Combine createLocalJWKSet and createRemoteJWKSet

[mbrevda]

What do you think of a function that takes the options of both functions, uses the local keys if there are any that match, and only reaches out for remote JWKs if there is no match? I.e. remote becomes a fallback for local

[panva]

I think that's something you should be easily able to achieve in your own code.

import * as jose from "jose";

const local = jose.createLocalJWKSet({ keys: [] });
const remote = jose.createRemoteJWKSet(new URL(""));

const combined: jose.JWTVerifyGetKey = async (...args) => {
  try {
    return await local(...args);
  } catch {
    return await remote(...args);
  }
};

[mbrevda]

oh, local will throw if it doesn't find any JWKs? Cool, I'll try that

[panva]

Would you expect any other behaviour?!

[mbrevda]

Yeah, duh. Thanks! Here's what I ended up with, might be worth including this in a future release:

function loadJWKSet(
  keys: Parameters<typeof createLocalJWKSet>[0]['keys'],
  url: Parameters<typeof createRemoteJWKSet>[0],
  options?: Parameters<typeof createRemoteJWKSet>[1],
): JWTVerifyGetKey {
  const localJWKSet = createLocalJWKSet({keys});
  const remoteJWKSet = createRemoteJWKSet(url, options);

  return async (...args): Promise<CryptoKey> => {
    try {
      return await localJWKSet(...args);
    } catch (err) {
      if (err instanceof JWKSNoMatchingKey) return await remoteJWKSet(...args);
      throw err;
    }
  };
}