feat: send/3 to sends to a NNTP socket

Similar to `gen_tcp:send/2`, but also wait for response from server.

Commands are sent with newline appended.

lib/gen_nntp.ex

@@ -28,6 +28,11 @@ defmodule GenNNTP do
   """
   defdelegate connect(address \\ "localhost", port \\ 119, options \\ []), to: :gen_nntp
 
+  @doc """
+  Sends a command and receives server's response.
+  """
+  defdelegate send(socket, command, args \\ []), to: :gen_nntp
+
   @callback init(any()) ::
     {:ok, state} | {:ok, state, timeout | :hibernate} |
     :ignore | {:stop, reason :: term}

src/gen_nntp.erl

@@ -9,7 +9,9 @@
   connect/0,
   connect/1,
   connect/2,
-  connect/3
+  connect/3,
+  send/2,
+  send/3
 ]).
 
 %% gen_server callbacks
@@ -128,6 +130,19 @@ connect(Address, Port, _Options) ->
       {error, Reason}
   end.
 
+%%-------------------------------------------------------------------
+%% @doc Sends a command to a NNTP socket
+%%
+%% The function will also wait for the response from server.
+%% @end
+%%-------------------------------------------------------------------
+send(Socket, Commamd) ->
+  send(Socket, Commamd, []).
+
+send(Socket, Command, _Args) when is_binary(Command) ->
+  ok = gen_tcp:send(Socket, <<Command/binary, "\r\n">>),
+  gen_tcp:recv(Socket, 0, 1000).
+
 %% ==================================================================
 %% ranch_protocol Callbacks
 %% ==================================================================

test/gen_nntp_test.exs

@@ -75,6 +75,27 @@ defmodule GenNNTPTest do
 
   end
 
+  describe "send/3" do
+
+    setup do
+      GenNNTP.start(TestNNTPServer, [], [])
+      {:ok, socket, _greeting} = GenNNTP.connect()
+
+      %{socket: socket}
+    end
+
+    test "sends QUIT command", %{socket: socket} do
+      assert {:ok, response} = GenNNTP.send(socket, "QUIT", [])
+      assert response =~ ~r/^205 /
+    end
+
+    test "send/2 default to empty arguments", %{socket: socket} do
+      assert {:ok, response} = GenNNTP.send(socket, "QUIT")
+      assert response =~ ~r/^205 /
+    end
+
+  end
+
   describe "@callback init/1" do
 
     test "is called when a client connects to it" do