user_exist.ex

defmodule Cli do
  @moduledoc " Cli to check if a gitlab username is taken"

  @doc " The entry point for the program"
  def main([]) do
    IO.puts "Usage: #{:escript.script_name()} <username>"
  end

  def main([user]) do
    Application.ensure_all_started(:inets)
    Application.ensure_all_started(:ssl)

    exists(user) |> IO.puts
  end

  defp exists(user) do
    {:ok, {{_proto, _code, _status}, _headers, body}} =
      :httpc.request(:get, {'https://gitlab.com/users/#{user}/exists', []}, [], [])

    body =~ 'true'
  end
end