params.ex

Short but not appreciated enough

  defp validate_params(params) do
    cond do
      !validate?(params["frequency"]) ->
        {:invalid, "The parameter 'frequency' isn't valid."}
      !validate?(params["storage_duration"]) ->
        {:invalid, "The parameter 'storage_duration' isn't valid."}
      !cr_status?(params["status"]) ->
        {:invalid, "The parameter 'status' isn't valid."}
      true ->
        {:ok}
    end
  end

  def validate?(nil), do: false
  def validate?(integer) when is_integer(integer), do: true
  def validate?(integer) do
    case Integer.parse(integer) do
      {_number, ""} -> true
      _ -> false
    end
  end
  def cr_status?(""), do: false
  def cr_status?(nil), do: false
  def cr_status?("off"), do: true
  def cr_status?("on"), do: true
  def cr_status?("on-scheduled"), do: true
  def cr_status?(status), do: false

Long but appreciated

  defp validate_params(params) do
    with :ok <- validate?("frequency", params["frequency"]),
         :ok <- validate?("storage_duration", params["storage_duration"]),
         :ok <- validate?("status", params["status"]),
         do: :ok
  end

  def validate?("status", "on"),            do: :ok
  def validate?("status", "off"),           do: :ok
  def validate?("status", "on-scheduled"),  do: :ok
  def validate?("status" = key, _invalid),  do: invalid(key)

  def validate?(key, value) when is_integer(value),   do: :ok
  def validate?(key, value) when value in [nil, ""],  do: invalid(key)
  def validate?(key, value) when is_bitstring(value), do: validate?(key, to_integer(value))

  def validate?(key, _invalid), do: invalid(key)

  defp invalid(key), do: {:invalid, "The parameter '#{key}' isn't valid."}
  defp to_integer(value) do
    case Integer.parse(value) do
      {number, _} -> number
      _ -> :error
    end
  end