Hi all,

I am learning how to create a basic API with Phoenix (I know, I do not need Phoenix, but I wanted to see how it is actually done). Everything works well but I have not been able to wrap my head around the process to filter results. For instance, my API JSON return is like this:

{
  "data": {
    "active": true,
    "carmaker": "Simca",
    "id": 1,
    "owner": "James Bon",
    "plate": 345671
  }
}

It all goes well if I simply do:

GET /api/customers/ or GET /api/customers/1. But I want to be able to do GET /api/customers?carmaker=carmaker_name

What I have so far is:

router.ex:

defmodule NukakApiWeb.Router do

  use NukakApiWeb, :router
  # use Pow.Phoenix.Router

  pipeline :api do
    plug :accepts, ["json"]
    plug NukakApiWeb.ApiAuthPlug, otp_app:  :nukak_api
  end

scope "/api", NukakApiWeb do
    pipe_through [:api]
    resources "/customers", CustomerController, only: [:show, :index]
    # resources "/customers/:id", CustomerController, :show
 end

end

customer_controller.ex:

defmodule NukakApiWeb.CustomerController do
  use NukakApiWeb, :controller
# I know the following line should better go on a different file. Just adding it here for simplicity.
 def get_customer!(id), do: Repo.get!(Customer, id)
 def list_customers do
   Repo.all(Customer)
end

  def index(conn, _params) do
    customers = list_customers()
    render(conn, "index.json", customers: customers)
  end

  def show(conn, %{"id" => id}) do
    customer = get_customer!(id)
    render(conn, "show.json", customer: customer)
  end

customer_view.ex:

defmodule NukakApiWeb.CustomerView do
  use NukakApiWeb, :view
  alias NukakApiWeb.CustomerView

  def render("index.json", %{customers: customers}) do
    %{data: render_many(customers, CustomerView, "customer.json")}
  end

  def render("show.json", %{customer: customer}) do
    %{data: render_one(customer, CustomerView, "customer.json")}
  end

  def render("customer.json", %{customer: customer}) do
    %{id: customer.id,
      name: customer.name,
      plate: customer.plate,
      carmaker: customer.carmaker,
      active: customer.active}
  end
  end

I tried following this guy idea but I got lost in the assign() function:

def valid_filters(conn, params) do
  filters = Enum.filter(conn.params, fn({k, v}) ->
    Enum.member?(params, k)
  end)
  conn |> assign(:filters, filters)
end

There is the json_api_query_builder package but it does not seem to be compatible with ecto 3.

Anyway, if anybody can give me a hint on what is it that I have to do I would really appreciate it.

Thanks very much!