fastify-guard

A simple user role and scope check plugin to protect endpoints for Fastify.

fastify-guard is designed to protect API endpoints by checking authenticated user roles and/or scopes if they met. guard is the registered Fastify decorator and can be used in anywhere.

Inspired by express-jwt-permissions.

Install

$ npm install fastify-guard

Compatibility

Usage

const fastify = require('fastify')()
const fastifyGuard = require('fastify-guard')
fastify.register(
  fastifyGuard,
  {
    errorHandler: (result, req, reply) => {
      return reply.send('you are not allowed to call this route')
    }
  }
)
// this route can only be called by users who has 'cto' and 'admin' roles
fastify.get(
  '/admin',
  { preHandler: [fastify.guard.role(['cto', 'admin'])] },
  (req, reply) => {
    // 'user' should already be defined in req object
    reply.send(req.user)
  }
)
// this route can only be called by users who has 'admin' or 'editor' role
fastify.get(
  '/',
  { preHandler: [fastify.guard.role('admin', 'editor')] },
  (req, reply) => {
    // 'user' should already be defined in req object
    reply.send(req.user)
  }
)
/*
http://localhost:3000 -> will print out below result if the authenticated user does not have 'admin' role
you are not allowed to call this route
*/
fastify.get(
  '/has-role',
  (req, reply) => {
    // 'user' should already be defined in req object
    reply.send(
      fastify.guard.hasRole(req, 'admin') // will return a boolean value
    )
  }
)
fastify.get(
  '/has-scope',
  (req, reply) => {
    // 'user' should already be defined in req object
    reply.send(
      fastify.guard.hasScope(req, 'profile') // will return a boolean value
    )
  }
)
fastify.listen(3000, () => {
  console.log('Fastify server is running on port: 3000')
})
/*
http://localhost:3000 -> will print out below result if the authenticated user does not have 'admin' role
you are not allowed to call this route
*/

Options

API

guard.role(role)

Returns a function which checks if the authenticated user has the given role(s). Multiple roles can be sent as separated parameters or in an array. If the given role(s) was not assigned to the authenticated user, the function will throw an HTTP Error (if no errorHandler provided in options otherwise the errorHandler will be invoked). The function supposed to be used in preHandler hook.

guard.hasRole(request, role)

Returns a boolean value which indicates the authenticated user has the given role.

request is the Fastify request object

role is role name

guard.scope(scope)

Returns a function which checks if the authenticated user has the given scope(s). Multiple scopes can be sent as separated parameters or in an array. If the given scope(s) was not assigned to the authenticated user, the function will throw an HTTP Error (if no errorHandler provided in options otherwise the errorHandler will be invoked). The function supposed to be used in preHandler hook.

guard.hasScope(request, scope)

Returns a boolean value which indicates the authenticated user has the given scope.

request is the Fastify request object

scope is scope name