Add Endpoints behaviour and refactor router and related methods

dialyzer.ignore-warnings

@@ -0,0 +1,11 @@
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.Atom':'__impl__'/1
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.BitString':'__impl__'/1
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.Float':'__impl__'/1
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.Function':'__impl__'/1
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.Integer':'__impl__'/1
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.List':'__impl__'/1
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.Map':'__impl__'/1
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.PID':'__impl__'/1
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.Port':'__impl__'/1
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.Reference':'__impl__'/1
+:0: Unknown function 'Elixir.Shortnr.Transport.Text.Encodable.Tuple':'__impl__'/1

lib/router.ex

@@ -3,57 +3,27 @@ defmodule Shortnr.Router do
   This module contains the Router for the Shortnr application. Do not import, other than
   Application entry.
   """
-  use Plug.ErrorHandler
-  use Plug.Router
+  alias Shortnr.Transport.HTTP
+  alias Shortnr.URL
 
   require Logger
 
-  alias Shortnr.Transport.{HTTP, Text}
-  alias Shortnr.URL
+  use Plug.ErrorHandler
+  use Plug.Router
 
   plug(Plug.Logger, log: :debug)
   plug(:match)
   plug(:dispatch)
 
-  get "/" do
-    conn
-    |> HTTP.wrap()
-    |> HTTP.handle(fn -> URL.list(URL.Repo.ETS) end)
-    |> Text.encode_response()
-    |> HTTP.send(:ok)
-  end
+  # BEGIN URL routes
+  post("/urls/:url", do: URL.Endpoints.select(conn, :create, url))
 
-  post "/urls/:url" do
-    conn
-    |> HTTP.wrap(url)
-    |> HTTP.handle(&URL.create(&1, URL.Repo.ETS))
-    |> Text.encode_response()
-    |> HTTP.send(:created)
-  end
+  get("/", do: URL.Endpoints.select(conn, :list))
+  get("/urls", do: URL.Endpoints.select(conn, :list))
+  get("/:id", do: URL.Endpoints.select(conn, :get, id))
 
-  get "/urls" do
-    conn
-    |> HTTP.wrap()
-    |> HTTP.handle(fn -> URL.list(URL.Repo.ETS) end)
-    |> Text.encode_response()
-    |> HTTP.send(:ok)
-  end
-
-  get "/:id" do
-    conn
-    |> HTTP.wrap(id)
-    |> HTTP.handle(&URL.get(&1, URL.Repo.ETS))
-    |> Text.encode_response()
-    |> HTTP.send(:found)
-  end
-
-  delete "/:id" do
-    conn
-    |> HTTP.wrap(id)
-    |> HTTP.handle(&URL.delete(&1, URL.Repo.ETS))
-    |> Text.encode_response()
-    |> HTTP.send(:ok)
-  end
+  delete("/:id", do: URL.Endpoints.select(conn, :delete, id))
+  # END
 
   match _ do
     conn

lib/shortnr.ex

@@ -3,15 +3,13 @@ defmodule Shortnr do
   The Shortnr application entry point. Check README for usage documenation.
   """
 
-  use Application
   require Logger
+  use Application
 
-  @impl true
+  @impl Application
   def start(_type, _args) do
-    port = port()
-
     children = [
-      {Plug.Cowboy, scheme: :http, plug: Shortnr.Router, options: [port: port]}
+      {Plug.Cowboy, scheme: :http, plug: Shortnr.Router, options: [port: port()]}
     ]
 
     if ets_implementation() == :dets do
@@ -20,11 +18,11 @@ defmodule Shortnr do
       :ets.new(:urls, [:set, :named_table])
     end
 
-    Logger.info("server starting", port: port)
+    Logger.info("server starting", port: port())
     Supervisor.start_link(children, strategy: :one_for_one)
   end
 
-  @impl true
+  @impl Application
   def stop(_state) do
     if ets_implementation() == :dets, do: :dets.close(:urls)
   end

lib/transport/http.ex

@@ -64,3 +64,12 @@ defmodule Shortnr.Transport.HTTP do
   defp status_to_code(:not_found), do: 404
   defp status_to_code(:internal_server_error), do: 500
 end
+
+defmodule Shortnr.Transport.HTTP.Endpoints do
+  @moduledoc """
+  This modules is a behaviour that should be implemented by each service that needs to be routed by
+  Plug.Router
+  """
+
+  @callback select(Plug.Conn.t(), atom, term) :: Plug.Conn.t()
+end

lib/transport/text.ex

@@ -3,28 +3,29 @@ defmodule Shortnr.Transport.Text do
   This modules contains functions to decode and encode text formatted http requests and responses.
   """
 
-  import Plug.Conn
   alias Shortnr.Transport.HTTP
   alias Shortnr.Transport.Text.Encodable
 
-  @spec decode_request(Plug.Conn.t()) :: HTTP.ok_error()
-  def decode_request(conn) do
+  import Plug.Conn
+
+  @spec decode(HTTP.ok_error()) :: HTTP.ok_error()
+  def decode({:ok, _body, conn}) do
     {:ok, body, conn} = read_body(conn)
     {:ok, body, conn}
   end
 
-  @spec encode_response(HTTP.ok_error()) :: HTTP.ok_error()
-  def encode_response(ok_error = {:error, _, _}), do: ok_error
+  @spec encode(HTTP.ok_error()) :: HTTP.ok_error()
+  def encode(ok_error = {:error, _, _}), do: ok_error
 
-  def encode_response({:ok, [], conn}) do
+  def encode({:ok, [], conn}) do
     {:ok, "", conn}
   end
 
-  def encode_response({:ok, body, conn}) when is_list(body) do
+  def encode({:ok, body, conn}) when is_list(body) do
     {:ok, for(item <- body, into: "", do: "#{item}\n"), conn}
   end
 
-  def encode_response({:ok, body, conn}) do
+  def encode({:ok, body, conn}) do
     {:ok, Encodable.encode(body), conn}
   end
 end

lib/url/endpoints.ex

@@ -0,0 +1,45 @@
+defmodule Shortnr.URL.Endpoints do
+  @moduledoc """
+  This module implements the Endpoints behaviour.
+  """
+  alias Shortnr.Transport.{HTTP, Text}
+  alias Shortnr.Transport.HTTP.Endpoints
+  alias Shortnr.URL
+
+  @behaviour Endpoints
+
+  @impl Endpoints
+  def select(conn, name, arg \\ nil)
+
+  def select(conn, :list, _arg) do
+    conn
+    |> HTTP.wrap()
+    |> HTTP.handle(fn -> URL.list(URL.Repo.ETS) end)
+    |> Text.encode()
+    |> HTTP.send(:ok)
+  end
+
+  def select(conn, :create, url) do
+    conn
+    |> HTTP.wrap(url)
+    |> HTTP.handle(&URL.create(&1, URL.Repo.ETS))
+    |> Text.encode()
+    |> HTTP.send(:created)
+  end
+
+  def select(conn, :get, id) do
+    conn
+    |> HTTP.wrap(id)
+    |> HTTP.handle(&URL.get(&1, URL.Repo.ETS))
+    |> Text.encode()
+    |> HTTP.send(:found)
+  end
+
+  def select(conn, :delete, id) do
+    conn
+    |> HTTP.wrap(id)
+    |> HTTP.handle(&URL.delete(&1, URL.Repo.ETS))
+    |> Text.encode()
+    |> HTTP.send(:ok)
+  end
+end

lib/url/repo/ets.ex

@@ -2,10 +2,11 @@ defmodule Shortnr.URL.Repo.ETS do
   @moduledoc """
   This module is an implemention of the Repo behaviour using the Erlang ETS library.
   """
+  alias Shortnr.URL.Repo
 
-  @behaviour Shortnr.URL.Repo
+  @behaviour Repo
 
-  @impl true
+  @impl Repo
   def get(key) do
     case ets().lookup(:urls, key) |> List.first() do
       {_, url} -> {:ok, url}
@@ -13,25 +14,25 @@ defmodule Shortnr.URL.Repo.ETS do
     end
   end
 
-  @impl true
+  @impl Repo
   def put(url) do
     :ok = ets().insert(:urls, {url.id, url})
     :ok
   end
 
-  @impl true
+  @impl Repo
   def list do
     resp = ets().select(:urls, [{:"$1", [], [:"$1"]}])
     {:ok, resp |> Enum.map(&elem(&1, 1))}
   end
 
-  @impl true
+  @impl Repo
   def delete(key) do
     :ok = ets().delete(:urls, key)
     :ok
   end
 
-  @impl true
+  @impl Repo
   def reset do
     :ok = ets().delete_all_objects(:urls)
   end

mix.exs

@@ -8,6 +8,7 @@ defmodule Shortnr.MixProject do
       version: "0.1.0",
       elixir: "~> 1.9",
       start_permanent: Mix.env() == :prod,
+      dialyzer: [ignore_warnings: "dialyzer.ignore-warnings"],
       deps: deps()
     ]
   end