Merge pull request #12 from wowica/response-cleanup

Response cleanup

Author: daveminer

lib/xander/messages.ex

@@ -18,21 +18,38 @@ defmodule Xander.Messages do
   # See the CDDL for details on mapping of messages to numbers.
   # https://github.com/IntersectMBO/ouroboros-network/blob/main/ouroboros-network-protocols/cddl/specs/local-state-query.cddl
   @message_query 3
-  @message_acquire 8
-  @message_release 5
+  @message_acquire [8]
+  @message_release [5]
 
-  def msg_acquire do
-    header = [<<0, 0, 44, 137, 0, 7, 0, 2>>]
-    payload = [<<129, @message_acquire>>]
+  @doc """
+  Acquires a snapshot of the mempool, allowing the protocol to make queries.
+
+  ## Examples
 
-    [header | payload]
+      iex> <<_timestamp::32, msg::binary>> = Xander.Messages.msg_acquire()
+      iex> msg
+      <<0, 7, 0, 2, 129, 8>>
+
+  """
+  def msg_acquire do
+    payload = CBOR.encode(@message_acquire)
+    header(@mini_protocols.local_state_query, payload) <> payload
   end
 
-  def msg_release do
-    header = [<<0, 0, 167, 211, 0, 7, 0, 2>>]
-    payload = [<<129, @message_release>>]
+  @doc """
+  Releases the current snapshot of the mempool, allowing the protocol to return
+  to the idle state.
+
+  ## Examples
 
-    [header | payload]
+      iex> <<_timestamp::32, msg::binary>> = Xander.Messages.msg_release()
+      iex> msg
+      <<0, 7, 0, 2, 129, 5>>
+
+  """
+  def msg_release do
+    payload = CBOR.encode(@message_release)
+    header(@mini_protocols.local_state_query, payload) <> payload
   end
 
   @doc """

lib/xander/query.ex

@@ -147,10 +147,10 @@ defmodule Xander.Query do
         {_tcp_or_ssl, socket, bytes},
         %__MODULE__{socket: socket} = data
       ) do
-    {:ok, current_era} = Response.parse_response(bytes)
+    {:ok, query_response} = Response.parse_response(bytes)
     {{:value, caller}, data} = get_and_update_in(data.queue, &:queue.out/1)
-    # This action issues the response back to the clinet
-    actions = [{:reply, caller, {:ok, current_era}}]
+    # This action issues the response back to the client
+    actions = [{:reply, caller, {:ok, query_response}}]
     {:keep_state, data, actions}
   end
 

lib/xander/query/response.ex

@@ -2,16 +2,22 @@ defmodule Xander.Query.Response do
   # See the CDDL for details on mapping of messages to numbers.
   # https://github.com/IntersectMBO/ouroboros-network/blob/main/ouroboros-network-protocols/cddl/specs/local-state-query.cddl
   @message_response 4
+  @slot_timeline 1
 
   def parse_response(full_response) do
-    <<_header_todo_investigate::binary-size(8), response_payload::binary>> = full_response
+    %{payload: response_payload} = Xander.Util.plex(full_response)
 
     case CBOR.decode(response_payload) do
       {:ok, decoded, ""} -> parse_cbor(decoded)
       {:error, _reason} -> {:error, :error_decoding_cbor}
     end
   end
 
+  # For get_current_block_height
+  defp parse_cbor([@message_response, [@slot_timeline, response]]) do
+    {:ok, response}
+  end
+
   defp parse_cbor([@message_response, response]) do
     {:ok, response}
   end

lib/xander/util.ex

@@ -1,10 +1,17 @@
 defmodule Xander.Util do
   @doc """
-  Unwrap the multiplexer header from the CDDL message.
+  Unwrap the multiplexer header from a CDDL message. This can be used to
+  extract the payload from node responses.
+
+  ## Examples
+
+      iex> Xander.Util.plex(<<0, 0, 0, 0, 1, 2, 0, 3, 97, 98, 99>>)
+      %{payload: <<97, 98, 99>>, protocol_id: <<1, 2>>, size: <<0, 3>>}
+
   """
   @spec plex(binary) :: map()
   def plex(msg) do
-    <<_ts::binary-size(4), protocol_id::binary-size(2), payload_size::binary-size(2),
+    <<_timestamp::binary-size(4), protocol_id::binary-size(2), payload_size::binary-size(2),
       payload::binary>> = msg
 
     %{payload: payload, protocol_id: protocol_id, size: payload_size}

test/xander/util_test.exs

@@ -0,0 +1,5 @@
+defmodule Xander.UtilTest do
+  use ExUnit.Case
+
+  doctest Xander.Util
+end