@annoto/ims-lti/src/redis-nonce-store.js

Module for building an LTI Tool Provider and accept LTI launch requests

/*
 * decaffeinate suggestions:
 * DS001: Remove Babel/TypeScript constructor workaround
 * DS102: Remove unnecessary code created because of implicit returns
 * DS207: Consider shorter variations of null checks
 * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
 */
const NonceStore = require('./nonce-store');

// Five minutes
const EXPIRE_IN_SEC = 5 * 60;

class RedisNonceStore extends NonceStore {
  constructor(redisClient) {
    super();
    if (typeof redisClient === 'string' && arguments.length === 2) {
      redisClient = arguments[1];
    }
    this.redis = redisClient;
  }

  isNew(nonce, timestamp, next) {
    if (next == null) {
      next = function() {};
    }
    if (
      typeof nonce === 'undefined' ||
      nonce === null ||
      typeof nonce === 'function' ||
      typeof timestamp === 'function' ||
      typeof timestamp === 'undefined'
    ) {
      return next(new Error('Invalid parameters'), false);
    }

    if (typeof timestamp === 'undefined' || timestamp === null) {
      return next(new Error('Timestamp required'), false);
    }

    // Generate unix time in seconds
    const currentTime = Math.round(Date.now() / 1000);
    // Make sure this request is fresh (within the grace period)
    const freshTimestamp =
      currentTime - parseInt(timestamp, 10) <= EXPIRE_IN_SEC;

    if (!freshTimestamp) {
      return next(new Error('Expired timestamp'), false);
    }

    // Pass all the parameter checks, now check to see if used
    return this.redis.get(nonce, (err, seen) => {
      if (seen) {
        return next(new Error('Nonce already seen'), false);
      }
      // Dont have to wait for callback b/c it's a sync op
      this.setUsed(nonce, timestamp);
      return next(null, true);
    });
  }

  setUsed(nonce, timestamp, next) {
    if (next == null) {
      next = function() {};
    }
    this.redis.set(nonce, timestamp);
    this.redis.expire(nonce, EXPIRE_IN_SEC);
    return next(null);
  }
}

module.exports = RedisNonceStore;