Handle Storing And Retrieving Output Files

lib/arc_ecto/type.ex

@@ -1,39 +1,34 @@
 defmodule Arc.Ecto.Type do
   def type, do: :string
 
-  @filename_with_timestamp ~r{^(.*)\?(\d+)$}
+  @filename_with_timestamp ~r{^(.*)\?(\d+)(&|$)}
+
+  @saved_versions ~r/(files=)(.*)?&?/
 
   # Support embeds_one/embeds_many
   def cast(_definition, %{"file_name" => file, "updated_at" => updated_at}) do
     {:ok, %{file_name: file, updated_at: updated_at}}
   end
+
+  def cast(_definition, %{"file_name" => file, "updated_at" => updated_at, "saved_versions" => saved_versions}) do
+    {:ok, %{file_name: file, updated_at: updated_at, saved_versions: saved_versions}}
+  end
+
   def cast(definition, args) do
     case definition.store(args) do
-      {:ok, file} -> {:ok, %{file_name: file, updated_at: Ecto.DateTime.utc}}
+      {:ok, file, saved_versions} -> {:ok, %{file_name: file, updated_at: Ecto.DateTime.utc, saved_versions: saved_versions}}
       _ -> :error
     end
   end
 
   def load(_definition, value) do
-    {file_name, gsec} =
-      case Regex.match?(@filename_with_timestamp, value) do
-        true ->
-          [_, file_name, gsec] = Regex.run(@filename_with_timestamp, value)
-          {file_name, gsec}
-        _ -> {value, nil}
-      end
-
-    updated_at = case gsec do
-      gsec when is_binary(gsec) ->
-        gsec
-        |> String.to_integer()
-        |> :calendar.gregorian_seconds_to_datetime()
-        |> Ecto.DateTime.from_erl()
-      _ ->
-        nil
+    {file_name, gsec} = filename_from(value)
+    updated_at = updated_time_from(gsec)
+    saved_versions = saved_versions_from(value)
+    case is_nil(saved_versions) do
+      true ->     {:ok, %{file_name: file_name, updated_at: updated_at}}
+      false ->     {:ok, %{file_name: file_name, updated_at: updated_at, saved_versions: saved_versions}}
     end
-
-    {:ok, %{file_name: file_name, updated_at: updated_at}}
   end
 
   def dump(_definition, %{file_name: file_name, updated_at: nil}) do
@@ -44,4 +39,43 @@ defmodule Arc.Ecto.Type do
     gsec = :calendar.datetime_to_gregorian_seconds(Ecto.DateTime.to_erl(updated_at))
     {:ok, "#{file_name}?#{gsec}"}
   end
+
+  def dump(_definition, %{file_name: file_name, updated_at: updated_at, saved_versions: nil}) do
+    gsec = :calendar.datetime_to_gregorian_seconds(Ecto.DateTime.to_erl(updated_at))
+    {:ok, "#{file_name}?#{gsec}"}
+  end
+
+  def dump(_definition, %{file_name: file_name, updated_at: updated_at, saved_versions: versions}) do
+    gsec = :calendar.datetime_to_gregorian_seconds(Ecto.DateTime.to_erl(updated_at))
+    {:ok, "#{file_name}?#{gsec}&files=#{versions}"}
+  end
+
+  defp filename_from(value) do
+    case Regex.match?(@filename_with_timestamp, value) do
+      true ->
+        [_, file_name, gsec, _] = Regex.run(@filename_with_timestamp, value)
+        {file_name, gsec}
+      _ -> {value, nil}
+    end
+  end
+
+  defp saved_versions_from(value) do
+    case Regex.match?(@saved_versions, value) do
+      true ->
+        [_, _, val] = Regex.run(@saved_versions, value)
+        String.split(val, "::")
+      _ -> nil
+    end
+  end
+
+  defp updated_time_from(gsec) do
+    case gsec do
+      gsec when is_binary(gsec) ->
+        gsec
+        |> String.to_integer()
+        |> :calendar.gregorian_seconds_to_datetime()
+        |> Ecto.DateTime.from_erl()
+      _ -> nil
+    end
+  end
 end

test/schema_test.exs

@@ -58,7 +58,7 @@ defmodule ArcTest.Ecto.Schema do
     assert cs.errors   == [avatar: {"can't be blank", []}]
   end
 
-  test_with_mock "cascades storage success into a valid change", DummyDefinition, [store: fn({%{__struct__: Plug.Upload, path: "/path/to/my/file.png", file_name: "file.png"}, %TestUser{}}) -> {:ok, "file.png"} end] do
+  test_with_mock "cascades storage success into a valid change", DummyDefinition, [store: fn({%{__struct__: Plug.Upload, path: "/path/to/my/file.png", file_name: "file.png"}, %TestUser{}}) -> {:ok, "file.png", "file.png"} end] do
     upload = build_upload("/path/to/my/file.png")
     cs = TestUser.changeset(%TestUser{}, %{"avatar" => upload})
     assert cs.valid?

test/type_test.exs

@@ -25,6 +25,18 @@ defmodule ArcTest.Ecto.Type do
     assert value == %{file_name: "image.php", updated_at: timestamp}
   end
 
+  test "loads filenames with an output file embedded" do
+    timestamp = Ecto.DateTime.cast!({{1970, 1, 1}, {0, 0, 0}})
+    {:ok, value} = DummyDefinition.Type.load("image.php?62167219200&files=image.png")
+    assert value == %{file_name: "image.php", updated_at: timestamp, saved_versions: ["image.png"]}
+  end
+
+  test "loads filenames with multiple output files embedded" do
+    timestamp = Ecto.DateTime.cast!({{1970, 1, 1}, {0, 0, 0}})
+    {:ok, value} = DummyDefinition.Type.load("image.php?62167219200&files=image.png::image2.png::image3.png")
+    assert value == %{file_name: "image.php", updated_at: timestamp, saved_versions: ["image.png", "image2.png", "image3.png"]}
+  end
+
   test "loads pathological filenames without timestamps" do
     {:ok, value} = DummyDefinition.Type.load("image^!?*!=@$.php")
     assert value == %{file_name: "image^!?*!=@$.php", updated_at: nil}