Initial commit of lib

Dummy ecto schema provided in macro. Plug+validation modules created by
macro. Time to tackle the validation DSL

.formatter.exs

@@ -0,0 +1,4 @@
+# Used by "mix format"
+[
+  inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
+]

.gitignore

@@ -1,9 +1,24 @@
-/_build
-/cover
-/deps
-/doc
+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where 3rd-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
 /.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
 erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
 *.ez
-*.beam
-/config/*.secret.exs
+
+# Ignore package tarball (built via "mix hex.build").
+pharams-*.tar
+

config/config.exs

@@ -0,0 +1,30 @@
+# This file is responsible for configuring your application
+# and its dependencies with the aid of the Mix.Config module.
+use Mix.Config
+
+# This configuration is loaded before any dependency and is restricted
+# to this project. If another project depends on this project, this
+# file won't be loaded nor affect the parent project. For this reason,
+# if you want to provide default values for your application for
+# 3rd-party users, it should be done in your "mix.exs" file.
+
+# You can configure your application as:
+#
+#     config :pharams, key: :value
+#
+# and access this configuration in your application as:
+#
+#     Application.get_env(:pharams, :key)
+#
+# You can also configure a 3rd-party app:
+#
+#     config :logger, level: :info
+#
+
+# It is also possible to import configuration files, relative to this
+# directory. For example, you can emulate configuration per environment
+# by uncommenting the line below and defining dev.exs, test.exs and such.
+# Configuration from the imported file will override the ones defined
+# here (which is why it is important to import them last).
+#
+#     import_config "#{Mix.env()}.exs"

lib/pharams.ex

@@ -0,0 +1,110 @@
+defmodule Pharams do
+  @moduledoc """
+  Documentation for Pharams.
+  """
+
+  def recusrive_map_from_struct(map) do
+    map
+    |> Map.from_struct()
+    |> Enum.map(fn
+      {key, %{__struct__: _} = value} -> {key, recusrive_map_from_struct(value)}
+      key_val -> key_val
+    end)
+    |> Map.new()
+  end
+
+  defmacro __using__(opts) do
+    error_module = Keyword.get(opts, :view_module, Pharams.ErrorView)
+    error_template = Keyword.get(opts, :view_template, "errors.json")
+    error_status = Keyword.get(opts, :error_status, :unprocessable_entity)
+
+    quote do
+      import Pharams, only: [pharams: 2]
+
+      def pharams_error_view_module, do: unquote(error_module)
+      def pharams_error_view_template, do: unquote(error_template)
+      def pharams_error_status, do: unquote(error_status)
+    end
+  end
+
+  defp generate_plug(validation_module, controller_module) do
+    quote do
+      use Phoenix.Controller
+
+      import Plug.Conn
+      import Ecto.Changeset
+
+      def init(opts), do: IO.inspect(opts)
+
+      def call(conn, key) do
+        validation_module = unquote(validation_module)
+        changeset = validation_module.changeset(struct(validation_module), conn.params)
+
+        if changeset.valid? do
+          new_params =
+            changeset
+            |> apply_changes()
+            |> Pharams.recusrive_map_from_struct()
+
+          %{conn | params: new_params}
+        else
+          controller_module = unquote(controller_module)
+
+          view_module = controller_module.pharams_error_view_module
+          view_template = controller_module.pharams_error_view_template
+          error_status = controller_module.pharams_error_status
+
+          conn
+          |> put_status(error_status)
+          |> render(view_module, view_template, changeset)
+          |> halt()
+        end
+      end
+    end
+  end
+
+  defp generate_validation do
+    quote do
+      use Ecto.Schema
+
+      import Ecto.Changeset
+
+      @primary_key false
+      embedded_schema do
+        field(:page, :integer)
+        field(:rawr, :integer)
+      end
+
+      def changeset(schema, params) do
+        schema
+        |> cast(params, [:page, :rawr])
+        |> validate_required([:page])
+        |> validate_number(:page, greater_than: 0)
+      end
+    end
+  end
+
+  defmacro pharams(controller_action, do: _block) do
+    camel_action =
+      controller_action
+      |> Atom.to_string()
+      |> Macro.camelize()
+
+    calling_module = __CALLER__.module
+
+    # Create validation module
+    validation_module_name = Module.concat([calling_module, PharamsValidator, camel_action])
+    validation_module_ast = generate_validation()
+    Module.create(validation_module_name, validation_module_ast, Macro.Env.location(__ENV__))
+
+    # Create Plug module
+    plug_module_name = Module.concat([calling_module, PharamsPlug, camel_action])
+    plug_module_ast = generate_plug(validation_module_name, calling_module)
+    Module.create(plug_module_name, plug_module_ast, Macro.Env.location(__ENV__))
+
+    # Insert the validation plug
+    quote do
+      plug(unquote(plug_module_name) when var!(action) == unquote(controller_action))
+    end
+  end
+end

lib/pharams_error_view.ex

@@ -0,0 +1,19 @@
+defmodule Pharams.ErrorView do
+  @doc """
+  Traverses changeset errors.
+  """
+
+  def translate_errors(changeset) do
+    Ecto.Changeset.traverse_errors(changeset, fn {msg, opts} ->
+      Enum.reduce(opts, msg, fn {key, value}, acc ->
+        String.replace(acc, "%{#{key}}", to_string(value))
+      end)
+    end)
+  end
+
+  def render("errors.json", %Ecto.Changeset{} = changeset) do
+    %{
+      errors: translate_errors(changeset)
+    }
+  end
+end

mix.exs

@@ -0,0 +1,29 @@
+defmodule Pharams.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :pharams,
+      version: "0.1.0",
+      elixir: "~> 1.7",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      {:phoenix, "~> 1.3.4"},
+      {:plug, "~> 1.6.2"},
+      {:ecto, "2.2.10"}
+    ]
+  end
+end

test/pharams_test.exs

@@ -0,0 +1,8 @@
+defmodule PharamsTest do
+  use ExUnit.Case
+  doctest Pharams
+
+  test "greets the world" do
+    assert Pharams.hello() == :world
+  end
+end

test/test_helper.exs

@@ -0,0 +1 @@
+ExUnit.start()