Add support for string-keyed attrs in from functions

README.md

@@ -203,6 +203,12 @@ unless defaulted or provided as attributes to the constructor.
     }
   ```
 
+## String keyed attributes
+The attributes map provided to the constructor functions can be either string-keyed or atom-key, not mixed.
+
+Under the covers we are using [Ecto.Changeset.cast/4](https://hexdocs.pm/ecto/Ecto.Changeset.html#cast/4), to
+copy and cast attributes into the struct being created.  
+
 ## Installation
 Because this plugin supports the interface defined by the `TypedStruct` macro, installation assumes you've already
 added that dependency.

lib/typed_struct_ctor.ex

@@ -196,13 +196,20 @@ defmodule TypedStructCtor do
 
   @doc false
   def do_from(mod, base_struct, attrs) when is_struct(base_struct) do
-    attrs =
-      base_struct
-      |> Map.from_struct()
-      |> Map.drop(mod.__not_mapped__())
-      |> Map.merge(attrs)
-
-    TypedStructCtor.do_new(mod, attrs)
+    # `attrs` could be string-keyed map, use Ecto to convert to validated atom-keys
+    case cast(mod.__struct__(), attrs, mod.__all__(), force_changes: true) do
+      %{valid?: true, changes: valid_attrs} ->
+        merged_attrs =
+          base_struct
+          |> Map.from_struct()
+          |> Map.drop(mod.__not_mapped__())
+          |> Map.merge(valid_attrs)
+
+        TypedStructCtor.do_new(mod, merged_attrs)
+
+      other ->
+        other
+    end
   end
 
   def do_from(_mod, _base_struct, _attrs), do: {:error, :base_struct_must_be_a_struct}

mix.exs

@@ -4,7 +4,7 @@ defmodule TypedStructCtor.MixProject do
   def project do
     [
       app: :typed_struct_ctor,
-      version: "0.1.1",
+      version: "0.1.2",
       elixir: "~> 1.15",
       start_permanent: Mix.env() == :prod,
       deps: deps(),
@@ -35,14 +35,14 @@ defmodule TypedStructCtor.MixProject do
   defp package() do
     [
       licenses: ["MIT"],
-      links: %{"Github" => "https://github.com/withbelay/typed_struct_ctor"}
+      links: %{"Github" => "https://github.com/leggebroten/typed_struct_ctor"}
     ]
   end
 
   defp deps do
     [
       {:credo, "~> 1.7", only: [:dev, :test]},
-      {:dialyxir, "~> 1.3", only: [:dev, :test]},
+      {:dialyxir, "~> 1.3", only: [:dev, :test], runtime: false},
       {:ecto, "~> 3.10"},
       {:ex_doc, "~> 0.30", only: :dev},
       {:typedstruct, "~> 0.5.2"},

test/typed_struct_ctor_test.exs

@@ -50,6 +50,7 @@ defmodule Mappable do
     plugin(TypedStructEctoChangeset)
     plugin(TypedStructCtor)
 
+    field(:defaulted, :string, default: "defaulted")
     field(:mapped_by_default, :string, default: "bar")
     field(:id, :string, mappable?: false, default_apply: {Ecto.UUID, :generate, []})
   end
@@ -75,6 +76,22 @@ defmodule TypedStructCtorTest do
                })
     end
 
+    test "when attributes are string keys, map to atoms" do
+      assert {:ok,
+              %AStruct{
+                not_required_defaulted: 1,
+                not_required_not_defaulted: 2,
+                required_defaulted: 3,
+                required_not_defaulted: 4
+              }} ==
+               AStruct.new(%{
+                 "not_required_defaulted" => "1",
+                 "not_required_not_defaulted" => "2",
+                 "required_defaulted" => "3",
+                 "required_not_defaulted" => "4"
+               })
+    end
+
     test "when no attributes supplied, use defaults" do
       assert {:error, message} = AStruct.new(%{})
 
@@ -192,6 +209,19 @@ defmodule TypedStructCtorTest do
       assert mapped_struct.id == "baz"
     end
 
+    test "when attributes have string keys, they're cast correctly as atom keys" do
+      original_struct = Mappable.new!(%{"mapped_by_default" => "foo"})
+
+      {:ok, %{id: "baz", mapped_by_default: "bar"}} =
+        Mappable.from(original_struct, %{"id" => "baz", "mapped_by_default" => "bar"})
+
+      {:ok, %{id: "baz", mapped_by_default: "foo"}} = Mappable.from(original_struct, %{"id" => "baz"})
+
+      {:ok, %{id: id, mapped_by_default: "foo"}} = Mappable.from(original_struct)
+      refute id == original_struct.id
+      {:ok, _uuid} = Ecto.UUID.cast(id)
+    end
+
     test "when fails validation, return error tuple" do
       original_struct = Mappable.new!(%{mapped_by_default: "foo"})
       {:error, changeset} = Mappable.from(original_struct, %{mapped_by_default: nil})