Store a phone number in e164 format

Ash Forum Ash Questions / Help
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1

A User resource has attribute :mobile_phone, :string, allow_nil?: false. The user can edit his/her phone number. The problem is that in Germany human users use different format to enter their phone number. But I want to save it in e164 format.

There is GitHub - ex-phone-number/ex_phone_number: Elixir port of libphonenumber which takes care of auto converting a string into e164 format.

I have to do the following code to format any string into e164:

{:ok, phone_number} = ExPhoneNumber.parse(mobile_phone, "DE")
ExPhoneNumber.format(phone_number, :e164)

How can I get the resource to automatically do that before validation kicks in or before it is saved?

2

Hello, I’m assuming that you want to store it in the database.

If you want to manipulate the data before it is saved and after it is fetched from DB, I would use the Ecto.Type behaviour to create your own custom field “Phone”. Here is the documentation.

You can take a look at this library ecto_phone_number | Hex to check if it does what you want. You can also read the definition of their custom Ecto.Type here as reference to implement yours.

1 Like
3

@rlopzc is correct except that you’ll want to us an Ash.Type in this instance :slight_smile: Often Ash.Type can be built to wrap another ecto type, for example:

defmodule YourApp.PhoneNumber do
  use Ash.Type

  def cast_input(value, constraints) do
    SomeEctoType.cast(value, constraints)
  end

  ...
end

and so on.

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4

In case somebody searches for the solution:

defmodule YourApp.AshPhoneNumber do
  @moduledoc """
  PhoneNumber Type to store the number in a e164 format.
  """

  use Ash.Type

  @impl Ash.Type
  def storage_type(_), do: :string

  @impl Ash.Type
  def cast_input(nil, _), do: {:ok, nil}

  def cast_input(value, _) do
    ecto_type_cast = Ecto.Type.cast(:string, value)
    {:ok, raw_phone_number} = ecto_type_cast

    case ExPhoneNumber.parse(raw_phone_number, "DE") do
      {:ok, phone_number} ->
        case ExPhoneNumber.is_possible_number?(phone_number) do
          true -> {:ok, ExPhoneNumber.format(phone_number, :e164)}
          _ -> ecto_type_cast
        end

      _ ->
        ecto_type_cast
    end
  end

  @impl Ash.Type
  def cast_stored(nil, _), do: {:ok, nil}

  def cast_stored(value, _) do
    Ecto.Type.load(:string, value)
  end

  @impl Ash.Type
  def dump_to_native(nil, _), do: {:ok, nil}

  def dump_to_native(value, _) do
    Ecto.Type.dump(:string, value)
  end
end
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