infinitered · danielberkompas · Jan 17, 2018 · Jan 17, 2018
diff --git a/lib/authority_ecto.ex b/lib/authority_ecto.ex
@@ -2,4 +2,4 @@ defmodule Authority.Ecto do
   @moduledoc """
   Provides `Ecto` integration for Authority.
   """
-end
+end
diff --git a/lib/authority_ecto/changeset.ex b/lib/authority_ecto/changeset.ex
@@ -2,4 +2,47 @@ defmodule Authority.Ecto.Changeset do
   @moduledoc """
   Convenient authentication-related functions for `Ecto.Changeset`s.
   """
-end
+
+  import Ecto.Changeset
+
+  @doc """
+  Based on the token's `purpose`, assign an `expires_at` timestamp. The value
+  of the `purpose` field should correspond to a key in the `config` list.
+
+  ## Examples
+
+      iex> put_token_expiration(changeset, :expires_at, :purpose, recovery: {24, :hours})
+      %Ecto.Changeset{}
+
+  """
+  def put_token_expiration(changeset, expiration_field, purpose_field, config)
+      when is_list(config) or is_map(config) do
+    expires_at =
+      config
+      |> get_in([get_change(changeset, purpose_field)])
+      |> parse_timespec()
+
+    if expires_at do
+      put_change(changeset, expiration_field, expires_at)
+    else
+      changeset
+    end
+  end
+
+  defp parse_timespec(nil), do: nil
+
+  defp parse_timespec({n, :hours}) do
+    parse_timespec({n * 60, :minutes})
+  end
+
+  defp parse_timespec({n, :minutes}) do
+    parse_timespec({n * 60, :seconds})
+  end
+
+  defp parse_timespec({n, :seconds}) do
+    DateTime.utc_now()
+    |> DateTime.to_unix()
+    |> Kernel.+(n)
+    |> DateTime.from_unix!()
+  end
+end
diff --git a/lib/authority_ecto/template.ex b/lib/authority_ecto/template.ex
@@ -1,3 +1,3 @@
 defmodule Authority.Ecto.Template do
   # TODO: Extract Authority.Template here
-end
+end
diff --git a/mix.exs b/mix.exs
@@ -5,7 +5,8 @@ defmodule Authority.Ecto.MixProject do
     [
       app: :authority_ecto,
       version: "0.1.0",
-      elixir: "~> 1.7-dev",
+      elixir: "~> 1.5",
+      elixirc_paths: elixirc_paths(Mix.env()),
       start_permanent: Mix.env() == :prod,
       deps: deps()
     ]
@@ -18,6 +19,9 @@ defmodule Authority.Ecto.MixProject do
     ]
   end
 
+  defp elixirc_paths(:test), do: ["lib", "test/support"]
+  defp elixirc_paths(_env), do: ["lib"]
+
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
@@ -26,4 +30,4 @@ defmodule Authority.Ecto.MixProject do
       {:ex_doc, ">= 0.0.0", only: [:dev, :test]}
     ]
   end
-end
+end
diff --git a/test/authority_ecto/changeset_test.exs b/test/authority_ecto/changeset_test.exs
@@ -1,3 +1,40 @@
 defmodule Authority.Ecto.ChangesetTest do
   use ExUnit.Case, async: true
-end
+
+  import Ecto.Changeset
+
+  alias Authority.Ecto.Changeset
+  alias Authority.Ecto.Test.Token
+
+  @expirations %{
+    "72_hours" => {72, :hours}
+  }
+
+  test "put_token_expiration/3 sets the expires_at" do
+    changeset =
+      %Token{}
+      |> Token.changeset(%{purpose: "72_hours"})
+      |> Changeset.put_token_expiration(:expires_at, :purpose, @expirations)
+
+    actual =
+      changeset
+      |> get_change(:expires_at)
+      |> DateTime.to_unix()
+
+    expected =
+      DateTime.utc_now()
+      |> DateTime.to_unix()
+      |> Kernel.+(259_200)
+
+    assert_in_delta actual, expected, 5
+  end
+
+  test "put_token_expiration/3 when no timespec is configured" do
+    changeset =
+      %Token{}
+      |> Token.changeset(%{purpose: "baloney"})
+      |> Changeset.put_token_expiration(:expires_at, :purpose, @expirations)
+
+    refute get_change(changeset, :expires_at)
+  end
+end
diff --git a/test/authority_ecto_test.exs b/test/authority_ecto_test.exs
@@ -2,4 +2,4 @@ defmodule Authority.EctoTest do
   use ExUnit.Case
 
   doctest Authority.Ecto
-end
+end
diff --git a/test/support/token.ex b/test/support/token.ex
@@ -0,0 +1,15 @@
+defmodule Authority.Ecto.Test.Token do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  schema "tokens" do
+    field(:token, :string)
+    field(:purpose, :string)
+    field(:expires_at, :utc_datetime)
+  end
+
+  def changeset(token, attrs \\ %{}) do
+    token
+    |> cast(attrs, [:purpose])
+  end
+end
-Original file line number
+Diff line change
@@ Expand Up / @@ -2,4 +2,4 @@ defmodule Authority.Ecto do @@
       @moduledoc """
       Provides `Ecto` integration for Authority.
       """
-    end
+    end