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How to get id user from encrypted user in idToken

See original GitHub issue

Describe the bug I’m trying to retrieve id user from token of lti.onConnect function. However, the token only returns the user with an encrypted value.

lti.onConnect((token, req, res) => {
	logger.debug(res.locals.token);
	if (token) {
		return res.sendFile(path.join(__dirname, '../../public'));
	} else {
		lti.redirect(res, '/nolti');
	} // Redirects to landing page
});

Response

{
  iss: 'https://test.domain.com',
  user: 'e26c4380-4d3c-45b9-94d6-b933322dd38a',
  platformInfo: {
    guid: 'OJwJhR6cNZVC9aiyUh8DLT9onnyVif2hOWpa5490:canvas-lms',
    name: 'Root account',
    version: 'cloud',
    product_family_code: 'canvas',
    validation_context: null
  },
  clientId: '10000000000015',
  platformId: '7bbe71fdde1a2b80db7d76ebb068e4ad',
  deploymentId: '63:89359961b094933bbad8477d368c335b99f84b79',
  createdAt: '2020-12-30T03:06:52.073Z',
  platformContext: {
    roles: [
      'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Administrator',
      'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Instructor',
      'http://purl.imsglobal.org/vocab/lis/v2/membership#Instructor',
      'http://purl.imsglobal.org/vocab/lis/v2/system/person#SysAdmin',
      'http://purl.imsglobal.org/vocab/lis/v2/system/person#User',
      [length]: 5
    ],
    contextId: 'https%3A%2F%2Ftest.domain.com1000000000001563%3A89359961b094933bbad8477d368c335b99f84b7989359961b094933bbad8477d368c335b99f84b79_89359961b094933bbad8477d368c335b99f84b79',
    path: '/',
    user: 'e26c4380-4d3c-45b9-94d6-b933322dd38a',
    targetLinkUri: 'http://localhost:3005',
    context: {
      id: '89359961b094933bbad8477d368c335b99f84b79',
      label: 'English',
      title: 'English',
      type: [
        'http://purl.imsglobal.org/vocab/lis/v2/course#CourseOffering',
        [length]: 1
      ],
      validation_context: null
    },
    resource: {
      id: '89359961b094933bbad8477d368c335b99f84b79',
      description: null,
      title: null,
      validation_context: null
    },
    launchPresentation: {
      document_target: 'iframe',
      height: null,
      width: null,
      return_url: 'https://test.domain.com/courses/31/modules',
      locale: 'en',
      validation_context: null
    },
    messageType: 'LtiResourceLinkRequest',
    version: '1.3.0',
    endpoint: {
      scope: [
        'https://purl.imsglobal.org/spec/lti-ags/scope/lineitem',
        'https://purl.imsglobal.org/spec/lti-ags/scope/lineitem.readonly',
        'https://purl.imsglobal.org/spec/lti-ags/scope/result.readonly',
        'https://purl.imsglobal.org/spec/lti-ags/scope/score',
        [length]: 4
      ],
      lineitems: 'https://test.domain.com/api/lti/courses/31/line_items',
      validation_context: null
    },
    namesRoles: {
      context_memberships_url: 'https://test.domain.com/api/lti/courses/31/names_and_roles',
      service_versions: [ '2.0', [length]: 1 ],
      validation_context: null
    },
    createdAt: '2020-12-30T03:06:52.081Z'
  }
}

Expected behavior The expected response will be look like the provided response in the documentation in idToken

{
  "iss": "http://localhost/moodle",
  "clientId": "CLIENTID",
  "deploymentId": "1",
  "platformId": "60b1fce753c875193d71b611e895f03d"
  "platformInfo": {
    "product_family_code": "moodle",
    "version": "2020042400",
    "guid": "localhost",
    "name": "moodle",
    "description": "Local Moodle"
  },
  "user": "2", // this is what i need
  "userInfo": {
    "given_name": "Admin",
    "family_name": "User",
    "name": "Admin User",
    "email": "local@moodle.com"
  }
}

Ltijs version

Version 1.3 (maybe…) i got this information form package.json file NodeJS version

Version 12.19.0 - containerized in Docker with image node:12.19.0-alpine Platform used

Canvas

Issue Analytics

State:
Created 3 years ago
Comments:7 (4 by maintainers)

Top GitHub Comments

2reactions

ntngoc96commented, Dec 31, 2020

Hi @Cvmcosta thanks for your help. I found the solution base on your idea.

Go to developer key -> Edit the key -> Additional Setting -> Custom Fields -> Then add the variables we want to get in platformContext of Ltijs token ( Get variables references via this link: https://github.com/instructure/canvas-lms/blob/master/doc/api/tools_variable_substitutions.md )
After setup developer key , we can found the custom variables on res.locals.token

{
  iss: https://test.domain.com,
  ...,
  platformContext: {
    roles: [
      'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Administrator',
      'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Instructor',
      [length]: 5
    ],
    contextId: 'https%3A%2F%2Ftest.domain.com1000000000001563%3A89359961b094933bbad8477d368c335b99f84b7989359961b094933bbad8477d368c335b99f84b79_89359961b094933bbad8477d368c335b99f84b79',
    path: '/',
    user: 'e26c4380-4d3c-45b9-94d6-b933322dd38a',
    custom: {  // <-------------- Our variables will appear here
        userid: 'value of user id',
        courseid: 'value of course id',
    },
    targetLinkUri: 'http://localhost:3005',
    context: {
      id: '89359961b094933bbad8477d368c335b99f84b79',
      label: 'English',
      title: 'English',
      type: [
        'http://purl.imsglobal.org/vocab/lis/v2/course#CourseOffering',
        [length]: 1
      ],
      validation_context: null
    },
...,
}

1reaction

Cvmcostacommented, Dec 31, 2020

Great! Happy to help!