Fastify JWT Authz

Created by Ethan Arrowood

fastifyJWTAuthz is a fastify plugin for verifying an authenticated request.user scope. Registering the plugin binds the jwtAuthz method to the fastify request instance. See the demo below on how to use the plugin.

const fastify = require('fastify')()
const jwt = require('fastify-jwt')
const jwtAuthz = require('fastify-jwt-authz')

fastify.register(jwt, {
  secret: 'superSecretCode'
})
fastify.register(jwtAuthz)

fastify.get('/api', {
  beforeHandler: [
    function(request, reply, done) {
      request.jwtVerify(done)
      /* The user's JWT auth token is
       * connected to the request object 
       * under `headers.authentication`.
       * 
       * The jwtVerify method will verify 
       * the JWT token with the secret.
       * 
       * If it verifies, the user object is 
       * populated onto the request object 
       * which is passed to the next function.
       * */
    }, 
    function(request, reply, done) {
      request.jwtAuthz(['read:data', 'write:data'], done)
      /* jwtAuthz will read the verified user's
       * scope off of the request object. It will 
       * then compare the scopes defined above to
       * the user's scopes aquired by the JWT verification
       * method.
       * */
    },
  ],
}, (request, reply) => {
  fastify.log.info('reached API endpoint')
  reply.send({ userVerified: true })
})

jwtAuthz takes a list of scopes for verification. Additionally, it takes an optional callback parameter. It returns a promise otherwise.