Arc Uploader resolver for Absinthe Graphql

arc_resolver.ex

defmodule MyApp.Schema.ArcResolver do
  defmacro __using__([uploader: uploader]) do
    quote do
      import unquote(__MODULE__), only: [
        get_file: 2
      ]
      @__arc_upload unquote(uploader)
    end
  end

  defmacro get_file(field, version) do
    quote do
      unquote(__MODULE__).get_file(@__arc_upload, unquote(field), unquote(version))
    end
  end

  def get_file(uploader, field, version) do
    fn parent, _, _ ->
      res = apply(uploader, :url, [{parent.picture, parent}, version])
      {:ok, res}
    end
  end
end

service.ex

defmodule MyApp.Context.Service do
  use Ecto.Schema
  use Arc.Ecto.Schema

  alias MyApp.Picture

  schema "services" do
    field :picture, Picture.Type
  end
end

types.ex

defmodule MyApp.Schema.Types do

  use Absinthe.Schema.Notation
  use MyApp.Schema.ArcResolver, uploader: MyApp.Picture

  object :service do
    field :thumb, :string, resolve: get_file(:picture, :thumb)
    field :original, :string, resolve: get_file(:picture, :original)
  end
end