From 2afe6a6efb06176ebeee279bfada49f44ab07d5d Mon Sep 17 00:00:00 2001
From: Alex Hultman <alexhultman@gmail.com>
Date: Fri, 1 Mar 2019 15:43:20 +0100
Subject: [PATCH] Only set sec-websocket-extensions if we have an offer

---
 src/App.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/App.h b/src/App.h
index 3fa5020..c608e71 100644
--- a/src/App.h
+++ b/src/App.h
@@ -169,7 +169,10 @@ public:
                         extensionsNegotiator.readOffer(extensions);
 
                         /* Todo: remove these mid string copies */
-                        res->writeHeader("Sec-WebSocket-Extensions", extensionsNegotiator.generateOffer());
+                        std::string offer = extensionsNegotiator.generateOffer();
+                        if (offer.length()) {
+                            res->writeHeader("Sec-WebSocket-Extensions", offer);
+                        }
 
                         /* Did we negotiate permessage-deflate? */
                         if (extensionsNegotiator.getNegotiatedOptions() & PERMESSAGE_DEFLATE) {