From 64be3e410c3828dc6250c12b401d41f2d7e8ea0b Mon Sep 17 00:00:00 2001
From: Matthew Holt <mholt@users.noreply.github.com>
Date: Fri, 22 Sep 2017 17:39:18 -0600
Subject: [PATCH] websocket: Avoid multiple calls to WriteHeader if Upgrade
 fails

---
 caddyhttp/websocket/websocket.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/caddyhttp/websocket/websocket.go b/caddyhttp/websocket/websocket.go
index 3bead97b0..a0188bd4a 100644
--- a/caddyhttp/websocket/websocket.go
+++ b/caddyhttp/websocket/websocket.go
@@ -86,7 +86,9 @@ func serveWS(w http.ResponseWriter, r *http.Request, config *Config) (int, error
 	}
 	conn, err := upgrader.Upgrade(w, r, nil)
 	if err != nil {
-		return http.StatusBadRequest, err
+		// the connection has been "handled" -- WriteHeader was called with Upgrade,
+		// so don't return an error status code; just return an error
+		return 0, err
 	}
 	defer conn.Close()