(websocket) fix #167, a long standing issue with sending empty messages with per-message deflate extension (and hopefully other zlib bug)

docs/CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 All changes to this project will be documented in this file.
 
+## [8.3.4] - 2020-03-23
+
+(websocket) fix #167, a long standing issue with sending empty messages with per-message deflate extension (and hopefully other zlib bug)
+
 ## [8.3.3] - 2020-03-22
 
 (cobra to statsd) port to windows and add a unittest

ixwebsocket/IXUdpSocket.cpp

@@ -7,8 +7,8 @@
 #include "IXUdpSocket.h"
 
 #include "IXNetSystem.h"
-#include <sstream>
 #include <cstring>
+#include <sstream>
 
 namespace ix
 {

ixwebsocket/IXWebSocketPerMessageDeflateCodec.cpp

@@ -89,8 +89,12 @@ namespace ix
 
         if (in.empty())
         {
-            uint8_t buf[6] = {0x02, 0x00, 0x00, 0x00, 0xff, 0xff};
+            // See issue #167
-            out.append((char*) (buf), 6);
+            // The normal buffer size should be 6 but
+            // we remove the 4 octets from the tail (#4)
+            uint8_t buf[2] = {0x02, 0x00};
+            out.append((char*) (buf), 2);
+
             return true;
         }
 

ixwebsocket/IXWebSocketVersion.h

@@ -6,4 +6,4 @@
 
 #pragma once
 
-#define IX_WEBSOCKET_VERSION "8.3.3"
+#define IX_WEBSOCKET_VERSION "8.3.4"