Grade Passback Tools

Graded external tools are configured just like regular external tools. The difference is that rather than adding the tool to a course as a link in a module, a navigation item, etc. the tool gets added as an assignment. Instructors will see a new assignment type called "External Tool" where they can select a tool configuration to use for the assignment. When students go to view the assignment instead of seeing a standard Canvas description they'll see the tool loaded in an iframe on the page. The tool can then send grading information back to Canvas.

Tools can know that they have been launched in a graded context because an additional parameter is sent across, lisoutcomeserviceurl, as specified in the LTI 1.1 specification. Grades are passed back to Canvas from the tool's servers using the <a href="http://www.imsglobal.org/lti/v1p1pd/ltiIMGv1p1pd.html#Toc309649691">outcomes component of LTI 1.1.

Data Return Extension

Canvas sends an extension parameter for assignment launches that allows the tool provider to pass back values as submission text in canvas. The key is ext_outcome_data_values_accepted and the value is a comma separated list of types of data accepted. The currently available data types are url and text. So the added launch parameter will look like this:

ext_outcome_data_values_accepted=url,text

Returning Data Values from Tool Provider

If the external tool wants to supply these values, it can augment the POX sent with the grading value. LTI replaceResult POX

Only one type of resultData should be sent, if multiple types are sent the tool consumer behavior is undefined and is implementation-specific. Canvas will take the text value and ignore the url value if both are sent.

Text

Add a resultData node with a text node of plain text in the same encoding as the rest of the document within it like this:

<?xml version = "1.0" encoding = "UTF-8"?>
<imsx_POXEnvelopeRequest xmlns="http://www.imsglobal.org/services/ltiv1p1/xsd/imsoms_v1p0">
  <imsx_POXHeader>
    <imsx_POXRequestHeaderInfo>
      <imsx_version>V1.0</imsx_version>
      <imsx_messageIdentifier>999999123</imsx_messageIdentifier>
    </imsx_POXRequestHeaderInfo>
  </imsx_POXHeader>
  <imsx_POXBody>
    <replaceResultRequest>
      <resultRecord>
        <sourcedGUID>
          <sourcedId>3124567</sourcedId>
        </sourcedGUID>
        <result>
          <resultScore>
            <language>en</language>
            <textString>0.92</textString>
          </resultScore>
          <!-- Added element -->
          <resultData>
            <text>text data for canvas submission</text>
          </resultData>
        </result>
      </resultRecord>
    </replaceResultRequest>
  </imsx_POXBody>
</imsx_POXEnvelopeRequest>

URL

Add a resultData node with a url node within it like this:

<?xml version = "1.0" encoding = "UTF-8"?>
<imsx_POXEnvelopeRequest xmlns="http://www.imsglobal.org/services/ltiv1p1/xsd/imsoms_v1p0">
  <imsx_POXHeader>
    <imsx_POXRequestHeaderInfo>
      <imsx_version>V1.0</imsx_version>
      <imsx_messageIdentifier>999999123</imsx_messageIdentifier>
    </imsx_POXRequestHeaderInfo>
  </imsx_POXHeader>
  <imsx_POXBody>
    <replaceResultRequest>
      <resultRecord>
        <sourcedGUID>
          <sourcedId>3124567</sourcedId>
        </sourcedGUID>
        <result>
          <resultScore>
            <language>en</language>
            <textString>0.92</textString>
          </resultScore>
          <!-- Added element -->
          <resultData>
            <url>https://www.example.com/cool_lti_link_submission</url>
          </resultData>
        </result>
      </resultRecord>
    </replaceResultRequest>
  </imsx_POXBody>
</imsx_POXEnvelopeRequest>