Fastify

Talon Auth integrates with Fastify as a preHandler hook. Decorate the request with the verified user so it's available in all downstream route handlers.

Setup

Install the packages:

npm install fastify talon-auth

Create a verifier with your app ID from the Talon dashboard:

import { createVerifier } from 'talon-auth'

const verifier = createVerifier({ appId: '[your-app-id]' })

Auth preHandler

Extend Fastify's FastifyRequest interface to add a user property, then use fastify.decorateRequest to initialise it. The authenticate function verifies the token and populates request.user, or replies with 401 on failure:

declare module 'fastify' {
  interface FastifyRequest {
    user: { email: string }
  }
}

fastify.decorateRequest('user', null)

async function authenticate(request: FastifyRequest, reply: FastifyReply) {
  try {
    const { user } = await verifier.verifyHeader(request.headers.authorization!)
    request.user = user!
  } catch {
    reply.status(401).send({ error: 'Unauthorized' })
  }
}

Pass it to any route via the preHandler option:

fastify.get('/message', { preHandler: authenticate }, async (request) => {
  return { message: `Hello ${request.user.email}!` }
})

Example

The example below serves an HTML page that loads the <talon-login> web component, authenticates the user in the browser, then calls a /message endpoint that verifies the JWT via the authenticate preHandler and returns a personalized greeting.