Connection not closed at TCP level with websocket application

Question

We have a websocket application which keeps writing data to the clients.

We found that when tabs (not whole browser) of Firefox (ver. 22) is closed, the websocket connection is not closed. Anyway, reproducibility is very low. And the sendQ (netstat -an) keeps growing

So, what we did is. we kept sending heart beat from client. If this heart beat timeout occurs, we are trying to close the connection as follows

ByteBuffer bbuff = ByteBuffer.allocate(1);
bbuff.put((byte) 0);
messageInbound.getWsOutbound().close(0, bbuff);

Is this correct approach to close the connection from server? Because, the connection is not closed at lower level (netstat -an). Anyway, writing data to it , is stopped and sendQ stops growing.

# netstat -an | grep :8080
tcp 0 402376 172.22.59.176:8080 198.162.18.207:64805 ESTABLISHED

Comments

A ping from the server followed by a close if no pong is received within a set timeout should be fine.

Answer 1

You can try to close the connection from the client with something like:
document.addEventListener('beforeunload', function() {ws.close();})