[racket] WebSocket server dropping connections

From: Jakub Piotr Cłapa (jpc-ml at zenburn.net)
Date: Tue Feb 8 08:32:27 EST 2011

On 07.02.11 16:19, Jay McCarthy wrote:
> I don't know much about Chrome 10, but is it possible that it has
> dropped support for the old framing mode? The WebSocket implementation
> supports both old and new, but defaults to old because that's what a
> lot of browsers (used to) default to.
> Look at framing-mode in the documentation.

The connections work fine most of the time so I do not think this is a 
problem with handling of the protocol itself. Sorry, I should have been 
more explicit about this in my e-mail.

> It is unlikely that they are being garbage collected, because it uses
> the same "connection manager" machinery as the Web server, that
> retains references to the ports.

Does this machinery kill its threads without warning? Like shutting down 
the custodian after the tcp sockets get closed by the other end?

After inspecting the source code for ws-closed? it also seams to me 
there is no way to find out if a websocket was closed but without proper 
Maybe ws-closed? should also check whether the underlaying sockets are 
open or the ws-send and ws-receive calls could change the ws-conn state 
on any tcp error?

The problem can get magnified by the fact that AFAICT ws-close! will not 
be able to set ws-conn-closed? to #f if there are errors in the shutdown 
sequence (i.e. if write-byte throws an exception).

Jakub Piotr Cłapa

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