Transponder

DSL for declarative Phoenix controllers.

Features

• Turns controllers into declarative code.
• Works with all context functions that return a tagged tuple like {:ok, ...} or {:error, ...}
• Supports rendering Ecto.Changeset errors.
• Built-in formatters for JSON and HTML with ability to add custom ones.

Disclaimer: This is intended for simple apps or when starting to build an application. More complex apps may require more complexity in their controllers, and then a standard Phoenix controller with tests would work better. This is just a starting point.

Installation

Add transponder to your list of dependencies in mix.exs:

def deps do
  [
    {:transponder, "~> 0.1.0"}
  ]
end

Add use Transponder to your controllers, and define actions with defaction:

defmodule MyAppWeb.Admin.ProductsController do
  use MyAppWeb, :controller
  use Transponder, format: Transponder.JSON

  defaction :index,  &Catalog.list_products(&1.params)
  defaction :show,   &Catalog.get_product(&1.params)
  defaction :create, &Catalog.create_product(&1.params["product"])
  defaction :update, &Catalog.update_product(&1.params["id"], &1.params["product"])
  defaction :delete, &Catalog.delete_product(&1.params["id"])
end

Then define a show.json.eex and index.json.eex. Or you can use a Phoenix.View:

defmodule MyAppWeb.Admin.ProductsView do
  use MyAppWeb, :view

  def render("index.json", %{records: products}) do
    %{products: Enum.map(&render("show.json", response: &1))}
  end

  def render("show.json", %{record: product}) do
    %{
      id: product.id,
      title: product.title,
      price: product.price,
    }
  end
end

To handle errors, configure the error view in config/config.exs:

config :transponder, :error_view, MyAppWeb.ErrorView

To render HTML instead of JSON use Transponder.HTML:

defmodule MayAppWeb.Admin.ProductController do
  use MyAppWeb, :controller
  use Transponder, format: Transponder.HTML

  # defaction ...
end

And then you'll need to create templates for the actions you use: index.html.eex, show.html.eex, etc..

You can also create a custom formatter:

defmodule MyFormat do
  @behaviour Transponder.Formatter

  # pattern match and render how you like
  @impl true
  def format(_action, conn, {:ok, bla}) do
    conn
    |> put_status(200)
    |> render("yay.html")
  end

  def format(_action, conn, {:error, bla}) do
    conn
    |> put_status(401)
    |> render("oops.html")
  end
end

Documentation:

https://hexdocs.pm/transponder.

License

MIT