@fastify/bearer-auth

@fastify/bearer-auth provides a simple Bearer auth request hook for the Fastify web framework.

Install

npm i @fastify/bearer-auth

Compatibility

Plugin version	Fastify version
^10.x	^5.x
^8.x	^4.x
^5.x	^3.x
^4.x	^2.x
^1.x	^1.x

Please note that if a Fastify version is out of support, then so are the corresponding versions of this plugin in the table above. See Fastify's LTS policy for more details.

Example

'use strict'

const fastify = require('fastify')()
const bearerAuthPlugin = require('@fastify/bearer-auth')
const keys = new Set(['a-super-secret-key', 'another-super-secret-key'])

fastify.register(bearerAuthPlugin, {keys})
fastify.get('/foo', (req, reply) => {
  reply.send({authenticated: true})
})

fastify.listen({port: 8000}, (err) => {
  if (err) {
    fastify.log.error(err.message)
    process.exit(1)
  }
  fastify.log.info('http://127.0.0.1:8000/foo')
})

API

@fastify/bearer-auth exports a standard Fastify plugin. This allows registering the plugin within scoped paths, so some paths can be protected by the plugin while others are not. See the Fastify documentation and examples for more details.

When registering the plugin a configuration object must be specified:

• keys: A Set or array with valid keys of type string (required)
• function errorResponse (err) {}: Method must synchronously return the content body to be sent to the client (optional)
• contentType: If the content to be sent is anything other than application/json, then the contentType property must be set (optional)
• bearerType: String specifying the Bearer string (optional)
• specCompliance: Plugin spec compliance. Accepts either rfc6749 or rfc6750. Defaults to rfc6750.
  • rfc6749 is about the generic OAuth2.0 protocol, which allows the token type to be case-insensitive
  • rfc6750 is about the Bearer Token Usage, which forces the token type to be an exact match
• function auth (key, req) {} : This function tests if key is a valid token. It must return true if accepted or false if rejected. The function may also return a promise that resolves to one of these values. If the function returns or resolves to any other value, rejects, or throws, an HTTP status of 500 will be sent. req is the Fastify request object. If auth is a function, keys will be ignored. If auth is not a function or undefined, keys will be used
• addHook: If false, this plugin will not register onRequest hook automatically. Instead it provides two decorations: fastify.verifyBearerAuth and fastify.verifyBearerAuthFactory
• verifyErrorLogLevel: An optional string specifying the log level for verification errors. It must be a valid log level supported by Fastify, or an exception will be thrown when registering the plugin. By default, this option is set to error

The default configuration object is:

{
  keys: new Set(),
  contentType: undefined,
  bearerType: 'Bearer',
  specCompliance: 'rfc6750',
  errorResponse: (err) => {
    return {error: err.message}
  },
  auth: undefined,
  addHook: true
}

The plugin registers a standard Fastify preHandler hook to inspect the request's headers for an authorization header in the format bearer key. The key is matched against the configured keys object using a constant time algorithm to prevent timing-attacks. If the authorization header is missing, malformed, or the key does not validate, a 401 response is sent with a {error: message} body, and no further request processing is performed.

Integration with @fastify/auth

This plugin can integrate with @fastify/auth by following this example:

const fastify = require('fastify')()
const auth = require('@fastify/auth')
const bearerAuthPlugin = require('@fastify/bearer-auth')
const keys = new Set(['a-super-secret-key', 'another-super-secret-key'])

async function server() {

  await fastify
    .register(auth)
    .register(bearerAuthPlugin, { addHook: false, keys, verifyErrorLogLevel: 'debug' })
    .decorate('allowAnonymous', function (req, reply, done) {
      if (req.headers.authorization) {
        return done(Error('not anonymous'))
      }
      return done()
    })

  fastify.route({
    method: 'GET',
    url: '/multiauth',
    preHandler: fastify.auth([
      fastify.allowAnonymous,
      fastify.verifyBearerAuth
    ]),
    handler: function (_, reply) {
      reply.send({ hello: 'world' })
    }
  })

  await fastify.listen({port: 8000})
}

server()

Passing { addHook: false } in the options causes the verifyBearerAuth hook to invoke done(someError) instead of immediately replying on error (reply.send(someError)). This allows fastify.auth to continue with the next authentication scheme in the hook list. Setting { verifyErrorLogLevel: 'debug' } in the options makes @fastify/bearer-auth emit all verification error logs at the debug level. If verifyBearerAuth is the last hook in the list, fastify.auth will reply with Unauthorized.

License

Licensed under MIT.