DPL Websocket: Add protocol param to encode_websocket_handshake_reply which allows a response Sec-WebSocket-Accept in handshake. (#14687)

DPL Websocket: Add overloaded encode_websocket_handshake_reply which allows a response Sec-WebSocket-Accept in handshake.

Author: nicolaspoffley

Framework/Core/src/DPLWebSocket.cxx

@@ -276,7 +276,7 @@ void WSDPLHandler::endHeaders()
   }
   /// Create an appropriate reply
   LOG(debug) << "Got upgrade request with nonce " << mHeaders["sec-websocket-key"].c_str();
-  std::string reply = encode_websocket_handshake_reply(mHeaders["sec-websocket-key"].c_str());
+  std::string reply = encode_websocket_handshake_reply(mHeaders["sec-websocket-key"].c_str(), "dpl");
   mHandshaken = true;
 
   uv_buf_t bfr = uv_buf_init(strdup(reply.data()), reply.size());

Framework/Core/src/HTTPParser.cxx

@@ -214,15 +214,16 @@ std::string HTTPParserHelpers::calculateAccept(const char* nonce)
   return fmt::format("{}", base);
 }
 
-std::string encode_websocket_handshake_reply(char const* nonce)
+std::string encode_websocket_handshake_reply(char const* nonce, const char* protocol)
 {
   constexpr auto res =
     "HTTP/1.1 101 Switching Protocols\r\n"
     "Upgrade: websocket\r\n"
     "Connection: Upgrade\r\n"
     "Access-Control-Allow-Origin: \"*\"\r\n"
+    "{}"
     "Sec-WebSocket-Accept: {}\r\n\r\n";
-  return fmt::format(res, HTTPParserHelpers::calculateAccept(nonce));
+  return fmt::format(res, protocol && protocol[0] ? fmt::format("Sec-WebSocket-Protocol: {}\r\n", protocol) : "", HTTPParserHelpers::calculateAccept(nonce));
 }
 
 void parse_http_request(char* start, size_t size, HTTPParser* parser)

Framework/Core/src/HTTPParser.h

@@ -125,7 +125,8 @@ std::string encode_websocket_handshake_request(const char* path, const char* pro
 
 /// Encodes the server reply for a given websocket connection
 /// @a nonce the nonce of the request.
-std::string encode_websocket_handshake_reply(char const* nonce);
+/// @a protocol the websocket subprotocol to confirm (optional)
+std::string encode_websocket_handshake_reply(char const* nonce, char const* protocol = "");
 
 /// Encodes the buffer @a src which is @a size long to a number of buffers suitable to be sent via libuv.
 /// If @a binary is provided the binary bit is set.