A RESTful router example with Dynamo

rest.exs

# Run this app from Dynamo root with:
#     mix run -r examples/rest.exs --no-halt
#
# Open a browser at URL http://localhost:3030 see the wonderment of rest.
#

defmodule Rest do
  # Cowboy Rest Handler resources
  #
  #   * User guide: http://ninenines.eu/docs/en/cowboy/HEAD/guide/rest_handlers
  #   * Reference: http://ninenines.eu/docs/en/cowboy/HEAD/manual/cowboy_rest
  #
  defmodule Handler do
    require :cowboy_req, as: R # Used for request body parsing.

    def init(_trans, _req, []) do
      {:upgrade, :protocol, :cowboy_rest}
    end

    # The following callbacks are all optional and have intelligent defaults as
    # defined int he links above.

    # Create new resource on POST
    def allow_missing_post do: true

    def allowed_methods(req, state) do
      {["GET", "OPTIONS", "PUT", "POST", "PATCH"], req, state}
    end

    # Define content types provided and their associated ProvideResource
    # callbacks as atoms
    def content_types_provided(req, state) do
      { [
          { "application/json", :get_json },
          { "text/html", :get_html },
          { "text/plain", :get_plain }
        ], req, state }
    end

    # Define content types accepted and their associated ProvideResource
    # callbacks as atoms
    def content_types_accepted(req, state) do
      { [
          { "application/json", :put_json}
      ], req, state }
    end

    # JSON ProvideResource callback
    def get_json(req, state) do
      {"{\"Hello\": \"JSON!\"}", req, state}
    end

    # HTML ProvideResource callback
    def get_html(req, state) do
      {"<ul><li>Hello</li><li>HTML!</li></ul>", req, state}
    end

    # Plain ProvideResource callback
    def get_plain(req, state) do
      {"Hello Plain!", req, state}
    end

    # Plain AcceptResource callback
    def put_json(req, state) do
      { :ok, body, req } = R.body req
      verb = case R.method(req) do
        { "PUT",   _ } -> "PUTTING"
        { "POST",  _ } -> "POSTING"
        { "PATCH", _ } -> "PATCHING"
      end
      IO.puts "#{verb} WITH: #{body}"
      {true, req, state}
    end

  end

  defmodule Router do
    use Dynamo
    use Dynamo.Router

    config :server,
      port: 3030,
      dispatch: [
        { :_,
          [
            {:_, Handler, []}
          ]
        }
      ]

  end
end

Rest.Router.start_link
Rest.Router.run