Ecto Postgres tsrange data type

README.md

A simple Ecto custom type for the Postgres tsrange type.

Based on: http://pedroassumpcao.ghost.io/using-postgres-range-data-type-in-ecto/ and elixir-ecto/postgrex#27

tsrange.ex

defmodule Postgrex.Extension.TSRange do
  @behaviour Ecto.Type

  def type, do: :tsrange

  def cast([lower, upper]) do
    case apply_func([lower, upper], &Ecto.DateTime.cast/1) do
      {:ok, [lower, upper]} -> {:ok, [lower, upper]}
      :error -> :error
    end
  end
  def cast(_), do: :error

  def load(%Postgrex.Range{lower: lower, upper: upper}) do
    apply_func([lower, upper], &Ecto.DateTime.load/1)
  end
  def load(_), do: :error

  def dump([lower, upper]) do
    case apply_func([lower, upper], &Ecto.DateTime.dump/1) do
      {:ok, [lower, upper]} -> {:ok, %Postgrex.Range{lower: lower, upper: upper, upper_inclusive: false}}
      :error -> :error
    end
  end
  def dump(_), do: :error

  defp to_float(value) do
   value |> Decimal.to_string |> Float.parse
  end

  defp apply_func([lower, upper], fun) do
    lower = apply_func(lower, fun)

    upper = apply_func(upper, fun)

    if lower != :error and upper != :error do
      {:ok, [lower, upper]}
    else
      :error
    end
  end

  defp apply_func(target, fun) do
    case fun.(target) do
      {:ok, target} -> target
      :error -> :error
    end
  end

end

Is to_float/1 needed?

No it's not.
Also to those stumbling upon this, it's outdated. Ecto.DateTime is deprecated.
Here is a more up-to-date version: https://gist.github.com/jgautsch/85bda57d53ada9f2d0106b3d4a379472

FYI here's a repo implementing tsrange and tstzrange columns, as well as examples of how to query for overlapping ranges: https://github.com/jgautsch/ecto_time_ranges