@Override public Mono<Void> execute(URI url, HttpHeaders requestHeaders, WebSocketHandler handler) { return getHttpClient() .headers(nettyHeaders -> setNettyHeaders(requestHeaders, nettyHeaders)) .websocket(StringUtils.collectionToCommaDelimitedString(handler.getSubProtocols())) .uri(url.toString()) .handle((inbound, outbound) -> { HttpHeaders responseHeaders = toHttpHeaders(inbound); String protocol = responseHeaders.getFirst("Sec-WebSocket-Protocol"); HandshakeInfo info = new HandshakeInfo(url, responseHeaders, Mono.empty(), protocol); NettyDataBufferFactory factory = new NettyDataBufferFactory(outbound.alloc()); WebSocketSession session = new ReactorNettyWebSocketSession(inbound, outbound, info, factory); if (logger.isDebugEnabled()) { logger.debug("Started session '" + session.getId() + "' for " + url); } return handler.handle(session); }) .doOnRequest(n -> { if (logger.isDebugEnabled()) { logger.debug("Connecting to " + url); } }) .next(); }