From 62c4253ed35ba37887fcabd6e740cb28cff16dad Mon Sep 17 00:00:00 2001
From: Alex Hultman <alexhultman@gmail.com>
Date: Tue, 8 Oct 2019 23:10:58 +0200
Subject: [PATCH] Add subprotocol response

---
 src/App.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/App.h b/src/App.h
index e1399a3..2a9095a 100644
--- a/src/App.h
+++ b/src/App.h
@@ -149,6 +149,12 @@ public:
                     ->writeHeader("Connection", "Upgrade")
                     ->writeHeader("Sec-WebSocket-Accept", secWebSocketAccept);
 
+                /* Select first subprotocol if present */
+                std::string_view secWebSocketProtocol = req->getHeader("sec-websocket-protocol");
+                if (secWebSocketProtocol.length()) {
+                    res->writeHeader("Sec-WebSocket-Protocol", secWebSocketProtocol.substr(0, secWebSocketProtocol.find(',')));
+                }
+
                 /* Negotiate compression */
                 bool perMessageDeflate = false;
                 bool slidingDeflateWindow = false;