From a33ee7c29b13e4eb61322bbc71505cae59457de6 Mon Sep 17 00:00:00 2001
From: William Yang <mscame@gmail.com>
Date: Sun, 2 Jul 2023 21:22:45 +0200
Subject: [PATCH] feat(api): quicer:negotiated_protocol/1

---
 src/quicer.erl        | 6 ++++++
 test/quicer_SUITE.erl | 1 +
 2 files changed, 7 insertions(+)

diff --git a/src/quicer.erl b/src/quicer.erl
index 796948e3..65d84b19 100644
--- a/src/quicer.erl
+++ b/src/quicer.erl
@@ -78,6 +78,7 @@
         , setopt/4
         , get_stream_id/1
         , getstat/2
+        , negotiated_protocol/1
         , peername/1
         , listeners/0
         , listener/1
@@ -817,6 +818,11 @@ getstat(Conn, Cnts) ->
       {ok, CntRes}
   end.
 
+%% @doc Returns the protocol negotiated through ALPN or NPN extensions.
+-spec negotiated_protocol(Conn::connection_handle()) -> {ok, Protocol::binary()} | {error, Reason::any()}.
+negotiated_protocol(Conn) ->
+  quicer:getopt(Conn, param_tls_negotiated_alpn, quic_tls).
+
 %% @doc Peer name
 %% mimic {@link ssl:peername/1}
 -spec peername(connection_handle()  | stream_handle()) ->
diff --git a/test/quicer_SUITE.erl b/test/quicer_SUITE.erl
index 69878815..dd81eff5 100644
--- a/test/quicer_SUITE.erl
+++ b/test/quicer_SUITE.erl
@@ -1844,6 +1844,7 @@ tc_alpn(Config) ->
       {ok, Conn} = quicer:connect("localhost", Port, default_conn_opts(), 5000),
       {ok, {_, _}} = quicer:sockname(Conn),
       {ok, <<"sample">>} = quicer:getopt(Conn, param_tls_negotiated_alpn, quic_tls),
+      {ok, <<"sample">>} = quicer:negotiated_protocol(Conn),
       ok = quicer:close_connection(Conn),
       SPid ! done
   after 1000 ->