RestQL

post_controller_v1.ex

defmodule Restql.Web.PostController do
  use Restql.Web, :controller

  def index(conn, _params) do
    posts = Restql.Blog.list_posts
    json conn, posts
  end
end

post_controller_v2.ex

defmodule Restql.Web.PostController do
  use Restql.Web, :controller

  alias Restql.Blog
  alias Restql.Blog.Post

  def index(conn, _params) do
    graphql conn, """
      {
        posts {
          title
          body
          author {
            name
          }
        }
      }
    """
  end
  
  defp graphql(conn, document, variables \\ %{}, schema \\ Restql.Blog.Schema) do
    with {:ok, data} <- Absinthe.run(document, schema, variables: variables) do
      json conn, data
    end
  end
end

post_controller_v3.ex

defmodule Restql.Web.PostController do
  # ...
  def create(conn, %{"post" => post_params}) do
    graphql conn, """
      mutation CreatePost($title: String!, $body: String!) {
        post(title: $title, body: $body) {
          id
        }
      }
    """, post_params
  end
  # ...
end

post_resolver_v1.ex

defmodule Restql.Blog.PostResolver do
  def all(_args, _info) do
    {:ok, Restql.Blog.list_posts |> Restql.Repo.preload(:author)}
  end
end

post_resolver_v2.ex

defmodule Restql.Blog.PostResolver do
  # ...
  def create(args, _info) do
    Restql.Blog.create_post(args)
  end
  # ...
end

schema_v1.ex

defmodule Restql.Blog.Schema do
  use Absinthe.Schema
  import_types Restql.Blog.Schema.Types

  query do
    field :posts, list_of(:post) do
      resolve &Restql.Blog.PostResolver.all/2
    end
  end
end

schema_v2.ex

defmodule Restql.Blog.Schema do
  # ...
  mutation name: "CreatePost" do
    field :post, type: :post do
      arg :title, non_null(:string)
      arg :body, non_null(:string)
      resolve &Restql.Blog.PostResolver.create/2
    end
  end
  # ...
end

types.ex

defmodule Restql.Blog.Schema.Types do
  use Absinthe.Schema.Notation

  object :post do
    field :id, :id
    field :title, :string
    field :body, :string
    field :author, :user
  end

  object :user do
    field :id, :id
    field :name, :string
  end
end