From d72ace2ae6cbc3785401c814abbc282031bf6293 Mon Sep 17 00:00:00 2001
From: Pierre Ossman <ossman@cendio.se>
Date: Wed, 30 Sep 2020 14:51:07 +0200
Subject: [PATCH] Allow sending empty messages

This is perfectly valid in the protocol, and may be meningful to some
applications. However send() is still stream oriented so it will ignore
an empty buffer.
---
 websockify/websocket.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/websockify/websocket.py b/websockify/websocket.py
index 03a52f0..a9f85a9 100644
--- a/websockify/websocket.py
+++ b/websockify/websocket.py
@@ -421,6 +421,9 @@ class WebSocket(object):
         WebSocketWantWriteError can be raised if there is insufficient
         space in the underlying socket.
         """
+        if len(bytes) == 0:
+            return 0
+
         return self.sendmsg(bytes)
 
     def sendmsg(self, msg):
@@ -435,8 +438,7 @@ class WebSocket(object):
         """
         if not self._sent_close:
             # Only called to flush?
-            if msg:
-                self._sendmsg(0x2, msg)
+            self._sendmsg(0x2, msg)
 
         self._flush()
         return len(msg)