Listener process

Any ideas on what the simplest way to implement a local listener process in REBOL would be? I want to have an [encapped] script that can be started and then "listens" for incoming requests from other [REBOL] scripts and passes results back. I could certainly do this via files, but is there a nifty way of doing it in-memory? If the answer to this question is simply, "Look at Rugby / Async", then that alone is worth knowing. ;) Regards, Ashley

Hi Ashley. Ports are probably the way to go. You will be able to see an example in ion.r in ion.pe release 1.1. I haven't had the time to look at ruby, so I don't know if that would be a good example. Elan Ashley Truter wrote:

Wednesday, September 3, 2003, 2:48:07 AM, Ashley wrote:

> If the answer to this question is simply, "Look at Rugby / Async", then > that alone is worth knowing. ;)

When I last looked at Rugby it allowed you to do the tcp/ip route in minutes. Maarten is doing more work in this area, but I don't know what stage he has achieved. It could be nice to have some local memory pipeline/mailbox scheme in REBOL. With library access maybe someone could cook one up and give it to RT to include in future :^) Tcp/ip port are probably easier to get going though :) Check that the OS you are going to use this on will support the throughput you need. (Eg. you may/may not have an issue in win95/98). Regards, Brett.

Hi Ashley, AT> Any ideas on what the simplest way to implement a local listener process in AT> REBOL would be? I want to have an [encapped] script that can be started and AT> then "listens" for incoming requests from other [REBOL] scripts and passes AT> results back. I could certainly do this via files, but is there a nifty way AT> of doing it in-memory? AT> If the answer to this question is simply, "Look at Rugby / Async", then AT> that alone is worth knowing. ;) It isn't hard to create a process that listens on a port and returns data to clients when they connect, but Rugby is a brilliant absolute-no-brainer if you want to serve up functions for remote execution. Of course, that means including it in your code, but it's really terrific stuff. I'd say try Rugby first. If you decide not to use it, for whatever reason, you won't have wasted much time, and maybe gained some good insight in the process. -- Gregg

Hi Ashley, P.S. If you decide to do it yourself, I (or others) can provide some boilerplate to get you going. -- Gregg

Hi Gregg,

> P.S. If you decide to do it yourself, I (or others) can provide some > boilerplate to get you going.

Ashley, Try Rugby, I'm sure that will work in your case. http://www.koopgoedkoop.net/rugby.zip or the async beta at http://www.koopgoedkoop.net/software/rugbyb1.zip --Maarten

Hi Ashley, AT> I am only interested in pretty basic stuff at the moment (more AT> command / response orientated than code passing, not worrying AT> about multiple callers). Here's the basic idea: ;; Server ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; REBOL [] listen-port-num: 2003 process-client-request: func [port /local cmd][ if error? set/any 'err try [ wait port cmd: copy port ; get cmd print [now/time/precise tab "client request:" cmd] result: switch/default load cmd [ 0 [quit] 1 ["one"] 2 ["two"] ][none] insert port result ; send result close port ; service only one request ][print mold disarm err] ] ; Open our main port that listens for client connections. if error? set/any 'err try [ server-port: open/no-wait join tcp://: listen-port-num ][ print ["Error opening listen port:" mold disarm err] halt ] print "Simple Server Now Listening..." forever [ process-client-request first wait reduce [server-port] ;-- The longer version ;wake-port: wait reduce [server-port] ;if wake-port = server-port [ ; process-client-request first wake-port ;] ] ;; Client ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; REBOL [] print "Simple Client" server-port: 2003 forever [ wait 2 port: open join tcp://127.0.0.1: server-port insert port first random [1 2] wait port print copy port close port ] If you want to handle multiple requests from a client, without them opening the port each time, you'll have to do things a little differently, but hopefully this will get you started. -- Gregg

Thanks Gregg, Works a treat! Now I've got something to experiment with before tackling [no pun intended] Rugby. ;) Regards, Ashley

Ashley,

> Works a treat! Now I've got something to experiment with before tackling > [no pun intended] Rugby. ;)

Hi Gregg, On Thursday, September 4, 2003, 2:03:28 AM, you wrote: GI> Here's the basic idea: Another way to pass the data around: send-message: func [port message /only /local res] [ message: mold/all message insert insert insert port length? message " " message if not only [ if object? res: get-message/only port [ make error! next next second res] ] ] buffer: none get-message: func [port /only /local pos len message err localbuff] [ either error? err: try [ if not string? buffer [buffer: clear ""] localbuff: make string! 65536 while [not found? pos: find buffer " "] [ wait port read-io port localbuff 65534 insert tail buffer localbuff clear localbuff ] if integer? len: attempt [to integer! copy/part buffer pos] [ buffer: next pos while [len > length? buffer] [ wait port read-io port localbuff 65534 insert tail buffer localbuff clear localbuff ] message: buffer buffer: copy skip buffer len clear skip message len message: load message ] ] [ if not only [send-message/only port disarm err] err ] [ if not only [send-message/only port 'OK] message ] ] They expect the port to be /BINARY. (I'm using READ-IO so /NO-WAIT shouldn't be necessary. I'm not using COPY because while trying to find out why it crashed sometimes I tried switching from COPY to READ-IO and then left it like that. The crash was due to LOAD.) You can use them to send and receive across a port any REBOL value. They are blocking, so you just send-message on one side and get-message on the other side. Use the Storm engine if you need anything better. :) Regards, Gabriele. -- Gabriele Santilli <[g--santilli--tiscalinet--it]> -- REBOL Programmer Amiga Group Italia sez. L'Aquila --- SOON: http://www.rebol.it/

GS> Another way to pass the data around: Excellent Gabriele! -- Gregg