Hi all, I'm trying to figure out whether this has been done before and/or looking for suggestions on the best way to implement it.
I would like the "publish" clients to connect to a server, then publish their message and disconnect. (Optionally, they can stay connected and publish more messages.) The "subscribe" clients would hold persistent connections to the server (there are only 2 subscribers, though there could be more) and receive the messages immediately after publication. My first crack at implementing this involves forks and pipe opens where the publisher is given a list of filehandles which are (mostly) subscribers. This drops some messages on the floor rather than sending them to the subscriber iff the publishers get in race (and repeating the race condition is difficult), but at least the overall form is roughly what I had in mind. http://scratchcomputing.com/svn/misc/pubsubserver To put that in some rough but short code: my $fh; while(my $client = $socket->accept()) { my $pid = open($fh, '|-') and next; if(pub) { while(<$client>) { print $fh $_ } } else { while(<>) { relay_to_subscriber($client) } } exit; } Nevermind the piped open, I'll probably just fork and use tempfiles or something. The real question is: before I start down the road of inventing a protocol, is there anything out there which already does it? I note wikipedia's "publish/subscribe" and "observer pattern" have various links to implementations, but apparently there is no standard? Failing that, my next step is to come up with some kind of scheme for performing delivery in distinct chunks (of YAML.) Thanks, Eric -- Don't worry about what anybody else is going to do. The best way to predict the future is to invent it. --Alan Kay --------------------------------------------------- http://scratchcomputing.com ---------------------------------------------------
