From: "Firestone, Mark - Technical Support" <mark.firestone@...>
Date: 2002-06-22T05:22:22+09:00
Subject: RE: detecting a socket dropping in multi-threaded app

Thanks for your reply.  I had tried doing what you described, and it never
generates an exception.  It just sits there.

If I set abort on exception = true, then the @socket.write command before
the interator generates an exception I can trap, just before the whole
program abends.

I tried testing for nils after the @socket.eachbyte, but that doesn't work
either.  I am not sure where to go from here.. ideas?  I don't understand
your ping idea, as the client is a telnet session.  Maybe I am being
thick...


Thanks,

Mark

> -----Original Message-----
> From:	why@rysa.inetz.com [SMTP:why@rysa.inetz.com]
> Sent:	21 June 2002 18:48
> To:	ruby-talk@ruby-lang.org
> Subject:	Re: detecting a socket dropping in multi-threaded app
> 
> Firestone, Mark - Technical Support (mark.firestone@gossgraphic.co.uk)
> wrote:
> > I'm still working on my Ruby BBS project.  I need to be able to run some
> > code when a user drops offline without logging off.  Right now, Ruby is
> just
> > killing the thread.  I need to know how to make it pass an exception (or
> > something) back to the main loop so the main loop can take the user out
> of
> > the online user database.  I've tried testing for nil and raising an
> > exception, but it doesn't seem to work.  Help please!! You guys never
> let me
> > down.
> > 
> > thanks in advance!
> > 
> > Mark
> 
> First, I don't see any begin..rescue around your TCPSocket#each_byte:
> 
>   begin
>     @sock.each_byte do |fred|
>       # Process bytes sent     
>     end
>   rescue
>     # Handle exception here..
>   end
> 
> I find the surest way of finding a disconnect is to implement a simple
> PING request from the server to the client.  It looks like your byte
> commands could include a PING response from the client.  I just run a
> separate thread that periodically checks that the PING count is climbing..
> Then, set Thread#abort_on_exception = false so you can make sure that only
> clients that don't return pings get killed.  If you go this route, then
> don't forget to use a mutex.
> 
> -- 
> 
> Jonathan Gillette
> iNetZ Media
> 
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