Description

Closes: #358

This PR fixes an issue causing fast-jwt verifier to be recreated on every request, which means the fast-jwt cache was not being used. By caching the fast-jwt verifier based on the options passed in, an existing verifier instance can be reused to verify incoming request JWTs instead of having to recreate a new verifier, and then the fast-jwt cache can be utilized (if enabled).

Benchmarks

Tested using a simple fastify server with autocannon used to create load

No auth: 77,978 req/s

Changes (no cache): 53,008 req/s
Changes (cache): 60,880 req/s

Main (no cache): 46,302 req/s
Main (cache): 34,669.1 req/s

Very odd behaviour on current main where enabling cache has a performance impact, I believe this is caused by fast-jwt having to recreate cache on every request.

Config used:

fastify.register(require('@fastify/jwt'), {
  secret: 'supersecret',
  decode: { complete: true },
  verify: {
     cache: true, // disabled for "no cache" tests
  },
})

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct