auth-context.md

Auth context

The auth context is used to load authentication data onto the MercuriusContext. The authContext promise is called within the preExecution Mercurius GraphQL request hook and when called, the returned data is assigned to MercuriusContext.auth.

• Usage with authContext
• Usage without authContext

Usage with authContext

'use strict'

const Fastify = require('fastify')
const mercurius = require('mercurius')
const mercuriusAuth = require('mercurius-auth')

const schema = `
  directive @auth(
    requires: Role = ADMIN,
  ) on OBJECT | FIELD_DEFINITION

  enum Role {
    ADMIN
    REVIEWER
    USER
    UNKNOWN
  }

  type Query {
    add(x: Int, y: Int): Int @auth(requires: USER)
  }
`

const resolvers = {
  Query: {
    add: async (_, { x, y }) => x + y
  }
}

const app = Fastify()
app.register(mercurius, {
  schema,
  resolvers
})

app.register(mercuriusAuth, {
  authContext (context) {
    return {
      identity: context.reply.request.headers['x-user']
    }
  },
  async applyPolicy (authDirectiveAST, parent, args, context, info) {
    return context.auth.identity === 'admin'
  },
  authDirective: 'auth'
})

app.listen({ port: 3000 })

Usage without authContext

Using a custom preExecution hook instead of authContext.

'use strict'

const Fastify = require('fastify')
const mercurius = require('mercurius')
const mercuriusAuth = require('mercurius-auth')

const schema = `
  directive @auth(
    requires: Role = ADMIN,
  ) on OBJECT | FIELD_DEFINITION

  enum Role {
    ADMIN
    REVIEWER
    USER
    UNKNOWN
  }

  type Query {
    add(x: Int, y: Int): Int @auth(requires: USER)
  }
`

const resolvers = {
  Query: {
    add: async (_, { x, y }) => x + y
  }
}

async function start () {
  const app = Fastify()

  app.register(mercurius, {
    schema,
    resolvers
  })

  await app.register(mercuriusAuth, {
    async applyPolicy (authDirectiveAST, parent, args, context, info) {
      return context.other.identity === 'admin'
    },
    authDirective: 'auth'
  })

  app.graphql.addHook('preExecution', async (schema, document, context) => {
    context.other = {
      identity: context.reply.request.headers['x-user']
    }
  })

  app.listen({ port: 3000 })
}

start()