Postgres date range type using ecto

daterange.ex

defmodule LocationService.Daterange do
   @behaviour Ecto.Type
 
   def type, do: :daterange
 
   def cast([lower, upper]) do
     {:ok, [lower, upper]}
   end
 
   def cast(_), do: :error
 
   def load(%Postgrex.Range{lower: lower, upper: nil}) do
     lower = lower |> to_datetime
     {:ok, [lower, nil]}
   end
 
   def load(%Postgrex.Range{lower: lower, upper: upper}) do
     lower = lower |> to_datetime
     upper = upper |> to_datetime
     {:ok, [lower, upper]}
   end
 
   def dump([lower, upper]) do
     {:ok, %Postgrex.Range{lower: lower, upper: upper, upper_inclusive: false}}
   end
 
   def dump(_), do: :error
 
   defp to_datetime(value) do
    datetime = value |> Ecto.DateTime.load
    elem(datetime, 1)
   end
end