ltijs/dist/Provider/Services/DeepLinking.js

Easily turn your web application into a LTI 1.3 Learning Tool.

"use strict";

function _classPrivateFieldInitSpec(e, t, a) { _checkPrivateRedeclaration(e, t), t.set(e, a); }
function _checkPrivateRedeclaration(e, t) { if (t.has(e)) throw new TypeError("Cannot initialize the same private elements twice on an object"); }
function _classPrivateFieldGet(s, a) { return s.get(_assertClassBrand(s, a)); }
function _classPrivateFieldSet(s, a, r) { return s.set(_assertClassBrand(s, a), r), r; }
function _assertClassBrand(e, t, n) { if ("function" == typeof e ? e === t : e.has(t)) return arguments.length < 3 ? t : n; throw new TypeError("Private element is not present on this object"); }
/* Provider Deep Linking Service */

const jwt = require('jsonwebtoken');
const provDeepLinkingDebug = require('debug')('provider:deepLinkingService');
const path = require('path');
const {
  sprightly
} = require('sprightly');
const deepLinkSubmissionForm = path.join(__dirname, '../../Templates', 'DeepLinkSubmissionForm.html');
var _getPlatform = /*#__PURE__*/new WeakMap();
var _ENCRYPTIONKEY = /*#__PURE__*/new WeakMap();
var _Database = /*#__PURE__*/new WeakMap();
class DeepLinking {
  constructor(getPlatform, ENCRYPTIONKEY, Database) {
    _classPrivateFieldInitSpec(this, _getPlatform, null);
    _classPrivateFieldInitSpec(this, _ENCRYPTIONKEY, '');
    _classPrivateFieldInitSpec(this, _Database, void 0);
    _classPrivateFieldSet(_getPlatform, this, getPlatform);
    _classPrivateFieldSet(_ENCRYPTIONKEY, this, ENCRYPTIONKEY);
    _classPrivateFieldSet(_Database, this, Database);
  }

  /**
   * @description Creates an auto submitting form containing the DeepLinking Message.
   * @param {Object} idtoken - Idtoken for the user.
   * @param {Array} contentItems - Array of contentItems to be linked.
   * @param {Object} options - Object containing extra options that mus be sent along the content items.
   * @param {String} options.message - Message the platform may show to the end user upon return to the platform.
   * @param {String} options.errMessage - Message the platform may show to the end user upon return to the platform if some error has occurred.
   * @param {String} options.log - Message the platform may log in it's system upon return to the platform.
   * @param {String} options.errLog - Message the platform may log in it's system upon return to the platform if some error has occurred.
   */
  async createDeepLinkingForm(idtoken, contentItems, options) {
    const message = await this.createDeepLinkingMessage(idtoken, contentItems, options);

    // Creating auto submitting form
    const form = sprightly(deepLinkSubmissionForm, {
      action: idtoken.platformContext.deepLinkingSettings.deep_link_return_url,
      message
    });
    return form;
  }

  /**
   * @description Creates a DeepLinking signed message.
   * @param {Object} idtoken - Idtoken for the user.
   * @param {Array} contentItems - Array of contentItems to be linked.
   * @param {Object} options - Object containing extra options that mus be sent along the content items.
   * @param {String} options.message - Message the platform may show to the end user upon return to the platform.
   * @param {String} options.errMessage - Message the platform may show to the end user upon return to the platform if some error has occurred.
   * @param {String} options.log - Message the platform may log in it's system upon return to the platform.
   * @param {String} options.errLog - Message the platform may log in it's system upon return to the platform if some error has occurred.
   */
  async createDeepLinkingMessage(idtoken, contentItems, options) {
    provDeepLinkingDebug('Starting deep linking process');
    if (!idtoken) {
      provDeepLinkingDebug('Missing IdToken object.');
      throw new Error('MISSING_ID_TOKEN');
    }
    if (!idtoken.platformContext.deepLinkingSettings) {
      provDeepLinkingDebug('DeepLinkingSettings object missing.');
      throw new Error('MISSING_DEEP_LINK_SETTINGS');
    }
    if (!contentItems) {
      provDeepLinkingDebug('No content item passed.');
      throw new Error('MISSING_CONTENT_ITEMS');
    }

    // If it's not an array, turns it into an array
    if (!Array.isArray(contentItems)) contentItems = [contentItems];

    // Gets platform
    const platform = await _classPrivateFieldGet(_getPlatform, this).call(this, idtoken.iss, idtoken.clientId, _classPrivateFieldGet(_ENCRYPTIONKEY, this), _classPrivateFieldGet(_Database, this));
    if (!platform) {
      provDeepLinkingDebug('Platform not found');
      throw new Error('PLATFORM_NOT_FOUND');
    }
    const platformActive = await platform.platformActive();
    if (!platformActive) throw new Error('PLATFORM_NOT_ACTIVATED');
    provDeepLinkingDebug('Building basic JWT body');
    // Builds basic jwt body
    const jwtBody = {
      iss: await platform.platformClientId(),
      aud: idtoken.iss,
      nonce: encodeURIComponent([...Array(25)].map(_ => (Math.random() * 36 | 0).toString(36)).join``),
      'https://purl.imsglobal.org/spec/lti/claim/deployment_id': idtoken.deploymentId,
      'https://purl.imsglobal.org/spec/lti/claim/message_type': 'LtiDeepLinkingResponse',
      'https://purl.imsglobal.org/spec/lti/claim/version': '1.3.0'
    };

    // Adding messaging options
    if (options) {
      if (options.message) jwtBody['https://purl.imsglobal.org/spec/lti-dl/claim/msg'] = options.message;
      if (options.errMessage || options.errmessage) jwtBody['https://purl.imsglobal.org/spec/lti-dl/claim/errormsg '] = options.errMessage || options.errmessage;
      if (options.log) jwtBody['https://purl.imsglobal.org/spec/lti-dl/claim/log'] = options.log;
      if (options.errLog || options.errlog) jwtBody['https://purl.imsglobal.org/spec/lti-dl/claim/errorlog'] = options.errLog || options.errlog;
    }

    // Adding Data claim if it exists in initial request
    if (idtoken.platformContext.deepLinkingSettings.data) jwtBody['https://purl.imsglobal.org/spec/lti-dl/claim/data'] = idtoken.platformContext.deepLinkingSettings.data;
    provDeepLinkingDebug('Sanitizing content item array based on the platform\'s requirements:');
    const selectedContentItems = [];
    const acceptedTypes = idtoken.platformContext.deepLinkingSettings.accept_types;
    const acceptMultiple = !(idtoken.platformContext.deepLinkingSettings.accept_multiple === 'false' || idtoken.platformContext.deepLinkingSettings.accept_multiple === false);
    provDeepLinkingDebug('Accepted Types: ' + acceptedTypes);
    provDeepLinkingDebug('Accepts Mutiple: ' + acceptMultiple);
    provDeepLinkingDebug('Received content items: ');
    provDeepLinkingDebug(contentItems);
    for (const contentItem of contentItems) {
      if (!acceptedTypes.includes(contentItem.type)) continue;
      selectedContentItems.push(contentItem);
      if (!acceptMultiple) break;
    }
    provDeepLinkingDebug('Content items to be sent: ');
    provDeepLinkingDebug(selectedContentItems);
    jwtBody['https://purl.imsglobal.org/spec/lti-dl/claim/content_items'] = selectedContentItems;
    const message = jwt.sign(jwtBody, await platform.platformPrivateKey(), {
      algorithm: 'RS256',
      expiresIn: 60,
      keyid: await platform.platformKid()
    });
    return message;
  }
}
module.exports = DeepLinking;