pubsub

#! /usr/bin/env scheme-script
; -*- mode: scheme -*-

; Getting Started with 'nanomsg'
; Pub/Sub
; from https://github.com/dysinger/nanomsg-examples#code-3
#!chezscheme

(import (nanomsg) (chezscheme))

(nanomsg-library-init)

(define server-name "server")
(define client-name "client")

(define date date-and-time)

(define (sleep-s sec)
  (sleep (make-time 'time-duration 0 sec)))

(define (server url)
  (define sock (nn-socket AF_SP NN_PUB))
  (define eid (nn-bind sock url))
  (let loop ()
    (let* ([d (date)])
      (printf "SERVER: PUBLISHING DATE ~d~n" d)
      (nn-send sock (string->utf8 d) 0)
      (sleep-s 1)
      (loop)))
  (nn-shutdown sock eid))

(define (client url name)
  (define sock (nn-socket AF_SP NN_SUB))
  (define eid #f)
  (nn-setsockopt sock NN_SUB NN_SUB_SUBSCRIBE 0 0)
  (set! eid (nn-connect sock url))
  (let loop ()
    (let* ([buf (box #t)]
	   [bytes (nn-recv sock buf NN_MSG 0)])
      (printf "CLIENT (~d): RECEIVED ~d~n" name (utf8->string (unbox buf)))
      (loop)))
  (nn-shutdown sock eid))

(define argv (command-line-arguments))
(define argc (length argv))

(cond
 [(and (> argc 1) (string=? server-name (car argv)))
  (server (cadr argv))]
 [(and (> argc 2) (string=? client-name (car argv)))
  (client (cadr argv) (caddr argv))]
 [else
  (printf "Usage: pubsub ~d|~d <URL> <ARG> ...'~n" server-name client-name)])


#!eof

./pubsub server ipc:///tmp/pubsub.ipc & server=$! && sleep 1
./pubsub client ipc:///tmp/pubsub.ipc client0 & client0=$!
./pubsub client ipc:///tmp/pubsub.ipc client1 & client1=$!
./pubsub client ipc:///tmp/pubsub.ipc client2 & client2=$!
sleep 5
kill $server $client0 $client1 $client2