catchall_controller.ex

#usage: use YourApp.CatchallController in web.ex right after use Phoenix.Controller
defmodule YourApp.CatchAllController do
  defmacro __using__(_opts) do
    quote do
      @before_compile unquote(__MODULE__)
    end
  end

  defmacro __before_compile__(env) do
    actions = Module.definitions_in(env.module, :def)
    #The following list might need to be updated if Phoenix.Controller adds more functions to your module in the future.
    |> Keyword.drop([:action, :call, :init, :phoenix_controller_pipeline])
    |> Enum.into(HashSet.new, fn({fun, _arity}) -> fun end)
    for action <- actions do
      quote do
        def unquote(action)(conn, _params) do
          Plug.Conn.send_resp(conn, 400, "")
        end
      end
    end
  end
end