AsyncWebSocket disconnected by client after 100s

[keduro]

This is my first post (so please take it easy on me); I would like to share an issue I've been having and how I resolved it. I have an ESP8266 running ESPAsyncWebServer which connects to a .net ClientWebSocket. Client connected just fine, websocket dialogue ensued, then after 100 seconds the client closed the connection. Google revealed the following similar issues .NET WebSockets forcibly closed despite keep-alive and activity on the connection and WebSocket Implementation Disconnects Every 100 Seconds

Critically If a "Content-Length: 0" header is included in the "101 Switching Protocols" response from a WebSocket server, WebSocketClient gets confused and schedules the connection for cleanup in 100 seconds. and According to RFC 7230 Section 3.3.2, Content-Length is prohibited in 1xx (Informational) messages. Using Wireshark I confirmed that the ESPAsyncWebServer was indeed including the "Content-Length: 0" header in the "101 Switching Protocols" response.

I have successfully resolved the issue by adding line

_sendContentLength = false;

after

_server = server;
_code = 101;

at the top of AsyncWebSocketResponse::AsyncWebSocketResponse in AsyncWebSocket.cpp.

Now the client happily remains connected to the server. 😃 😃 😃

Also want to say what a great library ESPAsyncWebServer is. Had been using ESP8266WebServer and not only was it slow but http: page requests to the server often resulted in corrupted websocket messages and exceptions being raised in the client. None of that now.

[me-no-dev]

Hahaha :D Thanks for the good find and the fact that you even took care of resolving it. Let me have a look and update :)