Phoenix 1.2中友好的URL Slugs

Question

我试图在较旧的Phoenix 1.2应用程序中添加友好URL的slugs。我有新的记录写入slug并在URL中显示，但以前的条目没有更新。不仅如此，从索引视图中，链接已删除了id参数。

以前的参赛作品使用slug我错过了什么？我在应用程序中没有错误。

radio.ex

defmodule Radios.Radio do
  use Radios.Web, :model

  schema "radios" do
    field :name, :string
    field :desc, :string
    field :price, :integer
    field :text1, :string
    field :text2, :string
    field :text3, :string
    field :text4, :string
    field :mainimg, :string
    field :mainimg2, :string
    field :slug, :string

    timestamps()
  end

  @doc """
  Builds a changeset based on the `struct` and `params`.
  """
  def changeset(struct, params \\ %{}) do
    params = Map.merge(params, slug_map(params))
    struct
    |> cast(params, [:name, :desc, :price, :text1, :text2, :text3, :text4, :mainimg, :mainimg2, :slug])
    |> validate_required([:name, :desc, :price, :text1, :text2, :mainimg])
  end

  # for writing URL as radio.name
  defimpl Phoenix.Param, for: Radios.Radio do
    def to_param(%{slug: slug}) do
      "#{slug}"
    end
  end

      defp slug_map(%{"name" => name}) do
        slug = String.downcase(name) |> String.replace(" ", "-")
        %{"slug" => slug}
      end

    defp slug_map(_params) do
    %{}
    end
end

radio_controller.ex

defmodule Radios.RadioController do
  use Radios.Web, :controller
...
  def show(conn, %{"id" => id}) do
    radio = Repo.get_by!(Radio, slug: id)
    render(conn, "show.html", radio: radio)
  end 


...