url encode/decode status-message header

lib/grpc/client/adapters/gun.ex

@@ -185,7 +185,7 @@ defmodule GRPC.Client.Adapters.Gun do
     case :gun.await(conn_pid, stream_ref, timeout) do
       {:response, :fin, status, headers} ->
         if status == 200 do
-          headers = Enum.into(headers, %{})
+          headers = GRPC.Transport.HTTP2.decode_headers(headers)
 
           case headers["grpc-status"] do
             nil ->
@@ -215,7 +215,7 @@ defmodule GRPC.Client.Adapters.Gun do
 
       {:response, :nofin, status, headers} ->
         if status == 200 do
-          headers = Enum.into(headers, %{})
+          headers = GRPC.Transport.HTTP2.decode_headers(headers)
 
           if headers["grpc-status"] && headers["grpc-status"] != "0" do
             {:error,

lib/grpc/transport/http2.ex

@@ -20,7 +20,7 @@ defmodule GRPC.Transport.HTTP2 do
   def server_trailers(status \\ Status.ok(), message \\ "") do
     %{
       "grpc-status" => Integer.to_string(status),
-      "grpc-message" => message
+      "grpc-message" => URI.encode(message)
     }
   end
 
@@ -78,7 +78,7 @@ defmodule GRPC.Transport.HTTP2 do
       if is_metadata(k) do
         decode_metadata({k, v})
       else
-        {k, v}
+        decode_reserved({k, v})
       end
     end)
   end
@@ -142,6 +142,12 @@ defmodule GRPC.Transport.HTTP2 do
     {key, val}
   end
 
+  defp decode_reserved({"grpc-message" = key, val}) do
+    {key, URI.decode(val)}
+  end
+
+  defp decode_reserved(kv), do: kv
+
   defp is_reserved_header(":" <> _), do: true
   defp is_reserved_header("grpc-" <> _), do: true
   defp is_reserved_header("content-type"), do: true

test/grpc/transport/http2_test.exs

@@ -1,6 +1,6 @@
 defmodule GRPC.Transport.HTTP2Test do
   use ExUnit.Case, async: true
-  alias GRPC.Channel
+  alias GRPC.{Channel, Status}
   alias GRPC.Transport.HTTP2
 
   alias GRPC.Client.Stream
@@ -113,4 +113,16 @@ defmodule GRPC.Transport.HTTP2Test do
                HTTP2.server_headers(stream)
     end
   end
+
+  test "decode_headers/2 url decodes grpc-message" do
+    trailers = HTTP2.server_trailers(Status.unknown(), "Unknown error")
+    assert %{"grpc-message" => "Unknown error"} = HTTP2.decode_headers(trailers)
+  end
+
+  test "server_trailers/3 sets url encoded grpc-message" do
+    assert %{"grpc-message" => "Ok"} = HTTP2.server_trailers(Status.ok(), "Ok")
+
+    assert %{"grpc-message" => "Unknown%20error"} =
+             HTTP2.server_trailers(Status.unknown(), "Unknown error")
+  end
 end