Node.js how to respond to an upgrade request?

Question

I'm handling a websocket 'upgrade' event from a Node.js http server - The upgrade handler is in the form function(req, socket, head) - How can I send a response to this upgrade request given that there is no res object? Is there a way to do it using the socket object? How to send back headers?

Answer 1

You just need to call socket.write with the appropriate HTTP syntax as plain text along these lines (from wikipedia):

HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: HSmrc0sMlYUkAGmm5OPpG2HaGWk=
Sec-WebSocket-Protocol: chat

Use \r\n line separators. After that point, HTTP is over and now you are just using the bare TCP socket.