Hello Controller with redis

hello_controller.ex

defmodule HelloPhoenix.HelloController do
  use HelloPhoenix.Web, :controller

  def index(conn, _params) do
    render conn, "index.html"
  end

  def show(conn, %{"messenger" => messenger} = params) do
    HelloPhoenix.Endpoint.subscribe(self(), "potato")
    receive do
      %Phoenix.Socket.Broadcast{event: "response", payload: %{message: message}, topic: "potato"} ->
        IO.puts "here's a message"
        IO.inspect message
        render conn, "show.html", messenger: messenger, message: message
    after
      120000 -> send_resp(conn, :no_content, "")
    end
  end

  def create(conn, %{"message" => message} = params) do
    HelloPhoenix.Endpoint.broadcast("potato", "response", %{message: message})
    send_resp(conn, :no_content, "")
  end
end