Dqcqc9LmN-z4HmNV7b23QZW4_mzKIOY4IqjmnUGgLU9ycFj5YGDCts7Q",
      "use":"sig"
   },
   "description":"1.3 Test Tool",
   "target_link_uri":"https://your.target_link_uri",
   "oidc_initiation_url":"https://your.oidc_initiation_url"
}

Once the developer key is configured, it can then be used to install the LTI tool. Links will then be exposed in the Canvas Rich Content Editor toolbar and Assignment edit view. Clicking the links will then initiate a deep linking LTI workflow to allow the user to select a resource from the tool and have them embedded in Canvas.

LTI 1.1 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 parameters 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.

Configuring Content-item

To use content-item, the tool provider must be configured correctly. The following is an overview of how to configure the tool provider to use content-item.

LTI Tool XML Configuration

Below is an example of a bare-bones tool provider LTI configuration that does not use content-item:

    <?xml version="1.0" encoding="UTF-8"?><cartridge_basiclti_link xmlns="http://www.imsglobal.org/xsd/imslticc_v1p0" xmlns:blti="http://www.imsglobal.org/xsd/imsbasiclti_v1p0" xmlns:lticm="http://www.imsglobal.org/xsd/imslticm_v1p0" xmlns:lticp="http://www.imsglobal.org/xsd/imslticp_v1p0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.imsglobal.org/xsd/imslticc_v1p0 http://www.imsglobal.org/xsd/lti/ltiv1p0/imslticc_v1p0.xsd http://www.imsglobal.org/xsd/imsbasiclti_v1p0 http://www.imsglobal.org/xsd/lti/ltiv1p0/imsbasiclti_v1p0p1.xsd http://www.imsglobal.org/xsd/imslticm_v1p0 http://www.imsglobal.org/xsd/lti/ltiv1p0/imslticm_v1p0.xsd http://www.imsglobal.org/xsd/imslticp_v1p0 http://www.imsglobal.org/xsd/lti/ltiv1p0/imslticp_v1p0.xsd">
      <blti:title>Example Tool Provider</blti:title>
      <blti:description>This is a Sample Tool Provider.</blti:description>
      <blti:launch_url>http://localhost:4040/messages/blti</blti:launch_url>
      <blti:extensions platform="canvas.instructure.com">
        <lticm:property name="selection_height">500</lticm:property>
        <lticm:property name="selection_width">500</lticm:property>
      </blti:extensions>
    </cartridge_basiclti_link>

Note: for more on the basics of LTI tool configuration see external tools documentation.

To begin using content-item we need to specify at least one valid placement for Canvas to use. Placements are used to help the tool consumer (Canvas in this case) know where the tool should be placed within the LMS. For example, adding the following node as a child of the blti:extensions element in the above XML would tell Canvas to add a link in the course navigation to the LTI tool:

    <lticm:options name="course_navigation">
      <lticm:property name="url">http://localhost:4040/messages/blti</lticm:property>
    </lticm:options>

For our example we will use assignment_selection.

To enable content-item with the assignment_selection placement, we add lines 6-9 to the example from above:

     1 <?xml version="1.0" encoding="UTF-8"?><cartridge_basiclti_link xmlns="http://www.imsglobal.org/xsd/imslticc_v1p0" xmlns:blti="http://www.imsglobal.org/xsd/imsbasiclti_v1p0" xmlns:lticm="http://www.imsglobal.org/xsd/imslticm_v1p0" xmlns:lticp="http://www.imsglobal.org/xsd/imslticp_v1p0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.imsglobal.org/xsd/imslticc_v1p0 http://www.imsglobal.org/xsd/lti/ltiv1p0/imslticc_v1p0.xsd http://www.imsglobal.org/xsd/imsbasiclti_v1p0 http://www.imsglobal.org/xsd/lti/ltiv1p0/imsbasiclti_v1p0p1.xsd http://www.imsglobal.org/xsd/imslticm_v1p0 http://www.imsglobal.org/xsd/lti/ltiv1p0/imslticm_v1p0.xsd http://www.imsglobal.org/xsd/imslticp_v1p0 http://www.imsglobal.org/xsd/lti/ltiv1p0/imslticp_v1p0.xsd">
     2   <blti:title>Example Tool Provider</blti:title>
     3   <blti:description>This is a Sample Tool Provider.</blti:description>
     4   <blti:launch_url>http://localhost:4040/messages/blti</blti:launch_url>
     5   <blti:extensions platform="canvas.instructure.com">
     6     <lticm:options name="assignment_selection">
     7       <lticm:property name="message_type">ContentItemSelectionRequest</lticm:property>
     8       <lticm:property name="url">http://localhost:4040/messages/blti</lticm:property>
     9     </lticm:options>
    10     <lticm:property name="icon_url">http://localhost:4040/selector.png</lticm:property>
    11     <lticm:property name="selection_height">500</lticm:property>
    12     <lticm:property name="selection_width">500</lticm:property>
    13   </blti:extensions>
    14 </cartridge_basiclti_link>

Adding the element on line 6 lets Canvas know the tool should be placed in the assignments menu. Line 7 tells Canvas the tool is using content-item, and line 8 provides Canvas the launch URL.