Twitter authorization controller

controller.ex

defmodule TestApp.TwitterController do
  use Phoenix.Controller

  # Routing configuration:
  #
  # scope "/twitter", TestApp do
  #   pipe_through :browser_session
  #   get "/:lang/authorize", TwitterController, :authorize
  #   get "/redirect", TwitterController, :authorize_return
  
  require Plug.Conn
  require Logger
  
  plug :action

  def configure_twitter(params, access_token \\ nil, access_token_secret \\ nil) do
    config = Application.get_env(:testapp, :twitter)
    if access_token != nil do
      config = [{:access_token, access_token}, {:access_token_secret, access_token_secret} | config]
    end
    ExTwitter.configure(:process, config)
  end
  
  def authorize(conn, params) do
    configure_twitter(params)

    r = ExTwitter.API.Authorize.request_token()

    redirect = Atom.to_string(conn.scheme) <> "://" <> get_host(conn) <> "/twitter/redirect"
    {:ok, url} = ExTwitter.API.Authorize.authorize_url(r["oauth_token"], redirect, %{lang: params["lang"]})

    conn
    |> put_session(:request_token, r["oauth_token"])
    |> put_session(:request_token_secret, r["oauth_token_secret"])
    |> redirect external: url
  end

  def authorize_return(conn, params) do
    configure_twitter(params)

    vars = case params["denied"] do
             nil ->
               case ExTwitter.API.Authorize.access_token(params["oauth_verifier"], get_session(conn, :request_token), get_session(conn, :request_token_secret)) do
                 {:error, code} ->
                   %{error: code}
                 params ->
                   %{params: params}
               end
             _ ->
               %{error: :denied}
           end

    render conn, "return.html", vars
  end

  def popup_close(conn, params) do
    render conn, "popup_close.html", %{params: params}
  end

  defp get_host(%Plug.Conn{port: port, host: host}) when port == 80 or port == 443 do
    host
  end

  defp get_host(%Plug.Conn{port: port, host: host}) do
    host <> ":" <> Integer.to_string(port)
  end
  
end