jwks-client/lib/wrappers/cache.js

Library to retrieve public keys from a JWKS endpoint

import ms from 'ms';
import memoizer from 'lru-memoizer';
import debug from 'debug';

export default function(client, { cacheMaxEntries = 5, cacheMaxAge = '10h' }) {
  const logger = debug('jwks');
  const getSigningKey = client.getSigningKey;
  let cacheAge = 3600000;

  if (typeof cacheMaxAge === 'string' || cacheMaxAge instanceof String) {
    cacheAge = ms(cacheMaxAge);
  }

  logger(`Configured caching of signing keys. Max: ${cacheMaxEntries} / Age: ${cacheAge}`);
  return memoizer({
    load: (kid, callback) => {
      getSigningKey(kid, (err, key) => {
        if (err) {
          return callback(err);
        }

        logger(`Caching signing key for '${kid}':`, key);
        return callback(null, key);
      });
    },
    hash: (kid) => kid,
    maxAge: cacheAge,
    max: cacheMaxEntries
  });
}