conn.Close() actually doesn't Close !

[dev-tathkarah]

I was facing an issue and i have reported it

gofiber/contrib#698

i feels like i have to report the same here also as the underlying websocket connection is fasthttp/websocket

I am getting issue from :

websocket/conn.go

Lines 346 to 354 in 82c8017

	func (c *Conn) Close() error {
	if c == nil {
	return ErrNilConn
	}
	if c.conn == nil {
	return ErrNilNetConn
	}
	return c.conn.Close()
	}

The Close() is working and returning nil. So it should be closing the underlying connection also but the client(i was using postman) is still connected even after i have called Close() and client can still send the message into the socket connection.

Any assistance from your side is highly appreciated

[corani]

Close() closes the underlying TCP connection, which is correct — but the client (Postman in your case) only learns the connection is gone when its own TCP stack processes the FIN segment and surfaces it, which may not happen until it next attempts to send or receive.

However, the deeper issue is that Close() is a hard TCP-level close with no WebSocket closing handshake. The correct way to close a WebSocket connection is to send a Close frame and wait for the peer to echo it back, as described in RFC 6455 §7.1:

  conn.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
  // then drain reads until you get an error

This gives the client a clean signal to close, which is why Postman (and other clients) may appear to stay connected when you use Close() directly; they never received a Close frame telling them to shut down.

Use Close() only as a last resort when you need to abort the connection immediately (e.g. after a protocol error or timeout).