Building the router DSL

In order for the use Goldcrest.Router, ... statement to work, we will first need to define a __using__/1 macro in the Goldcrest.Router module. This macro will be responsible for injecting all the router behavior into a module.

Let’s start by simply moving all the plug calls and private parse_body and decode_body_params functions to the __using__/1 macro:

defmodule Goldcrest.Router do
  import Plug.Conn
  defmacro __using__(opts) do
    quote do
      use Plug.Router
      @opts unquote(opts)
      plug Plug.Parsers,
        parsers: [:urlencoded, :multipart],
        pass: ["text/html", "application/*"]
      plug :parse_body
      plug :match
   ...