From 8076ea4316ef42d70ec82e228c48beac1b2d405d Mon Sep 17 00:00:00 2001
From: Michael Ries <riesmmm@gmail.com>
Date: Sat, 15 Oct 2022 10:43:38 +0100
Subject: [PATCH] parse status and description from headers

---
 lib/gnat/parsec.ex        | 20 +++++++++++++++++---
 test/gnat/parsec_test.exs | 16 ++++++++++++----
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/lib/gnat/parsec.ex b/lib/gnat/parsec.ex
index 4f31662..552264e 100644
--- a/lib/gnat/parsec.ex
+++ b/lib/gnat/parsec.ex
@@ -115,9 +115,23 @@ defmodule Gnat.Parsec do
 
   def parse_headers("NATS/1.0" <> rest) do
     case String.split(rest, "\r\n", parts: 2) do
+      [" " <> status, headers] ->
+
+        case :cow_http.parse_headers(headers) do
+          {parsed, ""} ->
+            case String.split(status, " ", parts: 2) do
+              [status, description] ->
+                {:ok, status, description, parsed}
+              [status] ->
+                {:ok, status, nil, parsed}
+            end
+
+          _other ->
+            {:error, "Could not parse headers"}
+        end
       [_status_line, headers] ->
         case :cow_http.parse_headers(headers) do
-          {parsed, ""} -> {:ok, parsed}
+          {parsed, ""} -> {:ok, nil, nil, parsed}
           _other -> {:error, "Could not parse headers"}
         end
       _other ->
@@ -142,8 +156,8 @@ defmodule Gnat.Parsec do
     payload_length = total_length - header_length
     case rest do
       << headers::size(header_length)-binary, payload::size(payload_length)-binary, "\r\n", rest::binary>> ->
-        {:ok, headers} = parse_headers(headers)
-        {:ok, {:hmsg, subject, sid, reply_to, headers, payload}, rest}
+        {:ok, status, description, headers} = parse_headers(headers)
+        {:ok, {:hmsg, subject, sid, reply_to, status, description, headers, payload}, rest}
       _other ->
         {:error, string}
     end
diff --git a/test/gnat/parsec_test.exs b/test/gnat/parsec_test.exs
index 6d39f21..1499c33 100644
--- a/test/gnat/parsec_test.exs
+++ b/test/gnat/parsec_test.exs
@@ -39,7 +39,7 @@ defmodule Gnat.ParsecTest do
 
     {state, [parsed]} = Parsec.new() |> Parsec.parse(binary)
     assert state.partial == nil
-    assert parsed == {:hmsg, "SUBJECT", 1, nil, [{"header", "X"}], "PAYLOAD"}
+    assert parsed == {:hmsg, "SUBJECT", 1, nil, nil, nil, [{"header", "X"}], "PAYLOAD"}
   end
 
   test "parsing messages with headers - single header" do
@@ -47,7 +47,7 @@ defmodule Gnat.ParsecTest do
 
     {state, [parsed]} = Parsec.new() |> Parsec.parse(binary)
     assert state.partial == nil
-    assert parsed == {:hmsg, "SUBJECT", 1, "REPLY",[{"header", "X"}], "PAYLOAD"}
+    assert parsed == {:hmsg, "SUBJECT", 1, "REPLY", nil, nil, [{"header", "X"}], "PAYLOAD"}
   end
 
   # This example comes from https://github.com/nats-io/nats-architecture-and-design/blob/cb8f68af6ba730c00a6aa174dedaa217edd9edc6/adr/ADR-9.md
@@ -56,7 +56,7 @@ defmodule Gnat.ParsecTest do
 
     {state, [parsed]} = Parsec.new() |> Parsec.parse(binary)
     assert state.partial == nil
-    assert parsed == {:hmsg, "my.messages", 2, nil,[{"nats-last-consumer", "0"}, {"nats-last-stream", "0"}], ""}
+    assert parsed == {:hmsg, "my.messages", 2, nil, "100", "Idle Heartbeat", [{"nats-last-consumer", "0"}, {"nats-last-stream", "0"}], ""}
   end
 
   # This example comes from https://github.com/nats-io/nats-architecture-and-design/blob/682d5cd5f21d18502da70025727128a407655250/adr/ADR-13.md
@@ -65,7 +65,15 @@ defmodule Gnat.ParsecTest do
 
     {state, [parsed]} = Parsec.new() |> Parsec.parse(binary)
     assert state.partial == nil
-    assert parsed == {:hmsg, "_INBOX.x7tkDPDLCOEknrfB4RH1V7.OgY4M7", 2, nil, [], ""}
+    assert parsed == {:hmsg, "_INBOX.x7tkDPDLCOEknrfB4RH1V7.OgY4M7", 2, nil, "404", "No Messages", [], ""}
+  end
+
+  test "parsing no_responders messages" do
+    binary = "HMSG _INBOX.10ahfXw89Nx5htVf.7Il73yuah/RHW6w8 0 16 16\r\nNATS/1.0 503\r\n\r\n\r\n"
+
+    {state, [parsed]} = Parsec.new() |> Parsec.parse(binary)
+    assert state.partial == nil
+    assert parsed == {:hmsg, "_INBOX.10ahfXw89Nx5htVf.7Il73yuah/RHW6w8", 0, nil, "503", nil, [], ""}
   end
 
   test "parsing PING message" do