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Speakeasy

Speakeasy is authentication agnostic middleware based authorization for Absinthe GraphQL powered by Bodyguard.

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Installation

Speakeasy can be installed by adding speakeasy to your list of dependencies in mix.exs:

def deps do
  [
    {:speakeasy, "~> 0.3"}
  ]
end

Configuration

Configuration can be done in each Absinthe middleware call, but you can set global defaults as well.

config :speakeasy,
  user_key: :current_user,                # the key the current user will be under in the GraphQL context
  authn_error_message: :unauthenticated  # default authentication failure message

Note: no authz_error_message is provided because it is set from Bodyguard.

Usage

tl;dr: A full example authentication, authorizing, loading, and resolving an Absinthe schema:

This example assumes:

• You are authorizing a standard phoenix context
• You already have a bodyguard policy
• Your :current_user is already in the Absinthe context or you are using Speakeasy.Plug

defmodule MyApp.Schema.PostTypes do
  use Absinthe.Schema.Notation
  alias Spectra.Posts

  object :post do
    field(:id, non_null(:id))
    field(:name, non_null(:string))
  end

  object :post_mutations do
    @desc "Create post"
    field :create_post, type: :post do
      arg(:name, non_null(:string))
      middleware(Speakeasy.Authn)
      middleware(Speakeasy.Authz, {Posts, :create_post})
      middleware(Speakeasy.Resolve, &Posts.create_post/2)
      middleware(MyApp.Middleware.ChangesetErrors) # :D
    end

    @desc "Update post"
    field :update_post, type: :post do
      arg(:name, non_null(:string))
      middleware(Speakeasy.Authn)
      middleware(Speakeasy.Authz, {Posts, :update_post})
      middleware(Speakeasy.Resolve, &Posts.update_post/3)
      middleware(MyApp.Middleware.ChangesetErrors) # :D
    end
  end

  object :post_queries do
    @desc "Get posts"
    field :posts, list_of(:post) do
      middleware(Speakeasy.Authn)
      middleware(Speakeasy.Resolve, fn(attrs, user) -> MyApp.Posts.search(attrs, user) end)
    end

    @desc "Get post"
    field :post, type: :post do
      arg(:id, non_null(:string))
      middleware(Speakeasy.Authn)
      middleware(Speakeasy.LoadResourceByID, &Posts.get_post/1)
      middleware(Speakeasy.Authz, {Posts, :get_post})
      middleware(Speakeasy.Resolve)
    end
  end
end

And of course you can use Absinthe's resolve function as well:

@desc "Get post"
field :post, type: :post do
  arg(:id, non_null(:string))
  middleware(Speakeasy.Authn)
  middleware(Speakeasy.LoadResourceByID, &Posts.get_post/1)
  middleware(Speakeasy.Authz, {Posts, :get_post})
  resolve(fn(_parent, _args, ctx) ->
    {:ok, ctx[:speakeasy].resource}
  end)
end

Middleware

Speakeasy is a collection of Absinthe middleware:

• Speakeasy.Authn - Resolution middleware for Absinthe.

• Speakeasy.LoadResource - Loads a resource into the speakeasy context.

• Speakeasy.LoadResourceById - A convenience middleware to LoadResource using the :id in the Absinthe arguments.

• Speakeasy.LoadResourceBy - A convenience middleware to LoadResource using a value from the attrs with the given key in the Absinthe arguments.

• Speakeasy.AuthZ - Authorization middleware for Absinthe.

• Speakeasy.Resolve - Resolution middleware for Absinthe.

Speakeasy.Plug

Speakeasy includes a Plug for loading the current user into the Absinthe context. It isn't required if you already have a method for loading the user into your Absinthe context.

defmodule MyAppWeb.Router do
  use MyAppWeb, :router

  pipeline :graphql do
    plug(Speakeasy.Plug, load_user: &MyApp.Users.whoami/1, user_key: :current_user)
  end
end