As far as I can tell, there are 2 values that matter here: the server sends heartbeats to the client every
heartbeat interval seconds; the client responds directly, if there is no response, the server decides the client is dead. The client waits for a heartbeat from the server for
heartbeat timeout seconds since the last heartbeat (which should obviously be higher than the
heartbeat interval). If it hasn't received word from the server in
heartbeat timeout seconds, it assumes the server is dead (and will start disconnecting / reconnecting based on the other options you have set.
Default values are
heartbeat interval = 25s and
heartbeat timeout = 60s. Both items are set on the server, the
heartbeat timeout is sent to the client upon connecting.
heartbeat timeout for a single client is easy:
var socket = io.connect(url);
socket.heartbeatTimeout = 20000; // reconnect if not received heartbeat for 20 seconds
However on the server, the
heartbeat interval value seems to be part of a shared object (the Manager, which is what you get back from your
var io = require("socket.io").listen(server) call), which means that it can't easily be changed for individual sockets.
I'm sure that with some socket.io hacking you should be able to make it happen, but you might break other stuff in the process...