Practicing Elixir by using exercise from Programming Erlang 2nd edition

file_server_v1.ex

defmodule FileServer do
  @doc """
  starting FileServer process.
  """
  def start(dir \\ ".") do
    spawn(FileServer, :loop, [dir])
  end

  def loop(dir) do
    receive do
      {client, :list_dir} ->
        send(client, {self(), :file.list_dir(dir)})

      {client, {:get_file, file}} ->
        full = :filename.join(dir, file)
        send(client, {self(), :file.read_file(full)})
    end
  end
end

defmodule FileClient do
  @doc """
  list file and directory on server.
  """
  def ls(server) do
    send(server, {self(), :list_dir})

    receive do
      {^server, dir} -> dir
    end
  end

  @doc """
  get file on server.
  """
  def get_file(server, file) do
    send(server, {self(), {:get_file, file}})

    receive do
      {^server, content} ->
        content
    end
  end
end

file_server_v2.ex

defmodule FileServer do
  @doc """
  starting FileServer process.
  """
  def start(dir \\ ".") do
    spawn(FileServer, :loop, [dir])
  end

  def loop(dir) do
    receive do
      {client, :list_dir} ->
        send(client, {self(), File.ls(dir)})

      {client, {:get_file, file}} ->
        full = Path.join([dir, file])
        send(client, {self(), File.read(full)})
    end
  end
end

defmodule FileClient do
  @doc """
  list file and directory on server.
  """
  def ls(server) do
    send(server, {self(), :list_dir})

    receive do
      {^server, dir} -> dir
    end
  end

  @doc """
  get file on server.
  """
  def get_file(server, file) do
    send(server, {self(), {:get_file, file}})

    receive do
      {^server, content} ->
        content
    end
  end
end